Clinical manifestations of candidemia caused by uncommon Candida species and antifungal susceptibility of the isolates in a regional hospital in Taiwan, 2007-2014

Abstract

Objective: This retrospective study investigated clinical manifestations of candidemia caused by uncommon Candida species and antifungal susceptibility of the isolates in a regional hospital in Taiwan.

Methods: The uncommon Candida species was initially defined as Candida species other than C. albicans, C. tropicalis, C. glabrata complex, C. parapsilosis complex and C. krusei. All uncommon Candida isolates were identified and confirmed by molecular methods. In vitro susceptibility testing of the uncommon Candida species to nine antifungal agents was conducted using the broth microdilution method with the Sensititre YeastOne (SYO) system (Trek Diagnostic Systems, Ltd., East Grimstead, UK).

Results: Twenty-one patients, comprising 11 males and 10 females with a median age of 69 years, were recruited. Cancer (n = 11) was the most common underlying disease, 19 (90.5%) cases had prior antibiotic exposure, and only two patients had prior antifungal use. The overall in-hospital mortality rate was 38.1% (n = 8). C. guilliermondii (n = 11) was the most common pathogen, followed by C. curvata (n = 3). C. guilliermondii isolates exhibited relatively high rates of azole minimum inhibitory concentrations (MICs) above epidemiological cut-off values (ECVs), whereas C. pelliculosa and C. lusitaniae isolates all remained susceptible to azoles. All three C. curvata isolates had high caspofungin (>8 mg/L) and fluconazole MICs (8 mg/L) and could be defined as multidrug-resistant.

Conclusions: Uncommon Candida species frequently exhibit high rates of non-susceptibility to antifungals. Identification of all Candida isolates at the species level from blood samples is of value for treatment.

Keywords: Antifungal susceptibility testing; Azoles; Candidemia; Echinocandin; Healthcare-associated infection; Uncommon candida species.