An outbreak of candidemia due to candida parapsilosis in an adult intensive care unit

Abstract

Candida spp. is one of the most common causes of nosocomial bloodstream infections, and Candida parapsilosis is an emerging pathogen that is associated with nosocomial outbreaks. We aimed to characterize an outbreak of candidemia due to C. parapsilosis in our hospital’s adult intensive care unit to investigate the clonal relationship of isolates. This is a retrospective study designed to investigate an outbreak of C. parapsilosis bloodstream infections (BSIs) which developed during an 11-week period from July to October 2012. Thirteen outbreak isolates and five isolates from the previous five sporadic cases were included in the study. Identification and antifungal susceptibilities of the isolates were determined by using MALDI-TOF MS (VITEK MS, bioMérieux, France) and by Etest (bioMérieux, France) on RPMI 1640-2% glucose agar (bioMérieux, France) at the Clinical Microbiology Laboratory. Clonal relationships were investigated by repetitive sequence-based PCR (rep-PCR) (DiversiLab, bioMérieux, Marcy L’Étoile, France). The mean age of the cases, seven of which were female, was 61 years. The mean Candida score was 3, the mean length of stay in the intensive care unit (ICU) before infection developed was 33 days. A microbiological cure was obtained in nine (69.2%) patients with appropriate antifungals and catheter removal. Six patients died in a mean of 24 days. All of these isolates were obtained from blood culture, three being also obtained from CVC tips culture. Sixteen isolates were C. parapsilosis, and two isolates were C. orthopsilosis. All of the isolates were susceptible to amphotericin B, voriconazole, and caspofungin. Three isolates were resistant to fluconazole, and two isolates were dose-dependent susceptible to fluconazole. Out of the 13 outbreak isolates and five previous isolates, 11 and three, respectively, showed the same repPCR genotypic profile (genotype 1). Two isolates were the second same genotypic profile (genotype 2), and two isolates were the third same genotypic profile (genotype 3). The outbreak was under control in 11 weeks. The sporadic cases occurred in a subsequent three-month period. Our study shows that if C. parapsilosis isolates are present in a unit, it can become colonized in the unit and can spread clonally and rapidly, being able to cause a nosocomial outbreak. Moreover, even one isolate of C. parapsilosis in a unit can trigger an outbreak. Molecular typing methods are essential in order to illustrate the epidemiology of hospital outbreaks. Early detection of outbreaks is crucial for the implementation of infection control measures such as disinfection and isolation. © 2019, EDIMES Edizioni Medico Scientifiche. All rights reserved.