Abstract
A cross sectional study was conducted from October 2010 to March 2011, on apparently healthy slaughtered cattle in Haramaya University Slaughter House to determine prevalence of Escherichia coli, with special emphasis on Escherichia coli O157:H7, and its antimicrobial susceptibility pattern. Carcass swab samples were collected and pre-enriched in buffered peptone water and plated on MacConkey agar plate. Presumptive colonies were confirmed by biochemical tests. Further identification of Escherichia coli O157:H7 was done by plating the isolatedm bacteria on Sorbitol MacConkey agar; and then colorless colonies were subjected to Escherichia coli O157:H7 Latex agglutination test. From a total of 113 samples collected, Escherichia coli was isolated from 35 (30.97%) and out of these, 3 (2.65%) were found to be Escherichia coli O157:H7. The difference in prevalence was not statistically significant (P>0.05) between local and cross breeds (χ2=0.11, df =4), among age group of animals (χ2=2.56, df=1) and origin of animals (χ2=2.56, df=2). The isolated bacteria were subjected to antimicrobial susceptibility testing and the majority were found to be susceptible to Chloramphenicol (30 μg), Kanamycin (30 μg), Spectinomycin (SH, 100 μg). The presence of E. coli O157:H7 in raw meats reaching to consumers indicated possible risks of infection to people through the consumption of raw (undercooked) meat and cross contamination of other food products. Therefore, control measures at all stages of food chain was recommended.
Highlights
Escherichia coli (E. coli) are normal inhabitants of the gastrointestinal tract of animals and human beings [1,2,3]
Outbreaks of E. coli O157 have been reported in different parts of the world and antibiotic use is controversial because of the potential to increase production and secretion of Shiga toxins
The overall prevalence of carcass contamination with E. coli species of the present study in the slaughtered animals was 30.97 % (n=113) which is higher than 4.4% (n=885) prevalence reported in Kenya [12]
Summary
Escherichia coli (E. coli) are normal inhabitants of the gastrointestinal tract (lower ileum and large intestine) of animals and human beings [1,2,3]. Infection with E. coli O157:H7 is a major food borne and zoonotic pathogen responsible for hemorrhagic colitis and hemolytic uremic syndromes in humans. Transmission to human occurs through consumption of undercooked meat, unpasteurized dairy products, and vegetables or water contaminated by feces of carrier animals [1]. Outbreaks of E. coli O157 have been reported in different parts of the world and antibiotic use is controversial because of the potential to increase production and secretion of Shiga toxins. Differentiation of pathogenic strains from the normal flora depends on the identification of virulence characteristics [4]
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