Virulence factors and antifungal susceptibility profile of non albicans Candida species isolated from blood stream infections

Abstract

Background: The spectrum of fungal infections, once only considered to be restricted only to cutaneous and mucocutaneous tissue has been changed. Invasive mycosis have emerged as an increase threat to mankind. Despite of the advent in both therapeutic and diagnostic modalities, invasive mycosis is associated with high mortality. Candida spp., is often the most important cause of blood stream infection. Although C. albicans is considered as the most pathogenic species from the genus, recent studies have documented the emergence of unusual, relatively uncommon and treatment resistant non albicans Candida (NAC) spp. Material and methods:NAC spp. isolated from blood cultures were included in the study. Candidaisolates were identified up to species level by standard mycological protocol. NAC spp. were screened for production of virulence factor like extracellular hydrolytic enzymes, haemolysin and biofilm formation. The antifungal susceptibility profile of these isolates was studied by Ezy MIC Strip.Results:The rates of isolation of bacterial and fungal pathogens from blood cultures were 78.4% and 21.6% respectively. Candida spp. was the only fungal pathogen isolated from blood cultures. The isolation of NAC spp. was highly significantly compared to C. albicans. C. tropicalis followed by C. glabrata and C. krusei were most common isolates from NAC spp. ICU admission and fluconazole prophylaxis/treatment were significantly associated with BSI due to NAC spp.Fluconazole resistance was observed in 40.7% of NAC spp. All isolates of C. krusei were resistant to fluconazole. No isolates were resistant to voriconazole and echinocandins. Conclusion: Hitherto rare and new fungal species and fungi once considered to be non-pathogenic are increasingly implicated in human infections.NAC spp. have emerged as an important cause of infections including candidemia. These NAC spp., produce virulence factors once attributed to C. albicans. As NAC spp. differ widely in susceptibility to routine used antifungal agents, antifungal susceptibility testing plays an important role in evaluating therapy for Candida infections.