scholarly journals In Vitro Susceptibility ofMycobacterium ulceransIsolates to Selected Antimicrobials

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Enid Owusu ◽  
Mercy J. Newman ◽  
Kwesi K. Addo ◽  
Phyllis Addo
Keyword(s):  
Inhibitory Activity ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Drug Misuse ◽  
Definitive Treatment ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
In Vitro Susceptibility ◽  
Antimicrobial Drug Resistance

Background.The current definitive treatment of Buruli ulcer with antibiotics makes the issue of antimicrobial drug resistance an unavoidable one. This is as a result of drug misuse by health personnel and patients’ noncompliance to treatment regimen. Monitoring of these factors and screening for new effective antimicrobials are crucial to effective management of Buruli ulcer disease. This study therefore investigated the inhibitory activity of some antibiotics against isolates ofMycobacterium ulcerans.Methods.Activity of eight antibiotics was tested against twelveM. ulceransisolates (2 reference strains and 10 clinical isolates). The anti-M. ulceransactivities were determined by the agar dilution method and the minimum inhibitory concentrations (MICs) were determined by the agar proportion method.Results.All antimicrobials investigated had activity againstM. ulceransisolates tested. The MICs ranged from 0.16 μg/mL to 2.5 μg/mL. Azithromycin recorded the highest inhibitory activity at a mean MIC of 0.39 μg/mL, whilst clofazimine a second-line antileprosy drug, recorded the lowest at a mean MIC of 2.19 μg/mL. Among the four antituberculosis drugs, rifampicin had the highest activity with a mean MIC of 0.81 μg/mL.Conclusion.Azithromycin could be considered as a lucrative alternative to existing treatment methods for inhibitingM. ulceransin Ghana.

scholarly journals Comparison of in vitro activity of five antifungal agents against dermatophytes, using the agar dilution and broth microdilution methods

2009 ◽  
Vol 42 (3) ◽  
pp. 250-254 ◽  
Author(s):  
Crystiane Rodrigues Araújo Mota ◽  
Karla Carvalho Miranda ◽  
Janine de Aquino Lemos ◽  
Carolina Rodrigues Costa ◽  
Lúcia Kioko Hasimoto e Souza ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Reference Method ◽  
Trichophyton Mentagrophytes ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Microsporum Canis ◽  
Broth Microdilution ◽  
In Vitro Susceptibility ◽  
Agar Dilution

The purpose of this study was to compare the agar dilution and broth microdilution methods for determining the minimum inhibitory concentration (MIC) of fluconazole, itraconazole, ketoconazole, griseofulvin and terbinafine for 60 dermatophyte samples belonging to the species Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. The percentage agreement between the two methods, for all the isolates with < 2 dilutions that were tested was 91.6% for ketoconazole and griseofulvin, 88.3% for itraconazole, 81.6% for terbinafine and 73.3% for fluconazole. One hundred percent agreement was obtained for Trichophyton mentagrophytes isolates evaluated with ketoconazole and griseofulvin. Thus, until a reference method for testing the in vitro susceptibility of dermatophytes is standardized, the similarity of the results between the two methods means that the agar dilution method may be useful for susceptibility testing on these filamentous fungi.

scholarly journals In Vitro Activities of 15 Antimicrobial Agents against 110 Toxigenic Clostridium difficile Clinical Isolates Collected from 1983 to 2004

2007 ◽  
Vol 51 (8) ◽  
pp. 2716-2719 ◽  
Author(s):  
David W. Hecht ◽  
Minerva A. Galang ◽  
Susan P. Sambol ◽  
James R. Osmolski ◽  
Stuart Johnson ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Antimicrobial Agents ◽  
Treatment Strategies ◽  
The United States ◽  
Clinical Isolates ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
In Vitro Susceptibility ◽  
Agar Dilution

