Journal articles: 'Class 3 integrons'

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Xu, Hai, Julian Davies, and Vivian Miao. "Molecular Characterization of Class 3 Integrons from Delftia spp." Journal of Bacteriology 189, no. 17 (2007): 6276–83. http://dx.doi.org/10.1128/jb.00348-07.

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ABSTRACT Two environmental strains, Delftia acidovorans C17 and Delftia tsuruhatensis A90, were found to carry class 3 integrons, which have seldom been reported and then only from pathogens in which they are associated with antibiotic resistance genes. The Delftia integrons comprised a highly conserved class 3 integrase gene, upstream and oppositely oriented from a set of three or four gene cassettes that encoded unidentified functions. The A90 integron had one more gene cassette than the C17 integron, but the two were otherwise the same; furthermore, they were located within regions of sequence identity in both strains and linked to chromosomal genes. A screen of other Delftia and related strains did not reveal the presence of additional class 3 integrons. The observations suggest that these integrons were horizontally transferred to Delftia as part of a larger region and reside as chromosomal elements that probably predate transposon dissemination, as has been proposed for certain class 1 integrons.

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Yang, Haifei, Yachao Pan, Lifen Hu, et al. "Antimicrobial resistance patterns and characterization of integrons in clinical isolates of Shigella from China." Canadian Journal of Microbiology 60, no. 4 (2014): 237–42. http://dx.doi.org/10.1139/cjm-2013-0893.

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One hundred fifty-three Shigella isolates were examined for multiple antibiotic resistance phenotypes and prevalence of class 1 and class 2 integron sequences. The gene cassettes dfrA17-aadA5, dfrA12-orfF-aadA2, and arr-3-aacA4 were found in typical class 1 integrons. The gene cassettes blaOXA-1-aadA1 and dfrA1-sat1-aadA1 were detected in atypical class 1 integrons and in class 2 integrons, respectively. This is the first report of arr-3-aacA4 cassette detected in typical class 1 integrons among Shigella isolates. Rates of antibiotic resistance were different between integron-positive and integron-negative strains (P < 0.05), and all integron-positive isolates were resistant to at least 3 different antimicrobial agents. Typical class 1 integron-positive isolates showed higher resistance rates to cefotaxime and ciprofloxacin than did integron-negative ones (P < 0.05). Typical class 1 integrons and β-lactamase genes were found in conjugative plasmids, otherwise class 2 and atypical class 1 integrons were located on chromosome. This study demonstrated the wide distribution of class 1 integrons in Shigella spp., which may lead resistance to cefotaxime and ciprofloxacin in China.

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Ploy, Marie-Cécile, François Denis, Patrice Courvalin, and Thierry Lambert. "Molecular Characterization of Integrons inAcinetobacter baumannii: Description of a Hybrid Class 2 Integron." Antimicrobial Agents and Chemotherapy 44, no. 10 (2000): 2684–88. http://dx.doi.org/10.1128/aac.44.10.2684-2688.2000.

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ABSTRACT Twenty Acinetobacter baumannii strains resistant to various antibiotics were analyzed for integron content and sequences of the amplification products. Sixteen clinical isolates had a class 1 integron, 2 contained an additional class 1 or class 2 integron, but no class 3 integron was detected. Thirteen strains had integrons with a single cassette: aac(3)-Ia (9 strains), ant(2")-Ia (2 strains), or aac(6′)-Ib (2 strains); 1 hadaac(6′)-Ib and oxa20cassettes and an unknown gene; and 1 had an integron containingant(2")-Ia and an oxa3cassette truncated by IS6100. The remaining strains harbored class 1 integrons with gene cassettes previously found inEnterobacteriaceae. One integron had a hybrid structure composed of intI2 and the 3′ conserved segment of class 1 integrons. These data indicate that integrons play a major role in multidrug resistance in Acinetobacter.

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Collis, Christina M., Mi-Jurng Kim, Sally R. Partridge, H. W. Stokes, and Ruth M. Hall. "Characterization of the Class 3 Integron and the Site-Specific Recombination System It Determines." Journal of Bacteriology 184, no. 11 (2002): 3017–26. http://dx.doi.org/10.1128/jb.184.11.3017-3026.2002.

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ABSTRACT Integrons capture gene cassettes by using a site-specific recombination mechanism. As only one class of integron and integron-determined site-specific recombination system has been studied in detail, the properties of a second class, the only known class 3 integron, were examined. The configuration of the three potentially definitive features of integrons, the intI3 gene, the adjacent attI3 recombination site, and the Pc promoter that directs transcription of the cassettes, was similar to that found in the corresponding region (5′ conserved segment) of class 1 integrons. The integron features are flanked by a copy of the terminal inverted repeat, IRi, from class 1 integrons on one side and a resolvase-encoding tniR gene on the other, suggesting that they are part of a transposable element related to Tn402 but with the integron module in the opposite orientation. The IntI3 integrase was active and able to recognize and recombine both known types of IntI-specific recombination sites, the attI3 site in the integron, and different cassette-associated 59-be (59-base element) sites. Both integration of circularized cassettes into the attI3 site and excision of integrated cassettes were also catalyzed by IntI3. The attI3 site was localized to a short region adjacent to the intI3 gene. Recombination between a 59-be and secondary sites was also catalyzed by IntI3, but at frequencies significantly lower than observed with IntI1, the class 1 integron integrase.

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Machado, Elisabete, Rafael Cantón, Fernando Baquero та ін. "Integron Content of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Strains over 12 Years in a Single Hospital in Madrid, Spain". Antimicrobial Agents and Chemotherapy 49, № 5 (2005): 1823–29. http://dx.doi.org/10.1128/aac.49.5.1823-1829.2005.

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ABSTRACT The contribution of integrons to the dissemination of extended-spectrum β-lactamases (ESBL) was analyzed on all ESBL-producing Escherichia coli isolates from 1988 to 2000 at Ramón y Cajal Hospital. We studied 133 E. coli pulsed-field gel electrophoresis types: (i) 52 ESBL-producing clinical strains (C-ESBL) (16 TEM, 9 SHV, 21 CTX-M-9, 1 CTX-M-14, and 5 CTX-M-10); (ii) 43 non-ESBL blood clinical strains (C-nESBL); and (iii) 38 non-ESBL fecal isolates from healthy volunteers (V-nESBL). Class 1 integrons were more common among C-ESBL (67%) than among C-nESBL (40%) or V-nESBL (26%) (P < 0.001) due to the high number of strains with bla CTX-M-9 , which is linked to an In6-like class 1 integron. Without this bias, class 1 integron occurrence would be similar in C-ESBL and C-nESBL groups (47% versus 40%). Occurrence of class 2 integrons was similar among clinical and community isolates (13 to 18%). No isolates contained class 3 integrons. The relatively low rate of class 1 integrons within transferable elements carrying blaTEM (23%) or blaSHV (33%) and the absence of class 2 integrons in all ESBL transconjugants mirror the assembly of translocative pieces containing blaTEM or blaSHV on local available transferable elements lacking integrons. The low diversity of class 1 integrons (seven types recovered in all groups) might indicate a wide dissemination of specific genetic elements in which they are located. In our environment, the spread of genetic elements encoding ESBL has no major impact on the dispersion of integrons, nor do integrons have a major impact on the spread of ESBL, except when blaESBL genes are within an integron platform such as bla CTX-M-9 .

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Huang, Jiangqing, Fangjun Lan, Yanfang Lu, and Bin Li. "Characterization of Integrons and Antimicrobial Resistance in Escherichia coli Sequence Type 131 Isolates." Canadian Journal of Infectious Diseases and Medical Microbiology 2020 (February 24, 2020): 1–8. http://dx.doi.org/10.1155/2020/3826186.

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Background. Escherichia coli sequence type 131 (ST131) is an important multidrug-resistant extraintestinal pathogen, which can cause many kinds of infections. Integrons may play a crucial role in the dissemination of antibiotic resistance genes. The purpose of this study was to characterize the prevelance of integrons among E. coli ST131 strains in China. Methods. Eighty-three E. coli ST131 isolates were used in this study. The antibiotic susceptibility test was performed by the disk diffusion method. The presence and characterization of class 1, 2, and 3 integrons, as well as promotor of gene cassettes and other antimicrobial resistance genes, were detected by PCR and DNA sequencing. Transfer of integrons was carried out using a broth culture mating method. Clonal relatedness of E. coli ST131 isolates was analyzed by PFGE. Results. Overall, 26.5% (22/83) of the E. coli ST131 isolates carried class 1 integrons. Class 2 and 3 integrons were not found in this study. Two types of gene cassette arrays were demonstrated in this study and were as follows: dfrA17-aadA5 and aac(6′)-Ib-cr-cmlA5. Only one type of Pc promoter variant was detected among 22 integron-positive isolates (PcW). In vivo transfer of integron was successful for 9 of integron-positive E. coli ST131 isolates harboring resistance gene cassettes. Results of PFGE demonstrated that the integron-positive E. coli ST131 isolates were grouped into 12 different PFGE clusters. Conclusions. Our study showed a low prevalence of integrons was detected in E. coli ST131. Continued surveillance of this mobile genetic element should be performed to study the evolution of antibiotic resistance among E. coli ST131.

