Comparison of Etest Method with Reference Broth Microdilution Method for Antimicrobial Susceptibility Testing of Yersinia pestis

ABSTRACT In recent years, the absence of acquired antimicrobial resistance has become an important criterion to evaluate the biosafety of lactobacilli used as industrial starter or probiotic cultures. At present, however, standards for susceptibility testing of Lactobacillus strains or approved guidelines for interpreting the test results are not available. Hence, this study was carried out to contribute to the establishment of a standardized procedure for antimicrobial susceptibility testing of lactobacilli. The results obtained by testing 104 strains of the Lactobacillus acidophilus group were compared based on broth microdilution, disk diffusion, and Etest. Except for some specific agent-related effects, agreement between MICs resulting from the broth microdilution method and the Etest was good. In addition, inhibition zone diameters determined with disk diffusion correlated well with MICs from Etest and broth microdilution.

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Antimicrobial susceptibility and association with serotypes of Streptococcus pneumoniae isolates in children with acute otitis media and acute sinusitis in Belarus

Clinical Microbiology and Antimicrobial Chemotherapy ◽

10.36488//cmac.2018.3.206-215 ◽

2018 ◽

Vol 20 (3) ◽

pp. 206-215

Author(s):

Alexander V. Davydov ◽

L.P. Titov ◽

N.L. Klyuiko ◽

V.V. Gurinovich ◽

A.V. Lazarev

Keyword(s):

Otitis Media ◽

Antimicrobial Susceptibility ◽

Susceptibility Testing ◽

Pneumococcal Infection ◽

Acute Otitis Media ◽

Incidence Rates ◽

Antimicrobial Susceptibility Testing ◽

Acute Rhinosinusitis ◽

Microdilution Method ◽

Broth Microdilution Method

Objective. To study antibiotic resistance and its association with serotypes of Streptococcus pneumoniaeisolated from hospitalized children with communityacquired ENT infections in Belarus during 20132016 and to analyze a potential for the use of different antibiotic classes in the treatment of those infections.Materials and methods. A total of 115 strains isolated from children with acute otitis media and 18 strains isolated from children with acute rhinosinusitis were tested. Antimicrobial susceptibility testing was performed by a broth microdilution method. Antimicrobial susceptibility testing results were interpreted according to the CLSI 2017 and EUCAST 2017 criteria.Results. Pneumococcal isolates obtained from the children with acute otitis media have the high rates (5074%) of nonsusceptibility to the majority of betalactams, 14/15/16membered macrolides, lincosamides, tetracyclines, folate pathway inhibitors. Rates of nonsusceptible to benzylpenicillin, amoxicillin, IIIIV generation cephalosporins, and ertapenem isolates were 3739%. All tested pneumococcal isolates were fully susceptible to fluoroquinolones, ansamycins, glycopeptides, and oxazolidinones. Wildtype strains were rare (13%). MDR and XDR strains were found in 71% and 38% of children, respectively, and belonged to vaccine serotypes, i.e. were fully covered by PCV13 and PPSV23, but partly covered by PCV10 (84% MDR and 80% XDR strains). Pneumococcal isolates from children with acute rhinosinusitis had lower antimicrobial resistance rates and incidence rates of MDR and XDR strains. It can be explained by different serotype distribution in different agegroup patients with different types of infection. There were found associations between a patient's age <5 years, “pediatric” serotype, and risk for antibiotic resistant pneumococcal infection.

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Susceptibility of Filamentous Fungi to Voriconazole in Malaysia Tested by Sensititre YeastOne and CLSI Microdilution Methods

10.21203/rs.3.rs-199013/v1 ◽

2021 ◽

Author(s):

Xue Ting Tan ◽

Stephanie Jane Ginsapu ◽

Fairuz binti Amran ◽

Salina binti Mohamed Sukur ◽

Surianti binti Shukor

Keyword(s):

