Determination of Glycopeptide Resistance Genes and Virulence Factors in Vancomycin-Resistant Enterococci Isolates and the Relationship Between Glycopeptide Resistance Genes and Endogenous/Exogenous Flora

Objective: This study aimed to identify glycopeptide resistance genes and virulence factors in vancomycin-resistant Enterococcus species and to investigate the influence of the microbiota and hospital environment on glycopeptide resistance. Materials and Methods: A total of 107 enterococcal isolates were collected from patients' rectal swab cultures and environmental samples taken for surveillance purposes. Multiplex Polymerase Chain Reaction (PCR) analysis was conducted to investigate specific virulence genes (esp, hyl, asa1, cyl, and galE) and glycopeptide resistance genes (vanA, vanB, van C1 -C2, van D, vanE, and vanG). Additionally, perirectal swab cultures were obtained from patients without vancomycin-resistant enterococcal colonization to investigate the presence of glycopeptide resistance genes in their microbiota. Results: Seven isolates (6.5%) were identified as infectious agents. The most common vancomycin resistance genes were vanA (23.3%), followed by vanA + vanB (14%) and vanB + vanD (14%), respectively. The Random Amplified Polymorphic DNA Polymerase Chain Reaction (RAPD-PCR) method showed that patient surveillance and environmental isolates were clonally related. Moreover, microbiota analysis of patients without vancomycin-resistant enterococcal colonization revealed Clostridium spp. in two patients and Lactobacillus spp. in one patient, with the vanG gene found in the microbiota of only one (2.5%) patient. Conclusion:The detection of genes responsible for dissemination indicates that colonized isolates also have the potential for infection, and the hospital environment plays a primary role in the acquisition of vancomycin-resistant enterococci.