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ABSTRACT INTRODUCTION: Vulvovaginal candidiasis is a prevalent opportunistic mucosal infection, caused predominantly by Candida albicans. Candida species vary in their susceptibility to the antifungal agents, thus, the susceptibility tests have clinical significance in determining the appropriate therapeutic choice. OBJECTIVE: To investigate the distribution of vulvovaginal yeasts and the susceptibility pattern to azoles antifungal isolated in southern Mato Grosso State, Brazil. MATERIAL AND METHODS: Clinical samples from 166 patients were obtained regardless signs and symptoms of vulvovaginal candidiasis. Vaginal swabs were collected, seeded onto plates containing Sabouraud Dextrose agar and incubated at 35ºC, for five days. A pool of colonies that grown on each plate was subcultured in CHROMagar Candida medium. On the basis of a pure culture, the yeasts were identified using traditional phenotypic identification methods. Susceptibility tests for antifungal fluconazole and ketoconazole were performed using the broth microdilution method according to the reference protocol M27A3 of the Clinical Laboratory Standards Institute (CLSI). RESULTS: The frequency of Candida spp. in the study population was 30%, of which 28% were in the group of asymptomatic women and 35% among symptomatic. Among the isolated strains were C. albicans (50%), C. glabrata (33%) and C. tropicalis (17%). The minimum inhibitory concentration (MIC) for fluconazole ranged from 0.5 μg/ml to 16 μg/ml and for ketoconazole from 0.03 μg/ml to 4 μg/ml. The resistance rates were 1.7% for fluconazole and 3.4% for ketoconazole. CONCLUSION: C. albicans was the predominant species. We observed a high susceptibility of Candida spp. to fluconazole and ketoconazole antifungal.
RESUMO INTRODUÇÃO: A candidíase vulvovaginal é uma prevalente infeccção mucosa oportunista, causada predominantemente por Candida albicans. As espéceis de Candida variam de acordo com a suscetibilidade aos agentes antifúngicos, assim os testes de sensibilidade têm importância clínica para uma adequada escolha terapêutica. OBJETIVO: Investigar a distribuição de leveduras vulvovaginais e o padrão de suscetibilidade a antifúngicos azólicos em isolados do sul de Mato Grosso. MATERIAL E MÉTODOS: Foram obtidas amostras clínicas de 166 pacientes, independentemente de sinais e sintomas para candidíase vulvovaginal. Swabs vaginais foram coletados, semeados em placas contendo ágar Sabouraud e incubados a 35ºC. Uma amostra das colônias que cresceram em cada placa foi subcultivada em meio CHROMagar Candida. Partindo de uma cultura pura, as leveduras foram identificadas por métodos fenotípicos clássicos. Os testes de suscetibilidade aos antifúngicos cetoconazol e fluconazol foram realizados, usando o método de microdiluição de acordo com o protocolo de referência M27A3 do Clinical Laboratory Standards Institute (CLSI). RESULTADOS: A frequência de Candida spp. na população em estudo foi de 30%, sendo 28% no grupo de mulheres assintomáticas e 35% entre as sintomáticas. As espécies isoladas foram C. albicans (50%), C. glabrata (33%) e C. tropicalis (17%). A concentração inibitória mínima (CIM) para o fluconazol variou de 0,5 μg/ml a 16 μg/ml e para o cetoconazol, de 0,03 μg/ml a 4 μg/ml. A frequência de resistência ao fluconazol foi de 1,7% e ao cetoconazol, de 3,4%. CONCLUSÃO: C. albicans foi a espécie predominante. Observamos elevada sensibilidade de Candida spp. aos antifúngicos fluconazol e cetoconazol.
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Objective To determine in vitro drug susceptibility to five antifungal agents of clinical Cryptococcus neoformans strains isolated from different areas of China in recent ten years. Methods Eighty clinical isolates of Cryptococcus neoformans were isolated from Shanghai, Guangdong, Fujian, Beijing and some other areas of China from 1998 to 2007. The minimal inhibitory concentrations (MIC) of the isolates to five antifungal agents, including amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole, were determined using broth microdilution procedure (document M27-A2) recommended by the Clinical and Laboratory Standards Institute (CLSI). Kruskal-Wallis rank sum test was employed for the statistical analysis. Results The MIC50 of the Cryptococcus neoforrnans isolates tested for amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole were 0.5, 4, 2, 0.25 and ≤0.031 3 mg/L, respectively; and the MIC<,90> of the isolates tested for the above antifungal agents were 1, 8, 4, 0.5 and 0.062 5 mg/L, respectively. Among the tested isolates, 3 (3.8 %) were resistant to flucytosine, 4 (5.0 %) were resistant to itraconazole. All isolates were susceptible to amphotericin B and voriconazole. There was no significant difference in MIC of the strains isolated from any particular years to the five agents (χ2=0.500,2.687,2.211, 2.660,0.677,P>0.05). Conclusions The Cryptococcusneoformans isolates are highly susceptible to the five antifungal agents, while a few strains are resistant to flucytosine or itraconazole. The drug susceptibilities of the strains isolated from particular years are similar.
