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Academic literature on the topic 'Microdilution checkerboard titration procedure'
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Journal articles on the topic "Microdilution checkerboard titration procedure"
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Dr., Muhammad Irfan Sharif Dr. Hammood ur Rehman Dr. Muhammad Danish. "A VIRTUAL INVESTIGATIONAL RESEARCH TO REGULATE THE ISSUES OF CURE DISAPPOINTMENT IN TYPHOID THROUGH ACTION AND NEW COMBINATION OF AQUEOUS GARLIC CUTTING AND CIPROFLOXACIN." INDO AMERICAN JOURNAL OF PHARMACEUTICAL SCIENCES 05, no. 11 (2018): 12700–12707. https://doi.org/10.5281/zenodo.1492765.
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<strong><em>Objective: </em></strong><em>To regulate developing a problem of cure disappointment in typhoid by assessing the action of the novel mixture of aqueous garlic cutting and ciprofloxacin. </em> <strong><em>Methodology:</em></strong><em> </em><em>This virtual investigational research was led in Services Hospital Lahore (November 2016 to August 2017). Synergism of garlic having ciprofloxacin in contrast to Typhi remained measured to resolve the serious matter of cure letdown having greatest identified anti-typhoid medicines till nowadays i-e fluoroquinolones. Twenty-six ciprofloxacin vulnerable Tyophi separates remained nominated. Aqueous garlic excerpt was set and remained separated for antiseptic action by agar healthy dispersal technique that showed a reserve region of 26.37±2.62 mm in contradiction of 1 verified separately. </em> <strong><em>Results: </em></strong><em>Least Inhibitory absorption 90 of ciprofloxacin and AGE was > 0.26μg/ml and > 21mg/ml correspondingly by way of strongminded through micro soup watering technique. Pseudomonas aerugeinosa (ATCC 27854) remained used in place of orientation training. Synergism of mixture remained measured by means of microdilution checkerboard titration method. Slight inhibitory attentiveness directory for altogether separates remained >0.6 <5. </em> <strong><em>Conclusion: </em></strong><em>Therefore, ciprofloxacin and Aqueous garlic excerpt (AGE) presented noteworthy antiseptic action independently in the inconsistency of Typhi nevertheless Cipro-AGE grouping did not demonstrate to be synergistic in contradiction of Tyophi or contrary to ATCC Pseudomonas aeruoginosa 27854. </em> <strong>Keywords:</strong><strong><em> </em></strong><em>Aqueous</em><em> garlic excerpt, Microdilution checkerboard titration procedure, Slight inhibitory attentiveness directory. </em>
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Ángyán, Virág D., Viktória L. Balázs, Marianna Kocsis, et al. "Synergistic Antibiofilm Effects of Chestnut and Linden Honey with Lavender Essential Oil Against Multidrug-Resistant Otitis Media Pathogens." Antibiotics 14, no. 2 (2025): 146. https://doi.org/10.3390/antibiotics14020146.
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Background/Objectives: Bacterial resistance to antibiotics is a major problem in healthcare, complicated by the ability of bacteria to form biofilms. Complementary therapy for infectious diseases can rely on natural substances with antibacterial activity, e.g., essential oils and honeys. The aim of the study was to investigate the effects of linden and chestnut honeys, lavender essential oil, and their combinations against the multidrug-resistant otitis media pathogens Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. The efficacy of these natural substances was compared with each other and antibiotics used in clinical practice. Methods: Microscopic pollen analysis and physicochemical traits were used to confirm the botanical origin of honey samples. The antibiotic sensitivity of bacteria was tested with a disk diffusion assay. Minimum inhibitory concentrations were determined using a microdilution assay. A 24 h immature biofilm eradication test was performed with a crystal violet assay. The efficacy of combinations was tested with a checkerboard titration method. The DNA release of damaged bacterial cells was measured using a membrane degradation assay. Results: Lavender essential oil displayed more potent antibacterial activity compared to the honey samples. However, honey–essential oil combinations showed higher inhibition rates for biofilm eradication, with P. aeruginosa being the most resistant bacterium. The combined use of chestnut honey and lavender oil resulted in a higher degree of membrane degradation in a shorter time, and their synergistic effect was proven with checkerboard titration. Conclusions: The combination of linden or chestnut honey with lavender essential oil was shown to be effective in the eradication of a 24 h immature biofilm formed by H. parainfluenzae, M. catarrhalis, and S. pneumoniae.
