Differences in biofilm production by three genotypes of Candida parapsilosis from clinical sources

Three distinct genotypes of Candida parapsilosis (group I, II, and III) have been identified among clinical isolates but their clinical significance remains unclear. We investigated the distribution of C. parapsilosis genotypes in isolates from blood, all other sites from patients, and the hands of health care workers (HCWs), and we examined the relationship between genotype and biofilm positivity. The 53 bloodstream isolates and 38 of 39 HCW isolates were categorized as group I, whereas the 67 non-blood isolates taken from patients were distributed in groups I (n=43),II (n=13), and III (n=11). Biofilm positivity was observed in 77% (103 of 134) of group I isolates versus 0% (0 of 25) of non-group I (groups II and III) isolates (P<0.01). There was no difference in biofilm production among group I isolates from blood (81%), other clinical specimens (72%), and the hands of HCWs (73%). This study has shown that biofilm production differs among three genotypes of C parapsilosis isolates and that a majority of C parapsilosis isolates from the bloodstream (100%), the hands of HCWs (97%), and all other sites from patients (64%) belong to group I, which has the ability to produce biofilm.