Healthcare workers' hands as a vehicle for the transmission of virulent strains of Candida spp.: A virulence factor approach

Abstract

Background: Although the majority of Candida infections are thought to come from endogenous sources, the healthcare workers' (HCWs) hands are being increasingly reported as vehicles for the transmission of pathogens. The aim of the present study was to evaluate the susceptibility of yeast isolated from the HCWs' hands and ICU (Intensive Care Unit) surfaces to antifungal agents and to determine the virulence potential and the genetic similarity between the same.

Methods: The susceptibility of yeasts from the HCWs' hands (n = 57) and ICU surfaces (n = 98) to conventional antifungals (fluconazole, voriconazole, amphotericin B and micafungin) was evaluated using the broth microdilution assay accordance with CLSI M27-A3. Additionally, some virulence factors such as adhesion and biofilm capacity on abiotic surfaces and on endothelial cells were evaluated, as well as germ tube formation. The similarity among yeast isolates were evaluated by the RAPD technique using the P4, OPA18 and OPE18 primers.

Results: Five species of Candida were found on the HCWs' hands (C. albicans, C. parapsilosis (sensu stricto), C. glabrata, C. tropicalis and C. krusei) and two on ICU surfaces (C. albicans and C. parapsilosis (sensu stricto)). The isolates from hands had higher resistance rates, with C. glabrata having the highest indices (100% FLU; 100% MFG). The similarity of C. albicans from HCWs and ICU surfaces was ≥80% according to the three primers analyzed. Candida spp. from hands had a greater potential for adhesion and biofilm formation on abiotic surfaces (p < 0.05). C. albicans from ICU surfaces had the greatest potential of adhesion on endothelial cells after 2 and 24 h, and presented high filamentation in SEM images and formed more and larger germ tubes (p < 0.05).

Conclusion: the present study showed the significant virulence potential of yeasts transmitted in the hospital environment for the first time. Additionally, healthy people working in the ICU can carry these yeasts, which are capable of surviving in hospital surfaces, on their hands, offering a risk to patients, especially those who are immunocompromised.

Keywords: Candida species; Cross infection; HAI; RAPD.