Extended spectrum ß lactamase-producing Enterobacteriaceae shedding by race horses in Ontario, Canada.

BACKGROUND: We aimed to investigate the prevalence, molecular epidemiology and prevalence factors for Extended Spectrum ß-Lactamase-producing Enterobacteriaceae (ESBL-E) shedding by race horses. A cross-sectional study was performed involving fecal samples collected from 169 Thoroughbred horses that were housed at a large racing facility in Ontario, Canada. Samples were enriched, plated on selective plates, sub-cultured to obtain pure cultures and ESBL production was confirmed. Bacterial species were identified and antibiotic susceptibility profiles were assessed. E. coli sequence types (ST) and ESBL genes were determined using multilocus sequence type (MLST) and sequencing. Whole genome sequencing was performed to isolates harboring CTX-M-1 gene. Medical records were reviewed and associations were investigated. RESULTS: Adult horses (n = 169), originating from 16 different barns, were sampled. ESBL-E shedding rate was 12% (n = 21/169, 95% CI 8-18%); 22 ESBL-E isolates were molecularly studied (one horse had two isolates). The main species was E. coli (91%) and the major ESBL gene was CTX-M-1 (54.5%). Ten different E. coli STs were identified. Sixty-four percent of total isolates were defined as multi-drug resistant. ESBL-E shedding horses originated from 8/16 different barns; whereas 48% (10/21) of them originated from one specific barn. Overall, antibiotic treatment in the previous month was found as a prevalence factor for ESBL-E shedding (p = 0.016, prevalence OR = 27.72, 95% CI 1.845-416.555). CONCLUSIONS: Our findings demonstrate the potential diverse reservoir of ESBL-E in Thoroughbred race horses. Multi-drug resistant bacteria should be further investigated to improve antibiotic treatment regimens and equine welfare.

Differential Infection Patterns and Recent Evolutionary Origins of Equine Hepaciviruses in Donkeys.

The hepatitis C virus (HCV) is a major human pathogen. Genetically related viruses in animals suggest a zoonotic origin of HCV. The closest relative of HCV is found in horses (termed equine hepacivirus [EqHV]). However, low EqHV genetic diversity implies relatively recent acquisition of EqHV by horses, making a derivation of HCV from EqHV unlikely. To unravel the EqHV evolutionary history within equid sister species, we analyzed 829 donkeys and 53 mules sampled in nine European, Asian, African, and American countries by molecular and serologic tools for EqHV infection. Antibodies were found in 278 animals (31.5%), and viral RNA was found in 3 animals (0.3%), all of which were simultaneously seropositive. A low RNA prevalence in spite of high seroprevalence suggests a predominance of acute infection, a possible difference from the mostly chronic hepacivirus infection pattern seen in horses and humans. Limitation of transmission due to short courses of infection may explain the existence of entirely seronegative groups of animals. Donkey and horse EqHV strains were paraphyletic and 97.5 to 98.2% identical in their translated polyprotein sequences, making virus/host cospeciation unlikely. Evolutionary reconstructions supported host switches of EqHV between horses and donkeys without the involvement of adaptive evolution. Global admixture of donkey and horse hepaciviruses was compatible with anthropogenic alterations of EqHV ecology. In summary, our findings do not support EqHV as the origin of the significantly more diversified HCV. Identification of a host system with predominantly acute hepacivirus infection may enable new insights into the chronic infection pattern associated with HCV. IMPORTANCE: The evolutionary origins of the human hepatitis C virus (HCV) are unclear. The closest animal-associated relative of HCV occurs in horses (equine hepacivirus [EqHV]). The low EqHV genetic diversity implies a relatively recent acquisition of EqHV by horses, limiting the time span for potential horse-to-human infections in the past. Horses are genetically related to donkeys, and EqHV may have cospeciated with these host species. Here, we investigated a large panel of donkeys from various countries using serologic and molecular tools. We found EqHV to be globally widespread in donkeys and identify potential differences in EqHV infection patterns, with donkeys potentially showing enhanced EqHV clearance compared to horses. We provide strong evidence against EqHV cospeciation and for its capability to switch hosts among equines. Differential hepacivirus infection patterns in horses and donkeys may enable new insights into the chronic infection pattern associated with HCV.

