Relevant bibliographies by topics / Plasmid and resistance

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Academic literature on the topic 'Plasmid and resistance'

Author: Grafiati
Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "Plasmid and resistance"

1

Ling, J. M., P. C. Shaw, K. M. Kam, A. F. Cheng, and G. L. French. "Molecular studies of plasmids of multiply-resistantShigellaspp. in Hong Kong." Epidemiology and Infection 110, no. 3 (June 1993): 437–46. http://dx.doi.org/10.1017/s095026880005086x.

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SUMMARYOne hundred and twoShigellaspp. isolated in two hospitals in Hong Kong were analysed for antibiotic resistances, resistance plasmids and plasmid profiles. Three quarters of the isolates wereS.flexneri. All isolates harboured plasmids, up to a maximum of ten within one strain. Plasmids of 220 kb encoding resistances to tetracycline, chloramphenicol and sulphonamide and probably also associated with invasivenes in the Sereny test were found in 80 strains and were transferable in 18% of cases. Resistance plasmids of 92 and 99 kb were found in 27 and 15 strains respectively and encoded resistances to ampicillin, tetracycline, chloramphenicol, kanamycin, sulphonamide, trimethoprim, cotrimoxazole and gentamicin; these plasmids were usually transferable. Four plasmids of 3·9, 2·8, 2·2 and 1·8 kb were commonly found inS. flexneristrains, but were rare in other species. In contrast, there was no predominant plasmid profile inS. sonnei. S. flexneriis endemic in Hong Kong and these plasmid studies suggest that the strains in circulation are derived from only a few clones.
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Jalasvuori, Matti, Ville-Petri Friman, Anne Nieminen, Jaana K. H. Bamford, and Angus Buckling. "Bacteriophage selection against a plasmid-encoded sex apparatus leads to the loss of antibiotic-resistance plasmids." Biology Letters 7, no. 6 (June 2011): 902–5. http://dx.doi.org/10.1098/rsbl.2011.0384.

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Antibiotic-resistance genes are often carried by conjugative plasmids, which spread within and between bacterial species. It has long been recognized that some viruses of bacteria (bacteriophage; phage) have evolved to infect and kill plasmid-harbouring cells. This raises a question: can phages cause the loss of plasmid-associated antibiotic resistance by selecting for plasmid-free bacteria, or can bacteria or plasmids evolve resistance to phages in other ways? Here, we show that multiple antibiotic-resistance genes containing plasmids are stably maintained in both Escherichia coli and Salmonella enterica in the absence of phages, while plasmid-dependent phage PRD1 causes a dramatic reduction in the frequency of antibiotic-resistant bacteria. The loss of antibiotic resistance in cells initially harbouring RP4 plasmid was shown to result from evolution of phage resistance where bacterial cells expelled their plasmid (and hence the suitable receptor for phages). Phages also selected for a low frequency of plasmid-containing, phage-resistant bacteria, presumably as a result of modification of the plasmid-encoded receptor. However, these double-resistant mutants had a growth cost compared with phage-resistant but antibiotic-susceptible mutants and were unable to conjugate. These results suggest that bacteriophages could play a significant role in restricting the spread of plasmid-encoded antibiotic resistance.
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Erac, Bayri, Fethiye Ferda Yilmaz, Ismail Ozturk, Sabire Sohret Aydemir, and Mine Hosgor-Limoncu. "Analyses of Plasmids Harbouring Quinolone Resistance Determinants in Enterobacteriaceae Members." Polish Journal of Microbiology 66, no. 4 (December 4, 2017): 529–32. http://dx.doi.org/10.5604/01.3001.0010.7084.

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The aim of this study was to explore the plasmid characteristics of eight clinical Enterobacteriaceae strains containing extended broad spectrum beta-lactamases and plasmid-mediated quinolone resistance. Plasmids were transferred by conjugation or transformation and resistance determinants were investigated by PCR. We showed that at least one plasmid harbouring qnrB or qnrS determinant was transferred by conjugation in five isolates. QepA determinant was confirmed to be on a non-conjugative plasmid. We found at least one beta-lactamase gene in seven of the eight clinical isolates having plasmid-mediated quinolone resistance, which indicated that these two resistance determinants were mostly on the same conjugative plasmids.
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Bottery, Michael J., A. Jamie Wood, and Michael A. Brockhurst. "Selective Conditions for a Multidrug Resistance Plasmid Depend on the Sociality of Antibiotic Resistance." Antimicrobial Agents and Chemotherapy 60, no. 4 (January 19, 2016): 2524–27. http://dx.doi.org/10.1128/aac.02441-15.

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ABSTRACTMultidrug resistance (MDR) plasmids frequently carry antibiotic resistance genes conferring qualitatively different mechanisms of resistance. We show here that the antibiotic concentrations selecting for the RK2 plasmid inEscherichia colidepend upon the sociality of the drug resistance: the selection for selfish drug resistance (efflux pump) occurred at very low drug concentrations, just 1.3% of the MIC of the plasmid-free antibiotic-sensitive strain, whereas selection for cooperative drug resistance (modifying enzyme) occurred at drug concentrations exceeding the MIC of the plasmid-free strain.
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Hoshino, Takayuki, Takayuki Ikeda, Hiroyuki Narushima, and Noboru Tomizuka. "Isolation and characterization of antibiotic-resistance plasmids in thermophilic bacilli." Canadian Journal of Microbiology 31, no. 4 (April 1, 1985): 339–45. http://dx.doi.org/10.1139/m85-065.

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Four antibiotic-resistance plasmids isolated from thermophilic bacilli were characterized in detail. Three tetracycline-resistance (Tcr) plasmids were designated as pTHT9 (7.7 kilobases (kb)), pTHT15 (4.5 kb) and pTHT22 (8.4 kb). From the results of restriction endonuclease analysis and the subsequent Southern hybridization, these were found to possess extensive genetic homology in the regions that include the replication origin and the Tcr gene. Detailed restriction maps of the smallest Tcr plasmid pTHT15 and a kanamycin-resistance (Kmr) plasmid pTHN1 (4.8 kb) were constructed. The positions of antibiotic-resistance loci and regions essential for plasmid replication were determined by cloning plasmid fragments in Bacillus subtilis. These four plasmids were found to replicate and express the resistance genes stably in both B. subtilis and B. stearothermophilus.
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Fricke, W. Florian, Timothy J. Welch, Patrick F. McDermott, Mark K. Mammel, J. Eugene LeClerc, David G. White, Thomas A. Cebula, and Jacques Ravel. "Comparative Genomics of the IncA/C Multidrug Resistance Plasmid Family." Journal of Bacteriology 191, no. 15 (May 29, 2009): 4750–57. http://dx.doi.org/10.1128/jb.00189-09.