ABSTRACT The incidence and severity of Clostridium difficile-associated disease (CDAD) is increasing, and standard treatment is not always effective. Therefore, more-effective antimicrobial agents and treatment strategies are needed. We used the agar dilution method to determine the in vitro susceptibility of the following antimicrobials against 110 toxigenic clinical isolates of C. difficile from 1983 to 2004, primarily from the United States: doripenem, meropenem, gatifloxacin, levofloxacin, moxifloxacin, OPT-80, ramoplanin, rifalazil, rifaximin, nitazoxanide, tizoxanide, tigecycline, vancomycin, tinidazole, and metronidazole. Included among the isolates tested were six strains of the toxinotype III, NAP1/BI/027 group implicated in recent U.S., Canadian, and European outbreaks. The most active agents in vitro were rifaximin, rifalazil, tizoxanide, nitazoxanide, and OPT-80 with MICs at which 50% of the isolates are inhibited (MIC50) and MIC90 values of 0.0075 and 0.015 μg/ml, 0.0075 and 0.03 μg/ml, 0.06 and 0.125 μg/ml, 0.06 and 0.125 μg/ml, 0.125 and 0.125 μg/ml, respectively. However, for three isolates the rifalazil and rifaximin MICs were very high (MIC of >256 μg/ml). Ramoplanin, vancomycin, doripenem, and meropenem were also very active in vitro with narrow MIC50 and MIC90 ranges. None of the isolates were resistant to metronidazole, the only agent for which there are breakpoints, with tinidazole showing nearly identical results. These in vitro susceptibility results are encouraging and support continued evaluation of selected antimicrobials in clinical trials of treatment for CDAD.

scholarly journals Problems Related to Determination of MICs of Oximino-Type Expanded-Spectrum Cephems for Proteus vulgaris

2000 ◽  
Vol 38 (2) ◽  
pp. 677-681
Author(s):  
Akira Ohno ◽  
Yoshikazu Ishii ◽  
Ling Ma ◽  
Keizo Yamaguchi
Keyword(s):  
Dilution Method ◽  
Agar Dilution Method ◽  
Proteus Vulgaris ◽  
In Vitro Susceptibility ◽  
Microdilution Method ◽  
Defective Mutant ◽  
Broth Microdilution Method ◽  
Agar Dilution ◽  
Isogenic Mutants

During in vitro susceptibility testing of clinical isolates ofProteus vulgaris, we noted that the MICs of several expanded-spectrum cephems were much higher in the broth microdilution method than in the agar dilution method (termed the MIC gap phenomenon). Here we investigated the mechanism of the MIC gap phenomenon. Cephems with the MIC gap phenomenon were of the oximino type, such as cefotaxime, cefteram, and cefpodoxime, which serve as good substrates for inducible class A β-lactamase (CumA) enzymes produced by P. vulgaris; this finding suggests a relationship between the MIC gap phenomenon and CumA. Since peptidoglycan recycling shares a system common to that inducing CumA, we analyzed the mechanism of the MIC gap phenomenon using P. vulgaris B317 and isogenic mutants with mutations in the peptidoglycan recycling and β-lactamase induction systems. The MIC gap phenomenon was observed in the parent strain B317 but not in B317G (cumG-defective mutant; defective peptidoglycan recycling) and B317R (cumR-defective mutant; defective CumA transcriptional regulator). No β-lactamase activity was detected in B317G and B317R. β-Lactamase activity and the MIC gap phenomenon were restored in B317G/pMD301 (strain transcomplemented by a clonedcumG gene) and B317R/pMD501 (strain transcomplemented by a cloned cumR gene). MICs determined by the agar dilution method increased when lower agar concentrations were used. Our results indicated that the mechanism of the MIC gap phenomenon is related to peptidoglycan recycling and CumA induction systems. However, it remains unclear how β-lactamase induction of P. vulgaris is suppressed on agar plates.

scholarly journals In Vitro Antimicrobial Susceptibility Profiles of Gram-Positive Anaerobic Cocci Responsible for Human Invasive Infections

2021 ◽  
Vol 9 (8) ◽  
pp. 1665
Author(s):  
François Guérin ◽  
Loren Dejoies ◽  
Nicolas Degand ◽  
Hélène Guet-Revillet ◽  
Frédéric Janvier ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gram Positive ◽  
In Vitro Susceptibility ◽  
Parvimonas Micra ◽  
Invasive Infections ◽  
Anaerobic Infections ◽  
Susceptibility Profiles