Methicillin-Resistant Staphylococcus aureus spa Type t002 Outbreak in Horses and Staff at a Veterinary Teaching Hospital after Its Presumed Introduction by a Veterinarian.

Methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization, involving MRSA strains which differ from common human health care-associated clones, have become serious emerging conditions in equine veterinary hospitals. In 2010, MRSA spa type t535 caused an outbreak involving both horses and personnel in a veterinary teaching hospital in Israel. Since then, surveillance continued, and occasional MRSA isolation occurred. Two years later, MRSA of another spa type, t002, was isolated from a veterinarian and, 3 weeks later, from a horse. The appearance of spa type t002, a common clone in human medicine in Israel, among both personnel and horses, prompted a point-prevalence survey of hospital personnel and hospitalized horses. Fifty-nine staff members (n = 16 equine; n = 43, other) and 14 horses were screened. Ten of 59 staff members (16.9%) and 7 of 14 horses (50%) were MRSA carriers. Among the staff, 44% of large animal department (LAD) personnel, compared with only 7% of non-LAD personnel, were carriers. Isolates from all horses and from 9 of 10 personnel were found to be of MRSA spa type t002. This clone was later isolated from an infected postoperative wound in a hospitalized horse. Measures were taken to contain transmission between horses and personnel, as was done in the previous outbreak, resulting in reduction of transmission and, finally, cessation of cross-transmission between horses and personnel.

Persistence of Anti-Rabies Antibody Response in Horses Following Vaccination.

Rabies is a fatal zoonotic disease affecting all mammalian species. It is caused by the rabies virus and is prevalent worldwide. Horses are not commonly infected with rabies but their vaccination is recommended due to the potential zoonotic risk. This study aimed to evaluate the duration of immunity following rabies vaccination in horses. A total of 126 serum samples were collected from 93 horses, vaccinated 6 to 91 months before sampling. Rabies-virus-neutralizing antibody (RVNA) levels were evaluated using the Rabies Fluorescent Focus Inhibition Test (RFFIT). A protective RVNA titer of above 0.5 IU/mL was found in 112 (88.9%) of the samples and 84 (90.3%) of the horses. Antibody titers declined over time (rho = -0.271, p = 0.002); however, there was no significant difference in antibody titers or the prevalence of unprotected horses between the time intervals following vaccination. Purebred horses had lower antibody titers (p = 0.024). The response to booster vaccination was inspected in ten horses, and increased antibody titers were found in eight of them. The results of this study demonstrate the prolonged persistence of protective immunity in horses following rabies vaccination, in some cases, for up to eight years. Therefore, the current annual vaccination strategy should be re-evaluated. A rate of 9.7% of poor responders should be considered from an epidemiological perspective in order to minimize the risk of emergence of the disease.

An Evaluation of the Impact of an OPEN Stewardship Generated Feedback Intervention on Antibiotic Prescribing among Primary Care Veterinarians in Canada and Israel.

An interrupted time-series study design was implemented to evaluate the impact of antibiotic stewardship interventions on antibiotic prescribing among veterinarians. A total of 41 veterinarians were enrolled in Canada and Israel and their prescribing data between 2019 and 2021 were obtained. As an intervention, veterinarians periodically received three feedback reports comprising feedback on the participants' antibiotic prescribing and prescribing guidelines. A change in the level and trend of antibiotic prescribing after the administration of the intervention was compared using a multi-level generalized linear mixed-effect negative-binomial model. After the receipt of the first (incidence rate ratios [IRR] = 0.88; 95% confidence interval (CI): 0.79, 0.98), and second (IRR = 0.85; 95% CI: 0.75, 0.97) feedback reports, there was a reduced prescribing rate of total antibiotic when other parameters were held constant. This decline was more pronounced among Israeli veterinarians compared to Canadian veterinarians. When other parameters were held constant, the prescribing of critical antibiotics by Canadian veterinarians decreased by a factor of 0.39 compared to that of Israeli veterinarians. Evidently, antibiotic stewardship interventions can improve antibiotic prescribing in a veterinary setting. The strategy to sustain the effect of feedback reports and the determinants of differences between the two cohorts should be further explored.