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ABSTRACT Multidrug resistance (MDR) plasmids belonging to the IncA/C plasmid family are widely distributed among Salmonella and other enterobacterial isolates from agricultural sources and have, at least once, also been identified in a drug-resistant Yersinia pestis isolate (IP275) from Madagascar. Here, we present the complete plasmid sequences of the IncA/C reference plasmid pRA1 (143,963 bp), isolated in 1971 from the fish pathogen Aeromonas hydrophila, and of the cryptic IncA/C plasmid pRAx (49,763 bp), isolated from Escherichia coli transconjugant D7-3, which was obtained through pRA1 transfer in 1980. Using comparative sequence analysis of pRA1 and pRAx with recent members of the IncA/C plasmid family, we show that both plasmids provide novel insights into the evolution of the IncA/C MDR plasmid family and the minimal machinery necessary for stable IncA/C plasmid maintenance. Our results indicate that recent members of the IncA/C plasmid family evolved from a common ancestor, similar in composition to pRA1, through stepwise integration of horizontally acquired resistance gene arrays into a conserved plasmid backbone. Phylogenetic comparisons predict type IV secretion-like conjugative transfer operons encoded on the shared plasmid backbones to be closely related to a group of integrating conjugative elements, which use conjugative transfer for horizontal propagation but stably integrate into the host chromosome during vegetative growth. A hipAB toxin-antitoxin gene cluster found on pRA1, which in Escherichia coli is involved in the formation of persister cell subpopulations, suggests persistence as an early broad-spectrum antimicrobial resistance mechanism in the evolution of IncA/C resistance plasmids.
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Lim, Suk-Kyung, Koichi Tanimoto, Haruyoshi Tomita, and Yasuyoshi Ike. "Pheromone-Responsive Conjugative Vancomycin Resistance Plasmids in Enterococcus faecalis Isolates from Humans and Chicken Feces." Applied and Environmental Microbiology 72, no. 10 (October 2006): 6544–53. http://dx.doi.org/10.1128/aem.00749-06.

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ABSTRACT The drug resistances and plasmid contents of a total of 85 vancomycin-resistant enterococcus (VRE) strains that had been isolated in Korea were examined. Fifty-four of the strains originated from samples of chicken feces, and 31 were isolated from hospital patients in Korea. Enterococcus faecalis KV1 and KV2, which had been isolated from a patient and a sample of chicken feces, respectively, were found to carry the plasmids pSL1 and pSL2, respectively. The plasmids transferred resistances to vancomycin, gentamicin, kanamycin, streptomycin, and erythromycin to E. faecalis strains at a high frequency of about 10−3 per donor cell during 4 hours of broth mating. E. faecalis strains containing each of the pSL plasmids formed clumps after 2 hours of incubation in broth containing E. faecalis FA2-2 culture filtrate (i.e., the E. faecalis sex pheromone), and the plasmid subsequently transferred to the recipient strain in a 10-min short mating in broth, indicating that the plasmids are responsive to E. faecalis pheromones. The pSL plasmids did not respond to any of synthetic pheromones for the previously characterized plasmids. The pheromone specific for pSL plasmids has been designated cSL1. Southern hybridization analysis showed that specific FspI fragments from each of the pSL plasmids hybridized with the aggregation substance gene (asa1) of the pheromone-responsive plasmid pAD1, indicating that the plasmids had a gene homologous to asa1. The restriction maps of the plasmids were identical, and the size of the plasmids was estimated to be 128.1 kb. The plasmids carried five drug resistance determinants for vanA, ermB, aph(3′), aph(6′), and aac(6′)/aph(2′), which encode resistance to vancomycin, erythromycin, kanamycin, streptomycin, and gentamicin/kanamycin, respectively. Nucleotide sequence analyses of the drug resistance determinants and their flanking regions are described in this report. The results described provide evidence for the exchange of genetic information between human and animal (chicken) VRE reservoirs and suggest the potential for horizontal transmission of multiple drug resistance, including vancomycin resistance, between farm animals and humans via a pheromone-responsive conjugative plasmid.
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Dimitriu, Tatiana, Andrew C. Matthews, and Angus Buckling. "Increased copy number couples the evolution of plasmid horizontal transmission and plasmid-encoded antibiotic resistance." Proceedings of the National Academy of Sciences 118, no. 31 (July 29, 2021): e2107818118. http://dx.doi.org/10.1073/pnas.2107818118.

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Conjugative plasmids are mobile elements that spread horizontally between bacterial hosts and often confer adaptive phenotypes, including antimicrobial resistance (AMR). Theory suggests that opportunities for horizontal transmission favor plasmids with higher transfer rates, whereas selection for plasmid carriage favors less-mobile plasmids. However, little is known about the mechanisms leading to variation in transmission rates in natural plasmids or the resultant effects on their bacterial host. We investigated the evolution of AMR plasmids confronted with different immigration rates of susceptible hosts. Plasmid RP4 did not evolve in response to the manipulations, but plasmid R1 rapidly evolved up to 1,000-fold increased transfer rates in the presence of susceptible hosts. Most evolved plasmids also conferred on their hosts the ability to grow at high concentrations of antibiotics. This was because plasmids evolved greater copy numbers as a function of mutations in the copA gene controlling plasmid replication, causing both higher transfer rates and AMR. Reciprocally, plasmids with increased conjugation rates also evolved when selecting for high levels of AMR, despite the absence of susceptible hosts. Such correlated selection between plasmid transfer and AMR could increase the spread of AMR within populations and communities.
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Giles, Janice S., Harry Hariharan, and Susan B. Heaney. "The plasmid profiles of fish pathogenic isolates of Aeromonas salmomcida, Vibrio anguillarum, and Vibrio ordalii from the Atlantic and Pacific coasts of Canada." Canadian Journal of Microbiology 41, no. 3 (March 1, 1995): 209–16. http://dx.doi.org/10.1139/m95-029.

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The plasmid profiles of oxytetracycline- and streptomycin-resistant isolates of Aeromonas salmonicida, Vibrio anguillarum, and Vibrio ordalii were examined by agarose gel electrophoresis. Bacterial isolates were from disease outbreaks in fish on the Atlantic and Pacific coasts. Resistant isolates were examined when grown in the presence and absence of antibiotic. Alkaline lysis methods were used for plasmid isolation. Vibrio spp. were predominantly plasmidless, except for a 47-kilobase (kb) plasmid. Atlantic coast isolates of A. salmonicida possessed four or six plasmids, with four smaller plasmids ranging in size from 4.3 to 8.1 kb being consistently observed. The plasmid profiles of antibiotic-sensitive ATCC strains were identical. The plasmid profiles of the Pacific coast isolates of A. salmonicida varied slightly from those of the Atlantic coast isolates with six plasmids observed, ranging in size from 4.2 to 8.9 kb. Resistance to the antibiotics was not altered following plasmid curing experiments and resistance was not transferable to Escherichia coli. Thus, resistance to oxytetracycline and streptomycin did not appear to be plasmid mediated.Key words: plasmids, antibiotics, Aeromonas, Vibrio, fish.
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Hunter, J. E. B., M. Bennett, C. A. Hart, J. C. Shelley, and J. R. Walton. "Apramycin-resistantEscherichia coliisolated from pigs and a stockman." Epidemiology and Infection 112, no. 3 (June 1994): 473–80. http://dx.doi.org/10.1017/s0950268800051177.

