The emergence of non-albicans Candida species as causes of invasive candidiasis and candidemia

The distribution and drug susceptibilities of clinical Candida species in TSARY 2014

The species distribution and drug susceptibilities of 1106 Candida isolates collected in Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) in 2014 were determined. Candida albicans is still the dominant species, accounting for 35.9%, followed by 28.3% C. glabrata, 26.6% C. tropicalis, 5.2% C. parapsilosis, 1.0% C. krusei, and 3.0% of 13 other species. Interestingly, the prevalence of candidemia caused by C. glabrata in the present study is significantly higher than that in previous three surveys (39/220 vs. 54/471, P=0.025). We found that 31 (2.8%), 24 (2.2%), 1 (0.09%), and 0 isolates were resistant to fluconazole, voriconazole, anidulafungin, and amphotericin B, respectively. There is a significant increase in fluconazole (P=0.00002) and voriconazole (P=0.00006) resistant rates when compared to the isolates collected in 2010. Importantly, all the 24 voriconazole resistant isolates identified were also resistant to fluconazole. Hence, cross-resistance among azole-type drugs is an emerging issue for managing fungal infections.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

In vitro activity of seven systemically active antifungal agents against a large global collection of rare Candida species as determined by CLSI broth microdilution methods

Five Candida species (C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, and C. krusei) account for over 95% of invasive candidiasis cases. Some less common Candida species have emerged as causes of nosocomial candidiasis, but there is little information about their in vitro susceptibilities to antifungals. We determined the in vitro activities of fluconazole, voriconazole, posaconazole, amphotericin B, anidulafungin, caspofungin, and micafungin against invasive, unique patient isolates of Candida collected from 100 centers worldwide between January 2001 and December 2007. Antifungal susceptibility testing was performed by the CLSI M27-A3 method. CLSI breakpoints for susceptibility were used for fluconazole, voriconazole, anidulafungin, caspofungin, and micafungin, while a provisional susceptibility breakpoint of < or = 1 microg/ml was used for amphotericin and posaconazole. Of 14,007 Candida isolates tested, 658 (4.7%) were among the less common species. Against all 658 isolates combined, the activity of each agent, expressed as the MIC50/MIC90 ratio (and the percentage of susceptible isolates) was as follows: fluconazole, 1/4 (94.8%); voriconazole, 0.03/0.12 (98.6%); posaconazole, 0.12/0.5 (95.9%); amphotericin, 0.5/2 (88.3%); anidulafungin, 0.5/2 (97.4%); caspofungin, 0.12/0.5 (98.0%); and micafungin, 0.25/1 (99.2%). Among the isolates not susceptible to one or more of the echinocandins, most (68%) were C. guilliermondii. All isolates of the less common species within the C. parapsilosis complex (C. orthopsilosis and C. metapsilosis) were susceptible to voriconazole, posaconazole, anidulafungin, caspofungin, and micafungin. Over 95% of clinical isolates of the rare Candida species were susceptible to the available antifungals. However, activity did vary by drug-species combination, with some species (e.g., C. rugosa and C. guilliermondii) demonstrating reduced susceptibilities to commonly used agents such as fluconazole and echinocandins.