Characterization of Enterococcus species isolated from abattoir environment in Benin city, Nigeria

Abstract

Enterococci are primarily inhabitants of the intestinal mucosa of animals and humans; however, they can also be recovered from water, soil, plants, insects and fermented food products. The aim of this study was to carry out quality indices survey for Enterococcus species from the abattoir environment in Benin City, Edo State, Nigeria. A total of 36 samples were obtained from two different abattoirs which comprised of water source (n = 12), effluent from point of usage (n = 12) and effluent from point of discharge (n = 12) between February and July, 2017. Physicochemical variables of the effluents were assessed using standard analytical techniques. The isolation of Enterococcus isolates was carried out using standard culture-based techniques. Analytical profile index 20E (API 20E) was used to confirm the identity of the Enterococcus species. Antimicrobial susceptibility profile of the Enterococcus species was determined using disk diffusion method. The mean ranges of physicochemical parameters of the water samples were: pH (5.36 ± 0.85- 7.35 ± 0.28), phosphate (0.39 ± 0.31 - 21.28 ± 0.01 mg/L), dissolved oxygen (0.83 ± 1.94 - 6.13 ± 0.13 mg/L) and chemical oxygen demand (COD) (35.66 ± 0.13 - 797.10 ± 0.35 mg/L). The mean range of mesophilic bacteria count was (6.51 ± 0.61) ×10⁷ - (1.92 ± 0.11) × 10⁸ cfu/ml and Enterococcus species- (6.66 ± 1.63) ×10¹– (1.16 ± 0.05) ×10⁴ cfu/ml. The percentage occurrence of Enterococcus species were: E. faecalis (29.7%), E. faecium (35.9%), E. durans (14.1%), E. casseliflavus (12.5%) and E. hirae (7.8%). A total of 23 (35.9%) of Enterococcus species were resistant to 9 antibiotics (PEN^R , PTZ^R , ETP^R , MEM^R , TET^R , CLI^R , CRO^R , CTX^R , and VAN^R ) which belong to 6 groups of antimicrobial with a multiple antibiotic resistance (MAR) index of 0.64. The presence of multiple antibiotic resistant indexes in Enterococcus species is of significance to ublic health. Findings from this study could be used as a baseline study to investigate outbreaks of pathogenic and multidrug resistant enterococci infections in abattoir environments.

Keywords: Enterococcus, Abattoir, Antimicrobial resistance, Environment, Multidrug resistance