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SUMMARYEscherichia coliserotype O147:K89:K88a,c was found to be associated with outbreaks of diarrhoea in preweaner pigs of up to 4 weeks of age on a pig unit. Resistance to apramycin, gentamicin, netilmicin, tobramycin and other antibiotics was associated with conjugative plasmids of approximately 62 kb. The presence of a gene which encoded for the aminoglycoside acetyltransferase enzyme AAC(3)IV was confirmed by DNA hybridization.Samples collected during the following 12 months revealed widespread dissemination of these resistance plasmids in non-serotypable, non-haemolyticE. colithroughout the farm. Apramycin-resistantE. coliwere also isolated from a stockman and it appeared from plasmid profile analysis and antibiotic sensitivity testing that the human isolates carried the same plasmid as that carried by the porcineE. coli.Klebsiella pneumoniae, with a slightly smaller conjugative plasmid and similar resistance pattern, was isolated from the stockman's wife.
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Dissertations / Theses on the topic "Plasmid and resistance"

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Bottery, Michael J. "The sociality and evolution of plasmid-mediated antimicrobial resistance." Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/19016/.

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Overuse and misuse of antibiotics has led to the global spread of antimicrobial resistance, threatening our ability to treat bacterial infections. The horizontal acquisition of multidrug resistance (MDR) plasmids, from other bacterial lineages, has been instrumental in spreading resistance. Newly acquired plasmids are often poorly adapted to hosts causing intragenomic conflicts, reducing the competitiveness of plasmid-carrying strains. Costs can be overcome by positive selection for plasmid-encoded adaptive traits in the short-term, or ameliorated by compensatory evolution in the long-term. How the selection and adaptation of MDR plasmids varies with antibiotic treatment remains unclear. First, I demonstrate that the selective conditions for the maintenance of an MDR plasmid are dependent upon the sociality of resistance it encodes. Selection for efflux of antibiotics, a selfish trait, occurred at very low concentrations of antibiotic, far below the minimum inhibitory concentration of sensitive plasmid-free strain. In contrast, selection for inactivation of antibiotics, a cooperative trait, increased the amount of antibiotic required to select for the MDR plasmid, allowing sensitive plasmid-free bacteria to survive high levels of antibiotic. These selection dynamics were only accurately predicted when mathematical models included the mechanistic details of antibiotic resistance. Secondly, I show that the trajectory of evolution following MDR plasmid acquisition varies with antibiotic treatment. Tetracycline treatment favoured a distinct coevolutionary trajectory of chromosomal resistance mutations coupled with plasmid mutations impairing plasmid-borne resistance. This led to high-level, low-cost antibiotic resistance, but also produced an integrated genome of co-dependent replicons that may limit the onward spread of co-adapted MGEs to other lineages. This evolutionary trajectory was strikingly repeatable across independently evolving populations despite the emergence of multiple competing lineages within populations. The results presented here demonstrate that the interaction between positive selection and compensatory evolution can help to explain the persistence of MDR plasmids in the clinic and the environment.
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Udo, Edet Ekpenyong. "Characterisation and molecular studies of plasmids from Nigerian staphylococci." Curtin University of Technology, School of Biomedical Sciences, 1991. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15648.

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Fifty three Staphylococcus aureus isolates were obtained from three centres, two hospitals and a private pathology laboratory, and studied for susceptibility to bacteriophages, resistance to antimicrobial agents and plasmid contents.Results of bacteriophage typing revealed that they belonged to a variety of phage types. Eighteen were untypable by any of the International Set of Phages, 16 belonged to phage group 111, nine to group I, four to group 11, two to group IV and two to the miscellaneous group.The isolates were resistant to one or more of methicillin (Mc), benzyl penicillin (Pc), gentamicin (Gm) , kanamycin (Km) , neomycin (Nm) , streptomycin (Sm) , trimethoprim (Tp), sulphonamides (Su), tetracycline (Tc), minocycline (Mn), chloramphenicol (Cm), novobiocin (Nb) and fusidic acid (Fa). Resistance to Pc was due to the production of beta-lactamase (Bla). No resistance to vancomycin, spectinomycin and erythromycin was detected. Resistance was also found to heavy metals such as cadmium (Cd), mercury (Hg), phenyl mercuric acetate (Pma), arsenate (Asa) and to the nucleic-acid binding compounds propamidine isethionate (Pi) and ethidium bromide (Eb).All but one of the isolates harboured plasmids. The number of plasmids the isolates carried varied from one to six and their sizes ranged from < 1.0 kb to c.48 kb.Location of the resistance determinants was ascertained by curing and transfer experiments. Loss of resistance was tested after growth at 43.5°C and transfer of resistance determinants was attempted by transduction, mixed-culture transfer and conjugation. The results revealed that resistance to Mc, Gm, Tp, Mn and Fa was chromosomal in all the resistant isolates and in some isolates Bla and resistance to Sm and Cd were chromosomal as well as plasmid encoded. In the majority of cases Bla and resistance to Km, Nm, Sm, Tc, Cin, Cd, Hg, Asa, Pma, Pi and Eb was encoded ++
by plasmids.Conjugation experiments led to the isolation of three unique conjugative plasmids which have not been found to confer resistance to antimicrobials or to produce haemolysins or diffusible pigment (Dip). The three plasmids, pWBG620, pWBG637 and pWBG661, were indistinguishable by restriction endonuclease analysis and DNA-DNA hybridisation. However pWBG620, unlike pWBG637 and pWBG661, was not detected in the cytoplasm of its host and was only detected in transconjugants after it mobilised a non-conjugative Sm-resistance (SmR) plasmid. Further analysis indicated that it is integrated into the chromosome of its host, excises during conjugation and mobilises the SmR plasmid.These plasmids were studied further using pWBG637 as a representative. It was compared with representatives of the two groups of conjugative plasmids which have been reported in the staphylococci. These are the plasmids which encode resistance to Gm, Km and Nm and those which code for the production of diffusible pigment. The three types of conjugative plasmids were compared by restriction endonuclease analysis and DNA- DNA hybridisation and were found to be different. A preliminary restriction map of pWBG637 has also been constructed.However since pWBG637 has no resistance phenotype direct selection for it was not possible in transfer experiments and for incompatibility (Inc.). To study it further it was necessary to construct resistant derivatives which could be selected for in transfer experiments. This was achieved by labelling pWBG637 with resistance transposons to generate two conjugative plasmids, pWBG636 carrying an insert of Tn3851 (Gm- resistance) and pWBG642 carrying an insert of Tn551 (hn- resistance). It was found that transposon labelling had not changed the incompatibility of pWBG637 and therefore pWBG636 and pWBG642 were used in further experiments in place of pWBG637. Inc. ++
tests with the pWBG637 derivatives revealed that the pWBG637 type of plasmid is not only different from the other two types of conjugative plasmids but is different from any of the described staphylococcal Inc. groups and therefore the pWBG637 type of plasmids represent a new Inc. group 15. The pWBG637 type of plasmids were studied further using plasmids pWBG636 and pWBG642. They were able to transfer conjugatively to a capsulated S.aureus strain either by the polyethylene glycol method or on filter membranes. They also transferred by conjugation to S. epidermidis and Streptococcus faecalis and were able to transfer back from these strains to S.aureus indicating that they also replicate in these hosts. Consequently they have been used to mobilise non-conjugative plasmids from S.epidermidis and non phage typable S.aureus. Both plasmids failed to transfer conjugatively to Bacillus subtilis and Escherichia coli.pWBG637 transferred non-conjugative plasmids by mobilising them in a manner similar to mobilisation (donation) in E.coli or by recombining with them to form new resistance plasmids. In one case, pWBG628 which encodes Bla and resistance to Cd, Km, Nm and Sm and has no homology with pWBG637 recombined with it during conjugation to produce three new conjugative plasmids pWBG629, pWBG630 and pWBG631 carrying resistance determinants from pWBG628. One of these plasmids, pWBG629, was found to be pWBG637 which had acquired a 4.5 kb element encoding resistance to Km, Nm and Sm. This element was shown to be transposable in both rec+ and rec- backgrounds and has been designated Tn3854. It expressed Sm resistance in E.coli and differs on this account from the Gram-negative transposon Tn5 which expresses resistance to Km, Nm and Sm in non-enteric bacteria but only resistance to Km and Nm in E. coli.Where possible the non-conjugative plasmids encoding resistance to ++
antimicrobial agents were compared with phenotypically similar plasmids isolated from other parts of the world. It was found that the Tc and Sm resistance plasmids were closely related to other plasmids with the same phenotype whereas the Cm resistance plasmids were different.Although the majority of the Bla plasmids belonged to Inc. group 1 they demonstrated significant restriction enzyme fragment length polymorphism when compared with other Bla plasmids.This study has provided the first data on the genetics of antimicrobial resistance in Nigerian S.aureus. Although many of the plasmids studied were found to be similar to those previously described the isolates also contained some unique and previously undescribed plasmids.
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Coons, Terry M. "Restriction mapping and expression of recombinant plasmids containing the arsenic resistance genes of the plasmid R45." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3597.