Diagnostic performance of a rapid immunochromatographic test for the simultaneous detection of antibodies to Theileria equi and Babesia caballi in horses and donkeys.

BACKGROUND: Equine piroplasmosis is caused by two tick-borne protozoan parasites, Theileria equi and Babesia caballi,, which are clinically relevant in susceptible horses, donkeys, and mules. Moreover, equine piroplasmosis significantly constrains international trading and equestrian events. Rapidly diagnosing both parasites in carrier animals is essential for implementing effective control measures. Here, a rapid immunochromatographic test for the simultaneous detection of antibodies to T. equi and B. caballi was evaluated using samples from horses and donkeys collected in Greece, Israel, and Italy. The results were compared with an improved competitive enzyme-linked immunosorbent assay (cELISA) for detecting antibodies to both parasites using the same panel of samples. METHODS: Blood samples were collected from 255 horses and donkeys. The panel consisted of 129 horses sampled at four locations in northern Greece, 105 donkeys sampled at four locations in Sicily, and 21 horses sampled at two locations in Israel. The rapid test and the cELISA were performed according to the manufacturer's instructions, and the results were subjected to a statistical analysis to determine the sensitivity and specificity of both tests and their association. RESULTS: The immunochromatographic test provided a result within 15 min and can be performed in the field, detecting both pathogens simultaneously. The overall coincidence rate between the rapid test and the cELISA for detecting antibodies against T. equi was 93% and 92.9% for B. caballi. The rapid test's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for T. equi were above 91.5%. Sixteen samples were positive for both parasites in the rapid test and eight in the cELISA. Either test had no significant association between T. equi and B. caballi detection. The detection rates of both parasites were significantly higher in Italy than in Greece or Israel and in donkeys than in horses. The agreement for T. equi between the results of both tests was high in Greece (93.8%) and Italy (95.2%) and moderate in Israel (76.2%). For B. caballi, the specificity and NPV of the rapid test were high (94.2% and 98.3%, respectively), although the sensitivity and PPV were moderate (69.2% and 39.1%, respectively) due to the small sample size. However, for B. caballi, the sensitivity was higher with the rapid test. CONCLUSIONS: The rapid test detected T. equi and B. caballi simultaneously in the field, potentially replacing laborious cELISA testing and is recommended for import/export purposes. The test can also be helpful for the differential diagnosis of clinical cases, since seropositivity may rule out equine piroplasmosis since it does not indicate current or active infection.

Successful medical management of intra-abdominal abscesses in 4 adult horses.

Four adult horses with large intra-abdominal abscesses, suspected to be complications of strangles, were treated with systemic antibiotics alone and made a full recovery. The 100% survival rate is significantly better than other reported survival rates. The median duration of treatment (35 days) was shorter than in most previous reports. This study suggests that penicillin G can be used for successful treatment of strangles associated intra-abdominal abscesses in horses.

Gestion médicale réussie d'abcès intra-abdominaux chez 4 chevaux adultes. Quatre chevaux adultes avec des abcès intra-abdominaux de grande taille, suspectés d'être des complications de la gourme, ont été traités seulement à l'aide d'antibiotiques systémiques et se sont rétablis complètement. Le taux de survie de 100 % est significativement meilleur que les autres taux de survie signalés. La durée médiane du traitement (35 jours) a été plus courte que celle indiquée dans la plupart des rapports antérieurs. Cette étude suggère que la pénicilline G peut être utilisée avec succès pour le traitement des abcès intra-abdominaux associés à la gourme chez les chevaux.(Traduit par Isabelle Vallières).

