title: The Epidemiology of Antimicrobial Resistant Escherichia coli in Hospitalised Companion Animals
Creators: name: Tuerena, Ian
Publisher: name: University of Liverpool Repository
Year: 2015

description: Antimicrobial resistance (AMR) among E. coli is a significant and growing problem in human medicine with particular concern regarding production of extended spectrum beta lactamase (ESBL) and AmpC enzymes which confer resistance to third and fourth generation cephalosporins. AMR among E. coli of animal origin is well documented, including ESBL-producing E. coli and an increasing number of pets may be at risk of nosocomial colonisation and infection with these organisms. The mains aims of the work presented in this thesis were to determine the prevalence of antimicrobial resistance E. coli, including several important AMR phenotypes and genotypes, from both the faecal microflora of animals hospitalised in referral practices and their practice environment. A further aim was to determine the risk factors for carriage of important resistance phenotypes by faecal commensal E. coli in these practices. Faecal (n = 333) and environmental (n = 257) samples were collected from dogs and cats hospitalised at five referral practices in Northwest England. Microbiological and molecular analyses including sequencing were performed to determine the resistance profile of each E. coli isolate and to identify ESBL and AmpC producing E. coli. Univariable followed by multivariable analyses were performed to identify risk factors associated with carriage of important resistance outcomes. The adjusted prevalence of important resistance types among faecal sample isolates were: clavulanic acid potentiated amoxicillin (CAPA) 14% (95% CI 6.7-27); ciprofloxacin 9.2% (95% CI 3.2-23.9); multidrug resistance (MDR) 13.1% (95% CI 6.9-23.6); ESBL-producer 14.0% (95% CI 5.3-35.0) and AmpC-producer 7.7% (95% CI2.5-21.1). There was significant variation by practice suggesting practice factors are potentially important. Among MDR isolates ciprofloxacin and CAPA resistance featured frequently. The blaCTX-M-15 and blaTEM-158 (inhibitor resistant) gene variants were the two most frequently identified ESBL genes. Among environmental samples similar resistance trends were observed in isolates to those isolated from faecal samples. Resistant isolates were more likely to be found in outside walking areas and ward floors than tables and keyboards. Neurosurgery and soft tissue surgery cases were generally at increased risk of several resistance outcomes compared to medical and orthopaedic cases. Use of fluoroquinolones and CAPA were associated with increased risk of a number of resistance outcomes, including ESBL production, and isolation of environmental AmpC-producers was associated with increased risk of CAPA resistance. Increased hospitalisation time was also identified as a risk factor for some outcomes. This study shows the presence of high rates of carriage of important AMR types in UK companion animal hospitals. The environment is likely to play an important role in the acquisition and spread of these bacteria within a hospital. Use of antimicrobials, hospitalisation, case type and individual practice were shown to be important risk factors for AMR acquisition.