Molecular epidemiology of vancomycin resistant enterococcus in tertiary care hospitals in Lebanon

Abstract

Background: The occurrence of infections caused by vancomycin-resistant Enterococcus (VRE) is on the rise, accompanied by high mortality rates and restricted treatment options. Various gene clusters contribute to vancomycin resistance in Enterococcus, with the vanA and vanB genes being the most clinically significant. There is scarce data on the molecular characterization of VRE in Lebanon. Objectives: This study aimed to conduct a genotypic analysis of VRE isolates collected from clinical samples in two hospitals in Lebanon. Clinical characteristics associated with VRE infections were also investigated. Methods: Bacterial isolates were from patients with VRE infections admitted to Saint George Hospital University Medical Centre (SGHUMC) and Hammoud Hospital University Medical Centre (HHUMC) between 2019 to 2020 and 2023 to 2024 respectively along with corresponding clinical data. Vancomycin resistance genes, including vanA and vanB, were amplified and identified in 29 VRE isolates using polymerase chain reaction (PCR). Results: All 29 (100%) VRE isolates carried the vanA gene, whereas none of the isolates carried vanB. Blood specimens yielded the highest percentage (48%), followed by urine (34.5%) of isolates from which VRE was obtained, with most patients affected being aged above 60 years. Conclusion: This study confirms that VRE isolates harbouring vanA genes are prevalent in the area of the study. PCR is a highly reliable, sensitive and specific method that enables the rapid detection of vancomycin resistance genes.