Medical Biochemistry

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Browsing Medical Biochemistry by Subject "Antimicrobials, Calf, Escherichia coli, Resistance Strains, Virulent Genes."

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    Molecular identification for six virulent genes of escherichia coli isolated from diarrheic calves and their resistance profile to antimicrobials in selected towns of south Wollo administrative zone, Amhara, Ethiopia.
    (Addis Ababa Universty, 2018-10) Hussen, Fentaw; Genet, Solomon (Ph.D., Assistant professor)
    Background: Escherichia coli are normal flora of the gastrointestinal tract frequently used as model for various research questions. Potential gain and loss of virulent genes enable them 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. Objective: To identify virulence genes informative for four pathogenic strains of E. coli and study their antibiotic resistance patterns to eleven antimicrobials agents. Methodology: The study was conducted in Kombolcha, Dessie and Haik areas. Purposive sampling was used to collect 123 fecal samples from 53 farms of all sites. E. coli isolates were identified based on their green metallic sheen appearance on EMB agar, their characteristic reactions on MacConkey agar and IMViC (+ + - -) biochemical tests. Antimicrobial susceptibility testing of the isolates was carried out using agar disc diffusion method on Muller Hinton agar following standard procedures. Genomic DNA was extracted from the isolates using boiling method for strain identification using PCR. Results: One hundred (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 14(18.2%), stx2 7(9.1%), eae 9(11.7%), hlyA 1(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, more spatial and temporal distribution of E. coli should be concerned. Additionally, Antibiotics should be alternatively used to avoid resistance.