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Ijaz, Saadia, Farheen Ansari, Muhammad Nawaz, et al. "Genomic Insights into and In Vitro Evaluation of Antimicrobial Combination Therapies for Carbapenem-Resistant Acinetobacter baumannii." Medicina 60, no. 7 (2024): 1086. http://dx.doi.org/10.3390/medicina60071086.
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Background and Objectives: Acinetobacter baumannii (A. baumannii), particularly carbapenem-resistant A. baumannii (CRAB), represents a grave concern in healthcare settings and is associated with high mortality. This study aimed to conduct molecular, mutational, and phylogenetic analyses of specific genes in CRAB and evaluate the synergistic effects of selected antimicrobial combinations. Materials and Methods: Phenotypic characterization was performed on six CRAB strains by using the Modified Hodge Test (MHT) and IMP-EDTA Double-Disc Synergy Test (IMP-EDTA DDST). Carbapenemase- and metallo-beta-lactamase-encoding genes were amplified by using Polymerase Chain Reaction. Phylogenetic analysis using the MEGA 11 tool was used to determine the evolutionary relatedness of these genes. Mutational analysis was performed by using I-Mutant, MUPro, and PHD-SNP bioinformatics tools to predict mutations in the carbapenemase-encoding genes. Microdilution checkerboard titration assessed the synergistic effects of antimicrobial combinations (azithromycin–meropenem, rifampicin–meropenem, meropenem–colistin, and azithromycin–colistin) on these CRAB isolates. Results: The phenotypic characterization of six CRAB isolates revealed positive results for MHT and IMP-EDTA DDST. The molecular characterization revealed that carbapenemase- and MBL-encoding genes were present in all isolates with varying frequencies, including blaOXA-51 (100%) and blaIMP (0%). The sequence analysis revealed high evolutionary relatedness to sequences in the NCBI database. The mutational analysis identified 16 mutations, of which 1 mutation (P116L) in the blaOXA-58 gene predicted a change in the protein product, potentially contributing to carbapenem resistance. The checkerboard titration method did not reveal any synergism among the tested antimicrobial combinations against CRAB. Conclusion: This study’s findings underscore the significant challenges posed by CRAB isolates harboring multiple resistant genes in treatment. This highlights the urgent need for novel antimicrobial agents, a crucial step towards reducing mortality rates not only in Pakistan but also globally.
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Krychowiak-Maśnicka, Marta, Mirosława Krauze-Baranowska, Sylwia Godlewska, et al. "Potential of Silver Nanoparticles in Overcoming the Intrinsic Resistance of Pseudomonas aeruginosa to Secondary Metabolites from Carnivorous Plants." International Journal of Molecular Sciences 22, no. 9 (2021): 4849. http://dx.doi.org/10.3390/ijms22094849.