Detection and Analysis of West Nile Virus Structural Protein Genes in Animal or Bird Samples.

West Nile virus (WNV) is an important zoonotic pathogen, which is detected mainly by identification of its RNA using PCR. Genetic differentiation between WNV lineages is usually performed by complete genome sequencing, which is not available in many research and diagnostic laboratories. In this chapter, we describe a protocol for detection and analysis of WNV samples by sequencing the entire region of their structural genes capsid (C), preM/membrane, and envelope. The primary step is the detection of WNV RNA by quantitative PCR of the NS2A gene or the C gene regions. Next, the entire region containing the structural protein genes is amplified by PCR. The primary PCR product is then amplified again in parallel reactions, and these secondary PCR products are sequenced. Finally, bioinformatic analysis enables detection of mutations and classification of the samples of interest. This protocol is designed to be used by any laboratory equipped for endpoint and quantitative PCR. The sequencing can be performed either in-house or outsourced to a third-party service provider. This protocol may therefore be useful for rapid and affordable classification of WNV samples, obviating the need for complete genome sequencing.

First Detection of Anti-Besnoitia spp. Antibodies in Equids in Israel and the Palestinian Authority.

Besnoitia is a tissue cyst forming coccidia, which affects multiple host species worldwide. Equine besnoitiosis is characterized mainly by generalized skin lesions and cysts in the scleral conjunctiva. Recent reports revealed exposure to Besnoitia in equines in Europe and the United States. However, the exposure to Besnoitia spp. in the Israeli equine population was never investigated. The aim of this study was to evaluate the seroprevalence and associated risk factors for besnoitiosis in equids in Israel. A cross-sectional serosurvey was performed using serum samples of apparently healthy horses (n = 347), donkeys (n = 98), and mules (n = 6), and exposure to Besnoitia spp. was determined by an immunofluorescent antibody test (IFAT). Anti-Besnoitia spp. antibodies were detected in 17.7% equids, 6.9% horses, 33.3% mules, and 55.1% donkeys. The seroprevalence in donkeys was significantly higher than in horses (p < 0.001). A significant association between the geographic location and seropositivity was found both in horses and donkeys, which was significantly higher (p = 0.004) in horses sampled in southern Israel, and donkeys sampled in Israel versus the Palestinian Authority (p < 0.001). This is the first serosurvey of Besnoitia infection in equines in Israel, and the results are consistent with reports from Europe. The clinical significance of equine besnoitiosis should be further investigated.

Equine Encephalosis Virus.

Equine encephalosis (EE) is an arthropod-borne, noncontagious, febrile disease of horses. It is caused by EE virus (EEV), an Orbivirus of the Reoviridae family transmitted by Culicoides. Within the EEV serogroup, seven serotypes (EEV-1-7) have been identified to date. This virus was first isolated from a horse in South Africa in 1967 and until 2008 was believed to be restricted to southern Africa. In 2008-2009, isolation of EEV in an outbreak reported from Israel demonstrated the emergence of this pathogen into new niches. Indeed, testing in retrospect sera samples revealed that EEV had already been circulating outside of South Africa since 2001. Although EEV normally does not cause severe clinical disease, it should be considered important since it may indicate the possible spread of other related, much more pathogenic viruses, such as African horse sickness virus (AHSV). The spread of EEV from South Africa to central Africa, the Middle East and India is an example of the possible emergence of new pathogens in new niches, as was seen in the case of West Nile virus, and should be a reminder not to limit the differential list when facing a possible outbreak or a cluster of clinical cases. This review summarizes current knowledge regarding EEV structure, pathogenesis, clinical significance, and epidemiology.

Virus Infection in Equine.