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NEMATI, F., and E. AHMADI. "Class1-3 integrons and antimicrobial resistance profile in Salmonella spp. isolated from broiler chicken in Western Iran." Journal of the Hellenic Veterinary Medical Society 71, no. 4 (2021): 2471. http://dx.doi.org/10.12681/jhvms.25922.

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Salmonella spp. are major etiologies of food-borne infections that are disseminated primarily through poultry to human. Nowadays, the high rate of antimicrobial resistance and the emergence of multi-drug resistant (MDR) strains, worse the threat imposed to the public health. Integrons are attributed as important contributors to MDR isolates. The present research aimed to identify the frequency of integrons 1-3 and the antimicrobial resistance patterns in Salmonella spp. isolated from broiler chicken in Western Iran. A total of 500 fecal samples were screened for Salmonella phenotypically. The isolates were confirmed genotypically and the frequency of integrons 1-3 was evaluated molecularly among the isolates. Besides, the antimicrobial resistance of the isolates was determined through the agar disk diffusion method. In general, 67 (13.4%) isolates of Salmonella spp. were recovered phenotypically, all of which were confirmed molecularly. The incidence of class 1, 2, and 3 integrons was 40.29% (27 isolates), 28.35% (19 isolates), and 11.94% (eight isolates), respectively. Coexistence of integrons was also detected in 26.86% of the isolates including class 1+2 (13 isolates, 40.62%), class 1+3 (2 isolates, 6.25%), and class 1+2+3 (3 isolates, 9.37%). No statistical association was detected between the frequencies of Salmonella spp. or Salmonella-bearing integron isolates with age, season, and location. The most frequent antimicrobial resistance was exhibited to ampicillin, nalidixic acid, trimethoprim-sulphamethoxazole, and tetracycline; while ciproﬂoxacin, gentamicin, and ceftazidime were the most effective drugs. 35.82% of the isolates were MDR, all of which harbored at least one class of integrons. Statistical assessment represented an association between the prevalence of integrons and tetracycline, chloramphenicol, streptomycin, and ceftazidime resistance rates. An alarming rate of integrons and MDR frequency among poultry-originated Salmonella spp. in the studied region demands the constant stewardship and prudent prescription and use of antibiotics to prevent human infections and preserve the effectiveness of those antibiotics in treating human salmonellosis.

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Corrêa, Fábio Ederson Lopes, Fabiana Gomes da Silva Dantas, Alexeia Barufatti Grisolia, Bruno do Amaral Crispim, and Kelly Mari Pires Oliveira. "Identification of class 1 and 2 integrons from clinical and environmental Salmonella isolates." Journal of Infection in Developing Countries 8, no. 12 (2014): 1518–24. http://dx.doi.org/10.3855/jidc.4734.

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Introduction: The indiscriminate use of antimicrobials has selected for the emergence of resistant strains. Many mechanisms contribute to the spread of antimicrobial-resistant genes, and integrons play a key role in this process. The aim of this study was to describe the serotypes and resistance profiles, and to characterize the presence of integrons in Salmonella strains isolated from Dourados, Mato Grosso do Sul, Brazil. Methodology: Thirty-six isolates from different sources were used. To evaluate the resistance profiles, the determination of minimum inhibitory concentrations together with polymerase chain reaction were used to screen for the presence of class 1 and class 2 integrons. Results: The Infantis serotype of Salmonella was the most frequently isolated serotype. Minimum inhibitory concentrations showed that out of the 36 isolates, 11 (30.5%) were resistant to all the antimicrobials tested. These resistant isolates were separated into three groups: 4 clinical isolates (36.4%), 3 food isolates (36.4%), and 4 water isolates (27.2%). Class 1 integrons occurred in 31 (86.1%) isolates and were found in all 11 resistant isolates (35.5 %) and in 20 (64.5%) of the non-resistant isolates. Class 2 integrons were found in 3 (8.3%) isolates, which were all non-resistant. Conclusion: The presence of an integron did not necessarily confer resistance. Future studies will seek to identify the mechanism behind integron-mediated antimicrobial resistance.

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Correia, Mário, Filipa Boavida, Filipa Grosso, et al. "Molecular Characterization of a New Class 3 Integron in Klebsiella pneumoniae." Antimicrobial Agents and Chemotherapy 47, no. 9 (2003): 2838–43. http://dx.doi.org/10.1128/aac.47.9.2838-2843.2003.

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ABSTRACT Klebsiella pneumoniae FFUL 22K was isolated in April 1999 from the urine of an intensive care unit patient in Portugal. The strain showed an extended-spectrum cephalosporin resistance profile. A typical synergistic effect between cefotaxime or cefepime and clavulanic acid was observed. An Escherichia coli transformant displayed a similar resistance phenotype and harbored a ca. 9.4-kb plasmid (p22K9). Cloning experiments revealed that the extended-spectrum β-lactamase was encoded by bla GES-1, previously described in class 1 integrons from K. pneumoniae ORI-1 and Pseudomonas aeruginosa Pa695. Further sequence analysis demonstrated that the bla GES-1 gene cassette was located on a new class 3 integron. The integron was 2,863 bp long and consisted of an intI3 integrase gene, an attI3 recombination site, two promoter regions, and two gene cassettes. The IntI3 integrase was 98.8% identical to that of Serratia marcescens AK9373. The bla GES-1 gene cassette was inserted at the attI3 site. The second gene cassette was the result of a fusion event between bla OXA-10-type and aac(6′)-Ib gene cassettes and conferred resistance to kanamycin. This is the second class 3 integron reported and the first time that the bla GES-1 gene cassette has been found on an integron belonging to this class, highlighting the considerable heterogeneity of their genetic environment and the spread of gene cassettes among different classes of integrons.

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Lee, Mei-Feng, Chien-Fang Peng, Hui-Jine Hsu, and Han-Siong Toh. "Use of Inverse PCR for Analysis of Class 1 Integrons Carrying an Unusual 3′ Conserved Segment Structure." Antimicrobial Agents and Chemotherapy 55, no. 2 (2010): 943–45. http://dx.doi.org/10.1128/aac.00988-10.

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ABSTRACTBy using inverse PCR and DNA sequencing, 13sul3-associated mutational integrons, 2 defective class 1 integrons, and 1qnrB2-associated complexsul1-type class 1 integrons were identified inSalmonella entericaserovar Choleraesuis,Pseudomonas aeruginosa, andEnterobacter cloacae, respectively. In addition, conjugation and Southern hybridization demonstrated that unusual class 1 integrons were located on plasmids or integrated into chromosomal DNA. Thus, an inverse PCR assay can be a valuable tool for the analysis of unusual structures of the 3′ conserved region of class 1 integrons.

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TAHERIKALANI, MOROVAT, ABBAS MALEKI, NOURKHODA SADEGHIFARD, et al. "Dissemination of Class 1, 2 and 3 Integrons among Different Multidrug Resistant Isolates of Acinetobacter baumannii in Tehran Hospitals, Iran." Polish Journal of Microbiology 60, no. 2 (2011): 169–74. http://dx.doi.org/10.33073/pjm-2011-024.

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A total of 100 non-duplicate Acinetobacter baumannii isolates were collected from different hospitals in Tehran and were confirmed as A. baumannii by conventional biochemical and API testing. Antimicrobial susceptibility of these isolates was checked by a disk diffusion method in accordance with CLSI guidelines. The isolates were then detected as carrying class 1 and 2 integron gene cassettes by PCR evaluation and then genotyped by REP-PCR. More than 50% (n = 50) of the isolates were multidrug resistant. The results showed that more than 80% of all multidrug resistant A. baumannii strains carry a class 1 integron. Distribution of IntI 1 and IntI2 among A. baumannii isolates was 58% and 14%, respectively. Analysis of a conserved segment of class 1 integron showed a range from 100 bp to 2.5 kb. REP-PCR fingerprinting showed more than 20 genotypes among A. baumannii strains. TIhere was no relationship between REP genotypes and the distribution of different classes of integrons. This is a comprehensive study on the distribution of different classes of integrons among A. baumannii in Iran. Considering the exact role of integrons in coding drug resistance in bacteria, the findings of this study could help us find antimicrobial resistant mechanisms among A. baumannii isolates in Iran.

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Sajjad, Ammara, Marita P. Holley, Maurizio Labbate, H. W. Stokes, and Michael R. Gillings. "Preclinical Class 1 Integron with a Complete Tn402-Like Transposition Module." Applied and Environmental Microbiology 77, no. 1 (2010): 335–37. http://dx.doi.org/10.1128/aem.02142-10.

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ABSTRACTThe presence of integrons was assessed in gut bacteria isolated from wild-caught prawns. A pseudomonad was recovered that contained a Tn402-like class 1 integron with a complete transposition module and two gene cassettes. One cassette was identical to a previously described cassette from a chromosomal class 3 integron inDelftiatsuruhatensis.