Filamentous Fungi ◽

Susceptibility Testing ◽

Rhizopus Oryzae ◽

Antifungal Susceptibility ◽

Sporothrix Schenckii ◽

Rank Test ◽

Broth Microdilution ◽

Syncephalastrum Racemosum ◽

Microdilution Method ◽

Broth Microdilution Method

Abstract Background: Voriconazole is a trizaole antifungal to treat fungal infection. In this study, the susceptibility pattern of voriconazole against filamentous fungi was studied using Sensititre® YeastOne and Clinical & Laboratory Standards Institute (CLSI) M38 broth microdilution method. Methods: The suspected cultures of Aspergillus niger, A. flavus, A. fumigatus, A. versicolor, A. sydowii, A. calidoutus, A. creber, A. ochraceopetaliformis, A. tamarii, Fusarium solani, F. longipes, F. falciferus, F. keratoplasticum, Rhizopus oryzae, R. delemar, R. arrhizus, Mucor sp., Poitrasia circinans, Syncephalastrum racemosum and Sporothrix schenckii were received from hospitals. Their identification had been confirmed in our lab and susceptibility tests were performed using Sensititre® YeastOne and CLSI M38 broth microdilution method. The significant differences between two methods were calculated using Wilcoxon Sign Rank test.Results: Mean of the minimum inhibitory concentrations (MIC) for Aspergillus spp. and Fusarium were within 0.25 μg/mL-2.00 μg/mL by two methods except A. calidoutus, F. solani and F. keratoplasticum. Moreover, mean of MIC for S. schenkii were around 3.00 μg/mL by two methods. In contrast, mean of MIC for Rhizopus spp., Mucor sp., P. circinans and S. racemosum were ≥6.00 μg/mL by two methods. Generally, the MIC obtained by Sensititre YeastOne was one two-fold increase or decrease compared with the results obtained by CLSI method. The overall agreement between Sensititre YeastOne and CLSI methods to test susceptibility testing of voricaonazole was more than 70% except A. sydowii. The significant differences between two methods were significant when tested on A. niger, A. flavus, A. fumigatus, A. versicolor, A. sydowii, F. solani and S. schenkii. Conclusions: In conclusion, Sensititre YeastOne method appears to be an alternative procedure for antifungal susceptibility testing for some Malaysian moulds.

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Flow Cytometry Antifungal Susceptibility Testing of Pathogenic Yeasts other than Candida albicans and Comparison with the NCCLS Broth Microdilution Test

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.10.2752-2758.2000 ◽

2000 ◽

Vol 44 (10) ◽

pp. 2752-2758 ◽

Cited By ~ 44

Author(s):

Rama Ramani ◽

Vishnu Chaturvedi

Keyword(s):

Flow Cytometry ◽

Candida Albicans ◽

Amphotericin B ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Antifungal Susceptibility Testing ◽

Broth Microdilution ◽

Nitrogen Base ◽

Microdilution Method ◽

Broth Microdilution Method

ABSTRACT Candida species other than Candida albicansfrequently cause nosocomial infections in immunocompromised patients. Some of these pathogens have either variable susceptibility patterns or intrinsic resistance against common azoles. The availability of a rapid and reproducible susceptibility-testing method is likely to help in the selection of an appropriate regimen for therapy. A flow cytometry (FC) method was used in the present study for susceptibility testing ofCandida glabrata, Candida guilliermondii,Candida krusei, Candida lusitaniae,Candida parapsilosis, Candida tropicalis, andCryptococcus neoformans based on accumulation of the DNA binding dye propidium iodide (PI). The results were compared with MIC results obtained for amphotericin B and fluconazole using the NCCLS broth microdilution method (M27-A). For FC, the yeast inoculum was prepared spectrophotometrically, the drugs were diluted in either RPMI 1640 or yeast nitrogen base containing 1% dextrose, and yeast samples and drug dilutions were incubated with amphotericin B and fluconazole, respectively, for 4 to 6 h. Sodium deoxycholate and PI were added at the end of incubation, and fluorescence was measured with a FACScan flow cytometer (Becton Dickinson). The lowest drug concentration that showed a 50% increase in mean channel fluorescence compared to that of the growth control was designated the MIC. All tests were repeated once. The MICs obtained by FC for all yeast isolates except C. lusitaniae were in very good agreement (within 1 dilution) of the results of the NCCLS broth microdilution method. Paired ttest values were not statistically significant (P = 0.377 for amphotericin B; P = 0.383 for fluconazole). Exceptionally, C. lusitaniae isolates showed higher MICs (2 dilutions or more) than in the corresponding NCCLS broth microdilution method for amphotericin B. Overall, FC antifungal susceptibility testing provided rapid, reproducible results that were statistically comparable to those obtained with the NCCLS method.

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Evaluation of a Modified EUCAST Fragmented-Mycelium Inoculum Method forIn VitroSusceptibility Testing of Dermatophytes and the Activity of Novel Antifungal Agents

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.04381-14 ◽

2015 ◽

Vol 59 (6) ◽

pp. 3675-3682 ◽

Cited By ~ 4

Author(s):

B. Risslegger ◽

C. Lass-Flörl ◽

G. Blum ◽

M. Lackner

Keyword(s):

Antifungal Agents ◽

Susceptibility Testing ◽

Preparation Method ◽

Antifungal Susceptibility ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Inoculum Preparation ◽

Minimal Effective Concentration

ABSTRACTFor antifungal susceptibility testing of nonsporulating or poorly sporulating dermatophytes, a fragmented-mycelium inoculum preparation method was established and compared to broth microdilution testing according to CLSI and EUCAST guidelines. Moreover, thein vitroactivity of new antifungal agents against dermatophytes was evaluated. Agreement between the mycelial inoculum method and the CLSI broth microdilution method was high (93% to 100%). Echinocandins (minimal effective concentration [MEC], ≤0.5 mg/liter) and posaconazole (MIC, ≤3.00 mg/liter) showed good activity against all tested dermatophytes.

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