Molecular detection of the predominant Vancomycin-resistant gene in enterococci samples from a tertiary care hospital in Lahore

Background. Vancomycin-resistant enterococci (VRE) are critical nosocomial pathogens with limited treatment options. We investigated the prevalence of vancomycin resistance genes in enterococcus isolates from Sheikh Zayd Hospital, Lahore, focusing on the dominant vancomycin resistance mechanism. Materials and methods. A total of 9000 clinical specimens (urine, blood, pus, and other fluids) were cultured over the study period, yielding 437 enterococcus isolates. These were identified by standard microbiological methods. Vancomycin resistance was confirmed phenotypically, and all VRE isolates were subjected to polymerase chain reaction (PCR) for vancomycin resistance genes vanA, vanB, vanC, and vanD. Patient demographics and clinical source data were recorded. Statistical analyses (chi-square tests) were performed to assess associations between VRE occurrence and patient factors (age, gender, department). Results. Out of 437 enterococcus-positive cultures, 40 isolates (9.1%) were confirmed as VRE. All 40 VRE isolates (100%) carried the vanA gene, while no vanB, vanC, or vanD genes were detected. Urine was the predominant specimen source for VRE, accounting for 85% of vanA-positive isolates, with the remainder from pus, blood, and other specimens. The median patient age was 58 years (range 5–85), and VRE cases were more frequent in older patients (50% of cases in 60 age group). Males comprised 60% of VRE cases. The highest number of VRE cases came from intensive care units (37.5%) and medical wards (25%), followed by surgical units (20%) and urology/nephrology (12.5%). Statistical analysis showed that VRE isolation was significantly associated with age 50 years (p = 0.01) and ICU admission (p = 0.02), whereas gender was not significantly associated (p = 0.40). Conclusions. vanA was the exclusive vancomycin resistance determinant in this hospital’s VRE isolates, underscoring that high-level vancomycin resistance in enterococci is primarily mediated by the vanA gene in our setting. The dominance of vanA-positive VRE in urine samples highlights the urinary tract as a common site of VRE infection. Our findings emphasize the need for vigilant antimicrobial stewardship and infection control measures to prevent the spread of vanA-mediated VRE. This first report from Lahore on molecular VRE typing aligns with regional data and reinforces that continuous surveillance of resistance genes is crucial for guiding effective infection control policies.