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Carnivorous plants are exemplary natural sources of secondary metabolites with biological activity. However, the therapeutic antimicrobial potential of these compounds is limited due to intrinsic resistance of selected bacterial pathogens, among which Pseudomonas aeruginosa represents an extreme example. The objective of the study was to overcome the intrinsic resistance of P. aeruginosa by combining silver nanoparticles (AgNPs) with secondary metabolites from selected carnivorous plant species. We employed the broth microdilution method, the checkerboard titration technique and comprehensive phytochemical analyses to define interactions between nanoparticles and active compounds from carnivorous plants. It has been confirmed that P. aeruginosa is resistant to a broad range of secondary metabolites from carnivorous plants, i.e., naphthoquinones, flavonoids, phenolic acids (MBC = 512 µg mL−1) and only weakly sensitive to their mixtures, i.e., extracts and extracts’ fractions. However, it was shown that the antimicrobial activity of extracts and fractions with a significant level of naphthoquinone (plumbagin) was significantly enhanced by AgNPs. Our studies clearly demonstrated a crucial role of naphthoquinones in AgNPs and extract interaction, as well as depicted the potential of AgNPs to restore the bactericidal activity of naphthoquinones towards P. aeruginosa. Our findings indicate the significant potential of nanoparticles to modulate the activity of selected secondary metabolites and revisit their antimicrobial potential towards human pathogenic bacteria.
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Szerencsés, Bettina, Mónika Vörös, Kristóf Bagi, et al. "Semi-Synthetic Ecdysteroid 6-Oxime Derivatives of 20-Hydroxyecdysone Possess Anti-Cryptococcal Activity." Microbiology Research 13, no. 4 (2022): 985–94. http://dx.doi.org/10.3390/microbiolres13040071.
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Cryptococcosis, a life-threatening fungal infection, frequently occurs in patients suffering from AIDS. The treatment of the disease is hampered by the limited number of the effective drugs and the increasing resistance; therefore, to find new active substances is needed. As meningitis is the most serious infection affecting the AIDS patients, effective drugs have to be capable of entering to the central nervous system. Ecdysteroids are natural bioactive molecules with considerable anabolic activity and without toxic side effects on humans. The aim of this work was to study the anti-cryptococcal activity of a natural ecdysteroid, 20E, and its three semi-synthetic derivatives obtained by structural modification of the original molecule. We established the minimum inhibitory concentration of the compounds with microdilution method and demonstrated their fungicidal activity by flow cytometry and cultivation of the drug-treated cells. The interaction of the compounds with each other and efflux transporter inhibitors was assessed by checkerboard titration method. Two derivatives, 20E-EOx and 20E-ZOx, inhibited the growth of Cryptococcus neoformans with minimum inhibitory concentration 2 mg/mL and 1 mg/mL, respectively; both compounds possess fungicidal effect. A combination of the ecdysteroids with each other and verapamil resulted in additive interaction. This study confirmed that structural modification of an originally non-antimicrobial molecule can enhance its effectiveness.
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Badawy, Mona Shaban E. M., Omnia Karem M. Riad, Marwa F. Harras, Reem Binsuwaidan, Asmaa Saleh, and Samar A. Zaki. "Chitosan–Aspirin Combination Inhibits Quorum-Sensing Synthases (lasI and rhlI) in Pseudomonas aeruginosa." Life 14, no. 4 (2024): 481. http://dx.doi.org/10.3390/life14040481.
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Background: Quorum sensing (QS) controls the virulence of P. aeruginosa. This study aims to determine the anti-QS activity of aspirin alone and in combination with chitosan to reach maximum inhibition. We tested ten virulent Pseudomonas aeruginosa (P. aeruginosa) isolates and screened for N-acyl homoserine lactone (AHL) production using Agrobacterium tumefaciens as a biosensor. P. aeruginosa isolates were treated with sub-minimum inhibitory concentrations (MICs) of aspirin and chitosan–aspirin. We used broth microdilution and checkerboard titration methods to determine the MICs and the synergistic effect of these two compounds, respectively. Real-time polymerase chain reaction (PCR) was used to estimate the anti-QS activity of the aspirin–chitosan combination on the expression of lasI and rhlI genes. Results: Aspirin decreased the motility and production of AHLs, pyocyanin, and biofilm. Chitosan potentiated the inhibitory effect of aspirin. The chitosan–aspirin combination inhibited lasI and rhlI gene expression in PAO1 (ATCC 15692) by 7.12- and 0.92-fold, respectively. In clinical isolates, the expression of lasI and rhlI was decreased by 1.76 × 102- and 1.63 × 104-fold, respectively. Molecular docking analysis revealed that aspirin could fit into the active sites of the QS synthases lasI and rhlI with a high binding affinity, causing conformational changes that resulted in their inhibition. Conclusions: The chitosan–aspirin combination provides new insights into treating virulent and resistant P. aeruginosa.
