Antimicrobial drug resistance in Escherichia coli isolated from commercial chicken eggs in Grenada, West Indies

Abstract

Objective: To determine the antimicrobial resistance profile of Escherichia coli (E coli) isolated from the shell membrane and yolk of commercial chicken eggs in Grenada.

Methods: A total of 450 eggs were collected from different locations including small (33.3%) and big farms (26.7%), roadside vendors (26.7%) and supermarkets (13.3%). The shell membranes and yolk were cultured separately on blood agar and McConkey Agar Escherichia coli were identified using biochemical tests and API20E strips. The isolates were tested for antimicrobial sensitivity.

Results: A total of 55 E coli isolates were obtained. Of which 34 isolates were from shell membrane and 21 from yolk samples. Twenty-two of the total 34 isolates from shell membrane exhibited resistance to one or more of the antibiotics used in the study whereas 11 of the 21 yolks isolate also showed resistance to one or more of the tested antibiotics. Among the six antibiotics tested, the highest level of resistance was observed for ampicillin, 42.9 per cent and 31.8 per cent respectively for shell membrane and yolk isolates. The lowest resistance rate among all the antibiotics was observed against enrofloxacin (0%). Multi-drug resistance (resistance to > or = 3 compounds) was observed in 10.9% of the isolates.

Conclusions: This study on E coli drug resistance in commercial chicken eggs in Grenada generated baseline data indicating that chicken eggs used for food can harbour resistant E coli. A regular monitoring of commensal and clinical isolates of E coli for antibacterial resistance is warranted.