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The trivalent (arsenite) and pentavalent (arsenate) forms of arsenic are introduced into the environment through the use of arsenic in herbicides, pesticides, fertilizers, and the smelting of arsenic-bearing ores. Bacteria resistant to arsenic are readily isolated from surface waters, sewage, and clinical infections. Although some bacterial resistance is provided by inducible phosphate transport systems that discriminate against arsenate, marked resistance is carried on bacterial plasmids. A 6.9 kilobase fragment previously derived from one such plasmid, R45, and containing the genes for inducible resistance to arsenite and arsenate was ligated into the cloning vectors puce and pUC9 in opposite orientations and transformed into Escherichia coli JM 105. Insertion into the multiple cloning site of the pUC vectors places the inserted fragment under the inducible control of the lac operon promoter. An attempt was made to determine the direction of transcription in the fragment by growth in 10-3 M isopropyl-β-D-thiogalactoside prior to challenge with arsenite.
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Tavakoli, Norma Parvin. "Characterisation of the plasmid pUB2380 and in particular its transposition system." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386071.

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Evans, Jane E. "The conjugation system of Staphylococcus aureus." Thesis, University of Oxford, 1986. https://ora.ox.ac.uk/objects/uuid:1c1f5c11-f854-4af5-b9cf-34fdf279fb28.

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A conjugation system in Staphylococcus aureus has been investigated and shown to be determined, at least in part, by genes carried on plasmids. Conjugation required cell-to-cell contact but not calcium ions. The frequency of conjugation depended on the recipient used and on the incubation conditions. Two conjugative plasmids were mapped by restriction enzyme analysis but experiments to clone the conjugation-determining region were unsuccessful although separate regions specifying gentamicin resistance, ethidium bromide resistance and cadmium resistance were cloned. The gentamicin resistance determinant was probably part of Tn4001. Deletion of various sized pieces of DNA from one of the plasmids resulted in reduction of its ability to specify conjugation but no specific part of this plasmid could be implicated in the process. Further experiments led to the conclusion that this particular plasmid (p8325-4) is probably not self-transmissible but transferred by a phage-mediated system. Strains of Staphylococcus aureus produced a pheromone-like substance that elicited a clumping response in Streptococcus faecalis but no evidence was found for the involvement of staphylococcal conjugative plasmids in this. The conjugative plasmid, p8325-2, mobilized a small plasmid (pT181) but not a chromosomal gene. Insertion of transposon Tn551 was used to produce mutants of the conjugative plasmid p8325-2. Some twenty-six mutants were studied and the position of Tn551 in them mapped. There were preferred regions of insertion for Tn551 and twenty out of the twenty-six mutants had altered ability to conjugate. One showed a significantly higher frequency of conjugation and the other nineteen, all with substantially lower frequencies of conjugation, were mapped to two well-separated regions of the plasmid. Similarity between the locations of these putative regions and those reported for some other conjugative plasmids from staphylococci is striking and suggests a common origin.
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Eldek, Ahmed. "Antibiotic-Regulated Plasmid Copy Number Variation: A Driver of Antibiotic Resistance?" Thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388523.

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Plasmids are small circular DNA molecules within bacterial cells that are separated from the bacterial chromosome and replicate independently. Also, they play a crucial role in the dissemination of antibiotic resistance genes among bacteria through horizontal gene transfer. They can be present in many copies within host cell, which is known as plasmid copy number. Plasmids can regulate their own copy number by different mechanisms. Additionally, the selective pressure can also play a pivotal role in determining plasmid copy number. The presence of antibiotics in the surrounding environment can drive variations of plasmid copy number. In this study, we examined plasmid copy number variations of multidrug resistance plasmids in presence of antibiotics by using EvaGreen® - based multiplexed digital droplet PCR. We could observe that cultures of Klebsiella pneumoniae and Escherichia coli harboring multidrug resistance plasmids grown in presence of sub-MIC concentrations of the antibiotics did not show high variations in plasmid copy numbers. On the other hand, mutants of K. pneumoniae selected for increased antibiotic resistance showed high increases in copy number of a multidrug-resistance plasmid.
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Khan, Azra. "An investigation into the association of plasmid-borne qacAB and antimicrobial resistance in meticillin-resistant Staphylococcus aureus." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/an-investigation-into-the-association-of-plasmidborne-qacab-and-antimicrobial-resistance-in-meticillinresistant-staphylococcus-aureus(49b2b0fc-936a-412a-b418-8d9d24d3b531).html.