The relationship between men and horses has significantly evolved over the last century [...].

West Nile Virus in Common Wild Avian Species in Israel.

In order to evaluate the contribution of different wild bird species to West Nile virus (WNV) circulation in Israel, during the months preceding the 2018 outbreak that occurred in Israel, we randomly sampled 136 frozen carcasses of a variety of avian species. Visceral and central nervous system (CNS) tissue pools were tested using WNV NS2A RT qPCR assay; of those, 15 (11.03%, 95% CI: 6.31-17.54%) tissue pools were positive. A total of 13 out of 15 WNV RT qPCR positive samples were successfully sequenced. Phylogenetic analysis indicated that all WNV isolates were identified as lineage 1 and all categorized as cluster 2 eastern European. Our results indicated that WNV isolates that circulated within the surveyed wild birds in spring 2018 were closely related to several of the isolates of the previously reported 2018 outbreak in birds in Israel and that the majority of infected birds were of local species.

Neospora spp. Seroprevalence and Risk Factors for Seropositivity in Apparently Healthy Horses and Pregnant Mares.

Equine Neospora infection has been linked to neurological disorders and infertility in horses. This study looked into the risk factors for infection and the exposure to Neospora spp. in horses. The study was performed in two independent populations in Israel. The first consisted of apparently healthy horses, and the second consisted of mares examined during pregnancy and after parturition. Sera samples collected from horses and mares were tested for Neospora exposure by the indirect fluorescent antibody test (IFAT). The study revealed seroprevalence of 24% in apparently healthy horses and 66.4% and 48.6% in mares during gestation and after parturition, respectively. Among the investigated risk factors, older age (p = 0.026) and housing in both stalls and paddocks (p = 0.033) in apparently healthy horses, and Arabian breeds (p = 0.005) in pregnant mares, were found to be significantly associated with Neospora spp. seropositivity in univariable, but not multivariable, statistical analysis. This study revealed high exposure of equines to Neospora parasites, especially mares. Horse farm management, in combination with active surveillance, including serological testing and follow up, could help reduce the spread of the parasite among horses in endemic areas.

Prevalence and Molecular Characterization of Extended-Spectrum ß-Lactamase Producing Enterobacterales in Healthy Community Dogs in Israel.

BACKGROUND: antimicrobial resistance is a global problem in human and veterinary medicine. We aimed to investigate the extended spectrum ß-lactamase-producing Enterobacterales (ESBL-PE) gut colonization in healthy community dogs in Israel. METHODS: Rectal swabs were sampled from 145 healthy dogs, enriched, plated on selective plates, sub-cultured to obtain pure cultures, and ESBL production was confirmed. Bacterial species and antibiotic susceptibility profiles were identified. WGS was performed on all of the ESBL-PE isolates and their resistomes were identified in silico. Owners' questionnaires were collected for risk factor analysis. RESULTS: ESBL-PE gut colonization rate was 6.2% (n = 9/145, 95% CI 2.9-11.5). Overall, ten isolates were detected (one dog had two isolates); the main species was Escherichia coli (eight isolates), belonging to diverse phylogenetic groups-B1, A and C. Two isolates were identified as Citrobacter braakii, and C. portucalensis. A phylogenetic analysis indicated that all of the isolates were genetically unrelated and sporadic. The isolates possessed diverse ESBL genes and antibiotic-resistance gene content, suggesting independent ESBL spread. In a multivariable risk factor analysis, coprophagia was identified as a risk factor for ESBL-PE gut colonization (p = 0.048, aOR = 4.408, 95% CI 1.014-19.169). CONCLUSIONS: healthy community dogs may be colonized with ESBL-PE MDR strains, some of which were previously reported in humans, that carry wide and diverse resistomes and may serve as a possible source for AMR.

Fecal Microbiome Features Associated with Extended-Spectrum ß-Lactamase-Producing Enterobacterales Carriage in Dairy Heifers.