The aim of this multicentre study was to determine the in vitro susceptibility to anti-anaerobic antibiotics of Gram-positive anaerobic cocci (GPAC) isolates responsible for invasive infections in humans. A total of 133 GPAC isolates were collected in nine French hospitals from 2016 to 2020. All strains were identified to the species level (MALDI-TOF mass spectrometry, 16S rRNA sequencing). Minimum inhibitory concentrations (MICs) of amoxicillin, piperacillin, cefotaxime, imipenem, clindamycin, vancomycin, linezolid, moxifloxacin, rifampicin, and metronidazole were determined by the reference agar dilution method. Main erm-like genes were detected by PCR. The 133 GPAC isolates were identified as follows: 10 Anaerococcus spp., 49 Finegoldia magna, 33 Parvimonas micra, 30 Peptoniphilus spp., and 11 Peptostreptococcus anaerobius. All isolates were susceptible to imipenem, vancomycin (except 3 P. micra), linezolid and metronidazole. All isolates were susceptible to amoxicillin and piperacillin, except for P. anaerobius (54% and 45% susceptibility only, respectively). MICs of cefotaxime widely varied while activity of rifampicin, and moxifloxacin was also variable. Concerning clindamycin, 31 were categorized as resistant (22 erm(A) subclass erm(TR), 7 erm(B), 1 both genes and 1 negative for tested erm genes) with MICs from 8 to >32 mg/L. Although GPACs are usually susceptible to drugs commonly used for the treatment of anaerobic infections, antimicrobial susceptibility should be evaluated in vitro.

scholarly journals Fosfomycin versus Nitrofurantoin for the Treatment of Lower UTI in Outpatients

2021 ◽  
Author(s):  
Shraddha Sharma ◽  
Pankaj Kumar Verma ◽  
Vinita Rawat ◽  
Umesh Varshney ◽  
Rajesh Kumar Singh
Keyword(s):  
Clinical Cure ◽  
Oral Treatment ◽  
Empirical Therapy ◽  
Signs And Symptoms ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
In Vitro Susceptibility ◽  
Sensitivity Pattern

Abstract Introduction Fosfomycin and nitrofurantoin are increasingly being prescribed in outpatients for the oral treatment of urinary tract infection (UTI). Although ample literature is available on the in vitro sensitivity pattern of fosfomycin and nitrofurantoin in UTI cases, clinical data are scant. Methodology Voided midstream urine, collected from patients ≥ 16 years of age of both genders with suspected sign and symptoms, was plated on cystine lactose electrolyte-deficient agar. Uropathogen was defined as an organism known to be associated with the signs and symptoms of UTI with > 105 colony forming units/mL of urine. Antimicrobial susceptibility testing was determined by Kirby-Bauer disc diffusion method. Further, for fosfomycin, agar dilution method was also performed. Results A total of 143 patients, 47 treated with fosfomycin and 96 with nitrofurantoin, were followed for clinical outcome. The most common isolated uropathogen was Escherichia coli. In vitro susceptibility rate of uropathogens against fosfomycin and nitrofurantoin was 99.3% and 81.2%, respectively. Overall, the clinical cure rate with fosfomycin and nitrofurantoin treatment groups was 80.85% and 90.06% respectively (not statistically significant). Conclusion Fosfomycin and nitrofurantoin showed good in vitro activity against uropathogens from lower UTI and can be used for empirical therapy in our area. Multiple confounding factors may have contributed to the discrepancy between in vitro susceptibility and clinical cure, which needs to be studied further.

scholarly journals e-Pharmacophore model-guided design of potential DprE1 inhibitors: synthesis, in vitro antitubercular assay and molecular modelling studies

2021 ◽  
Author(s):  
Avinash Kumar ◽  
Revathi Rajappan ◽  
Suvarna G. Kini ◽  
Ekta Rathi ◽  
Sriram Dharmarajan ◽  
...  
Keyword(s):  
Pharmacophore Model ◽  
Antitubercular Activity ◽  
Stable Complex ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Standard Drug ◽  
Docking Score ◽  
Mycobacterium Tuberculosis H37rv ◽  
Cytotoxicity Studies

