Hazard assessment and resistance profile of Escherichia coli strains isolated from bovine carcasses at the main slaughterhouses of Dakar, Senegal

Foodborne bacterial hazards and antibiotics resistance are a public health threat. This study aimed at assessing the slaughter conditions, the bacteriological quality of bovine carcasses and at determining the antimicrobial resistance of Escherichia coli strains isolated from bovine carcasses. A questionnaire was administered to 41 stakeholders on the slaughter line. Swabbed carcasses were analyzed according to the French standard NF ISO 17604. E. coli were plated on Tryptone Bile X Glucuronide and their sensitivity to 15 antibiotics was tested by the disk diffusion method. The results indicate deficiencies in slaughter practices, control of critical operations such as evisceration and also at the level of the training of stakeholders. The prevalence of contaminated carcasses was 99% with an average of 3.03 log10 CFU/cm2. Susceptibility testing showed E. coli to be resistant to tetracycline (32%), colistin (26%), cefepim (12%), ceftazidime (9%) and ciprofloxacin (5%). However, all E. coli strains were susceptible to cefotaxime, imipenem and norfloxacin. It is concluded that bovine carcasses from Dakar slaughterhouses represent a potential risk to public health due to the occurence of E. coli that are possible indicators of enteropathogenic agents. It also suggests the presence of E. coli resistant to critical betalactamins such as third and fourth generation cephalosporins.   Key words: Antibiotic resistance, indicator bacteria, cattle, slaughter hygiene, risk factors.