Co-occurrence of Vancomycin and Multidrug Resistance in Enterococci obtained from clinical samples in a Tertiary hospital in Port Harcourt, Nigeria

Abstract

Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens often regarded as  "superbugs", with very limited  treatment options. Continuous surveillance is essential to monitor  changes in epidemiology and possible treatment options. This study  was aimed to explore the cooccurrence of vancomycin and multidrug resistance in clinical enterococci isolates from Port  Harcourt,  Rivers State. Identities of clinical enterococci were confirmed and susceptibility was carried  out using Kirby-Bauer disc diffusion method.  Multidrug resistance status of the isolates was  determined. Vancomycin-resistant isolates were tested for the presence of vanA and vanB  vancomycin  resistance determinants using PCR following DNA extraction using the boiling method. Isolates  exhibited high levels  of resistance to most antibiotics with 100% resistance noted to  amoxicillin/clavulanate potassium, ceftazidime, cefuroxime and  cloxacillin. Isolates were however  generally susceptible to gentamicin and ofloxacin with a 16% resistance rate in both. A total of 7  antibiogram patterns were observed, though majority of the isolates (60%, 15/25) had the same  antibiogram pattern (AUG-CAZ-CRX-CTR- CXC-ERY). Fifteen (60%) of the isolates were  vancomycin-resistant, and all 15 (100%) were multidrug-resistant. The vanB gene was  detected in  53.3% (8/15) of the vancomycin-resistant isolates, while no vanA gene was detected. Though reporting  a high association of  VRE with multidrug resistance, this study notes that majority of these isolates  were sensitive to the aminoglycoside gentamicin indicating  a possible treatment option. Vancomycin  resistance of enterococci in this study was mediated by vanB rather than vanA  genes. More wide scale  surveillance is needed for understanding the epidemiology of VRE in Nigeria.