Detection of neonatal unit clusters of Candida parapsilosis fungaemia by microsatellite genotyping: Results from laboratory-based sentinel surveillance, South Africa, 2009-2010

Mycoses. 2017 May;60(5):320-327. doi: 10.1111/myc.12596. Epub 2017 Jan 19.

Abstract

Neonatal candidaemia is a common, deadly and costly hospital-associated disease. To determine the genetic diversity of Candida parapsilosis causing fungaemia in South African neonatal intensive care units (NICUs). From February 2009 through to August 2010, cases of candidaemia were reported through laboratory-based surveillance. C. parapsilosis isolates from neonatal cases were submitted for identification by internal transcribed spacer (ITS) region sequencing, antifungal susceptibility testing and microsatellite genotyping. Cluster analysis was performed using Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Of 1671 cases with a viable Candida isolate, 393 (24%) occurred among neonates. Isolates from 143 neonatal cases were confirmed as C. parapsilosis sensu stricto. Many isolates were resistant to fluconazole (77/143; 54%) and voriconazole (20/143; 14%). Of 79 closely-related genotypes, 18 were represented by ≥2 isolates; 61 genotypes had a single isolate each. Seven clusters, comprised of 82 isolates, were identified at five hospitals in three provinces. Isolates belonging to certain clusters were significantly more likely to be fluconazole resistant: all cluster 7 isolates and the majority of cluster 4 (78%), 5 (89%) and 6 (67%) isolates (P<.001). Candida parapsilosis-associated candidaemia in public-sector NICUs was caused by closely related genotypes and there was molecular evidence of undetected outbreaks as well as intra-hospital transmission.

Keywords: Candida parapsilosis; South Africa; candidaemia; neonates.

MeSH terms

  • Antifungal Agents / pharmacology
  • Candida / classification*
  • Candida / drug effects
  • Candida / genetics
  • Candida / isolation & purification
  • Candidemia / epidemiology
  • Candidemia / microbiology*
  • Candidemia / transmission
  • Cluster Analysis
  • DNA, Ribosomal Spacer / genetics
  • Female
  • Fluconazole / pharmacology
  • Genetic Variation
  • Genotype
  • Genotyping Techniques
  • Humans
  • Infant, Newborn
  • Intensive Care Units, Neonatal*
  • Male
  • Microbial Sensitivity Tests
  • Microsatellite Repeats*
  • Mycological Typing Techniques
  • Phylogeny
  • Sentinel Surveillance*
  • South Africa / epidemiology
  • Voriconazole / pharmacology

Substances

  • Antifungal Agents
  • DNA, Ribosomal Spacer
  • Fluconazole
  • Voriconazole