The activities of fluconazole and voriconazole against isolates of Candida spp. (n ؍ 400) were tested by the E-test, disk diffusion, and the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 broth microdilution-based reference methods. More than 96% of isolates found to be susceptible to fluconazole by the reference method were identified as susceptible by the agar-based methods. Lesser degrees of correlation with the reference method were seen for isolates identified as resistant by the agar-based methods. Interpretive categories are not available for voriconazole, but results qualitatively similar to those for fluconazole were seen. The agar-based E-test and disk diffusion methods are reliable alternatives to the NCCLS M27-A2 reference microdilution method for isolates that test susceptible to fluconazole.The development of standardized antifungal susceptibility testing methods has been the subject of numerous studies during the last decade. Reference methods for yeasts (the National Committee for Clinical Laboratory Standards [NCCLS] M27-A2 method) and molds (the NCCLS M38-A method) are now available (16). Agar-based susceptibility testing methods have been a focus of interest for many researchers and include the classical disk diffusion (DD) methods and the E-test (ET) method (3, 6-10, 13, 14, 16-18). Those tests are very attractive due to their simplicity, reproducibility, and lack of requirements for specialized equipment (11,16). Recent studies have documented comparable results between those methods and the results of standard reference broth microdilution (MD) susceptibility testing (7,11,13).In this study, we compared the NCCLS M27-A2 MD method with the ET and DD methods for determination of the susceptibilities of 400 Candida species isolates to fluconazole and voriconazole. The ET and DD methods are well studied for fluconazole (3,(6)(7)(8)(9)(10)(11)14), and this work extends their usage to include voriconazole. MATERIALS AND METHODSIsolates. Four hundred bloodstream isolates of Candida species were randomly selected for testing. These included 205 isolates of Candida albicans, 56 isolates of C. tropicalis, 39 isolates of C. glabrata, 66 isolates of C. parapsilosis, 24 isolates of C. krusei, and 10 isolates of other species. The isolates were identified with the API 20C AUX system (Biomerieux Vitek, Hazelwood, Mo.) and were subsequently stored in sterile distilled water at room temperature until susceptibility tests were performed. Each isolate was subcultured at least twice on Sabouraud dextrose agar and incubated at 35°C prior to testing to ensure purity and optimal growth.Inoculum suspensions. Yeast inoculum suspensions were prepared as described for the NCCLS M27-A2 method (12). The turbidity was measured with a spectrophotometer at 530 nm and was adjusted to match a 0.5 McFarland density standard, resulting in a concentration of 1 ϫ 10 6 to 5 ϫ 10 6 yeast cells/ml. This inoculum was used directly for inoculation of agar plates (see below) or was diluted as needed for the MD ...
Background There is a lack of official national antimicrobial resistance (AMR) data in Lebanon. Individual hospitals generate their own antibiotic susceptibility data in the form of yearly pamphlets. Methods In this study, antibiotic susceptibility data from 13 hospitals distributed across different governorates of Lebanon were collected to conduct a compilation-based surveillance of AMR in Lebanon for the years 2015–2016. The findings were compared with those of a previous nationwide study in this country conducted between 2011 and 2013 as well as with similar data obtained from the 2015 and 2016 European surveillance reports of AMR. To provide a clear presentation of the AMR situation, mean percent susceptibility of different antibiotic–microbe combinations was calculated. Results During 2015–2016, the percent susceptibility of Enterobacteriaceae to third-generation cephalosporins and to carbapenems was 59 and 97%, respectively. Among Pseudomonas aeruginosa and Acinetobacter spp., carbapenem susceptibility reached 70 and 12%, respectively. Among Gram positive organisms, the percent susceptibility to methicillin in Staphylococcus aureus was 72%, that to vancomycin in Enterococcus spp. was 98% and that to penicillin in Streptococcus pneumoniae was 75%. Compared with results of 2011–2013, there was an overall trend of decreased susceptibility of bacteria to the tested antibiotics, with a variation of 5 to 10%. The antibiotic susceptibility data from Lebanon were found to be comparable with those from Eastern and South-eastern European countries. Conclusion This study highlights the need to establish a robust national AMR surveillance system that enables data from Lebanon to be included in global AMR maps. Electronic supplementary material The online version of this article (10.1186/s13756-019-0487-5) contains supplementary material, which is available to authorized users.
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