AbstractTuberculosis continues to wreak havoc worldwide and caused around 1.4 million deaths in 2019. Hence, in our pursuit of developing novel antitubercular compounds, we are reporting the e-Pharmacophore-based design of DprE1 (decaprenylphosphoryl-ribose 2′-oxidase) inhibitors. In the present work, we have developed a four-feature e-Pharmacophore model based on the receptor–ligand cavity of DprE1 protein (PDB ID 4P8C) and mapped our previous reported library of compounds against it. The compounds were ranked on phase screen score, and the insights obtained from their alignment were used to design some novel compounds. The designed compounds were docked with DprE1 protein in extra-precision mode using Glide module of Maestro, Schrodinger. Some derivatives like B1, B2, B4, B5 and B12 showed comparable docking score (docking score > − 6.0) with respect to the co-crystallized ligand. The designed compounds were synthesized and characterized. In vitro antitubercular activity was carried out on Mycobacterium tuberculosis H37Rv (ATCC27294) strain using the agar dilution method, and minimum inhibitory concentration (MIC) was determined. The compound B12 showed a MIC value of 1.56 μg/ml which was better than the standard drug ethambutol (3.125 μg/ml). Compounds B7 and B11 were found to be equipotent with ethambutol. Cytotoxicity studies against Vero cell lines proved that these compounds were non-cytotoxic. Molecular dynamic simulation study also suggests that compound B12 will form a stable complex with DprE1 protein and will show the crucial H-bond interaction with LYS418 residue. Further in vitro enzyme inhibition studies are required to validate these findings.

scholarly journals Antifungal and Antibacterial Metabolites from a French Poplar Type Propolis

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Séverine Boisard ◽  
Anne-Marie Le Ray ◽  
Anne Landreau ◽  
Marie Kempf ◽  
Viviane Cassisa ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Antimicrobial Effect ◽  
Antibacterial Activities ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gram Positive ◽  
Weak Activity ◽  
Agar Dilution

During this study, thein vitroantifungal and antibacterial activities of different extracts (aqueous and organic) obtained from a French propolis batch were evaluated. Antifungal activity was evaluated by broth microdilution on three pathogenic strains:Candida albicans, C. glabrata, andAspergillus fumigatus. Antibacterial activity was assayed using agar dilution method on 36 Gram-negative and Gram-positive strains includingStaphylococcus aureus. Organic extracts showed a significant antifungal activity againstC. albicansandC. glabrata(MIC80between 16 and 31 µg/mL) but only a weak activity towardsA. fumigatus(MIC80= 250 µg/mL). DCM based extracts exhibited a selective Gram-positive antibacterial activity, especially againstS. aureus(SA) and several of its methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) strains (MIC10030–97 µg/mL). A new and active derivative of catechin was also identified whereas a synergistic antimicrobial effect was noticed during this study.

scholarly journals Triple oral beta-lactam containing therapy for Buruli ulcer treatment shortening

2018 ◽  
Author(s):  
María Pilar Arenaz Callao ◽  
Rubén González del Río ◽  
Ainhoa Lucía Quintana ◽  
Charles J. Thompson ◽  
Alfonso Mendoza-Losana ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Beta Lactam ◽  
Beta Lactams ◽  
Amoxicillin Clavulanate ◽  
Low Toxicity ◽  
Potential Use ◽  
Ulcer Treatment

ABSTRACTThe potential use of clinically approved beta-lactams for Buruli ulcer (BU) treatment was investigated with representative classes analyzed in vitro for activity against Mycobacterium ulcerans. Beta-lactams tested were effective alone and displayed a strong synergistic profile in combination with antibiotics currently used to treat BU, i.e. rifampicin and clarithromycin; this activity was further potentiated in the presence of the beta-lactamase inhibitor clavulanate. In addition, quadruple combinations of rifampicin, clarithromycin, clavulanate and beta-lactams resulted in multiplicative reductions in their minimal inhibitory concentration (MIC) values. The MIC of amoxicillin against a panel of clinical isolates decreased more than 200-fold within this quadruple combination. Amoxicillin/clavulanate formulations are readily available with clinical pedigree, low toxicity, and orally and pediatric available; thus, supporting its potential inclusion as a new anti-BU drug in current combination therapies.

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