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Partridge, Sally R., Heidi J. Brown, H. W. Stokes, and Ruth M. Hall. "Transposons Tn1696 and Tn21and Their Integrons In4 and In2 Have Independent Origins." Antimicrobial Agents and Chemotherapy 45, no. 4 (2001): 1263–70. http://dx.doi.org/10.1128/aac.45.4.1263-1270.2001.

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ABSTRACT The first 13.6 kb of the mercury and multidrug resistance transposon Tn1696, which includes the class 1 integron In4, has been sequenced. In4 is 8.33 kb long and contains the 5′-conserved segment (5′-CS) and 2.24 kb of the 3′-conserved segment (3′-CS) flanking four integrated cassettes. The 3′-CS region is followed by one full copy and an adjacent partial copy of the insertion sequence IS6100 flanked, in inverse orientation, by two short segments (123 and 152 bp) from the outer right-hand end of class 1 integrons. This structure is representative of a distinct group of class 1 integrons that differs from In2, found in Tn21, and other related class 1 integrons. In4 does not include transposition genes but is bounded by characteristic 25-bp inverted repeats and flanked by a direct duplication of 5 bp of the target sequence, indicating that it was inserted by a transpositional mechanism. In4 lies between the resII and resIsites of a backbone mercury resistance transposon which is >99.5% identical to Tn5036. Although Tn21 and Tn1696 are both classified as members of the Tn21 subfamily of the Tn3 transposon family, the backbone mercury resistance transposons are only 79 to 96% identical. Tn21 also contains a region of about 0.7 kb not found in Tn1696. The integrons In2 and In4 carrying the antibiotic resistance genes have been inserted at different locations into distinct ancestral mercury resistance transposons. Thus, Tn21 and Tn1696 have independent histories and origins. Other transposons (Tn1403 and Tn1412) that include a class 1 integron also have independent origins. In all except Tn21, the integron is located within theres region of the backbone transposon.

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Cao, Jianming, Meimei Li, Chunquan Xu, et al. "Characterization of Integrons and qnr Genes in Proteeae from a Teaching Hospital in China." Chemotherapy 62, no. 1 (2016): 12–18. http://dx.doi.org/10.1159/000445426.

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Background: Proteeae isolates displaying multidrug-resistance (MDR) are the second most common causes of hospital-associated infections. The aim of this study was to screen class 1-3 integrons and plasmid-mediated quinolone resistance (PMQR) genes in Proteeae isolates from the First Affiliated Hospital of the Wenzhou Medical University. Materials and Methods: 176 Proteeae isolates were collected from clinical specimens of inpatients between January 2011 and December 2013. Susceptibility testing was determined by the agar dilution method. Class 1-3 integrons and PMQR genes were amplified by polymerase chain reaction, and the variable regions of integrons were determined by restriction fragment length polymorphisms. Results: 68.2% Proteeae isolates exhibited MDR phenotypes: 46.6 and 10.8% Proteeae isolates were positive for intI1 and intI2, respectively. The resistance rate of integron-positive isolates to aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole was significantly higher than integron-negative isolates. Sequence analysis revealed that dfrA1-sat2-aadA1, dfrA1-catB2-sat2-aadA1, and sat2-aadA1 were first detected in Morganella morganii strains isolated from China. PMQR was determined by qnrD in 40 strains (22.7%). Conclusion: Our results indicate that class 1 and 2 integrons are common among Proteeae isolates. Meanwhile, qnrD are highly prevalent in Proteeae isolated from our hospital.

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Lapierre, Lisette, Betty San Martín, Carolina Araya-Jordán, and Consuelo Borie. "Comparison of integron-linked antibiotic resistance genes in strains of Salmonella spp. isolated from swine in Chile in 2005 and 2008." Canadian Journal of Microbiology 56, no. 6 (2010): 515–21. http://dx.doi.org/10.1139/w10-033.

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Salmonella spp. isolates obtained from healthy swine in 2008 were analyzed for antibiotic resistance phenotypes and genotypes. The resistance profiles of the 2008 isolates were compared with those of a Salmonella collection isolated from the same geographical area in 2005. The 2008 isolates consisted of strains that were 97% oxytetracycline resistant, 33.3% amoxicillin resistant, 31.8% amoxicillin- plus clavulanic acid resistant, 27.5% trimethoprim–sulfamethoxazole resistant, 17.3% streptomycin resistant, and 7.2% enrofloxacin–ciprofloxacin resistant. The presence of integrons and resistance genes and their topological association in resistant strains was assessed by PCR. The prevalence of class 1 integrons was the highest, at 46.2%, while class 2 integrons were present in 17.9% of the isolates. In strains that harboured class 1 integrons, we identified 3 different gene cassette arrangements; a single class 2 integron arrangement of dfrA1–sat1–aadA1 was found. Comparison of these results with data obtained from the 2005 isolates showed that Salmonella strains resistant to amoxicillin and amoxicillin plus clavulanic acid had clearly emerged over the span of 3 years, along with an increase in the prevalence of class 1 integrons and the acquisition of new gene cassette arrangements. These findings highlight the need for continual monitoring of regional isolates to establish more efficient vigilance programs that can address variations in resistance over short periods of time within the same geographical area.

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Dubois, Véronique, Marie-Pierre Parizano, Corinne Arpin, Laure Coulange, Marie-Christine Bezian, and Claudine Quentin. "High Genetic Stability of Integrons in Clinical Isolates of Shigella spp. of Worldwide Origin." Antimicrobial Agents and Chemotherapy 51, no. 4 (2007): 1333–40. http://dx.doi.org/10.1128/aac.01109-06.

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ABSTRACT Over a 12-year period, 68 Shigella strains (31 S. sonnei, 30 S. flexneri, 4 S. dysenteriae, and 3 S. boydii strains) were collected in a French University Hospital from the stools of patients who generally had a recent history of travel to various parts of the world (91%), particularly Africa (67%). These strains were often resistant (streptomycin, spectinomycin, trimethoprim, tetracycline, and sulfonamides, 66 to 84%; ampicillin and chloramphenicol, 34 to 38%; nalidixic acid, 4%) and even multiresistant (87%), and they generally carried integrons (81%) of class 1 (21%), class 2 (47%), or both (13%). Class 1 integrons were associated with ampicillin resistance due to the production of an OXA-30 β-lactamase in S. flexneri and S. dysenteriae. Class 2 integrons were associated with trimethoprim resistance in S. sonnei. Class 1 and class 2 integrons were inserted within transposons Tn21 and Tn7, respectively, themselves located on the bacterial chromosome, except in one strain. Class 1 integrons showed an atypical organization consisting of the insertion sequence IS1 at the 3′ end instead of the typical 3′ conserved segment and two bla OXA-30 and aadA1 gene cassettes, despite the absence of epidemiological relationships between the strains, and an apparently functional integrase. Class 2 integrons showed the same albeit classical organization with the three dfrA1, sat, and aadA1 gene cassettes. Occasionally, the 3′ end was deleted and the aadA1 gene cassette was unexpressed. Thus, integrons contributed only in part to the multidrug resistance of the Shigella strains. The highly conserved organization of integrons might be related to their location within mobile genetic superstructures.

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Garnier, Fabien, Nabil Raked, Amy Gassama, François Denis, and Marie-Cécile Ploy. "Genetic Environment of Quinolone Resistance Gene qnrB2 in a Complex sul1-Type Integron in the Newly Described Salmonella enterica Serovar Keurmassar." Antimicrobial Agents and Chemotherapy 50, no. 9 (2006): 3200–3202. http://dx.doi.org/10.1128/aac.00293-06.

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ABSTRACT A qnrB2 determinant was described for a new complex sul1-type integron from Salmonella enterica serovar Keurmassar. The genetic structure contained two class 1 integrons surrounding two common regions (CRs) separated by a partial 3′ conserved segment. The qnrB2 gene is adjacent to the first CR.

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Valverde, Aránzazu, Rafael Cantón, Juan Carlos Galán, Patrice Nordmann, Fernando Baquero, and Teresa M. Coque. "In117, an Unusual In0-Like Class 1 Integron Containing CR1 and blaCTX-M-2 and Associated with a Tn21-Like Element." Antimicrobial Agents and Chemotherapy 50, no. 2 (2006): 799–802. http://dx.doi.org/10.1128/aac.50.2.799-802.2006.

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ABSTRACT An unusual In0-like class 1 integron containing a common region that includes the putative recombinase gene named orf513 (CR1) and bla CTX-M-2 was characterized from Escherichia coli. The integron contained an unusual gene cassette array, estX-aadA1, embedded between the 5′-conserved segment (5′-CS) and 3′-CS1 regions and was flanked by mer-Tn21 sequences downstream of the tni truncated module. This element constitutes one of the few examples of CR1-bearing class 1 integrons that has been fully characterized.

