Epidemiology of Candida kefyr in patients with hematologic malignancies

Abstract

Candida kefyr is an emerging pathogen among patients with hematologic malignancies (HM). We performed a retrospective study at Johns Hopkins Hospital to evaluate the epidemiology of C. kefyr colonization and infection in HM patients between 2004 and 2010. Eighty-three patients were colonized and/or infected with C. kefyr, with 8 (9.6%) having invasive candidiasis (IC). The yearly incidence of C. kefyr colonization and candidemia increased over the study period (P < 0.01), particularly after 2009. In 2010, C. kefyr caused 16.7% of candidemia episodes. The monthly incidence of C. kefyr was higher during the summer throughout the study. In a cohort of patients with acute myelogenic leukemia receiving induction chemotherapy, risks for C. kefyr colonization included the summer season (odds ratio [OR], 3.1; P = 0.03); administration of an azole (OR, 0.06; P < 0.001) or amphotericin B (OR, 0.35; P = 0.05) was protective. Fingerprinting of 16 isolates by repetitive sequence-based PCR showed that all were different genotypes. The epidemiology of C. kefyr candidemia was evaluated in another hospital in Montreal, Canada; data confirmed higher rates of C. kefyr infection in the summer. C. kefyr appears to be increasing in HM patients, with prominent summer seasonality. These findings raise questions about the effect of antifungal agents and health care exposures (e.g., yogurt) on the epidemiology of this yeast.

FIG 1

Time trends in Candida kefyr (Ck) colonization and candidemia among patients hospitalized on hematologic malignancy (HM)-dedicated wards between 2004 and 2010; yearly incidence of C. kefyr colonization (open bars) and proportion of candidemia episodes caused by C. kefyr (closed triangles) are shown.

FIG 2

Seasonal distribution of Candida kefyr between 2004 and 2010: monthly incidence of C. kefyr colonization among patients hospitalized on hematologic malignancy (HM)-dedicated wards at the Johns Hopkins Hospital (A) with combined data from all study years with (empty bars) and without (solid bars) 2009 data (B) and monthly total numbers of positive cultures for C. kefyr at Hôpital Maisonneuve-Rosemont (combined data for all study years) (C).

FIG 3

Cluster analysis of rep-PCR profiles of 16 Candida kefyr isolates from 14 patients from 2009 and 2010. A dendrogram derived from the UPGMA algorithm is presented; scale represents percent similarity between isolates. Band profile, date of collection, and specimen origin are shown for each isolate. Isolates from the same patients are indicated with a gray box. Six groups of genotypes with genetic similarity scores of >0.90 are indicated.