Multi-drug resistant Escherichia coli in diarrhoeagenic foals: pulsotyping, phylotyping, serotyping, antibiotic resistance and virulence profiling

Authors: KENNEDY, CARRIE-ANN - University College - Ireland; WALSH, CIARA - University College - Ireland; KARCZMARCZYK, MARIA - University College - Ireland; O’BRIEN, STEPHEN - University College - Ireland; AKASHEH, NADIM - University College - Ireland; QUIRKE, MARTIN - University College - Ireland; FARRELL-WARD, SINEAD - University College - Ireland; BUCKLEY, TOM - Irish Equine Center; FOGHERTY, URSULA - Irish Equine Center; KAVANAGH, KERRIE - Irish Equine Center; Parker, Craig; SWEENEY, TORRES - University College - Ireland; FANNING, SÉAMUS - University College - Ireland

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2018
Publication Date: 8/7/2018
Citation: Kennedy, C., Walsh, C., Karczmarczyk, M., O’Brien, S., Akasheh, N., Quirke, M., Farrell-Ward, S., Buckley, T., Fogherty, U., Kavanagh, K., Parker, C., Sweeney, T., Fanning, S. 2018. Multi-drug resistant Escherichia coli in diarrhoeagenic foals: pulsotyping, phylotyping, serotyping, antibiotic resistance and virulence profiling. Veterinary Microbiology. 223:144-152. https://doi.org/10.1016/j.vetmic.2018.08.009.
DOI: https://doi.org/10.1016/j.vetmic.2018.08.009

Interpretive Summary: In this report, we describe a study of multi-drug resistant (MDR) equine Escherichia coli isolated from diarrhoeagenic foals from the Irish Equine Centre. We phenotypically and genotypically characterized the MDR and virulence associated genotypes. Bacterial isolates expressing resistance to critically important antimicrobial agents, including fluoroquinolones along with a high prevalence of extended-spectrum ß-lactamase genes, was noted. The majority of isolates (85%) possessed class 1 or class 2 integrons. Further, we also investigated the potenital pathogenicity of a selected number of these equine isolates. Human clinically important serotypes were identified and over a quarter of isolates belonged to pathogenic phylogroups. In addition, almost half of the isolates were classified as extraintestinal pathogenic E. coli (ExPEC). Our study highlights the need for increased attention to be focused on companion/sport animal reservoirs as public health threats.

Technical Abstract: Extraintestinal pathogenic E. coli (ExPEC) possess the ability to cause extraintestinal infections such as urinary tract infections, neonatal meningitis and sepsis. While information is readily available describing pathogenic E. coli populations in food-producing animals, studies in companion/sports animals such as horses are limited. In addition, many of the antimicrobial agents used in the treatment of equine infections belong to the same families as used in human medicine, potentially contributing to the spread of antibiotic resistance determinants among pathogenic strains. Thirty-nine (46%) of the isolates in this study were classified as ExPEC and hence are considered to be potentially pathogenic to humans and animals. Identified serogroups O1, O19a, O40, O101 and O153 are among previously reported human clinical ExPEC isolates. Over a quarter of the E. coli were assigned to pathogenic phylogroups B2 (6%) and D (23%). Class 1 and class 2 integrons were detected in 85% of E. coli, revealing their potential to transfer MDR to other pathogenic and non-pathogenic bacteria. With 65% of potentially pathogenic isolates harbouring one or more TEM, SHV and CTX-M extended-spectrum ß-lactamases (ESBL) added to the high levels of resistance to quinolones and flouroquinolones observed, our findings signal the need for increased attention to companion/sport animal reservoirs as public health threats.