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Meticillin-resistant Staphylococcus aureus (MRSA) is globally recognised as a major causative organism of hospital acquired infection (HAI) and continues to present many challenges for infection prevention and control. Once established within hospitals and healthcare centers, the control of spread of MRSA and therapy is difficult due to resistance to otherwise effective antimicrobials. Government initiatives in the United Kingdom (UK) have led to considerable investments in improving infection control practices, with emphasis on improving hand hygiene compliance of healthcare professionals and hospital environmental cleanliness to control the spread and limit the source of MRSA and other HAIs. This has resulted in the subsequent increase in disinfectant and antiseptic usage containing, quaternary ammonium compounds (QACs), cationic biocides such as chlorhexidine and the bisphenol ether, triclosan, for decontamination of surfaces and disinfection of skin. Thus, there is serious concern that as with antibiotic resistance, continual and intensive exposure of MRSA (and other hospital pathogens) to biocides, may result in the emergence of resistance to these agents with further detrimental consequences and substantial burden for prevention, treatment and control of hospital infections. MRSA carry a number of plasmid-borne qac genes, predominantly qacA, qacB and smr that encode resistance to commonly used antiseptics and disinfectants in hospitals, nursing homes and other healthcare establishments. The proteins encoded by qacA and qacB mediate efflux via active transport; QacA multidrug exporter mediates resistance to monovalent, divalent cationic and lipophilic antimicrobial compounds, whilst the closely related export protein QacB mediates lower levels of resistance to divalent cations. In this research a “snapshot” study of hospital strains of MRSA stored at the Hospital Infection Research Laboratory (HIRL), City Hospital, Birmingham, was carried out to determine the prevalence and distribution of qacAB in these isolates and determine a possible association between presence of these genes and biocide resistance. The intercalating dye, ethidium bromide (EtBr) is a substrate for many S. aureus multi-drug resistant (MDR) efflux pumps and was used in the present study as a marker for detection of efflux pump activity. Previous studies have reported that MRSA strains with an MIC of ≥ 64 mg/L to EtBr have qacAB, however, the present study used a lower baseline value of ≥ 32 mg/L resistance to EtBr to capture any isolates with low MICs that may have qacAB and may be missed. Initially 3,400 MRSA strains collected between October 2002 and October 2006 were screened to identify and select isolates with ≥ 32 mg/L resistance to EtBr. A second MRSA collection stored at the Antimicrobial Chemotherapy Laboratory, City Hospital, Birmingham, comprised 63 isolates that showed MICs of ≥ 64mg/L, were also included in the study. At this stage the study set (Set A) comprised 112 isolates with varying MIC to EtBr ranging from ≥ 32 mg/L to 256 mg/L. At a later date an additional 400 strains were screened from the same stored collection to include strains with lower MICs, i.e. < 32 mg/L. Thus a total of 336 isolates with varying levels of resistance to EtBr were studied. PCR was carried out on all 336 isolates for detection o qacAB, smr, qacG, qacH and qacJ to determine the presence and prevalence of the genes. Set A isolates positive for qacAB were further investigated to differentiate between qacA and qacB. Restriction digestion using the restriction enzyme Rsa1 was carried out on PCR products followed by PCR using specific primers for detection of the two genes. Urease activity and neomycin sensitivity were used as a means of basic characterization applied to all the study isolates. A select number of samples negative for qacA and qacB were typed using spa typing. Transfer studies involving, conjugation, plate mating and transformation on selected strains were carried out to attempt transfer of qacAB using the marker EtBr from a strain of MRSA with an MIC of ≥ 256 mg/L to EtBr and qacAB positive to a strain with < 32mg/L MIC to EtBr and lacking qacAB. Unfortunately, conjugation experiments were not successful in this study. Plasmid curing experiments were also carried out to demonstrate loss of plasmid through continual passaging onto selective plates. A variety of antiseptics and disinfectants are used in hospitals for prevention of HAIs. The present study was limited to carrying out minimum bactericidal concentration (MBC) determinations and MIC of four commonly used hospital biocides against randomly selected strains. The strains reflected ranges of MICs to EtBr and presence or absence of qacAB. These experiments, determined the efficacy of the biocides tested, to effectively destroy MRSA on skin and environment when used in healthcare settings. The results suggest that in the majority of strains showing high MICs to EtBr i.e. ≥ 64 mg/L, qacAB is present and thus, the mechanism of resistance to biocides may be attributed to an efflux protein pump encoded by these genes. Following restriction digestion of qacAB positive strains, with the restriction enzyme Rsa1, 81 of the 112 qacAB positive strains tested positive for qacA, i.e. 90% and 9 (11%) for qacB. The predominant prevalence of the qacA gene indicates that most of these strains are likely to be resistant to organic cationic biocides and intercalating dyes such as EtBr and acriflavine. However, the results of the MIC and MBC determinations carried out on a selection of biocides commonly used in the healthcare environment implies that the four biocides tested are likely to be 99.9% effective at killing the majority of isolates in this study set. However, five isolates demonstrated MBCs to chlorhexidine of > 32 mg/L. Chlorhexidine is a compound that is widely used in hand hygiene and surgical antisepsis products, and the results suggest that solutions containing this compound would be ineffective in removing MRSA from the hands of healthcare workers and skin sites if used. Molecular spa typing of selected samples negative for qacAB revealed that Endemic-MRSA (EMRSA) type 15 was the most frequent spa type identified in this study, followed by EMRSA-16 and EMRSA-1. Three strains identified jointly as EMRSA-3 and EMRSA-1. One strain identified as the Berlin clone. With regards to the challenges presented to infection prevention and control, MRSA has the potential to develop increased tolerance to biocides commonly used in the hospital environment, due to expression of efflux pumps, although currently there is little evidence of this. Further research is required to understand and learn of the various mechanisms of resistance, supported by adherence to control of infection strategies for prevention and spread of infections in healthcare facilities.
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Hamilton, Michelle Ann Elizabeth. "The relationship between plasmid presence, antibiotic resistance and surface structures in Bacteroides." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/28187.

