Correlation between the antibiotic resistance and virulence determinants of vancomycin-resistant enterococci: paradoxical involvement of vanA in phenotypic resistance to teicoplanin

Enterococcus faecium and E. faecalis were identified as predominant multidrug-resistant species carrying multiple virulence determinants, with esp and gelE strongly linked to biofilm formation and gelatinase activity. Linezolid, teicoplanin, and chloramphenicol remained the most effective agents. Our findings demonstrate the coexistence of resistance and virulence traits, along with unexpected genotype-phenotype variations, underscoring the need for integrated molecular and phenotypic approaches in surveillance and clinical management.