Role of yeasts as nosocomial pathogens & their susceptibility to fluconazole & amphotericin B.

ABSTRACT

A total of 213 and 208 yeasts were isolated as nosocomial pathogens from various infected specimens during 1996 and 1997 respectively. Yeasts ranked fifth among uropathogens in both the years and from eighth to eleventh in other specimens. Increasing trend in nosocomial urinary tract yeast infection (11.9 in 1996 to 12.6 in 1997) and decreasing trend in wound and other infections (5.1 in 1996 to 2.9 in 1997) per 1000 patients' discharges were observed; blood stream infection remained unchanged (2/1000 discharges) in both the years. Eighty two (41 from each year) randomly selected yeasts were identified to species level following standard protocol and tested for antifungal susceptibility against fluconazole and amphotericin B by reference broth macrodilution technique and agar dilution (AD) method. The frequency of various yeast species identified was Candida albicans 39 (47.6%), C.tropicalis 29 (35.4%), C. krusei 4 (4.9%), C. glabrata 3 (3.7%), C. zeylanoides 2 (2.4%), C. guilliermondii 2 (2.4%), one strain (1.2%) each of C. kefyr, C. parapsilosis, and Trichosporon beigelii. Resistance to fluconazole (MIC > or = 64 micrograms/ml) as per NCCLS criteria was observed in 2 Candida sp. (2.4%). Significantly higher number of non-albicans Candida sp. (8/43; 18.6%) had MIC > 8 micrograms/ml as compared to C. albicans (2/39; 5.1%) (P < 0.05). Only one strain of C. tropicalis had MIC 8 micrograms/ml to amphotericin B and none had MIC > 8 micrograms/ml. Agreement between the reference and the AD methods for fluconazole was 88 per cent and for amphotericin B was 94 per cent. The present study indicates that Candida sp. are emerging as important nosocomial pathogens and the tendency of yeasts to develop resistance to antifungal agents appears to be a challenge for patient management.