OBJECTIVE: This study investigated the occurrence of C. nivariensis and C. bracarensis in a culture collection of 185 C. glabrata isolates at a Malaysian teaching hospital.
METHODS: C. nivariensis was discriminated from C. glabrata using a PCR assay as described by Enache-Angoulvant et al. (J Clin Microbiol 49:3375-9, 2011). The identity of the isolates was confirmed by sequence analysis of the D1D2 domain and internal transcribed spacer region of the yeasts. The isolates were cultured on Chromogenic CHROMagar Candida (®) agar (Difco, USA), and their biochemical and enzymic profiles were determined. Antifungal susceptibilities of the isolates against amphotericin B, fluconazole, voriconazole and caspofungin were determined using E tests. Clotrimazole MICs were determined using a microbroth dilution method.
RESULTS: There was a low prevalence (1.1 %) of C. nivariensis in our culture collection of C. glabrata. C. nivariensis was isolated from a blood culture and vaginal swab of two patients. C. nivariensis grew as white colonies on Chromogenic agar and demonstrated few positive reactions using biochemical tests. Enzymatic profiles of the C. nivariensis isolates were similar to that of C. glabrata. The isolates were susceptible to amphotericin B, fluconazole, voriconazole and caspofungin. Clotrimazole resistance is suspected in one isolate.
CONCLUSION: This study reports for the first time the emergence of C. nivariensis in our clinical setting.
METHODS: A total of seven Candida strains that includes Candida albicans ATCC14053, Candida dubliniensis ATCCMYA-2975, Candida glabrata ATCC90030, Candida krusei ATCC14243, Candida lusitaniae ATCC64125, Candida parapsilosis ATCC22019 and Candida tropicalis ATCC13803 were used in this study. The antifungal activity, minimum inhibitory concentration and minimum fungicidal concentration of B. javanica extract were evaluated. Each strain was cultured in Yeast Peptone Dextrose broth under four different growth environments; (i) in the absence and presence of B. javanica extract at respective concentrations of (ii) 1 mg/ml (iii) 3 mg/ml and (iv) 6 mg/ml. The growth inhibitory responses of the candidal cells were determined based on changes in the specific-growth rates (μ) and doubling time (g). The values in the presence of extract were computed as percentage in the optical density relative to that of the total cells suspension in the absence of extract.
RESULTS: B. javanica seeds extract exhibited antifungal properties. C. tropicalis showed the highest growth rate; 0.319 ± 0.002 h(-1), while others were in the range of 0.141 ± 0.001 to 0.265 ± 0.005 h(-1). In the presence of extract, the lag and log phases were extended and deviated the μ- and g-values. B. javanica extract had significantly reduced the μ-values of C. dubliniensis, C. krusei and C. parapsilosis at more than 80% (ρ Candida species. The fungistatic and growth inhibiting effects of B. javanica extract have shown that it has potential to be considered as a promising candidate for the development of antifungal agent in oral health products.