Antibiogram of Escherichia coli strains isolated from food of bovine origin in selected Woredas of Tigray, Ethiopia

Escherichia coli is a food borne pathogen causing a major public health problems. The use of antimicrobials in food animals produces resistant bacteria. To determine antimicrobial resistance of E. coli species isolated from food of bovine origin, a total of 384 of milk samples (n=192) and meat samples (n=192) were collected from different sources in 1:1 ratio in selected Woredas of Tigray, Ethiopia. Samples were cultured on sheep blood agar and sub-cultured on Eosin Methylene and further sub-cultured on Biolog Universal Growth Agar (BUG media). Pure colonies were taken and suspension was made and inoculated into micro plates. The bacteria were identified by BiOLOG Identification system. Antimicrobial resistance of E. coli isolates was done by disk diffusion method using twenty antimicrobials and minimum inhibitory concentration was determined for resistant isolates. The study revealed that out of 384 samples of milk and meat, E. coli 0157:H7 (10.4%), E. coli, Non 157 STEC (2.6%) and E. coli enterotoxigenic (10.7%) were isolated. Antimicrobial resistance pattern of E. coli isolates (n=91) revealed high resistance against cephalothin (84.6%), chloroamphenicol (83.3%), tetracycline (88.9%), gentamicin (65.9%), but low resistance for sulphoxazole-trimethoprim (16.5%), neomycin (15.4%), streptomycin (29.7%), kanamycin (30.8%), ciprofloxacin (10%), nitrofurantoine (3.3%), norfloxon (3.3%) and ciftriaxone (9.9%). Multidrug resistance was observed in 82 (93.2%) of species. The high prevalence of 0157:H7 and  enterotoxigenic and high rates of multiple drug resistance indicate there is a need for timely designing prevention and control strategies.   Key words: Antimicrobial, Escherichia coli, meat, milk, resistance, zoonoses.