A Cross Sectional Study On Molecular Prevalence Of Virulent Genes Of Calves Diarrheagenic Escherichia Coli And Bacterial Resistance Profile To Antimicrobials In Selected Towns Of South Wollo Administrative Zone, Amhara, Ethiopia

Abstract

Background: Escherichia coli is a known normal flora of the gastrointestinal tract frequently used as model for various research trials. Potential gain and loss of virulent genes enable it to become pathogenic and causes calf diarrhea while beneficial ones subsidize vitamin K2. These virulent genes are found on plasmids, genomes or integrated on bacteriophages and horizontal gene transfer plays in its epidemiology. This study was conducted to identify virulence genes informative to four pathogenic strains of E. coli and study their antibiotic resistance patterns to eleven antimicrobials.Results: 100 (81.3%) pure isolates of E. coli were harvested, of which, 23 (29.9%) isolates carried one or more of the tested virulent genes. stx1 (18.2%), stx2 (9.1%), eae (11.7%), hlyA (1.3%) were the detected virulent genes with their respective frequency. However, no isolates were detected for bfpA and aatA genes. Virulent genes were detected in 2-4 weeks aged calves at significantly higher order (P ≤ 0.05). Calves housed with their dam and those given supplement feed were significantly associated with detected genes (P ≤ 0.05). From samples processed using PCR, 14 (18.2%) were confirmed as STEC strain, 5 (6.5%) of EHEC and 4 (5.2%) of EPEC. Most isolates were resistant to sulfonamide, clindamycine, ampicillin, Oxytetracyclne, trimethoprime and streptomycin and sensitive to nitrfurantoin, gentamycin, neomycin, clorampfenicol and ciprofloxacine. Conclusion: Zoonotic STEC and EHEC strains are collectively found highest and implies reservoir of calves to both farm animals and humans. Poor farm hygiene and frequent use of limited antibiotics was a problem observed. As a consequence, farms hygiene as well as spatial and temporal distribution of E. coli should be concerned. Additionally, Antibiotics should alternatively be used to avoid resistance.