Comparative evaluation of ATB Fungus 2 and Sensititre YeastOne panels for testing in vitro Candida antifungal susceptibility.
ABSTRACT ATB Fungus 2 and SensititreYeastOne are commercial methods for antifungal susceptibility testing of yeasts. The agreement between these two methods was assessed with a total of 133 Candida strains (60 Candida albicans, 18 Candida dubliniensis, 29 Candida glabrata, and 26 Candida krusei). MIC endpoints were established after 24 h of incubation at 36-/+1 degrees C by each method. Intra-laboratory reproducibility of both methods was excellent (=or>99%). Overall agreement between ATB Fungus 2 and Sensititre YeastOne 3 MICs (within 2 dilutions) was 91.2-97.7% for amphotericin B, 5-fluorocytosine and itraconazole, and 82.7% for fluconazole. The categorical agreement when ATB Fungus 2 results were compared to those by SensititreYeastOne 3 was 93.2-98.5% for 5-fluorocytosine and amphotericin B, but lower for the triazoles (72.9-75.9%). This easy to perform method could be an alternative for routine use in the clinical microbiology laboratory for susceptibility testing of common Candida spp.
SourceAvailable from: Carole P Mcarthur[Show abstract] [Hide abstract]
ABSTRACT: Candida species are a common cause of infection in immune-compromised HIV-positive individuals, who are usually treated with the antifungal drug, fluconazole in public hospitals in Africa. However, information about the prevalence of drug resistance to fluconazole and other antifungal agents on Candida species is very limited. This study examined 128 Candida isolates from South Africa and 126 Cameroonian Candida isolates for determination of species prevalence and antifungal drug susceptibility. The isolates were characterized by growth on chromogenic and selective media and by their susceptibility to nine antifungal drugs tested using the TREK™ YeastOne9 drug panel (Thermo Scientific). Eighty three percent (82.8%) of South African isolates were C. albicans (106 isolates), 9.4% were C. glabrata (12 isolates) and 7.8% were C. dubliniensis (10 isolates). Of the Cameroonian isolates, 73.02% were C. albicans (92 isolates); 19.05% C. glabrata (24 isolates); 3.2% C. tropicalis (4 isolates); 2.4% C. krusei (3 isolates); 1.59% either C. kefyr, C. parapsilopsis or C. lusitaneae (2 isolates); and 0.79% C. dubliniensis (1 isolate). Widespread C. albicans resistance to azoles was detected phenotypically in both populations. Differences in drug resistance were seen within C. glabrata found in both populations. Echinocandin drugs were more effective on isolates obtained from the Cameroon than in South Africa. A multiple drug resistant (MDR) C. dubliniensis strain isolated from the South African samples was inhibited only by 5-flucytosine in vitro on the YO9 panel. Drug resistance among oral Candida species is common among African HIV patients in these two countries. Regional surveillance of Candida species drug susceptibility should be undertaken to ensure effective treatment for HIV-positive patients. The final author submission can be accessed without copyright infringement on: http://repository.uwc.ac.za/xmlui/handle/10566/1082Diagnostic Microbiology and Infectious Disease 06/2014; 79:222-27. DOI:10.1016/j.diagmicrobio.2013.09.016 · 2.57 Impact Factor
Conference Paper: HIV/Candida co-infection in Sub-Saharan African women on ART[Show abstract] [Hide abstract]
ABSTRACT: Introduction: Sub-Saharan Africa has 23.5 million cases of HIV and is home to 92% of the world’s HIV-positive pregnant women of whom 24% die of pregnancy related complications. Oral candidiasis is a common condition in HIV-AIDS patients, caused by commensal yeasts which may colonise the mucous membranes of the mouth causing morbidity due to several factors including immunosuppression, smoking, poor nutrition and the use of antibiotics. Methods: One hundred and ninety-four South African and Cameroonian HIV-positive women participated in the study. Only subjects who had white pseudomembranous plaque on the tongue or visible oral candidiasis were included. Samples were collected by scraping the patient’s oral mucosa and tongue with a sterile swab. Candida species were differentiated using selective and chromogenic media and their susceptibility to antifungal drugs was tested using the TREK Sensititre system. Results and conclusion: One hundred and ninety-six isolates, representative of six Candida species were identified. C. albicans was the predominating species, with C. glabrata and C. dubliniensis being the more frequent of the non-albicans isolates. Azole drug resistance patterns were very high for C. albicans, while C. glabrata showed high resistance patterns to echinocandins drugs. The duration of ART could be associated with the presence of different Candida species but no concrete conclusions could be drawn concerning HIV/Candida co-infection when controlling for other risk factors such as HIV stage, pregnancy, age and treatment for tuberculosis. This may be a cause for concern, particularly in the case of pregnancy, where co-infection may pose a risk for maternal morbidity and mortality.Federation of Infectious Diseases Societies of Southern Africa 5th Congress, Winterton, South Africa; 10/2013
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ABSTRACT: The rapid development in the clinical microbiology diagnostic assays presents more challenges for developing countries than for the developed world, especially in the area of test validation before the introduction of new tests. Here we report on the misleading high MICs of Candida spp. to azoles using the ATB FUNGUS 3 (bioMérieux, La Balme-les Grottes, France) with automated readings in China to highlight the dangers of introducing a diagnostic assay without validation. ATB FUNGUS 3 is the most commonly used commercial antifungal susceptibility testing method in China. An in-depth analysis of data showed higher levels of resistance to azoles when ATB FUNGUS 3 strips were read automatically than when read visually. Based on this finding, the performance of ATB FUNGUS 3, read both visually and automatically, was evaluated by testing 218 isolates of five clinically important Candida species, using broth microdilution (BMD) following CLSI M27-A3 as the gold-standard. The overall essential agreement (EA) between ATB visual readings and BMD was 99.1%. In contrast, the ATB automated readings showed higher discrepancies with BMD, with overall EA of 86.2%, and specifically lower EA was observed for fluconazole (80.7%), voriconazole (77.5%), and itraconazole (73.4%), which was most likely due to the trailing effect of azoles. The major errors in azole drug susceptibilities by ATB automated readings is a concern in China that can result in misleading clinical antifungal drug selection and pseudo high rates of antifungal resistance. Therefore, the ATB visual reading is generally recommended. In the meantime, we propose a practical algorithm to be followed for ATB FUNGUS 3 antifungal susceptibility for Candida spp. before the improvement in the automated reading system.PLoS ONE 12/2014; 9(12):e114004. DOI:10.1371/journal.pone.0114004 · 3.53 Impact Factor