Investigation of a Cluster ofCandida albicansInvasive Candidiasis in a Neonatal Intensive Care Unit by Pulsed-Field Gel Electrophoresis

Jihene Ben Abdeljelil,Akila Fathallah,Soukeina Gheith,Imene Khammari,Fatma Saghrouni,Jalel Boukadida,Moncef Ben Said

doi:10.1100/2012/138989

Jihene Ben Abdeljelil, Akila Fathallah + Show 5 more

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https://doi.org/10.1100/2012/138989

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Journal: TheScientificWorldJournal	Publication Date: Jan 1, 2012
Citations: 36	License type: CC BY 3.0

Affiliation: Hôpital Farhat Hached

Abstract

Nosocomial invasive candidiasis (IC) has emerged as a major problem in neonatal intensive care units (NICUs). We investigated herein the temporal clustering of six cases of neonatal IC due to Candida albicans in an NICU. Eighteen isolates obtained from the six neonates and two isolates from two health care workers (HCWs) working at the same unit and suffering from fingers' onychomycosis were genotyped by electrophoretic karyotyping (EK) and restriction endonuclease analysis of genomic DNA by using Sfi I (PFGE-Sfi I). PFGE-Sfi I was more effective in discriminating between temporally related isolates. It showed that (i) both HCWs had specific strains excluding them as a source of infections in neonates. (ii) Isolates collected from three neonates were identical providing evidence of their clonal origin and the occurrence of a horizontal transmission of C. albicans in the unit. (iii) The three remaining neonates had specific strains confirming that the IC cases were coincidental. (iv) Microevolution occurred in one catheter-related candidemia case. Our results illustrate the relevance of the molecular approach to investigate suspected outbreaks in hospital surveys and the effectiveness of PFGE-Sfi I for typing of epidemiologically related C. albicans isolates.

Highlights

Invasive candidiasis (IC) has substantially increased in neonatal intensive care units (NICUs) over the two past decades and is still associated with a high morbidity and mortality [1, 2]
It showed that (i) both health care workers (HCWs) had specific strains excluding them as a source of infections in neonates. (ii) Isolates collected from three neonates were identical providing evidence of their clonal origin and the occurrence of a horizontal transmission of C. albicans in the unit. (iii) The three remaining neonates had specific strains confirming that the invasive candidiasis (IC) cases were coincidental. (iv) Microevolution occurred in one catheter-related candidemia case
It has long been assumed that the vertical transmission of the Candida species, mainly C. albicans, is an important mode of acquisition of the yeasts by neonates at delivery [4]

Summary

Introduction

Invasive candidiasis (IC) has substantially increased in neonatal intensive care units (NICUs) over the two past decades and is still associated with a high morbidity and mortality [1, 2]. Many outbreaks of neonatal IC caused by strains originating from hospital staff, biomedical devices, parenteral nutrition, environment, or from other patients have been reported [5,6,7,8]. In order to type outbreak-related isolates and to assess their clonality and identify the source and the routes of their transmission, many molecular techniques have been used. They include electrophoretic karyotyping, southern blot hybridization, restriction fragment length polymorphism (RFLP) analysis, randomly amplified polymorphic DNA (RAPD) analysis, PCR-based fingerprinting, and multilocus sequence typing [5, 9,10,11,12]

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Conclusion