Extended-spectrum ß-lactamases (ESBLs) are a growing public health threat, and one key human exposure point is through livestock and the food supply. Understanding microbiome factors associated with fecal ESBL carriage can help detect and ideally assist with controlling and preventing ESBL dissemination among livestock. The objective of this study was to investigate the diversity and composition of the heifer fecal microbiota in ESBL-producing Enterobacterales (ESBL-PE) carriers and noncarriers. A total of 59 fecal samples were collected from replacement heifers between 12 and 18 months old from eight dairy farms in central Israel. Genomic DNA was extracted, and 16S rRNA amplicon sequencing was performed (Illumina short reads), focusing on a comparison between 33 ESBL-PE carriers (55.9%) and 26 (44.1%) noncarriers. Samples were analyzed and compared using QIIME2 (DADA2 pipeline and taxonomic assignment with SILVA database) and associated R packages for alpha and beta diversity and taxonomic abundances. Alpha diversity (Shannon diversity) and beta diversity (unweighted UniFrac) showed no significant difference between ESBL-PE carriers and noncarriers. Heifers from farms feeding calves with pooled colostrum had higher ESBL-PE carriage rates than heifers from farms feeding with individual mother colostrum (p < 0.001). Taxonomical abundance analysis revealed that the most common bacterial phyla were Bacteroidetes (44%) and Firmicutes (38%). There was no significant difference in taxonomic composition between ESBL-PE carriers and noncarriers at the phylum and genus levels. However, LEfSe biomarker discovery analysis identified several genera which were significantly different between carriers and noncarriers. For example, Prevotellacaea, Bacteroides, Rikenellaceae, and uncultured Bacteroidales were more abundant in ESBL carriers than noncarriers. Some aspects of microbiota composition differ between ESBL carriers and noncarriers in dairy heifers, specifically the abundance of certain genera. Feeding with pooled colostrum may play a role in that assembly. These could potentially serve as markers of ESBL-PE carriage. However, further research is needed to determine whether these observed differences have a significant impact on colonization with ESBL-PE.

Isolation and phylogenetic grouping of equine encephalosis virus in Israel.

During 2008-2009 in Israel, equine encephalosis virus (EEV) caused febrile outbreaks in horses. Phylogenetic analysis of segment 10 of the virus strains showed that they form a new cluster; analysis of segment 2 showed ≈92% sequence identity to EEV-3, the reference isolate. Thus, the source of this emerging EEV remains uncertain.

Seroprevalence and Risk Factors for Exposure to Equine Coronavirus in Apparently Healthy Horses in Israel.

Equine coronavirus (ECoV) infection is the cause of an emerging enteric disease of adult horses. Outbreaks have been reported in the USA, EU and Japan, as well as sporadic cases in the UK and Saudi Arabia. Infection of ECoV in horses in Israel has never been reported, and the risk of exposure is unknown. Importation and exportation of horses from and into Israel may have increased the exposure of horses in Israel to ECoV. While the disease is mostly self-limiting, with or without supportive treatment, severe complications may occur in some animals, and healthy carriers may pose a risk of infection to other horses. This study was set to evaluate the risk of exposure to ECoV of horses in Israel by using a previously validated, S1-based enzyme-linked immunosorbent assay (ELISA). A total of 41 out of 333 horses (12.3%) were seropositive. Exposure to ECoV was detected in 17 of 29 farms (58.6%) and the seroprevalence varied between 0 and 37.5% amongst farms. The only factor found to be significantly associated with ECoV exposure in the multivariable model was the geographical area (p < 0.001). ECoV should be included in the differential diagnosis list of pathogens in cases of adult horses with anorexia, lethargy, fever and gastrointestinal signs in Israel.

Serological and Molecular Prevalence of Babesia caballi in Apparently Healthy Horses in Israel.