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Zhu, Jing Yuan, Guang Cai Duan, Hai Yan Yang, Qing Tang Fan, and Yuan Lin Xi. "Atypical Class 1 Integron Coexists with Class 1 and Class 2 Integrons in Multi-Drug Resistant Shigella flexneri Isolates from China." Current Microbiology 62, no. 3 (2010): 802–6. http://dx.doi.org/10.1007/s00284-010-9790-3.

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Park, J. C., J. C. Lee, J. Y. Oh, et al. "Antibiotic selective pressure for the maintenance of antibiotic resistant genes in coliform bacteria isolated from the aquatic environment." Water Science and Technology 47, no. 3 (2003): 249–53. http://dx.doi.org/10.2166/wst.2003.0203.

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Coliform bacteria isolated from the aquatic environment were investigated for antibiotic susceptibility and detailed structures of class 1 integrons. A high proportion of isolates were found to be resistant to sulfamethoxazole, aminoglycosides, and β-lactams. The 750 (53.6%) isolates were resistant to one or more of the antibiotics tested out of 1,400 coliform bacteria. Based on the MIC of antibiotics and antibiogram, 150 isolates were selected and further studied for class 1 integrons. The intI1 gene was found in 36 (24.0%) of the 150 isolates. Twelve isolates carried the gene cassettes responsible for antibiotic resistance, while no gene cassettes were found in 24 isolates. Seven different genes, dfrA5, dfrA7, dfrA12, dfrA17, aaA2, aaA5, and aad(3’), were detected in gene cassettes. The dfrA and aad genes located on class 1 integrons were responsible for resistance to trimethoprim and aminoglycosides. The remaining 24 coliform bacteria had the incomplete or non-functional class 1 integrons. These results indicated that antibiotic selective pressures may play an important role to maintain gene cassettes of class 1 integrons and in the absence of sustained antibiotic pressures, such as the aquatic environment, coliform bacteria may carry empty or non-functional class 1 integrons.

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JOUINI, AHLEM, KARIM BEN SLAMA, YOLANDA SÁENZ, et al. "Detection of Multiple-Antimicrobial Resistance and Characterization of the Implicated Genes in Escherichia coli Isolates from Foods of Animal Origin in Tunis." Journal of Food Protection 72, no. 5 (2009): 1082–88. http://dx.doi.org/10.4315/0362-028x-72.5.1082.

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Phenotypic and genotypic characterization of antimicrobial resistance was conducted for 98 Escherichia coli isolates recovered from 40 food samples of animal origin (poultry, sheep, beef, fish, and others) obtained in supermarkets and local butcheries in Tunis during 2004 and 2005. Susceptibility to 15 antimicrobial agents was tested by disk diffusion and agar dilution methods, the mechanisms of resistance were evaluated using PCR and sequencing methods, and the clonal relationship among isolates was evaluated using pulsed-field gel electrophoresis. High resistance was detected to tetracycline, sulphonamides, nalidixic acid, ampicillin, streptomycin, and trimethoprim-sulfamethoxazole (29 to 43% of isolates), but all isolates were susceptible to cefotaxime, ceftazidime, cefoxitin, azthreonam, and amikacin. One-third of the isolates had multiresistant phenotypes (resistance to at least five different families of antimicrobial agents). Different variants of blaTEM, tet, sul, dfrA, aadA, and aac(3) genes were detected in most of the strains resistant to ampicillin, tetracycline, sulphonamide, trimethoprim, streptomycin, and gentamicin, respectively. The presence of class 1 and class 2 integrons was studied in 15 sulphonamide-resistant unrelated E. coli strains, and 14 of these strains harbored class 1 integrons with five different arrangements of gene cassettes, and a class 2 integron with the dfrA1 + sat + aadA1 arrangement was found in one strain. This study revealed the high diversity of antimicrobial resistance genes, some of them included in integrons, in E. coli isolates of food origin.

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Soto, S. M., M. J. Lobato, and M. C. Mendoza. "Class 1 Integron-Borne Gene Cassettes in Multidrug-Resistant Yersinia enterocolitica Strains of Different Phenotypic and Genetic Types." Antimicrobial Agents and Chemotherapy 47, no. 1 (2003): 421–26. http://dx.doi.org/10.1128/aac.47.1.421-425.2003.

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ABSTRACT Seventy nine strains of Yersinia enterocolitica resistant to one or more antimicrobials were analyzed for integrons. Only class 1 sul1 integrons containing aadA1a (28 strains), aadA1a-dfr1-sat1 (2 strains), and dfr1-aadA1a (1 strain) gene cassettes were found. The first two types were found in clinical isolates belonging to serotype O:3, biotypes 2 to 4, and eight combined ribotypes, and the third was found in the reference strain, CECT4054 (O:8). All screened resistance markers were found in strains with and without integrons (except for chloramphenicol resistance, encoded by catA1 gene, which was only present in strains with integrons), but in different resistance profiles (R profiles). A profile (ampicillin, streptomycin, sulfadiazine, and trimethoprim resistance, encoded by the tem1, aadA1a, sul1, and dfr1 genes, respectively) was found in strains, with and without integrons. Integrons and some of the resistance genes are located on plasmids with sizes ranging between 65 and 140 kb. This is the first report of class 1 integrons in Y. enterocolitica.

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Oprea, Mihaela, Madalina Cornelia Militaru, Adriana Simona Ciontea, Daniela Cristea, Violeta Cristea, and Codruta Romanita Usein. "Characterization of antibiotic resistance integrons harbored by Romanian Escherichia coli uropathogenic strains." Revista Romana de Medicina de Laborator 28, no. 3 (2020): 331–40. http://dx.doi.org/10.2478/rrlm-2020-0023.

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AbstractBecause little is known about the integrons which constitute an important means of spreading resistance in bacteria circulating in Romania, this study aimed to detect antibiotic resistance gene cassettes embedded in integrons in a convenient collection of 60 ciprofloxacin-resistant Escherichia coli isolates of various phylogroups, associated with community-acquired urinary tract infections. Characterization of the integrons was accomplished by PCR, restriction fragment length polymorphism typing, and DNA sequencing of each identified type. More than half of the tested E. coli strains were positive for integrons of class 1 (31 strains) or 2 (1 strain). These strains derived more frequently from phylogenetic groups A (15 of 21 strains), B1 (10 of 14 strains), and F (3 of 4 strains), respectively. While 20 strains carried class 1 integrons which could be assigned to nine types, eleven strains carried integrons that lacked the 3’-end conserved segment. The attempts made to characterize the gene cassettes located within the variable region of the various integrons identified in this study revealed the presence of genes encoding resistance to trimethoprim, aminoglycosides, beta-lactams or chloramphenicol. The evidence of transferable resistance determinants already established in the autochthonous E. coli strains highlights the need for improved control of resistance-carrying bacteria.

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Zhang, Hongna, Xiaonan Zhao, Zhenzhen Zhai, Qing Li, Shuyuan Guo, and Weishan Chang. "Antimicrobial resistance and integrons of ESBL-producing thermotolerant coliforms from a water reservoir in Tai'an, China." Journal of Infection in Developing Countries 11, no. 10 (2017): 740–46. http://dx.doi.org/10.3855/jidc.8449.

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Introduction: The contamination of water environments by extended-spectrum β-lactamases-producing thermotolerant coliforms (ESBL-TC) has aroused public concern. However, little epidemiological data on ESBL-TC isolates from water reservoirs is available in China. Methodology: This study was designed to investigate antibiotic resistance, bla gene types, and the presence of integrons (class 1, 2, and 3) and gene cassettes in ESBL-TC isolated from the Huangqian Reservoir of Tai'an, China. Results: A total of 96 non-duplicate ESBL-TC were obtained in this study and the ESBL genes included blaCTX-M-14 (n = 47), blaCTX-M-15 (n = 27), blaCTX-M-55 (n = 18), blaSHV-12 (n = 4), blaCTX-M-3 (n = 3), and blaCTX-M-123 (n = 1). Eighty-three of the ninety-six ESBL-TC contained class 1 integrons (86.5%), and 2 isolates harbored class 2 integrons. The sizes of gene cassette regions within integrons were ranged from 0.2 kb to 3.2 kb. Conclusions: The findings of this study indicated the widespread presence of ESBL-TC strains in the Huangqian Reservoir and spotlighted the potential role of water bodies as reservoirs for antibiotic resistant genes.

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Nógrády, Noémi, Margit Király, Klára Borbás, Ákos Tóth, Judit Pászti, and István Tóth. "Antimicrobial resistance and genetic characteristics of integron-carrier shigellae isolated in Hungary (1998–2008)." Journal of Medical Microbiology 62, no. 10 (2013): 1545–51. http://dx.doi.org/10.1099/jmm.0.058917-0.