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Saial, Dolores Cristina Conceição. "Use of antimicrobials and cephamicin resistance in companion animals." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2013. http://hdl.handle.net/10400.5/6251.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Objectives: This work includes two separate studies. In study 1 the aim was to investigate the use of antimicrobials in companion animals in Portugal while in study 2 the objective was to evaluate and characterize the prevalence of blaCMY-2 gene in Enterobacteriaceae and the phylogenetic relatedness among plasmids from companion animals and humans. Materials and Methods: In study 1 in order to understand the patterns of antimicrobial prescription a national survey was submitted to veterinarians. In study 2 plasmids harboring blaCMY-2 were transferred into GeneHog® E. coli by electroporation and typed by S1 endonuclease pulsed-field gel electrophoresis, PCR-based replicon typing, and plasmid multilocus sequence typing (pMLST). Results: In study 1, the use of amoxicillin-clavulanate (28%) and enrofloxacin (18%) were the most common antimicrobials used in dogs and cats, whereas clindamycin (3%) cefovecin (2%) and pradofloxacin (2%) were the less prescribed. In study 2, twenty three blaCMY-2 genes were plasmid encoded. Replicon typing demonstrated that from animal isolates, thirteen isolates were IncFII plasmids, five isolates were IncI1 plasmid, one isolate carried an A/C plasmid and the remaining isolate was non-typeable by PBRT. Regarding human isolates, one isolate was IncFII, one was IncI1 and the third isolate was also non-typeable. IncI1 blaCMY-2 plasmids showed that three were sequence type (ST2), three were non-typeable and fourteen IncFII plasmids were F2;FIA-;FIB- by pMLST. Conclusions and Clinical Importance: This work showed that in order to understand how antimicrobials are prescribed, further studies and implementation of a surveillance system for antimicrobial usage in these species would be recommended. Plasmid encoded resistant genes are an important factor for selection and dissemination of genes such as blaCMY-2. The transmission of resistant genes in humans and animals is due to plasmid encoding which is of great concern, and further research is still necessary to understand about the mechanisms which have led to the rapid spread of resistant bacteria worldwide.
RESUMO - USO DE ANTIMICROBIANOS E RESISTÊNCIA ÀS CEFAMICINAS EM ANIMAIS DE COMPANHIA - Objetivos: Este trabalho inclui 2 estudos. O objetivo do primeiro estudo consistiu em investigar o uso de antimicrobianos em animais de companhia em Portugal enquanto no segundo estudo, o objetivo consistiu na análise e caraterização da prevalência do gene blaCMY-2 em Enterobacteriaceas, ao mesmo tempo que pretendeu determinar a semelhança filogenética dos respetivos plasmídeos, em animais e humanos. Materiais e Métodos: No estudo 1, para compreender os hábitos de prescrição de antimicrobianos em Portugal foi realizado um inquérito nacional aos Veterinários. No estudo 2, os plasmídeos com o gene blaCMY-2 foram transferidos para uma célula electrocompetente GeneHog® E. coli por electroporação, e caraterizados por S1 endonuclease pulsed-field gel electrophoresis, PCR-based replicon typing e plasmid multilocus sequence typing (pMLST). Resultados: No estudo 1, os antimicrobianos mais utilizados em cães e gatos foram a amoxicilina/acido clavulânico (28%) e enrofloxacina (18%). Clindamicina (3%), cefovecina (2%) e pradofloxacina (2%) foram os menos utilizados em ambas as espécies. No estudo 2, vinte e três genes blaCMY-2 estavam codificados em plasmídeos. De acordo com o método replicon typing, os isolados de origem animal, treze pertenciam ao plasmídeo IncFII, cinco estavam codificados no plasmídeo IncI1, um estava presente no plasmídeo A/C e um isolado foi considerado “non-typeable”. Dos 3 isolados humanos, 1 estava incorporado num plasmídeo IncI1, 1 estava inserido no plasmídeo IncFII e o terceiro foi considerado “non-typeable”. Pelo método pMLST, os plasmídeos IncI1 foram caraterizados como ST2, e três foram considerados “non-typeable”. Catorze plasmídeos IncFII foram caraterizados como sendo F2;FIA-;FIB-. Conclusões e Importância Clínica: Para compreender os hábitos de prescrição de antimicrobianos, seriam recomendáveis estudos complementares e a implementação de um sistema de monitorização para o consumo de antimicrobianos nestas espécies. A presença de genes de resistência em plasmídeos é um fator importante para a seleção e disseminação de genes como o gene blaCMY-2. A transmissão destes genes em humanos e animais é mediada por plasmídeos, o que é preocupante. Investigação contínua é pois necessária para entender quais os principais mecanismos que conduziram à disseminação de bactérias com genes de resistência no mundo.
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Risley, Claire. "The population dynamics of plasmid-mediated antibiotic resistance in salmonella typhimurium in chickens." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:a70bda98-533f-41d0-b9a0-630457b3f982.

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A model of growth and plasmid transfer between strains of Escherichia coli and Salmonella typhimurium was developed with reference to the literature. This was the organising principle for the collection of a complete set of in vitro life history parameters of one S. typhimurium and one E. coli strain. In the course of estimating these parameters two results of note were obtained. Fits of the Lotka-Volterra competition model were obtained for data on S. typhimuiurm growing in competition with E. coli. The first noteworthy discovery was the failure of this model to account for several characteristics of growth of these strains under competition. The growth rates of plasmid-bearing and plasmid-free strains were obtained. The second main result came from examination of the results of the growth rate data, which revealed that the cost to S. typhimuiurm 576 of bearing the resistance plasmid was low (4%). The model was also used to simulate the effect of antibiotic dose on the density of the donor, recipient and transconjugant populations over time. These simulations predicted that there would be a convex relationship between antibiotic dose and transconjugant density (i.e. that the density would first rise, then fall, with increasing dose). Following from this result, laboratory experiments and in vivo experiments in chickens were directed towards obtaining information on the relationship between these two variables. This convex relationship was not demonstrated within a single experiment, although some experimental environments produced an increase in transconjugant density with dose, and others, a decrease. Few transconjugants were formed in vivo. In order to investigate the low cost of resistance and low rate of in vivo transconjugant production, cost of resistance and plasmid transfer rate of this plasmid in several strain combinations of E. coli and S. typhimuiurm was evaluated.
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Books on the topic "Plasmid and resistance"

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Barrett, Siobhán. Studies on plasmid-mediated copper resistance in Escherichia coli. Birmingham: Universityof Birmingham, 1994.

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Laroussi, M. Plasma medicine: Applications of low-temperature gas plasmas in medicine and biology. Cambridge: Cambridge University Press, 2012.

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Foley, Ian Michael. Population dynamics in enterococcal biofilms: Resistance plasmids and antibiotic susceptibility. Manchester: University of Manchester, 1996.

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Goel, Subhash C. Performance-based plastic design: Earthquake-resistant steel structures. Country Club Hills, IL: International Code Council, 2008.

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Goel, Subhash C. Performance-based plastic design: Earthquake-resistant steel structures. Country Club Hills, IL: International Code Council, 2008.

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Shih-Ho, Chao, and National Council of Structural Engineers Associations., eds. Performance-based plastic design: Earthquake-resistant steel structures. Country Club Hills, IL: International Code Council, 2008.

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Mallinson, John H. Corrosion-resistant plastic composites in chemical plant design. New York: M. Dekker, 1988.

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Goel, Subhash C. Performance-based plastic design: Earthquake-resistant steel structures. Country Club Hills, IL: International Code Council, 2008.

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Goel, Subhash C. Performance-based plastic design: Earthquake-resistant steel structures. Country Club Hills, IL: International Code Council, 2008.

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Hibberd, Guy G. A. The effect of plasma nitriding on the corrosion resistance of titanium. Birmingham: University of Birmingham, 1991.

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Book chapters on the topic "Plasmid and resistance"

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Taylor, Diane E., Amera Gibreel, Trevor D. Lawley, and Dobryan M. Tracz. "Antibiotic Resistance Plasmids." In Plasmid Biology, 473–91. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555817732.ch23.

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Gooch, Jan W. "Resistance (R) Plasmid." In Encyclopedic Dictionary of Polymers, 920. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_14681.

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Jacoby, George A., Jacob Strahilevitz, and David C. Hooper. "Plasmid-Mediated Quinolone Resistance." In Plasmids, 475–503. Washington, DC, USA: ASM Press, 2015. http://dx.doi.org/10.1128/9781555818982.ch25.

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Jacoby, George A. "Plasmid-Mediated Quinolone Resistance." In Antimicrobial Drug Resistance, 265–68. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-46718-4_17.

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Jacoby, George A. "Plasmid-Mediated Quinolone Resistance." In Antimicrobial Drug Resistance, 207–10. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-59745-180-2_17.