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Marques, M. B., E. S. Brookings, S. A. Moser, P. B. Sonke, and K. B. Waites. "Comparative in vitro antimicrobial susceptibilities of nosocomial isolates of Acinetobacter baumannii and synergistic activities of nine antimicrobial combinations." Antimicrobial Agents and Chemotherapy 41, no. 5 (1997): 881–85. http://dx.doi.org/10.1128/aac.41.5.881.
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The in vitro susceptibilities of 69 nosocomial Acinetobacter isolates were determined by the broth microdilution method. Fourteen (20%) isolates were resistant to at least two aminoglycosides and two extended-spectrum penicillins. Nine antimicrobial combinations were then tested for synergy against these 14 isolates by checkerboard titration: imipenem with ciprofloxacin, amikacin, and tobramycin and ampicillin-sulbactam, piperacillin-tazobactam, and ticarcillin-clavulanate with amikacin and tobramycin. Synergy was detected with one or more antimicrobial combinations against 9 of 14 (64%) isolates, partial synergy was detected with one or more combinations against all 14 isolates, and an additive effect alone was observed with two different combinations against two isolates. No antagonism was detected with any combination. Imipenem plus either amikacin or tobramycin resulted in a synergistic or partial synergistic response against all 14 isolates. Specific combinations showing synergy against A. baumannii isolates were imipenem with tobramycin (four isolates), imipenem with amikacin (three isolates), ampicillin-sulbactam with tobramycin (six isolates), ampicillin-sulbactam with amikacin (three isolates), and ticarcillin-clavulanate with tobramycin (one isolate). Genotyping by randomly amplified polymorphic DNA analysis showed that 9 of the 14 isolates were of one strain, 4 isolates were of a second strain, and the remaining isolate was of a different strain. Eight of 14 (57%) patients infected with resistant A. baumannii isolates died. Only 3 of 14 patients had received a therapeutic regimen which was tested for synergy. Clinical studies are needed to determine the significance of these findings.
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Pietschmann, Jan, Holger Spiegel, Hans-Joachim Krause, Stefan Schillberg, and Florian Schröper. "Sensitive Aflatoxin B1 Detection Using Nanoparticle-Based Competitive Magnetic Immunodetection." Toxins 12, no. 5 (2020): 337. http://dx.doi.org/10.3390/toxins12050337.
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Food and crop contaminations with mycotoxins are a severe health risk for consumers and cause high economic losses worldwide. Currently, different chromatographic- and immuno-based methods are used to detect mycotoxins within different sample matrices. There is a need for novel, highly sensitive detection technologies that avoid time-consuming procedures and expensive laboratory equipment but still provide sufficient sensitivity to achieve the mandated detection limit for mycotoxin content. Here we describe a novel, highly sensitive, and portable aflatoxin B1 detection approach using competitive magnetic immunodetection (cMID). As a reference method, a competitive ELISA optimized by checkerboard titration was established. For the novel cMID procedure, immunofiltration columns, coated with aflatoxin B1-BSA conjugate were used for competitive enrichment of biotinylated aflatoxin B1-specific antibodies. Subsequently, magnetic particles functionalized with streptavidin can be applied to magnetically label retained antibodies. By means of frequency mixing technology, particles were detected and quantified corresponding to the aflatoxin content in the sample. After the optimization of assay conditions, we successfully demonstrated the new competitive magnetic detection approach with a comparable detection limit of 1.1 ng aflatoxin B1 per mL sample to the cELISA reference method. Our results indicate that the cMID is a promising method reducing the risks of processing contaminated commodities.