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Antimicrobial susceptibility, integron carriage, genetic relationship and presence of some important virulence genes of the integron-carrier strains of Shigella sonnei (n = 230) and Shigella flexneri (n = 22) isolated from stool samples of patients in Hungary between 1998 and 2008 were investigated. Sixty-seven per cent (168/252) of the strains were resistant to sulfamethoxazole/trimethoprim (SxT) followed by streptomycin (S, 47 %), ampicillin (A, 32 %) and tetracycline (Tc, 28 %). Thirty-six per cent (90/252) exhibited multidrug resistance, mostly showing SSxTTc or ASSxTc, ASSxTTc resistance patterns. An S. sonnei strain of imported origin was resistant to cefotaxime and harboured a bla CTX-M-55-type extended-spectrum β-lactamase gene. Altogether 33 % of the S. sonnei (n = 75) and 14 % of the S. flexneri (n = 3) strains had either class 1 or class 2 integrons or both. The variable regions encoded aadA1 or dfrA1-aadA1 genes for the class 1 and dfrA1-sat2-aadA1 or dfrA1-sat2 genes for the class 2 integrons. Pulsed-field gel electrophoresis analysis revealed that those strains that have different integron types represented different genetic clusters. The Shiga toxin (stx1) gene was identified in one S. sonnei strain and the cdtB gene was detected in an S. flexneri strain. The results reveal the high incidence of antibiotic resistance among Shigella isolates and the presence of the stx1 gene in S. sonnei and the cdtB gene in S. flexneri. The genetic diversity of Shigella spp. isolated recently in Hungary was also demonstrated.

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Dropa, Milena, Livia Carminato Balsalobre, Nilton Lincopan, Glavur Rogério Matté, and Maria Helena Matté. "Complex class 1 integrons harboring CTX-M-2-encoding genes in clinical Enterobacteriaceae from a hospital in Brazil." Journal of Infection in Developing Countries 9, no. 08 (2015): 890–97. http://dx.doi.org/10.3855/jidc.6241.

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Introduction: CTX-M enzymes are the most prevalent extended-spectrum beta-lactamases (ESBLs) in Brazil and around the world. The spread of CTX-M lies in their ability to be mobilized by insertion sequences and integrons. This study aimed to identify the mobile genetic structures associated with blaCTX-M genes from clinical Enterobacteriaceae strains. Methodology: Twenty-eight clinical non-clonal Enterobacteriaceae were screened by PCR for the presence of blaCTX-M genes and class 1 integrase (int1), and for the association of blaCTX-M with class 1 integrons. Plasmid incompatibility groups were assessed by PBRT. Wild-type plasmids were transformed into electrocompetent E. coli, and the S1-PFGE technique was used to verify the presence of high-molecular-weight plasmids in both wild-type strains and E. coli transformants. Results: Sequencing showed that strains carried blaCTX-M-2 (n = 25) and blaCTX-M-59 (n = 3) genes inserted into the 3’-end of complex class 1 integrons. Thirteen strains also carried blaTEM and blaSHV genes. CTX-M-2/59-containing complex class 1 integrons were also present in E. coli transformants. The most frequent Inc groups were IncA/C (n = 10) and IncF (n = 8). Heavy plasmids were observed in both wild-type strains and E. coli transformants. Conclusions: The presence of the same blaCTX-M-2-group-containing genetic structure in seven Enterobacteriaceae species isolated at seven hospital wards shows the great mobility potential of complex class 1 integrons. Also, this is the first report of TEM-15, SHV-45, and SHV-55 in Latin America. The genetic environment of blaCTX-M-2 accounts for their maintenance and spread among Gram-negative bacteria.

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Antunes, Patrícia, Jorge Machado, and Luísa Peixe. "Dissemination of sul3-Containing Elements Linked to Class 1 Integrons with an Unusual 3′ Conserved Sequence Region among Salmonella Isolates." Antimicrobial Agents and Chemotherapy 51, no. 4 (2007): 1545–48. http://dx.doi.org/10.1128/aac.01275-06.

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ABSTRACT A sul3 domain (IS440-sul3-orf1-IS26) was found linked to an unusual 3′ conserved sequence region (qacH) of class 1 integrons and detected among nontyphoid Salmonella isolates (n = 47) from different sources. Three types of integrons differing in the gene cassette array (dfrA12-orfF-aadA2-cmlA1-aadA1, dfrA12-orfF-aadA2/1, and estX-psp-aadA2-cmlA1-aadA1) were found associated with this sul3 domain. They were associated with particular clones and specific high-molecular-weight plasmids.

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Orman, Betina E., Silvia A. Piñeiro, Sonia Arduino, et al. "Evolution of Multiresistance in Nontyphoid Salmonella Serovars from 1984 to 1998 in Argentina." Antimicrobial Agents and Chemotherapy 46, no. 12 (2002): 3963–70. http://dx.doi.org/10.1128/aac.46.12.3963-3970.2002.

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ABSTRACT Molecular evolution of multiresistance in nontyphoid Salmonella spp. was investigated with 155 isolates obtained in Argentina from 1984 to 1998. In 74 isolates obtained from 1984 to 1988 resistance was associated with the presence of Tn3, Tn9, class I (In0) and II (Tn7) integrons, and the aac(3)-IIa gene. Extended-spectrum cephalosporin (ESC) resistance in Salmonella spp. emerged in 1989, and 81 isolates resistant to at least one ESC and one aminoglycoside were collected thereafter. Among these, two patterns of antimicrobial resistance mechanisms were found: from 1989 to 1992, resistance was related to the spreading of Tn1331 and bla CTX-M-2, in addition to the persistence of In0 and Tn7. From 1993 to 1998, several integrons were added to the first pattern and three integron groups (IG), namely, IG1 (38% of the isolates), IG2 (51%), and IG3 (11%), were identified. At least two β-lactamase genes were detected in 65% of the isolates (after 1989) by PCR analysis. Furthermore, five β-lactamase genes, bla CTX-M- 2 , bla OXA-9, bla OXA-2, bla TEM-1, and bla PER-2, were found in two isolates. The bla CTX-M-2 gene was found in several complex sulI-type integrons with different rearrays within the variable region of class I integrons, suggesting evolution of these integrons in nontyphoid Salmonella. In conclusion, progressive acquisition and accumulation of plasmid-mediated resistance determinants occurred from 1984 to 1998 in nontyphoid Salmonella isolates of the most prevalent serovars from Argentina. It is suggested that antimicrobial resistance mechanisms in these bacteria may have been the consequence of plasmid exchange between Salmonella enterica serovar Typhimurium and Escherichia coli or Shigella flexneri and/or spreading of mobile elements from the nosocomial environment.

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White, Peter A., Christopher J. McIver, and William D. Rawlinson. "Integrons and Gene Cassettes in theEnterobacteriaceae." Antimicrobial Agents and Chemotherapy 45, no. 9 (2001): 2658–61. http://dx.doi.org/10.1128/aac.45.9.2658-2661.2001.

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ABSTRACT Integrons were detected in 59 of 120 (49%) urinary isolates ofEnterobacteriaceae by PCR using degenerate primers targeted to conserved regions of class 1, 2, and 3 integrase genes. PCR sequencing analysis of the cassette arrays revealed a predominance of cassettes that confer resistance to the aminoglycosides and trimethoprim.

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JAPONI, SARA, AZIZ JAPONI, SHOREH FARSHAD, AHYA ABDI ALI, and MARZIEH JAMALIDOUST. "Association between Existence of Integrons and Multi-Drug Resistance in Acinetobacter Isolated from Patients in Southern Iran." Polish Journal of Microbiology 60, no. 2 (2011): 163–68. http://dx.doi.org/10.33073/pjm-2011-023.

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Nosocomial infections caused by multi-drug resistant Acinetobacter pose a serious problem in many countries. This study aimed at determining the antibiotic susceptibility patterns and prevalence of different classes of integrons in isolated Acinetobacter. In addition, the association between production of specific bands in PCR assay and magnitude of multi-drug resistance was investigated. In total, 88 Acinetobacter strains were isolated from patients from October 2008 through September 2009. The Minimal inhibitory concentration (MIC) of 12 antibiotics conventionally used in clinics against the isolates, was determined by E-test method. The existence of integron classes was investigated by PCR assay through the amplification of integrase genes. The most effective antibiotic against Acinetobacter was colistin with 97.7% activity, followed by imipenem (77.3%) and meropenem (72.7%). The presence ofintegron classes 1 and 2 in 47 (53.4%) isolates was confirme, However, no class 3 was detected. The proportion of class 1, compared with class 2, was high (47.7% vs. 3.4%). The association between multi-drug resistance to norfloxacin, ceftazidime, gentamicin, ciprofloxacin, cefepime and amikacin and the presence of integrons was statistically significant. However, the association was not remarkable in many of the isolates which exhibited resistance to the rest of antibiotics. This may imply that in addition to integrons, other resistance determinants such as transposon and plasmid may also contribute to resistance. To reduce the pressure on sensitive isolates, comprehensive control measures should be implemented. Furthermore, wise application of effective antibiotics could help alleviate the situation. Colistin is the most effective antibiotic in vitro against Acinetobacter.

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Rizk, Dina E., and Areej M. El-Mahdy. "Emergence of class 1 to 3 integrons among members of Enterobacteriaceae in Egypt." Microbial Pathogenesis 112 (November 2017): 50–56. http://dx.doi.org/10.1016/j.micpath.2017.09.023.

