Contribution of healthy chickens to antimicrobial-resistant Escherichia coli associated with human extraintestinal infections in Egypt

Authors: RAMADAN, HAZEM - Mansoura University; Jackson, Charlene; TAHA, SAMAA - Suez Canal University; MOAWAD, AMIRA - Agricultural Research Center Of Egypt; Barrett, John; Woodley, Tiffanie

Submitted to: Vector-Borne and Zoonotic Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2018
Publication Date: 8/18/2018
Citation: Ramadan, H., Jackson, C.R., Taha, S., Moawad, A., Barrett, J.B., Woodley, T.A. 2018. Contribution of healthy chickens to antimicrobial-resistant Escherichia coli associated with human extraintestinal infections in Egypt. Vector-Borne and Zoonotic Diseases. 18(8):408-416. https://doi.org/10.1089/vbz.2017.2237.
DOI: https://doi.org/10.1089/vbz.2017.2237

Interpretive Summary: ß-lactam resistant Escherichia coli in both humans and food animals is cause for concern on a worldwide level. In this study,clinical samples from patients with extraintestinal infections and healthy broiler chickens were collected from Egypt during the 2nd half of 2015 and examined for the presence of E. coli. The isolates were tested for susceptibility against ß-lactam antimicrobials and screened for the presence of extended-spectrum ß-lactamase (ESBL) and virulence genes; clonal and phylogenetic types were also determined. While both human and chicken samples were positive for E. coli, more isolates from humans were resistant to the ß-lactam antimicrobials than those from chickens and ESBL genes were prevalent among all E. coli isolates. The majority of resistant E. coli isolates from human and chicken belonged to commensal rather than virulent groups. Using Pulsed-field gel electrophoresis, some E. coli clustered based upon source, but the majority of clusters contained E. coli from both humans and chickens. Results of this study suggest that although no single clone appeared to be circulating among the ß-lactam resistant E. coli, some shared characteristics exist among isolates from the two sources. Increased study will aide researchers and regulatory personnel to determine the role of humans and food animals in dissemination of ß-lactam resistant E. coli for effective use of antimicrobials intervention strategies.

Technical Abstract: ß-lactam resistant Escherichia coli in both humans and food animals is a cause for concern on a worldwide level. Clinical samples from patients with extraintestinal infections and healthy broiler chickens were collected from Egypt during the 2nd half of 2015 and examined for the presence of E. coli. The isolates were tested for susceptibility against ß-lactam antimicrobials and screened for the presence of extended-spectrum ß-lactamase (ESBL) and virulence genes; clonal and phylo types were also determined. Forty-eight percent (48/100) of human samples and 31.3% (50/160) of chicken samples were positive for E. coli. Although only 4% (2/50) of the chicken isolates were resistant to the antimicrobials tested, over 58% (28/48) of human E. coli were resistant with the highest levels against cefotaxime (58.3%; 28/48). For ESBLs, 52.1%, 33.3%, 20.8% and 6.25% of human E. coli were positive for blaCTX-M, blaTEM, blaOXA and blaCMY, while blaTEM, blaOXA and blaCMY were found in 32%, 4% and 34% of chicken isolates, respectively. The majority of resistant E. coli isolates from human and chicken belonged to commensal phylogroups. Using Pulsed-field gel electrophoresis (PFGE), some E. coli grouped based upon source, but the majority of clusters contained E. coli from both human and chicken. Results of this study suggest that although no single clone appeared to be circulating among the ß-lactam resistant E. coli, some shared characteristics exist among isolates from both sources. Increased study will aide to determine the role of humans and food animals in dissemination of ß-lactam resistant E. coli for effective intervention strategies.