Extended-Spectrum β-lactamase-Producing Enterobacteriaceae Shedding in Farm Horses Versus Hospitalized Horses: Prevalence and Risk Factors

Abstract

We aimed to investigate the prevalence, molecular characteristics and risk factors of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) shedding in horses. A prospective study included three cohorts: (i) farm horses (13 farms, n = 192); (ii) on hospital admission (n = 168) and; (iii) horses hospitalized for ≥72 h re-sampled from cohort (ii) (n = 86). Enriched rectal swabs were plated, ESBL-production was confirmed (Clinical and Laboratory Standards Institute (CLSI)) and genes were identified (polymerase chain reaction (PCR)). Identification and antibiotic susceptibility were determined (Vitek-2). Medical records and owners’ questionnaires were analyzed. Shedding rates increased from 19.6% (n = 33/168) on admission to 77.9% (n = 67/86) during hospitalization (p < 0.0001, odds ratio (OR) = 12.12). Shedding rate in farms was 20.8% (n = 40/192), significantly lower compared to hospitalized horses (p < 0.0001). The main ESBL-E species (n = 192 isolates) were E. coli (59.9%, 115/192), Enterobacter sp. (17.7%, 34/192) and Klebsiella pneumoniae (13.0%, 25/192). The main gene group was CTX-M-1 (56.8%). A significant increase in resistance rates to chloramphenicol, enrofloxacin, gentamicin, nitrofurantoin, and trimethoprim-sulpha was identified during hospitalization. Risk factors for shedding in farms included breed (Arabian, OR = 3.9), sex (stallion, OR = 3.4), and antibiotic treatment (OR = 9.8). Older age was identified as a protective factor (OR = 0.88). We demonstrated an ESBL-E reservoir in equine cohorts, with a significant ESBL-E acquisition, which increases the necessity to implement active surveillance and antibiotic stewardship programs.

Extended-Spectrum β-Lactamase-Producing Enterobacterales Shedding by Dogs and Cats Hospitalized in an Emergency and Critical Care Department of a Veterinary Teaching Hospital

“…Shedding rate on admission does not necessarily represent the healthy companion animal community, since these animals were referred to a tertiary referral center, 63.2% of them were previously treated in a veterinary clinic and 17.7% were hospitalized in the previous year. This shedding rate is similar to what was found among horses in the same veterinary hospital, where ESBL-PE shedding upon hospital admission was 19.6% [ 18 ]. Data from human medicine reported in Israel more than a decade ago, indicated lower ESBL-PE shedding rates upon hospital admission of 13.7% [ 19 ] and 10.7% in another study [ 20 ].…”

“…These findings could be the result of acquisition of resistant bacteria or mobile genetic elements from the hospital environment. Alternatively, these could be the result of an increase in resistant bacteria that were undetected in the gastrointestinal flora as was previously suggested [ 18 , 22 ]. In a similar study in a veterinary teaching hospital in the United States, multidrug resistant (MDR) E. coli was acquired in 6.8% of the animals and was persistent in 3% [ 22 ].…”

“…The only significant difference was the decrease in E. coli prevalence post admission, when combining both periods, alongside with insignificant increase in K. pneumoniae prevalence. In similar studies conducted in the large animal department in the same veterinary teaching hospital and during similar time periods, the main ESBL-PE species found were E. coli and K. pneumoniae , but there were significant changes in bacterial species distribution, including new species that were acquired during hospitalization [ 18 , 25 ]. This may be due to differences in pathologies and antibiotic stewardships between the small and large animals as well as differences in hospitalization facilities, and therefore calls for further investigation.…”

Emergence and Spread of Different ESBL-Producing Salmonella enterica Serovars in Hospitalized Horses Sharing a Highly Transferable IncM2 CTX-M-3-Encoding Plasmid

“…In a previous study, we investigated the shedding rate of ESBL-producing Enterobacterales in farm horses versus hospitalized horses and observed a significant increase in ESBL shedding rate among hospitalized horses together with first isolation of three colonizing isolates that we identified as ESBL-S isolates (Shnaiderman-Torban et al, 2020). The present study investigated and characterized the molecular epidemiology of ESBL-S isolates that were isolated during our surveys, together with ESBL-S isolates recovered from clinical infections from hospitalized horses during the study period.…”

Antimicrobial Resistance in Horses

“…ESBL colonization in neonatal foals was associated with umbilical infection and ampicillin treatment during hospitalization [ 11 ]. In Israel, risk factors for ESBL-E shedding in farm horses included horses’ breed, sex, and previous antibiotic treatment [ 12 ]. In a similar cohort of healthy horses from Canada, the number of staff members and equestrian event participation were identified as risk factors for MDR E. coli shedding [ 13 ].…”