Molecular and Phenotypic Characterization of Some Antimicrobial Resistance Genes in Escherichia coli Isolated from Human and Broiler Chickens

Abstract

Antimicrobial resistance is an issue of global concern and threats both animal and human health worldwide. The current research was carried out to characterize the genetic characteristics of antibiotic resistance in Escherichia coli isolates from hospitalized patients and fecal E. coli of broiler chickens. A total of 97 E. coli strains isolated from urine specimens of hospitalized patients and fecal samples of broiler chickens were subjected to bacteriological and biochemical examination. Samples were analyzed by agar disc diffusion to determine their susceptibility patterns to 13 antimicrobial agents. Ten of different resistant pattern strains were screened by molecular methods to detect 10 resistance genes. All the E. coli isolates showed high resistance to multiple drugs. The resistance pattern of all isolates was most frequently observed against Ampicillin 78.4%, Trimethoprim/sulfameth 71.1%, Streptomycin 75.3%, Amoxicillin-Sulbactam 69.1% and Tetracyciln 65%, but less frequently with Levofloxacin 11.3%, Ceftriaxone 26.8% and Ciprofloxacin 33%. Strains of E. coli from human were highly resistant to Ampicillin 72.7% but the highest level of antibiotic resistance in broiler isolates recorded against Amoxicillin-Sulbactam 85.7%. However, the lowest level of antimicrobial resistant recorded with Levofloxacin either in human 12.7% or in broiler 9.5%. Ten E. coli isolates (five for each human and broiler) with different resistance pattern were selected and screened by molecular methods for resistance genes. The sulI (sulfonamide), tetA (Tetracycline) and tetB resistance encoding genes were detected in all the tested isolates (100%) but no one of tested E. coli isolates contained TEM (Beta-lactam) gene. The antibiotic resistance genes OXA, SHV, dhfrV, dhfrI, cmlA and cat1 were detected in both human isolates and animal isolates. E. coli from both humans and broiler chickens recorded resistance to the commonly used antibiotics. Moreover, multi-drug resistance to E. coli isolated from broiler samples was higher in frequency than those isolated from clinical specimens. Therefore, regular monitoring and regulated use of antimicrobial in broiler farms should be encouraged. K e y w o r d s Escherichia coli, poultry, antimicrobial resistance genes TEM (Beta-lactam) gene.