Multilocus Sequence Typing of Candida albicans Bloodstream Isolates in an Intensive Care Unit

Objective Investigate the molecular epidemiological characteristics of bloodstream infections (BSI) due to Candida albicans (C.albicans) in the intensive care unit (ICU) of West China Hospital, Sichuan University. Methods C.albicans isolates recovered from blood cultures in West China Hospital, Sichuan University between 2009 and 2011 were collected. Multilocus sequence typing (MLST) was performed to assess the genetic relationships among BSI isolates of C.albicans collected from the ICU. Results 135 BSI isolates of Candida species were obtained from 2009 to 2011. C.albicans was the leading pathogen (51 isolates, 37.8%). 17 C.albicans BSI isolates from 15 patients of ICU were analyzed by MLST. Among the 17 isolates, 15 were recovered from peripheral blood and 2 from central venous catheters (CVC) (Peripheral blood and CVC were sent for culture and both had positive results for 2 patients). The 17 isolates yielded 15 unique sequence types (STs) by MLST. While 14 STs were each derived from a single isolate, 1 STs were shared by 3 isolates. 5 (29.4%) isolates were clustered within Group 46, 2 (11.8%) isolates were clustered within Group 47, and 10 isolates (58.8%) typed as singletons. The strains (Calb-36 and Calb-40) recovered from one blood sample and one CVC from one patient were indistinguishable by MLST, while two distinct strains were found in one blood sample and one CVC from another patient. Conclusion C.albicans was the most frequently isolated species of candidemia in West China Hospital. Predominant strains of C.albicans caused BSI in the ICU belonged to Group 46 and Group 47. There was not yet an outbreak of BSI caused by C.albicans, but catheter-related candidemia was confirmed by our research.