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Barraud, O., M. C. Baclet, F. Denis, and M. C. Ploy. "Quantitative multiplex real-time PCR for detecting class 1, 2 and 3 integrons." Journal of Antimicrobial Chemotherapy 65, no. 8 (2010): 1642–45. http://dx.doi.org/10.1093/jac/dkq167.

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Xiong, Jianhui, David C. Alexander, Jennifer H. Ma, et al. "Complete Sequence of pOZ176, a 500-Kilobase IncP-2 Plasmid Encoding IMP-9-Mediated Carbapenem Resistance, from Outbreak Isolate Pseudomonas aeruginosa 96." Antimicrobial Agents and Chemotherapy 57, no. 8 (2013): 3775–82. http://dx.doi.org/10.1128/aac.00423-13.

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ABSTRACTPseudomonas aeruginosa96 (PA96) was isolated during a multicenter surveillance study in Guangzhou, China, in 2000. Whole-genome sequencing of this outbreak strain facilitated analysis of its IncP-2 carbapenem-resistant plasmid, pOZ176. The plasmid had a length of 500,839 bp and an average percent G+C content of 57%. Of the 618 predicted open reading frames, 65% encode hypothetical proteins. The pOZ176 backbone is not closely related to any plasmids thus far sequenced, but some similarity to pQBR103 ofPseudomonas fluorescensSBW25 was observed. Two multiresistant class 1 integrons and several insertion sequences were identified. TheblaIMP-9-carrying integron containedaacA4→blaIMP-9→aacA4, flanked upstream by Tn21 tnpMRAand downstream by a completetnioperon of Tn402and amermodule, named Tn6016. The second integron carriedaacA4→catB8a→blaOXA-10and was flanked by Tn1403-liketnpRAand asul1-type 3′ conserved sequence (3′-CS), named Tn6217. Other features include three resistance genes similar to those of Tn5, a tellurite resistance operon, and twopiloperons. The replication and maintenance systems exhibit similarity to a genomic island ofRalstonia solanacearumGM1000. Codon usage analysis suggests the recent acquisition ofblaIMP-9. The origins of the integrons on pOZ176 indicated separate horizontal gene transfer events driven by antibiotic selection. The novel mosaic structure of pOZ176 suggests that it is derived from environmental bacteria.

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Xiong, Jianhui, Maxime Déraspe, Naeem Iqbal, et al. "Genome and Plasmid Analysis ofblaIMP-4-Carrying Citrobacter freundii B38." Antimicrobial Agents and Chemotherapy 60, no. 11 (2016): 6719–25. http://dx.doi.org/10.1128/aac.00588-16.

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ABSTRACTSequencing of theblaIMP-4-carryingC. freundiiB38 using the PacBio SMRT technique revealed that the genome contained a chromosome of 5,134,500 bp and three plasmids, pOZ172 (127,005 bp), pOZ181 (277,592 bp), and pOZ182 (18,467 bp). Plasmid pOZ172 was identified as IncFIIY, like pP10164-NDM and pNDM-EcGN174. It carries a class 1 integron with four cassettes (blaIMP-4-qacG2-aacA4-aphA15) and a complete hybridtnimodule (tniR-tniQ-tniB-tniA). The recombination oftniRfrom Tn402(identical) withtniQBAfrom Tn5053(99%) occurred within theressite of Tn402/5053. The Tn402/5053-like integron, named Tn6017, was inserted into Tn1722at theresII site. The replication, partitioning, and transfer systems of pOZ181 were similar to those of IncHI2 plasmids (e.g., R478) and contained asul1-type class 1 integron with the cassette arrayorf-dfrA1-orf-gcu37-aadA5linked to an upstream Tn1696 tnpA-tnpRand to a downstream 3′ conserved sequence (3′-CS) and ISCR1. A Tn2transposon encoding ablaTEM-1β-lactamase was identified on pOZ182. Other interesting resistance determinants encoded on the B38 chromosome included multidrug resistance (MDR) efflux pumps, an AmpC β-lactamase, and resistances to Cu, Ag, As, and Zn. This is the first report of a completetnimodule linked to ablaIMP-4-carrying class 1 integron, which, together with other recently reported non-sul1integrons, represents the emergence of a distinct evolutionary lineage of class 1 integrons lacking a 3′-CS (qacEΔ1-sul1). The unique cassette array, completetnimodule of Tn6017, and incompatibility group of pOZ172 suggest ablaIMP-4evolutionary pathway inC. freundiiB38 different from that for otherblaIMP-4genes found in Gram-negative bacteria in the Western Pacific region.

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Lei, Chang-Wei, Tian-Ge Yao, Jia Yan, et al. "Identification of Proteus genomic island 2 variants in two clonal Proteus mirabilis isolates with coexistence of a novel genomic resistance island PmGRI1." Journal of Antimicrobial Chemotherapy 75, no. 9 (2020): 2503–7. http://dx.doi.org/10.1093/jac/dkaa215.

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Abstract Objectives To characterize the MDR genomic islands (GIs) in Proteus mirabilis isolates. Methods Two P. mirabilis strains (C55 and C74) of chicken origin were subjected to WGS (HiSeq and PacBio) and the MDR GIs were determined. Results P. mirabilis strains C55 and C74 are clonal strains and harbour different Proteus genomic island 2 (PGI2) variants (PGI2-C55 and PGI2-C74). The MDR region of PGI2-C55 is composed of two class 1 integrons, separated by a region containing seven copies of IS26 and eight resistance genes, including blaCTX-M-3 and fosA3. The region in PGI2-C74 is a complete In4-type class 1 integron, harbouring five gene cassettes (dfrA16, blaCARB-2, aadA2, cmlA1 and aadA1). In addition, C55 and C74 carry an SXT/R391 integrative and conjugative element (ICEPmiJpn1), harbouring blaCMY-2, and a novel 50.46 kb genomic resistance island named PmGRI1-C55. PmGRI1-C55 harbours a tyrosine-type recombinase/integrase that might be responsible for the integration of PmGRI1-C55 at the 3′ end of tRNA-Sec. It carries an MDR region derived from Tn2670 that harbours a Tn21 region and carries six resistance genes (catA1, blaTEM-1b, aphA1a, sul2, strA and strB). Blast analysis showed diverse PmGRI1 variants in P. mirabilis and Escherichia coli strains. Conclusions The finding of the two new PGI2 variants highlights that the homologous recombination between shared components of class 1 integrons and transposition by IS26 promote the diversity of MDR regions in PGI2. PmGRI1 is a new GI that carries various resistance genes identified in P. mirabilis and E. coli.

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Levings, Renee S., Sally R. Partridge, Steven P. Djordjevic, and Ruth M. Hall. "SGI1-K, a Variant of the SGI1 Genomic Island Carrying a Mercury Resistance Region, in Salmonella enterica Serovar Kentucky." Antimicrobial Agents and Chemotherapy 51, no. 1 (2006): 317–23. http://dx.doi.org/10.1128/aac.01229-06.

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ABSTRACT A multiple-antibiotic-resistant Salmonella enterica serovar Kentucky strain was found to contain SGI1-K, a variant form of the Salmonella genomic island 1 (SGI1) with an In4-type class 1 integron that contains only one cassette array, aacCA5-aadA7, and an adjacent mercury resistance module. Part of the 3′-conserved segment (3′-CS) of the integron, together with the inverted short segment from the right-hand end of the integron transposition module normally found between the 3′-CS and IS6100 in In4 family integrons, has been removed by an IS6100-mediated deletion. IRt, the right-hand inverted repeat found at the outer end of the integron, abuts a mercury resistance region instead of the usual SGI1 backbone segment. The mer module is a hybrid of those found in Tn501 and Tn21. This mer region and a further uncharacterized segment of at least 10 kb appear to have been incorporated between IRt and the SGI1 backbone. These findings demonstrate that the multidrug resistance region in SGI1 can incorporate new DNA segments in the same way as multiple antibiotic resistance regions in plasmids.

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Rodríguez, Irene, M. Rosario Rodicio, M. Carmen Mendoza, and M. Cruz Martín. "Large Conjugative Plasmids from Clinical Strains of Salmonella enterica Serovar Virchow Contain a Class 2 Integron in Addition to Class 1 Integrons and Several Non-Integron-Associated Drug Resistance Determinants." Antimicrobial Agents and Chemotherapy 50, no. 4 (2006): 1603–7. http://dx.doi.org/10.1128/aac.50.4.1603-1607.2006.

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ABSTRACT Two large conjugative resistance (R) plasmids from clinical strains of Salmonella enterica serovar Virchow carried a class 2 integron with the 5′ conserved sequence (5′CS)-dfrA1-sat1-aadA1-3′CS gene array, which is associated with defective Tn7 transposons. In addition, each contained a different class 1 integron (with 5′CS-aadA1-3′CS or 5′CS-sat-smr-aadA1-3′CS gene arrays) linked to Tn21-Tn9 sequences, and several non-integron-associated R determinants. An intact copy of Tn7 (including the class 2 integron) was present in the chromosome of each strain.

