Detection of the VanA and VanB Gene in Clinical Isolates of Vancomycin-Resistant Enterococci

To determine the prevalence of vancomycin-resistant enterococci (VRE) among clinical isolates and to detect the presence of the vanA and vanB genes through polymerase chain reaction (PCR).

A descriptive cross-sectional study. Place and Duration of the Study: Department of Microbiology, Pak Emirates Military Hospital, Rawalpindi, Pakistan, from February to July 2025.

A total of 107 Enterococcus isolates from various clinical specimens were identified according to standard guidelines. Antimicrobial susceptibility testing was performed according to the CLSI recommendations, including the vancomycin agar dilution method. Minimum inhibitory concentration (MIC) was determined using the Vitek 2 system. Isolates identified as VRE were further analysed for the presence of vanA and vanB genes.

Among the 107 isolates, 84 (78.5%) were Enterococcus faecium, 21 (19.6%) were Enterococcus faecalis, and 2 (1.9%) were classified as other Enterococcus species. Seventeen isolates were identified as VRE; hence, the observed prevalence of VRE in clinical isolates was (15.9%), all of which exhibited resistance to teicoplanin. Additionally, two VRE isolates (1.9%) were resistant to linezolid. Out of 17 VRE isolates, the vanA gene was detected in 8 (7.5%) isolates, while the vanB gene was not detected in any isolate.

The presence of VRE and the vanA gene among clinical isolates in a tertiary care setting underscores the need for stringent surveillance and effective infection control practices.

Enterococcus faecium, Enterococcus faecalis, polymerase chain reaction, VanA gene, VanB gene.