Identification and Biochemical Characterization of Pathogenic Escherichia coli in Raw Beef Sold in Otuoke Market, Bayelsa State, Nigeria

Abstract

Meat and meat products are a very important category of food consumed widely to meet the nutritional requirements of humans. Due to the high nutrient and moisture content of meat, they readily support the growth of diverse microorganisms. The consumption of these products, when contaminated by pathogenic microorganisms can pose a risk to health leading to possible food poisoning, with Escherichia coli being the most implicated organism. Thus, this research focused on the isolation of Escherichia coli from raw beef (Bos taurus) retailed in Otuoke market, its biochemical identification, pathogenicity testing and antibiogram. A total of 90 raw beef samples were collected from three retail points (30 samples per point) over 3 months and cultured on Eosin-Methylene Blue (EMB) agar for the elucidation of E. coli. Conventional biochemical tests were performed on isolates to identify E. coli. The isolates were subjected to Congo-red assay to test for pathogenicity and the agar-diffusion assay to test sensitivity to commonly utilized antibiotics. A total of 51 samples (56%) were contaminated with E. coli of which 24 samples (26.6%) had mean aerobic bacteria counts greater than 5.0 Log CFU/gm which is above the European Commission Regulation No. 2073/2005 guideline for fresh beef. All E. coli isolates tested positive to the Congo-red assay, thus indicating their potential pathogenicity. Antimicrobial sensitivity assay indicates the resistance of isolates to Tetracycline (60%), Erythromycin (80%) and Amoxicillin (85%). However, the isolates were sensitive to Nitrofurantoin (90%), Gentamicin (78%) and Ciprofloxacin (82%). The results obtained highlights the high level of contamination by potentially pathogenic E. coli in retailed fresh meats which are highly resistant to some of the commonly used antibiotics. The results obtained from this study is of public health significance as it indicates possible risks of infection to people through the consumption of inadequately cooked meat or the cross-contamination of other food items by the meat products which may lead to outbreaks of food poisoning.