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Estabraghi, Ehsan, Taghi Zahraei Salehi, Kumarss Amini та Mahmoud Jamshidian. "Molecular Identification of Extended-Spectrum β-lactamase and Integron Genes in Klebsiella pneumonia". Journal of Nepal Medical Association 54, № 202 (2016): 72–78. http://dx.doi.org/10.31729/jnma.2822.

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Introduction: Infections caused by Gram negative bacteria, producing extended-spectrum β-lactamase, including Klebsiella pneumoniae are increasing all over the world with high morbidity and mortality. The aim of the present study was determined antimicrobial profile susceptibility and the prevalence of antibiotic resistance genes by multiplex PCR. Methods: In the present study, we obtained one-hundred isolates of K. pneumoniae from different clinical samples. The antibiotic susceptibility testing was done in thirteen antibiotic and, therefore, M-PCRs were conducted using the DNA amplification for detection of ESBLs (blaTEM, blaCTX-M, blaSHV) and int (I, II, III) genes. Results: The results of resistance to amoxicillin/clavulanate, ciprofloxacin, amikacin, trimethoprim-sulfamethoxazole, cefotaxime, ampicillin, aztreonam, imipenem, gentamicin, ceftazidime, Cefepime, ceftriaxone and levofloxacin were obtained 37%, 37%, 93%, 84%, 52%, 87%, 59%, 8%, 24%, 67%, 52%, 43% and 26%, respectively. The frequency of the extended-spectrum β-lactamase K. pneumoniae was obtained 37%. The prevalence of resistance genes of ESBLs in the M-PCR method showed that the blaTEM, blaCTX and blaSHV were 38%, 24% and 19%, respectively, however, only 8 (8%) out of 100 isolates were found to have positive outcomes for the existence of class 1 integrons and there were no detected class 2 or class 3 integrons. Conclusions: Our results recommend the likely co-carriage of some ESBLs genes and antibiotic resistance integrons on the same plasmids harboring the MDR genes. Keywords: fKlebsiella pneumonia, integrons, drug resistance. | PubMed

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Daly, M., J. Buckley, E. Power, et al. "Molecular Characterization of IrishSalmonella enterica Serotype Typhimurium: Detection of Class I Integrons and Assessment of Genetic Relationships by DNA Amplification Fingerprinting." Applied and Environmental Microbiology 66, no. 2 (2000): 614–19. http://dx.doi.org/10.1128/aem.66.2.614-619.2000.

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ABSTRACT Salmonella enterica is among the principal etiological agents of food-borne illness in humans. Increasing antimicrobial resistance in S. enterica is a cause for worldwide concern. There is concern at present in relation to the increasing incidence of human infection with antimicrobial agent-resistant strains of S. enterica serotype Typhimurium, in particular of phage type DT104. Integrons appear to play an important role in the dissemination of antimicrobial resistance genes in many Enterobacteriaceaeincluding S. enterica. In this study the antimicrobial susceptibilities and phage types of 74 randomly collected strains ofS. enterica serotype Typhimurium from the Cork region of southern Ireland, obtained from human, animal (clinical), and food sources, were determined. Each strain was examined for integrons and typed by DNA amplification fingerprinting (DAF). Phage type DT104 predominated (n = 48). Phage types DT104b (n = 3), -193 (n = 9), -195 (n = 6), -208 (n = 3), -204a (n = 2), PT U302 (n = 1), and two nontypeable strains accounted for the remainder. All S. enterica serotype Typhimurium DT104 strains were resistant to ampicillin, chloramphenicol, streptomycin, Sulfonamide Duplex, and tetracycline, and one strain was additionally resistant to trimethoprim. All DT104 strains but one were of a uniform DAF type (designated DAF-I) and showed a uniform pattern of integrons (designated IP-I). The DT104b and PT U302 strains also exhibited the same resistance phenotype, and both had the DAF-I and IP-I patterns. The DAF-I pattern was also observed in a single DT193 strain in which no integrons were detectable. Greater diversity of antibiograms and DAF and IP patterns among non-DT104 phage types was observed. These data indicate a remarkable degree of homogeneity at a molecular level among contemporary isolates of S. enterica serotype Typhimurium DT104 from animal, human, and food sources in this region.

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Mohamed, Mona Sallam Embarek, Alaa Thabet Hassan, and Soheir Mostafa Kasem Ahmed. "Prevalence of Class 1, 2 and 3 Integrons and Carbapenem-Resistance in Gram-Negative Bacteria." Egyptian Journal of Medical Microbiology 25, no. 3 (2016): 67–73. http://dx.doi.org/10.12816/0036812.

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Tariq, Aaysha, Abdul Haque, Aamir Ali, et al. "Molecular profiling of antimicrobial resistance and integron association of multidrug-resistant clinical isolates of Shigella species from Faisalabad, Pakistan." Canadian Journal of Microbiology 58, no. 9 (2012): 1047–54. http://dx.doi.org/10.1139/w2012-085.

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Bacillary dysentery, common in developing countries, is usually caused by Shigella species. A major problem in shigellosis is the rapid emergence of multidrug-resistant strains. This is the first detailed molecular study on drug resistance of Shigella isolates from the Faisalabad region of Pakistan. Ninety-five Shigella isolates obtained after screening of 2500 stool samples were evaluated for in vitro resistance to commonly used antimicrobial agents; the presence or absence of 20 of the most relevant drug resistance genes; and the prevalence of integrons 1, 2, and 3. Shigella flexneri was found to be the most prevalent and most resistant species. Collectively, high resistance was found towards ampicillin (96.84%), tetracycline (93.68%), streptomycin (77.89%), and chloramphenicol (72.63%). Significant emerging resistance was detected towards the modern frontline drugs ciprofloxacin (12.63%), cefradine (17.89%), ceftriaxone (20.00%), cefoperazone (22.10%), and cefixime (28.42%). Prevalence rates for blaTEM, blaCTX-M, gyrA, gyrB, qnrS, aadA1, strAB, tetA, tetB, catA, and catP were 78.94%, 12.63%, 20.00%, 21.05%, 21.05%, 67.36%, 42.10%, 12.63%, 53.68%, 33.68%, and 25.26%, respectively. Class 2 integrons (42.10%) were more common in the local isolates. Simultaneous detection of class 1 and 2 integrons in some isolates and a rapidly emerging resistance to modern frontline drugs are the major findings of this study.

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Lee, Margie D., Susan Sanchez, Martha Zimmer, Umelaalim Idris, Mark E. Berrang, and Patrick F. McDermott. "Class 1 Integron-Associated Tobramycin-Gentamicin Resistance in Campylobacter jejuni Isolated from the Broiler Chicken House Environment." Antimicrobial Agents and Chemotherapy 46, no. 11 (2002): 3660–64. http://dx.doi.org/10.1128/aac.46.11.3660-3664.2002.

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ABSTRACT Using PCR, we screened 105 isolates of poultry-associated Campylobacter jejuni for the presence of class 1 integrons. Of those isolates, 21% (22 of 105) possessed the integrase gene, but only 5 isolates produced an amplicon in a 5′-3′ conserved sequence PCR directed toward amplification of the resistance cassettes. DNA sequencing demonstrated that all five isolates possessed the aminoglycoside resistance gene, aacA4.

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Elizabeth, Rajkumari, Debadatta Dhar Chanda, Atanu Chakravarty, et al. "Association of Glycerol Kinase Gene with Class 3 Integrons: A Novel Cassette Array within Escherichia coli." Indian Journal of Medical Microbiology 36, no. 1 (2018): 104–7. http://dx.doi.org/10.4103/ijmm.ijmm_17_188.

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Riccio, Maria Letizia, Lucia Pallecchi, Roberta Fontana, and Gian Maria Rossolini. "In70 of Plasmid pAX22, ablaVIM-1-Containing Integron Carrying a New Aminoglycoside Phosphotransferase Gene Cassette." Antimicrobial Agents and Chemotherapy 45, no. 4 (2001): 1249–53. http://dx.doi.org/10.1128/aac.45.4.1249-1253.2001.

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ABSTRACT An Achromobacter xylosoxydans strain showing broad-spectrum resistance to β-lactams (including carbapenems) and aminoglycosides was isolated at the University Hospital of Verona (Verona, Italy). This strain was found to produce metallo-β-lactamase activity and to harbor a 30-kb nonconjugative plasmid, named pAX22, carrying abla VIM-1 determinant inserted into a class 1 integron. Characterization of this integron, named In70, revealed an original array of four gene cassettes containing, respectively, thebla VIM-1 gene and three different aminoglycoside resistance determinants, including an aacA4allele, a new aph-like gene named aphA15, and an aadA1 allele. The aphA15 gene is the first example of an aph-like gene carried on a mobile gene cassette, and its product exhibits close similarity to the APH(3′)-IIa aminoglycoside phosphotransferase encoded by Tn5 (36% amino acid identity) and to an APH(3′)-IIb enzyme fromPseudomonas aeruginosa (38% amino acid identity). Expression of the cloned aphA15 gene in Escherichia coli reduced the susceptibility to kanamycin and neomycin as well as (slightly) to amikacin, netilmicin, and streptomycin. Characterization of the 5′ and 3′ conserved segments of In70 and of their flanking regions showed that In70 belongs to the group of class 1 integrons associated with defective transposon derivatives originating from Tn402-like elements. The structure of the 3′ conserved segment indicates the closest ancestry with members of the In0-In2 lineage. In70, with its array of cassette-borne resistance genes, can mediate broad-spectrum resistance to most β-lactams and aminoglycosides.

