Drug resistant Candida colonization among ICU patients in a Nigerian teaching hospital

Colonisation of body surfaces with resistant strains is an initial step in the pathogenesis of drug resistant invasive Candida infections. Nigeria has little data on the species distribution and resistance pattern of colonising Candida species in intensive care unit(ICU) patients. This study set out to investigate the burden of Candida colonisation in the ICU of a tertiary health institution in Ile-Ife, Nigeria.

At admission, 72 hours and 7 days, swabs of skin, oropharynx, perianal region, surgical wounds, tracheal aspirates and urine samples taken from adult ICU patients were cultured on media selective for fungi. Candida species were identified by standard microbiological methods. Sensitivity to fluconazole, voriconazole and caspofungin was determined by disc diffusion according to CLSI guidelines. Strain interrelatedness was investigated by Randomly Amplified Polymorphic DNA (RAPD).

Of 744 samples from 110 patients, 142 samples (18.3%) yielded Candida. The average colonisation index increased with duration of admission (p=0.001). Most frequently colonized were the oropharynx (39.5%) and the perianal region (22.4%). Species isolated were C. albicans 97 (68.3%), C. tropicalis 20 (14.1%), C. glabrata 12 (8.5%), C. parapsilosis 7 (4.9%) and C. krusei 6 (4.2%). About 1 in every 3 isolates was resistant to fluconazole (42/142; 29.6%). In addition, resistance to voriconazole was 12/142 (8.5%) while 10/142 (7%) were resistant to caspofungin. RAPD showed identical strains across several body sites of many patients.

Candida species with high rates of resistance to the first line antifungal agent colonise and are transmitted among ICU patients. These can potentially cause difficult to treat invasive infections, underscoring a need for better infection control practices.