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Kelly, Michael D., and Joel E. Mortensen. "A Low-Copy Number Plasmid Mediating β-Lactamase Production by Xanthomonas Maltophilia." In Antimicrobial Resistance, 71–80. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4757-9203-4_6.

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Schwarz, Stefan, Jianzhong Shen, Sarah Wendlandt, Andrea T. Feßler, Yang Wang, Kristina Kadlec, and Cong-Ming Wu. "Plasmid-Mediated Antimicrobial Resistance in Staphylococci and Other Firmicutes." In Plasmids, 421–44. Washington, DC, USA: ASM Press, 2015. http://dx.doi.org/10.1128/9781555818982.ch22.

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Jacoby, George A. "Study of Plasmid-Mediated Quinolone Resistance in Bacteria." In Methods in Molecular Biology, 317–25. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7459-7_22.

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Cullen, D. W., I. M. Packer, and D. J. Platt. "Plasmid Mediated Resistance to Hexavalent Chromium in Agrobacterium." In The Release of Genetically Modified Microorganisms—REGEM 2, 237–40. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4613-0493-7_47.

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Li, Xian-Zhi, and Manisha Mehrotra. "Role of Plasmid-Encoded Drug Efflux Pumps in Antimicrobial Resistance." In Efflux-Mediated Antimicrobial Resistance in Bacteria, 595–623. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-39658-3_23.

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Conference papers on the topic "Plasmid and resistance"

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Omer, Lawin, Zirak Abdulrahman, and Rastee Saeed. "Curing analysis of Drug Resistance Plasmid in Proteus mirabilis." In 4th International Scientific Conference of Cihan University-Erbil on Biological Sciences. Cihan University-Erbil, 2017. http://dx.doi.org/10.24086/bios17.05.

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Dheyab, Ali. "Cloning Antibiotic Resistance Plasmid of Staph .aureus Isolated From Clinical Sample." In المؤتمر العلمي الدولي التاسع - "الاتجاهات المعاصرة في العلوم الاجتماعية، الانسانية، والطبيعية". شبكة المؤتمرات العربية, 2018. http://dx.doi.org/10.24897/acn.64.68.145.

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Sauer, S., U. Pudich, B. Bernd Gericke, Rita Prager, A. Fruth, E. Brockhaus, H. Tschäpe, and W. Rabsch. "An outbreak caused by S. Typhimurium DT177, BTa in Bavaria characterized by an unusual antibiotic resistance and plasmid profile." In Fourth International Symposium on the Epidemiology and Control of Salmonella and Other Food Borne Pathogens in Pork. Iowa State University, Digital Press, 2001. http://dx.doi.org/10.31274/safepork-180809-1136.

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Ding, Z., R. Knight, and R. W. Smith. "Abrasive Wear Characteristics of Ni-base Self-fluxing Alloy Spraywelding Overlays." In ITSC 1997, edited by C. C. Berndt. ASM International, 1997. http://dx.doi.org/10.31399/asm.cp.itsc1997p0091.

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Abstract The results of low stress, pin-on-disc and high stress grinding abrasive wear tests on coatings produced by plasma and oxy-acetylene flame spraywelding are presented. FNil5A and FNiWC35 Ni-based self-fluxing alloys were selected as typical spraywelding materials for abrasive wear resistance. The abrasive wear resistance mechanisms of welded overlays produced by various materials and processes were also characterized by hardness tests, microstructural and compositional analyses, and through analysis of the effect of different kinds of abrasive on the wear resistant of Ni-base self-fluxing spraywelding overlays. Results showed that FNiWC35 overlays exhibited improved resistance under low stress abrasion, but the relative wear resistances of FNiWC35 and FNil5A still depended primarily on the type and hardness of the abrasive medium used. For the same material, the abrasive wear resistance of oxyacetylene flame sprayed overlays was higher than that produced by plasma spraywelding. The wear resistance of the plasma spraywelding overlays depended not only on the material, but also strongly on the spraywelding process parameters.
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Alexeff, Igor, Stephen A. Kania, Randall J. Kania, and David A. Bemis. "Methicillin resistant staphyloccus pseudintermedius do not develop resistance to atmospheric pressure cold plasma discharges." In 2011 IEEE 38th International Conference on Plasma Sciences (ICOPS). IEEE, 2011. http://dx.doi.org/10.1109/plasma.2011.5993043.

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Hollis, K. J., D. P. Butt, and R. G. Castro. "Impression Creep Behavior of Atmospheric Plasma-Sprayed and Hot Pressed MoSi2/Si3N4." In ITSC 1997, edited by C. C. Berndt. ASM International, 1997. http://dx.doi.org/10.31399/asm.cp.itsc1997p0751.

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Abstract The use of MoSi2 as a high temperature oxidation resistant structural material is hindered by its poor elevated temperature creep resistance. The addition of second phase Si3N4 holds promise for improving the creep properties of MoSi2 without decreasing oxidation resistance. The high temperature impression creep behavior of atmospheric plasma sprayed (APS) and hot pressed (HP) MoSi2/Si3N4 composites was investigated. Values for steady state creep rates, creep activation energies, and creep stress exponents were measured. Grain boundary sliding and splat sliding were found to be the dominant creep mechanisms for the APS samples while grain boundary sliding and plastic deformation were found to be the dominant creep mechanisms for the HP samples.
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Ryntz, Rose A., Brad D. Abell, and Felicia Hermosillo. "Scratch Resistance of Automotive Plastic Coatings." In International Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1998. http://dx.doi.org/10.4271/980973.

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Khor, K. A., Y. W. Gu, and Z. L. Dong. "Properties of Plasma Sprayed Functionally Graded YSZ/NiCoCrAlY Composite Coatings." In ITSC 2000, edited by Christopher C. Berndt. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.itsc2000p1241.

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Abstract Plasma sprayed thermal barrier coatings often face the problems of spallation and cracking in service owing to their poor bond strength and high residual stresses. Functionally graded thermal barrier coatings with a gradual compositional variation from heat resistant ceramics to fracture resistant metals are proposed to mitigate these problems. In this paper, functionally graded Y2O3 stabilized ZrO2 (YSZ) / NiCoCrAlY composite coatings were prepared using pre-alloyed and spheroidized composite powders. The mechanical and thermal properties of graded YSZ/NiCoCrAlY composite coatings, such as elastic modulus, bond strength, coefficient of thermal expansion, thermal cycling and oxidation resistance were investigated. Results showed that the bond strength and thermal cycling resistance of FGM coatings were much better than that of the duplex coatings. The coefficient of thermal expansion and elastic modulus changed gradually through the 5-layer functionally graded coating.
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Kumpulainen, E., M. Vippola, P. Vuoristo, P. Sorsa, and T. Mäntylä. "Characteristics of Phosphoric Acid Sealed Ceramic Oxide Coatings." In ITSC 1996, edited by C. C. Berndt. ASM International, 1996. http://dx.doi.org/10.31399/asm.cp.itsc1996p0489.