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Naas, Thierry, Daniel Aubert, Thierry Lambert та Patrice Nordmann. "Complex Genetic Structures with Repeated Elements, a sul-Type Class 1 Integron, and the blaVEB Extended-Spectrum β-Lactamase Gene". Antimicrobial Agents and Chemotherapy 50, № 5 (2006): 1745–52. http://dx.doi.org/10.1128/aac.50.5.1745-1752.2006.

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ABSTRACT Two clinical isolates of Pseudomonas aeruginosa, TL-1 and TL-2, were isolated from a patient transferred from Bangladesh and hospitalized for osteomyelitis in Paris, France. P. aeruginosa TL-1 expressed the extended-spectrum β-lactamase VEB-1a and was susceptible only to imipenem and colistin, while P. aeruginosa TL-2 expressed only the naturally occurring bla AmpC gene at a basal level and exhibited a wild-type β-lactam resistance phenotype. In TL-1, the typical 5′-end conserved sequence (5′-CS) region of class 1 integrons usually present upstream of the bla VEB-1a gene was replaced by a truncated 3′-CS and a 135-bp repeated element (Re). Downstream of the bla VEB-1a gene, an insertion sequence, ISPa31 disrupted by ISPa30, and an orf513 sequence, belonging to a common region (conserved region 1 [CR1]) immediately upstream of the aphA-6 gene, were present. Further downstream, a second truncated 3′-CS region in direct repeat belonged to In51, an integron containing two gene cassettes (aadA6 and the OrfD cassette). Thus, the overall structure corresponded to a sul-type class 1 integron termed In121. Genetic analyses revealed that both isolates were clonally related and differed by a ca. 100-kb fragment that contained In121. Both isolates contained another integron, In122, that carried three gene cassettes: aadB, dfrA1, and the OrfX cassette. This work identifies for the first time the spread of Re-associated bla VEB genes located on a sul-type integron. It also reports for the first time a CR1 element in P. aeruginosa that is associated with an aminoglycoside resistance aphA-6 gene that is expressed from a composite promoter.

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Ploy, Marie-Cécile, Patrice Courvalin, and Thierry Lambert. "Characterization of In40 of Enterobacter aerogenes BM2688, a Class 1 Integron with Two New Gene Cassettes, cmlA2 and qacF." Antimicrobial Agents and Chemotherapy 42, no. 10 (1998): 2557–63. http://dx.doi.org/10.1128/aac.42.10.2557.

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ABSTRACT Enterobacter aerogenes BM2688, which is resistant to multiple antibiotics, and its aminoglycoside-susceptible derivative BM2688-1 were isolated from the same clinical sample. Strain BM2688 harbored plasmid pIP833, which carries a class 1 integron, In40, containing (in addition to qacEΔ1 and sul1, which are characteristic of class 1 integrons) four gene cassettes:aac(6′)-Ib, qacF, cmlA2, andoxa-9. The cmlA2 gene had 83.7% identity with the previously described nonenzymatic chloramphenicol resistancecmlA1 gene. The qacF gene conferred resistance to quaternary ammonium compounds and displayed a high degree of similarity with qacE (67.8% identity) which, however, has been found as part of a cassette with a very different 59-base element. The oxa-9 gene was not expressed due to a lack of promoter sequences. Study of the antibiotic-susceptible derivative BM2688-1 indicated that a 3,148-bp deletion between the 3′ end of theaac(6′)-Ib gene and the 3′ conserved segment of In40 was responsible for the loss of resistance. The occurrence of this DNA rearrangement, which did not involve homologous sequences, suggests that the In40 integrase could promote recombination at secondary sites.

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Pérez-Etayo, Lara, Melibea Berzosa, David González, and Ana Vitas. "Prevalence of Integrons and Insertion Sequences in ESBL-Producing E. coli Isolated from Different Sources in Navarra, Spain." International Journal of Environmental Research and Public Health 15, no. 10 (2018): 2308. http://dx.doi.org/10.3390/ijerph15102308.

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Mobile genetic elements play an important role in the dissemination of antibiotic resistant bacteria among human and environmental sources. Therefore, the aim of this study was to determine the occurrence and patterns of integrons and insertion sequences of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from different sources in Navarra, northern Spain. A total of 150 isolates coming from food products, farms and feeds, aquatic environments, and humans (healthy people and hospital inpatients), were analyzed. PCRs were applied for the study of class 1, 2, and 3 integrons (intI1, intI2, and intI3), as well as for the determination of insertion sequences (IS26, ISEcp1, ISCR1, and IS903). Results show the wide presence and dissemination of intI1 (92%), while intI3 was not detected. It is remarkable, the prevalence of intI2 among food isolates, as well as the co-existence of class 1 and class 2 (8% of isolates). The majority of isolates have two or three IS elements, with the most common being IS26 (99.4%). The genetic pattern IS26–ISEcp1 (related with the pathogen clone ST131) was present in the 22% of isolates (including human isolates). In addition, the combination ISEcp1–IS26–IS903–ISCR1 was detected in 11 isolates being, to our knowledge, the first study that describes this genetic complex. Due to the wide variability observed, no relationship was determined among these mobile genetic elements and β-lactam resistance. More investigations regarding the genetic composition of these elements are needed to understand the role of multiple types of integrons and insertion sequences on the dissemination of antimicrobial resistance genes among different environments.

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Dalsgaard, A., A. Forslund, N. V. Tam, D. X. Vinh, and P. D. Cam. "Cholera in Vietnam: Changes in Genotypes and Emergence of Class I Integrons Containing Aminoglycoside Resistance Gene Cassettes in Vibrio cholerae O1 Strains Isolated from 1979 to 1996." Journal of Clinical Microbiology 37, no. 3 (1999): 734–41. http://dx.doi.org/10.1128/jcm.37.3.734-741.1999.

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The number of cholera cases and the mortality rates reported from different regions of Vietnam varied considerably in the period from 1979 to 1996, with between 2,500 and 6,000 cases reported annually from 1992 to 1995. Annual mortality rates ranged from 2.0 to 9.6% from 1979 to 1983 to less than 1.8% after 1983. Major cholera outbreaks were reported from the High Plateau region for the first time in 1994 and 1995; this is an area with limited access to health services and safe drinking-water supplies. All cases were associated with Vibrio cholerae O1. Using ribotyping, cholera toxin (CT) genotyping, and characterization of antibiotic susceptibility patterns and antibiotic resistance genes by PCR, we show that strains isolated after 1990 were clearly different from strains isolated before 1991. In contrast to strains isolated before 1991, 94% of 104 strains isolated after 1990 showed an identical ribotype R1, were resistant to sulfamethoxazole and streptomycin, and showed a different CT genotype. Furthermore, PCR analysis revealed that sulfamethoxazole-resistant strains harbored class I integrons containing a gene cassette ant(3")-1aencoding resistance to streptomycin and spectinomycin. This is, to our knowledge, the first report of class I integrons in V. cholerae. The development of cholera and the changes in the phenotypic and genotypic properties of V. cholerae O1 shown in the present study highlight the importance of monitoring V. cholerae O1 in Vietnam as in other parts of the world. In particular, the emergence of the new ribotype R1 strain containing class I integrons should be further studied.

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Zong, Zhiyong, Sally R. Partridge, and Jonathan R. Iredell. "A blaVEB-1 Variant, blaVEB-6, Associated with Repeated Elements in a Complex Genetic Structure." Antimicrobial Agents and Chemotherapy 53, no. 4 (2009): 1693–97. http://dx.doi.org/10.1128/aac.01313-08.

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ABSTRACT bla VEB-6 was found on the Proteus mirabilis chromosome in a context similar to those of bla VEB-1a and bla VEB-1b, in a truncated gene cassette flanked by 135-bp elements and duplications of the 3′-conserved segment of class 1 integrons. A linked aacA4-aadB-dfrA1-orfC cassette array includes components of Tn1331, illustrating the complex mosaicism of multiresistance regions.

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USTA, Egemen, Cafer EROĞLU, Keramettin YANIK, Adil KARADAĞ, Akif Koray GÜNEY, and Murat GÜNAYDIN. "Investigation of the Presence of Class 1, 2, 3 Integrons and Their Relationships with Antibiotic Resistance in Clinical Stenotrophomonas maltophilia Isolates." Mikrobiyoloji Bulteni 49, no. 1 (2015): 35–46. http://dx.doi.org/10.5578/mb.8459.

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Journal articles on the topic 'Class 3 integrons'

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