GeneXpert vanA/vanB test and culture method in evaluation of Vancomycin Resistant Enterococcus (VRE) colonisation in a tertiary hospital

Year 2018, Volume: 10 Issue: 2, 33 - 39, 07.12.2018

Nida Özcan , Nezahat Akpolat Selahattin Atmaca Kadri Gül

Abstract

Background: Enterococci are responsible for various nosocomial infections. The spread of vancomycin-resistant enterococci (VRE) especially in intensive care units (ICU) is a major threat in hospitals. Determination of VRE colonisers is crucial in order to prevent spreading of VRE. It was aimed to determine the colonisation of VRE among ICU patients by GeneXpert vanA/vanB test and culture method in a period of two years.
Method: From April 2015 to March 2017, a total of 788 rectal swab specimens were obtained from 292 ICU patients hospitalized at Dicle University hospitals. Swab samples were evaluated for VanA and VanB genes by GeneXpert® vanA / vanB, (Cepheid, USA) real time polymerase chain reaction (Rt-PCR) commercial system. Enterococcosel agar with 8 μg/mL vancomycin was used for cultivation of the samples. Swab samples were inoculated at 37°C, in aerobic condition for 48 hours. The growing bacteria were identified by Maldi Biotyper (Bruker, Germany) and antimicrobial susceptibilities were carried by BD Phoenix (Becton Dickinson, U.S.A) authomated microbiology system.
Results:Among 788 swab samples 116 (14,7%) were detected as VRE with GeneXpert vanA/vanB method. Of PCR positive samples, 107 (92,2%) were VanA, 7 (6%) were VanB and 2 (1,7%) were both VanA and VanB harbouring. Among VanA detected samples, 75 grew Enterococcus faecium, 8 grew Enterococcus faecalis isolates while 24 samples had no growth in cultivation. Among 7 VanB harbouring samples, 1 was identified as E. faecium while other 6 had no growth.Two samples with both VanA and VanB genes were isolated as E. faecium.
Conclusion: Active VRE surveillance and isolation of VRE carriers is crucial in hospitals. Molecular methods have important advantages in early diagnosis and on time isolation of the patients.

Keywords

vancomycin-resistant enterococci, vanA / vanB

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