Comparative Analysis of Prevalence and Antibiotic Resistance in Vancomycin-Resistant Enterococcus from Clinical Samples – Demographics and Phenotypes

Abstract

Background: Of all enterococci species, the most renowned clinically as multidrug-resistant pathogens are Enterococcus faecium and Enterococcus faecalis. Vancomycin-resistant Enterococcus (VRE) species are the principal cause of opportunistic hospital-acquired infections, due to numerous resistance mechanisms. Methods: In this study, the prevalence and antibiotic resistance profiles of VRE according to clinical sources from three selected hospitals in Southwest-Nigeria were investigated. Altogether, 431 samples (urine, rectal, and wound swabs - caesarian section (CS), automobile accidents, and other skin lesions and abrasions) were collected from three selected hospitals in Osun State, Nigeria. Established techniques were employed for the recovery of enterococci and screening for VRE while antibiotic susceptibility tests were carried out by disc diffusion technique. Results: Altogether, 208 (48.3%) enterococci strains were recovered from which 85 (40.9%) were VRE. E. faecium predominated at 71.8% (61/85) and E. faecalis at 28.2% (24/85) as determined by phenotypic characterization. VRE isolates exhibited 100%, 97.6%, and 92.9% resistance to ampicillin, clindamycin, and quinupristin-dalfopristin (Q/D) respectively. The least resistance in-vitro was to tigecycline (27.1%). None of the antibiotics exhibited 100% activity against all the isolates. vanA resistant phenotype was prevalent at 65.9%. E. faecium from all study locations displayed higher levels of resistance than E. faecalis. Multiple antibiotic resistance (MAR) indices in all VRE isolates were ≥0.2, all being multidrug-resistant. Conclusions: The high prevalence rate along with the high level of multidrug resistance observed in the present study is worrisome and poses a continuous threat in the therapy of illnesses triggered by VRE as vancomycin was perceived as a drug of choice to curb enterococcal infections.

Prevalence, molecular characterization and risk factors of vancomycin-resistant enterococci: evidence from patients admitted in University of Benin Teaching Hospital, Benin City Nigeria

“…In this study, the vanA and vanB genes screened conforms to other studies where vanA genes were detected and vanB gene was not detected (Adegoke et al, 2022). This disagrees with other studies that reported the absence of vanA genes (Adeyemi et al, 2021). Reportedly, vanA gene has been the most common vancomycin resistance gene (Igbinosa and Beshiru, 2019a).…”

“…The detection of phenotypic virulence factors have also been reported (Igbinosa and Beshiru, 2019). These virulence determinants including hemolysin and gelatinase aid nutrient acquisition from host tissues and advance invasion, thereby increasing the severity of human infections (Adeyemi et al, 2021). Biofilm formation aids disease development as it boosts the persistence of infections and reduces antimicrobial activity (Igbinosa et al, 2021).…”

“…One-gram (1 g) stool samples, 1 mL urine and blood samples, and the swab samples from wounds were aseptically inoculated into 10 mL of sterile tryptone soy broth (TSB) (Merck, Darmstadt, Germany) and incubated at 37 o C for 24 h. After incubation, a loopful of the bacterial growth from TSB was streaked on bile aesculin azide (BAA) agar (TM Media, Rajasthan, India) supplemented with 6 μg/mL vancomycin and the agar plates were incubated for 24 h at 37 °C. Black colonies on BAA agar were classified as presumptive vancomycin-resistant enterococci isolates (Beshiru et al, 2017;Adeyemi et al, 2021;Yusuf-Omoloye et al, 2023). Presumptive vancomycin-resistant enterococci were purified on nutrient agar (Lab M, Lancashire, UK).…”