Detection of extended‐spectrum β‐lactam, AmpC and carbapenem resistance in Enterobacteriaceae in beef cattle in Great Britain in 2015

• Published in: Journal of applied microbiology Vol. 126; no. 4; pp. 1081 - 1095
• Main Authors: Velasova, M., Smith, R.P., Lemma, F., Horton, R.A., Duggett, N.A., Evans, J., Tongue, S.C., Anjum, M.F., Randall, L.P.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-04-2019
• Subjects: Agar; Amides; Antibiotics; Beef; Beef cattle; Bovidae; Carbapenemase; Cattle; Citrobacter; E coli; Electrophoresis; Enterobacteria; Enterobacteriaceae; epidemiology; Farms; Gel electrophoresis; Gene sequencing; Genes; Genetic diversity; Genomes; Impact resistance; Mass spectrometry; Mass spectroscopy; Phenotypes; resistance; Risk analysis; Risk factors; veterinary; epidemiology; veterinary; Enterobacteria; antibiotics; resistance
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.14211

Aims
This study investigated the occurrence and genetic diversity of Enterobacteriaceae with extended‐spectrum β‐lactamase (ESBL)‐, AmpC‐ and carbapenemase‐mediated resistance in British beef cattle, and related risk factors.
Methods and Results
Faecal samples (n = 776) were obtained from farms in England and Wales (n = 20) and Scotland (n = 20) in 2015. Isolates from selective agars were identified by MALDI ToF mass spectrometry. Selected isolates were characterized by multiplex PCR (blaCTX‐M, blaOXA, blaSHV and blaTEM genes), whole‐genome sequencing (WGS), minimum inhibitory concentrations and pulsed‐field gel electrophoresis. None of the faecal samples yielded carbapenem‐resistant Escherichia coli. Ten (25%) of the farms tested positive for ESBL‐producing CTX‐M Enterobacteriaceae, 15 (37·5%) of the farms were positive for AmpC phenotype E. coli and none were positive for carbapenem‐resistant E. coli. WGS showed a total of 30 different resistance genes associated with E. coli, Citrobacter and Serratia from ESBL agars, and colocation of resistance genes with blaCTX‐M1. Buying bulls and bringing in fattening cattle from another farm were identified as significant risk factors for positive samples harbouring CTX‐M Enterobacteriaceae or AmpC phenotype E. coli respectively.
Conclusions
Beef cattle on a proportion of farms in GB carry ESBL‐producing Enterobacteriaceae. Factors, such as operating as a closed herd, may have an important role in reducing introduction and transmission of resistant Enterobacteriaceae. The results indicate management factors may play an important role in impacting ESBL prevalence. In particular, further study would be valuable to understand the impact of maintaining a closed herd on reducing the introduction of resistant Enterobacteriaceae.
Significance and Impact of the Study
This is the first study showing the presence of ESBL‐producing Enterobacteriaceae in British beef cattle.