Infections with yeast and yeast like fungi in cancer patients with special emphasis on non- neoformans cryptococcal infections: Retrospective study

Abstract

Candida spp. and Cryptococcus spp. are important fungal pathogens in cancer patients. Nonalbicans Candida are of special concern, since some are highly virulent and show reduced susceptibility to antifungal agents. Nonneoformans Cryptococcal infections have also shown an incremental rise over the past four decades. The aim of this retrospective study was to evaluate the prevalence, distribution and susceptibility pattern of various species of Candida and Cryptococcus causing infections in cancer patients. This Retrospective study was conducted from Jan 2011 to Aug 2016. Yeasts/yeast like fungi isolated in various specimens received for fungal and also bacterial culture were included. Fully automated VITEK 2 compact was used for final species identification and susceptibility testing of isolated yeasts. The prevalence of infections was 1.36% during the study period with prevalence being 0.54% in patients with haematological cancer and 2.45 in patients with Solid tumours. Among various solid tumours maximum infection rate was seen in patients with head and neck cancers i.e. 4.01%. A total of 9.09% growths were responsible for Blood Stream Infections (BSI). Most common Candida sp. isolated was C.tropicalis (37.06%) followed by C.albicans (36.87%). Out of total 35 Cryptococcus sp. isolated 30 were Cryptococcus laurentii and only 5 were Cryptococcus neoformans. Low level of resistance was shown by C.albicans to all the antifungal agents. C.tropicalis also showed low resistance with only 2.01% resistance to Fluconazole and Amphotericin B. Higher resistance rate was observed in C.krusei with 7.69% isolates resistant to Fluconazole and 15.38% resistant to Amphotericin B. Rate of resistance shown by C.glabrata to Fluconzole was also quite high i.e. 9.09%. Most of the Candida sp. showed good sensitivity to both Caspofungin and Micafungin except C.krusei with 15.38% resistance to both candins. Out of all the antifungal agents tested for Voriconazole was the most effective for all the yeasts isolated with highest resistance rate being 7.69% shown by C. krusei. All Cryptococcus neoformans isolated were sensitive to the antifungal agents tested for. i.e. Amphotericin B, Flucytosine, Fluconazole and Voriconazole. Our study emphasizes the need to make new prophylaxis policies for Candida infections. Also further studies should be conducted to determine the antifungal susceptibility pattern of Cryptococcus laurentii.