Vancomycin-Resistant Enterococcal Infections: A Report of Three Clinical Cases and Literature Review

Abstract

Introduction: Enterococci are Gram-positive bacteria that are part of the normal human gut flora but have emerged as major nosocomial pathogens, causing severe infections such as bacteremia, urinary tract infections, and peritonitis. Enterococcus faecium is particularly concerning due to its remarkable ability to acquire resistance genes, especially vanA and vanB, leading to vancomycin resistance. Materials and Methods: Three cases of vancomycin-resistant Enterococcus faecium (VRE) infection were identified in the onco-hematology, pediatrics, and urology departments. Bacterial identification and susceptibility testing were performed using the API gallery and E-test, complemented by the BD Phoenix™ automated system, while the presence of vanA and vanB genes was confirmed by multiplex PCR. Clinical Cases: All patients had risk factors for VRE infection, including prior antibiotic exposure, invasive devices, or immunosuppression. The E. faecium isolates were multidrug-resistant, showing susceptibility only to linezolid. Clinical outcomes were favorable following targeted antibiotic therapy and, when indicated, removal of the infected device. Discussion: Vancomycin-resistant enterococci, especially E. faecium, are an increasing global health concern due to multidrug resistance and healthcare-associated infections. VRE prevalence has significantly increased worldwide, reaching 32.5% in Europe in 2023 and 73.5% of healthcare-associated E. faecium infections in the United States. Their spread is mainly linked to the vanA and vanB resistance genes and to biofilm formation, which enhances persistence, colonization, and antibiotic resistance in hospital settings. Conclusion: Rapid identification of VRE and close collaboration between microbiology laboratories and infection control teams are crucial to prevent nosocomial transmission. These findings highlight the importance of continuous surveillance and enhanced awareness of VRE infections within healthcare facilities.