Epidemiology of Candida colonization in an intensive care unit of a teaching hospital in Kuwait

Abstract

The incidence of Candida infections in intensive care units (ICU) is increasing. Although most cases of candidemia are caused by commensal strains colonizing the patients' own body sites, recent studies have suggested that the source of Candida infection can also be exogenous. This study was carried out to prospectively investigate the frequency of Candida colonization among patients and health care personnel of an ICU of a teaching hospital in Kuwait. A total of 57 patients and 45 nurses were investigated. Candida isolates were identified to the species level by the Vitek identification system. The typing of selected isolates was performed by randomly amplified polymorphic DNA (RAPD) using three different arbitrary primers (CARAPD1, AP3, CT5). Of the 526 samples collected from 57 patients, 180 (34%) yielded Candida species. These included 112 (62%) C. albicans, 37 (21%) C. glabrata, 15 (8%) C. parapsilosis, 11 (6%) C. tropicalis, 3 (2%) C. krusei and 2 (1%) C. lusitaniae isolates. Thirty-seven patients (65%) were colonized by Candida at some point of stay in the ICU. Seven (12%) patients yielded more than one Candida species from the sites/specimens tested. The frequency of Candida isolation was highest from oropharynx, followed by rectum, groin, urine and trachea. Twenty-five (6%) of the 448 swabs from the nurses yielded Candida and included C. albicans (n = 16), C. parapsilosis (n = 4) and C. famata (n= 5). While all the three primers yielded varying patterns in RAPD analyses for each Candida species, the results obtained by AP3 were most discriminatory. The data showed that the colonizing Candida isolates recovered from yarious body sites of the patients, as well as the nursing staff, were different. However, when RAPD profiles of three blood culture isolates from candidemic patients were analyzed, the DNA fingerprint produced by one C. parapsilosis blood culture isolate was similar to C. parapsilosis recovered from the hands of two nurses, suggesting exogenous acquisition of infection.