Candidemia by Candida parapsilosis in a neonatal intensive care unit: human and environmental reservoirs, virulence factors, and antifungal susceptibility

Braz J Microbiol. 2020 Sep;51(3):851-860. doi: 10.1007/s42770-020-00232-1. Epub 2020 Feb 15.

Abstract

The Candida parapsilosis complex has emerged as one of the main causes of candidemia worldwide. This study aims to evaluate possible C. parapsilosis sensu stricto reservoirs in a NICU, the expression of virulence factors, and antifungal susceptibility, and to analyze their genetic and phenotypic similarity. The study included 17 isolates of C. parapsilosis: seven environmental, one from a newborn's mother, and nine samples from six newborns. We used molecular and phenotypic tests to characterize the isolates and to trace possible routes of infection. The genetic similarity was determined by random amplified polymorphic DNA. The hemolytic and DNAse activity was determined using sheep's blood and DNAse agar, biofilm production by XTT method, and the susceptibility to antifungals through microdilution methodology. Two environmental strains isolated in the same month had high similarity. The 17 isolates expressed at least one of the three virulence factors studied, and one environmental isolate was resistant to fluconazole. This study shows that environmental contamination can be an important reservoir of potentially pathogenic microorganisms, since isolates of C. parapsilosis sensu stricto collected from the hospital environment were able to express virulence factors. Therefore, we emphasized the importance of determining the transmission routes in NICU in order to detect pathogen sources and reservoirs, as well as to establish prevention measures, such as adequate disinfection of the environment.

Keywords: Antifungals; Candida parapsilosis; NICU; Neonates; RAPD-PCR; Virulence.

MeSH terms

  • Antifungal Agents / pharmacology
  • Antifungal Agents / therapeutic use
  • Candida parapsilosis / classification
  • Candida parapsilosis / drug effects
  • Candida parapsilosis / genetics
  • Candida parapsilosis / isolation & purification*
  • Candidemia / diagnosis
  • Candidemia / drug therapy
  • Candidemia / microbiology*
  • Candidemia / transmission
  • Disease Reservoirs / microbiology
  • Drug Resistance, Fungal
  • Humans
  • Infant, Newborn
  • Intensive Care Units, Neonatal*
  • Microbial Sensitivity Tests
  • Molecular Typing
  • Mycological Typing Techniques
  • Virulence Factors

Substances

  • Antifungal Agents
  • Virulence Factors