Author/Authors :
Hristova ، Preslava Mihaylova Department of Microbiology and Virology - Medical University-Pleven , Nankov ، Vladislav Milkov Scientific Molecular Laboratory - Medical University-Pleven , Stoikov ، Ivan National Reference Laboratory for Control and Monitoring of Antimicrobial Resistance - National Center of Infectious and Parasitic Diseases-Sofia , Nikolaev Ivanov ، Ivan National Reference Laboratory for Control and Monitoring of Antimicrobial Resistance - National Center of Infectious and Parasitic Diseases-Sofia , Vaskova Ouzounova-Raykova ، Vessela Department of Medical Microbiology - Medical University of Sofia , Hitkova ، Hristina Yotova Department of Microbiology and Virology - Medical University-Pleven
Abstract :
Background: Vancomycin-resistant enterococci (VRE) are recognized as nosocomial pathogens with increased importance in re-cent years. These bacteria are frequently isolated from patients admitted to intensive care units (ICUs). Enterococcal pathogenicity is enhanced by di erent antibiotic resistance and virulence determinants. Objectives: The present study aimed to assess the prevalence of genes encoding resistance to antibiotics and virulence factors in intestinal VRE isolates from ICU patients. Methods: In this study, 23 VREs were investigated. Minimum inhibitory concentrations (MICs) to nine antimicrobial agents were examined using E-test. Genes encoding vancomycin resistance (vanABCDMN), aminoglycoside-modifying enzymes (aac(6’)-Ie-aph(2 )-Ia, aph(2 )-Ib, aph(2 )-Ic, aph(2 )-Id, aph(3’)-IIIa, ant(3’)-Ia, ant(4’)-Ia, ant(6’)-Ia), together with genes for various virulence factor (ace/acm, asa1, cylA, efaA, esp, gelE and hyl), were detected using multiplex PCR. Results: The species distribution of the tested VRE was as follows: Nine Enterococcus casseliflavus, seven E. gallinarum, and seven E. faecium. The vanA gene was found in all E. faecium, in six of which the classical VanA phenotype was observed. The vancomycin (vanC) phenotype was associated with the presence of vanC1 gene in E. gallinarum and the vanC2 gene in E. casseliflavus isolates. The aac(6’)-Ie-aph(2 )-Ia gene was encoding high-level gentamicin resistance (HLGR) in the studied VRE. All E. faecium were positive for acm and esp, while acm in combination with esp or hyl was detected in 2 vanC enterococci. Conclusions: According to the findings, there was a correlation between the phenotype and the genotype of glycopeptide resis-tance in the tested VRE. HLGR was more prevalent in E. faecium because of the presence of aac(6’)-Ie-aph(2 )-Ia. The higher prevalence of virulence determinants was confirmed in vanA isolates compared to the studied vanC-carrying enterococci.
Keywords :
Vancomycin , Resistant Enterococci (VRE) , Prevalence , Virulence Factors , Intensive Care Unit (ICU)