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Abstract Plasma sprayed ceramic coatings usually have relatively high open porosity in order to provide a good corrosion protection. By using sealants the porosity values can be reduced. In this study atmospheric plasma sprayed (APS) aluminium oxide, chromium oxide and zirconium oxide coatings were sealed by a phosphoric acid treatment. After impregnation the coatings were heat treated at a curing temperature of 400°C. Phosphoric acid was found to react with the coating material during the heat treatment. Wear resistance was evaluated by rubber wheel abrasion tests and corrosion resistance by electrochemical potentio-dynamic polarization tests. Hardness values were also measured. Corrosion resistance and hardness values of sealed coatings were remarkable better in comparison to the unsealed coatings. Rubber wheel abrasion resistances of the sealed coatings were equal to those of Al2O3, ZTA, SiC and Si3N4 sintered ceramics.
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Warne, L. K., J. M. Lehr, and R. E. Jorgensen. "Resistance of a water switch." In The 33rd IEEE International Conference on Plasma Science, 2006. ICOPS 2006. IEEE Conference Record - Abstracts. IEEE, 2006. http://dx.doi.org/10.1109/plasma.2006.1707042.

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Reports on the topic "Plasmid and resistance"

1

Trezona, Thomas. Plasmid-mediated resistance to arsenite and arsenate in Escherichia coli. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.3125.

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Coons, Terry. Restriction mapping and expression of recombinant plasmids containing the arsenic resistance genes of the plasmid R45. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.5481.

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Saadeh, Shadi, and Pritam Katawał. Performance Testing of Hot Mix Asphalt Modified with Recycled Waste Plastic. Mineta Transportation Institute, July 2021. http://dx.doi.org/10.31979/mti.2021.2045.

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Plastic pollution has become one of the major concerns in the world. Plastic waste is not biodegradable, which makes it difficult to manage waste plastic pollution. Recycling and reusing waste plastic is an effective way to manage plastic pollution. Because of the huge quantity of waste plastic released into the world, industries requiring a large amount of material, like the pavement industry, can reuse some of this mammoth volume of waste plastics. Similarly, the use of reclaimed asphalt pavement (RAP) has also become common practice to ensure sustainability. The use of recycled waste plastics and RAP in HMA mix can save material costs and conserve many pavement industries’ resources. To successfully modify HMA with RAP and waste plastic, the modified HMA should exhibit similar or better performance compared to conventional HMA. In this study, recycled waste plastic, linear low-density polyethylene (LLDPE), and RAP were added to conventional HMA, separately and together. The mechanical properties of conventional and modified HMA were examined and compared. The fatigue cracking resistance was measured with the IDEAL Cracking (IDEAL CT) test, and the Hamburg Wheel Tracking (HWT) test was conducted to investigate the rutting resistance of compacted HMA samples. The IDEAL CT test results showed that the cracking resistance was similar across plastic modified HMA and conventional HMA containing virgin aggregates. However, when 20% RAP aggregates were used in the HMA mix, the fatigue cracking resistance was found to be significantly lower in plastic modified HMA compared to conventional HMA. The rutting resistance from the HWT test at 20,000 passes was found to be similar in all conventional and modified HMA.
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Top, Eva M., and Ben Ridenhour. Persistence of Antibiotic Resistance Plasmids in Biofilms. Fort Belvoir, VA: Defense Technical Information Center, October 2014. http://dx.doi.org/10.21236/ada614277.

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Top, Eva M., and Silvia E. Smith. Persistence of Antibiotic Resistance Plasmids in Biofilms. Fort Belvoir, VA: Defense Technical Information Center, October 2013. http://dx.doi.org/10.21236/ada615372.

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Hutchinson, M. L., J. E. L. Corry, and R. H. Madden. A review of the impact of food processing on antimicrobial-resistant bacteria in secondary processed meats and meat products. Food Standards Agency, October 2020. http://dx.doi.org/10.46756/sci.fsa.bxn990.

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For meat and meat products, secondary processes are those that relate to the downstream of the primary chilling of carcasses. Secondary processes include maturation chilling, deboning, portioning, mincing and other operations such as thermal processing (cooking) that create fresh meat, meat preparations and ready-to-eat meat products. This review systematically identified and summarised information relating to antimicrobial resistance (AMR) during the manufacture of secondary processed meatand meat products (SPMMP). Systematic searching of eight literature databases was undertaken and the resultantpapers were appraised for relevance to AMR and SPMMP. Consideration was made that the appraisal scores, undertaken by different reviewers, were consistent. Appraisal reduced the 11,000 initially identified documents to 74, which indicated that literature relating to AMR and SPMMP was not plentiful. A wide range of laboratory methods and breakpoint values (i.e. the concentration of antimicrobial used to assess sensitivity, tolerance or resistance) were used for the isolation of AMR bacteria.The identified papers provided evidence that AMR bacteria could be routinely isolated from SPMMP. There was no evidence that either confirmed or refuted that genetic materials capable of increasing AMR in non-AMR bacteria were present unprotected (i.e. outside of a cell or a capsid) in SPMMP. Statistical analyses were not straightforward because different authors used different laboratory methodologies.However, analyses using antibiotic organised into broadly-related groups indicated that Enterobacteriaceaeresistant to third generation cephalosporins might be an area of upcoming concern in SPMMP. The effective treatment of patients infected with Enterobacteriaceaeresistant to cephalosporins are a known clinical issue. No AMR associations with geography were observed and most of the publications identified tended to be from Europe and the far east.AMR Listeria monocytogenes and lactic acid bacteria could be tolerant to cleaning and disinfection in secondary processing environments. The basis of the tolerance could be genetic (e.g. efflux pumps) or environmental (e.g. biofilm growth). Persistent, plant resident, AMR L. monocytogenes were shown by one study to be the source of final product contamination. 4 AMR genes can be present in bacterial cultures used for the manufacture of fermented SPMMP. Furthermore, there was broad evidence that AMR loci could be transferred during meat fermentation, with refrigeration temperatures curtailing transfer rates. Given the potential for AMR transfer, it may be prudent to advise food business operators (FBOs) to use fermentation starter cultures that are AMR-free or not contained within easily mobilisable genetic elements. Thermal processing was seen to be the only secondary processing stage that served as a critical control point for numbers of AMR bacteria. There were significant linkages between some AMR genes in Salmonella. Quaternary ammonium compound (QAC) resistance genes were associated with copper, tetracycline and sulphonamide resistance by virtue of co-location on the same plasmid. No evidence was found that either supported or refuted that there was any association between AMR genes and genes that encoded an altered stress response or enhanced the survival of AMR bacteria exposed to harmful environmental conditions.
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7

Almoumen, Rawan. Undrained Cyclic Shear Resistance of Low Plastic Silts. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.7512.

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8

Sanders, John, and Grant Davidson. Wet Slip Resistance of Plastic Based Material Flooring (PBM Flooring). Clemson University, December 2019. http://dx.doi.org/10.34068/report.01.

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9

Clark, Joshua. Determination of homology between the arsenic resistance plasmids R45 and R773 in Escherichia coli. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.5644.

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10

Rangineni, Jyothi, and Jeremy Tzeng. Comparison Study of Mold Growth Resistance of Plastic Based Material Flooring (PBM Flooring) and Ceramic Tile Flooring. Clemson University, December 2019. http://dx.doi.org/10.34068/report2.

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