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Objective To investigate antifungal activities of AMB, ICZ, VRC, CBF against 72 strains of filamentous fungi in vitro. Methods Based on CLSI M38-P and M38-A scheme, MIC of antifungal drugs were determined. The growing inhibitory concentration of 100%, 100%,≥80%, for AMB, VRC ,ICZ act as respective MIC. For caspofungin, the minimal effective concentration (MEC) was determined as the lowest drug concentration showing morphology change of filaments. The fractional inhibitory concentration (FIC) was used to evaluate the effect of combination therapy. FIC was calculated by the following equation: FIC = MICcombination/MICA drug alone+ MICcombination/MICB drug alone. Results MIC90 of AMB, ICZ, CBF, VRC against 72 isolates of filamentous fungi were 8 μg/ml, 4 μg/ml, 2 μg/ml, 8 μg/ml, respectively. MICs range of combined AMB + ICZ, AMB + VRC, ICZ + VRC were 0. 125-16. 97, 0. 2452-1.25, and 0.0625-8. 25 μg/ml respectively. The percent of synergistic interaction of AMB + VRC against filamentous fungi (20.0%-88.9% ) was higher than those of AMB + ICZ ( 10.0% -62.5% ) and ICZ + VRC ( 20.0% - 44.4% ) ( P=0.007 <0.05 ). Conclusions The antifungal activities of four kinds antifungal drugs against 72 strains of filamentous fungi vary in vitro. The therapy of AMB combined with VRC is maybe better than AMB + ICZ and ICZ + VRC for severe fungi infection.
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Objecflve To evaluate the performance of two rapid and low-cost metheds(MTT test,and rosazurin mierotitre assay)for the detection of resistance to first-line drugs in Mycobacterium tuberculosis.Methods sixty-four Myeobaeterium tuberculosis clinical isohtes were tested by the MTT test and the rosazuxin microtitre assay(REMA)respectively,and the results were compared with those obtained with the absolute concentration method on L(o)wenstein Jensen medium.Results The MTT test and the resazurin microtitre assay showed a good agreement compared with the absolute concentration method for all first-line drugs tested.The sensitibity,specificity and accuracy of the MTT test were 94.8%,96.0%,95.3%,for RFP;93.8%,93.8%,93.8% for INH;92.9%,96.O%,95.3% for EMB,90.6%,87.5%,89.1% for SM,respectively.The sensitivity,specificity and accuracy of the resazurin microtitre assay were 92.3%,96.0%,93.8%,for RFP;90.6%,90.6%,90.6% for INH;92.9%,94.0%,93.8% for EMB,87.5%,87.5%,87.5% for SM,respectively.The Kappa value of the MTT test and the absolute concentration method for the detection of resistance to RFP,INH,EMB,SM were 0.857,0.831,0.714,0.792.respeedvely;The Kappa value of the regazurin mierotitre assay and the absolute concentration method for the detection of resistance to RFP,INH,EMB,SM were 0.871,0.826,0.826,0.750,respectively.The Kappa value of the MTT test and the resazurin microtitre assay for the detection of resistance to RFP,INH,EMB,SM wefe 0.889,0.875.0.787,0.844,respectively.Conclusions Both MTT test and the resazurin microtitre assays are simple,rapid,low-cost and sensitive for rapid detection of resistance to first-line drugs.They could be promising methods for susceptibility assay of the first-line antituberculosis drugs in low-resource countries.
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BACKGROUND: We evaluated the BD Phoenix Automated Microbiology System (Phoenix) for its ability to detect methicillin resistant Staphylococcus aureus (MRSA) and compared the results to those obtained by the Clinical and Laboratory Standards Institute (CLSI) agar dilution method, a mecA gene PCR method, and the MicroScan WalkAway 96 System (MicroScan). METHODS: One hundred seventy S. aureus strains (Group I) isolated from blood and urine cultures were collected from eight university hospitals and 58 strains (Group II) including 20 blood isolates among Group I and 38 isolates from skin lesions of atopic patients were collected from Asan Medical Center. All 208 isolates were tested with Phoenix using PMIC/ID-53 panels, and the tests were repeated when the results were indeterminate. The results by Phoenix were compared to the susceptibility results obtained by reference methods: the CLSI method for oxacillin MIC for Group I strains, and a PCR assay method for detection of the mecA gene and MicroScan tests for oxacillin susceptibility for Group II strains. RESULTS: One hundred strains (58.8%) in Group I were MRSA and 28 strains (48.3%) were mecA positive in Group II. Compared to the CLSI method, Phoenix showed the sensitivity and specificity of 100% and MIC agreement of 99.4% for Group I strains. The level of agreement between Phoenix and MicroScan for oxacillin MIC and their interpretation were 98.3% and 100%, respectively, for Group II strains. Both MicroScan and Phenix failed to detect one mecA-positive strain: its MIC was shown as 2 microgram/mL twice by MicroScan and 2 microgram/mL twice and > 2 microgram/mL once by Phoenix. The frequency of the indeterminate results was 5.5% and the mean time to completion of the tests was 12.8 (10.2-16) hours in Phoenix. CONCLUSION: Phoenix showed a high level of sensitivity and specificity for the detection of MRSA with an excellent correlation with MicroScan. Further evaluation is required for detection of heterogeneous MRSA.