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Adeniji, Oluwaseun Ola, Nolonwabo Nontongana, and Anthony Ifeanyin Okoh. "Prevalence of Class 1 Integron and In Vitro Effect of Antibiotic Combinations of Multidrug-Resistant Enterococcus Species Recovered from the Aquatic Environment in the Eastern Cape Province, South Africa." International Journal of Molecular Sciences 24, no. 3 (2023): 2993. http://dx.doi.org/10.3390/ijms24032993.
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Enterococci are regarded as a better indication of faecal pollution in freshwater and marine waters. Their levels in seawater are positively connected with swimming-related gastrointestinal disorders. This study used an Enterococcus-specific polymerase chain reaction (PCR) to characterize the isolates. Classes 1 and 2 integrons were examined for environmental Enterococcus isolates using a standard biological procedure. All strains were assessed against a panel of 12 antibiotics from various classes using disc diffusion methods. The microdilution method was used to work out the minimum inhibitory concentration (MIC) according to the CLSI guiding principles. The combination therapy of the resistant drugs was evaluated using a checkerboard assay and a time-dependent test for assessing their bactericidal or bacteriostatic activity. The gene diversity of the tested organisms was analyzed with the aid of Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR. In total, 57 Enterococcus spp. environmental samples were recovered, in which Enterococcus faecalis (33.33%) and Enterococcus faecium (59.65%) were the dominant species. Resistance to linezolid, ciprofloxacin, erythromycin, gentamicin, vancomycin, rifampicin, and tetracycline was prevalent. Fifty (50) strains tested positive for class 1 integron, more frequent in Enterococcus faecium and Enterococcus faecalis isolates, with no gene cassette array discovered. A combination of gentamicin (MIC 4 µg/mL) with vancomycin (MIC 256 µg/mL) antibiotics against Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin (1 µg/mL) with Ampicillin (16 µg/mL) antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The ERIC-PCR analysis pointed out that most of the assessed isolates have close genetic similarities.
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Deepachandi, Bhagya, Sudath Weerasinghe, Himali Gunathilake, et al. "Prevalidation of an ELISA for Detection of a New Clinical Entity: Leishmania donovani-Induced Cutaneous Leishmaniasis." International Journal of Analytical Chemistry 2020 (July 15, 2020): 1–8. http://dx.doi.org/10.1155/2020/9289651.
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Human leishmaniasis which is considered a neglected tropical parasitic disease presents in three main clinical forms (i.e., cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), and visceral leishmaniasis (VL)) that are mainly determined by its causative species. Leishmania donovani, the most virulent and visceralizing parasite, is increasingly reported to cause CL in many countries in the world. Although CL is generally not considered to evoke a humoral immune response except for a nonrobust and a variable response in minority of cases, VL is associated with a clear strong humoral response. However, humoral response in L. donovani-induced CL has not been well evaluated before. A suitable serology-based assay is an essential primary step in such a study. An indirect enzyme-linked immunosorbent assay (ELISA) based on Leishmania promastigote crude antigen (Ag) was designed and optimized in order to utilize in further serological studies on this new clinical entity. Optimization included quantification of crude Ag, checkerboard titration method for determination of optimal concentrations for coating Ag, human sera and secondary antibody (Ab) with suitable coating buffer, blocking buffer, and incubating temperatures. The selected coating buffer was 0.02 M phosphate buffer, pH 6.8, and the blocking buffer was 2% fetal bovine serum with 0.01 M phosphate-buffered saline. At least 1 μg of crude Ag was required for coating the ELISA plate, while 1 : 1000 serum was used as primary Ab. The optimized concentration of secondary Ab was 1 : 64000 which might be altered according to manufacturer recommendations. The assay specificity was pre-evaluated using sera (n = 20 from each category) from confirmed CL patients and controls (other skin diseases which mimic CL, other systemic diseases that mimic VL, nonendemic healthy controls, and endemic healthy controls). This procedure described an optimization procedure of an ELISA technique for detection of anti-Leishmania antibodies in patients with L. donovani caused CL.