Babesia caballi is a tick-borne hemoparasite of equines and one of the causative agents of equine piroplasmosis, which poses a great concern for the equine industry regarding animal welfare and international horse movement. The parasite is endemic in Israel; however, its seroprevalence in the area was never evaluated due to antigenic heterogenicity in the gene used in the commercially available kit. Blood samples were collected from 257 horses at 19 farms throughout the country and screened for the presence of anti-B. caballi antibodies via an indirect immunofluorescent antibody test (IFAT) and for the presence of parasite DNA by nested PCR. The seroprevalence of B. caballi was 69.6% and its molecular prevalence was 9.7%. The geographical area, horse's sex, breed, housing, exposure to ticks, and specifically to Hyalomma marginatum, and co-infection with Theileria equi were found to be significantly associated with serologic exposure in univariable analysis, while the geographical area and horses' sex remained significant in the multivariable analysis. The results of this study demonstrate a high level of exposure to B. caballi and identify important risk factors for infection. The difference between the serological and molecular prevalence, probably related to parasite clearance, is also highlighted.

Seroprevalence of Leptospira spp. in Horses in Israel.

Leptospirosis has been reported in both humans and animals in Israel but has not been reported in horses. In 2018, an outbreak of Leptospira spp. serogroup Pomona was reported in humans and cattle in Israel. In horses, leptospirosis may cause equine recurrent uveitis (ERU). This report describes the first identification of Leptospira serogroup Pomona as the probable cause of ERU in horses in Israel, followed by an epidemiological investigation of equine exposure in the area. Serologic exposure to Leptospira was determined by microscopic agglutination test (MAT) using eight serovars. In 2017, serovar Pomona was identified in a mare with signs of ERU. Seven of thirteen horses from that farm were seropositive for serogroup Pomona, of which three had signs of ERU. During the same time period, 14/70 horses from three other farms were positive for serogroup Pomona. In 2015, two years prior to this diagnosis, 259 horses from 21 farms were sampled and one horse tested seropositive for serovar Icterohaemorrhagiae. In 2018, one year later, 337 horses were sampled on 29 farms, with none testing seropositive. Although horses are not considered a major host of Leptospira spp., it appears that horses may be infected, and clinically affected, in the course of an outbreak in other species. The identification of leptospirosis in stabled horses may impose a significant zoonotic risk to people.

Third Generation Cephalosporin Resistant Enterobacterales Infections in Hospitalized Horses and Donkeys: A Case-Case-Control Analysis.

In human medicine, infections caused by third-generation cephalosporin-resistant Enterobacterales (3GCRE) are associated with detrimental outcomes. In veterinary medicine, controlled epidemiological analyses are lacking. A matched case-case-control investigation (1:1:1 ratio) was conducted in a large veterinary hospital (2017-2019). In total, 29 infected horses and donkeys were matched to 29 animals with third-generation cephalosporin-susceptible Enterobacterales (3GCSE) infections, and 29 uninfected controls (overall n = 87). Despite multiple significant associations per bivariable analyses, the only independent predictor for 3GCRE infection was recent exposure to antibiotics (adjusted odds ratio (aOR) = 104, p < 0.001), but this was also an independent predictor for 3GCSE infection (aOR = 22, p < 0.001), though the correlation with 3GCRE was significantly stronger (aOR = 9.3, p = 0.04). In separated multivariable outcome models, 3GCRE infections were independently associated with reduced clinical cure rates (aOR = 6.84, p = 0.003) and with 90 days mortality (aOR = 3.6, p = 0.003). Klebsiella spp. were the most common 3GCRE (36%), and blaCTX-M-1 was the major ß-lactamase (79%). Polyclonality and multiple sequence types were evident among all Enterobacterales (e.g., Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae). The study substantiates the significance of 3GCRE infections in equine medicine, and their independent detrimental impact on cure rates and mortality. Multiple Enterobacterales genera, subtypes, clones and mechanisms of resistance are prevalent among horses and donkeys with 3GCRE infections.