The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine host is increasingly recognized. A collection of 108 Lancefield group C (n = 96) or L (n = 12) horse isolates recovered in the United States and in three European countries presented multilocus sequence typing (MLST) alleles, sequence types and emm types (only 56% of the isolates could be emm typed) that were, with few exceptions, distinct from those previously found in human Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of horse isolates by multilocus sequence analysis (MLSA) and 16S rRNA gene sequence showed that most equine isolates could also be differentiated from S. dysgalactiae strains from other animal species, supporting the existence of a horse specific genomovar. Draft genome information confirms the distinctiveness of the horse genomovar and indicates the presence of potentially horse-specific virulence factors. While this genomovar represents most of the isolates recovered from horses, a smaller MLST and MLSA defined sub-population seems to be able to cause infections in horses, other animals and humans, indicating that transmission between hosts of strains belonging to this group may occur.

A 14-month-old, male German Shepherd dog was admitted with a six-week history of lameness and swelling of the right hindlimb. Clinical examination revealed polyarthritis, fever, petechiae and ecchymoses of the abdominal skin and prepuce. The haematology and blood chemistry were indicative of sepsis. Mediolateral radiographic views of both of the stifle joints revealed signs of bilateral articular capsule swelling. The radiographical, bacteriological and necropsy findings confirmed a diagnosis of septic polyarthritis due to infection with Erysipelothrix rhusiopathiae.

Horse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of peri-operative antibiotic prophylaxis (PAP) based on a combination of penicillin and gentamicin on the gut microbiota is limited. Therefore, we collected fecal samples of horses from a non-hospitalized control group (CG) and from horses receiving either a pre-surgical single-shot (SSG) or a peri-operative 5-day (5DG) course of PAP. To assess differences between the two PAP regimens and the CG, all samples obtained at hospital admission (t0), on days three (t1) and ten (t2) after surgery, were screened for ESBL-producing Enterobacterales and subjected to 16S rRNA V1– V2 gene sequencing.We included 48 samples in the SSG (n=16 horses), 45 in the 5DG (n=15) and 20 in the CG (n=10). Two samples (6.5%) were positive for ESBL-producing Enterobacterales at t0while this rate increased to 67% at t1and decreased only slightly at t2(61%). Shannon diversity index (SDI) was used to evaluate alpha-diversity changes, revealing that horses suffering from acute colic seemed to have a compromised fecal microbiota composition (5DG, SDImeanof 5.90; SSG, SDImeanof 6.17) when compared to the CG (SDImeanof 6.53) at t0, although the difference lacked significance. Alpha-diversity decreased significantly in both PAP groups at t1, while at t2the onset of microbiome recovery was noticed. Although we did not identify a significant SDImeandifference with respect to PAP duration, the community structure (beta-diversity) was considerably restricted in samples of the 5DG at t1, most likely due to the ongoing administration of antibiotics. An increased abundance ofEnterobacteriaceae,especiallyEscherichia, was noted for both study groups at t1. Further studies are needed to reveal important factors promoting the increase and residency of ESBL-producing Enterobacterales among hospitalized horses.

Extended spectrum beta-lactamase (ESBL)-producing Escherichia coli are an emerging problem in veterinary and human medicine. Our study concentrated on the estimation of the prevalence and factors associated with the carriage of ESBL-producing E. coli in dogs who visited a veterinary clinic in northern Germany in 2017. For this reason, 1000 patients (healthy and sick dogs) were tested, resulting in 1000 samples originating from rectal swabs. Additional data were collected using a self-reported questionnaire that was completed by the dog owner. Factors associated with ESBL carriage were considered for further modeling if p < 0.05 using a two-sided Fisher test. Using a backward elimination procedure, the variables for the final multivariable logistic regression model were identified. In total, 8.9% of the dogs tested were positive for carriage of ESBL-producing E. coli. Seven factors were associated with the colonization of dogs with ESBL-E. coli within the multivariable model, namely husbandry system (p = 0.0019, OR = 3.00; 95% CI: 1.50–6.00), contact with puppies (p = 0.0044, OR = 2.43; 95% CI: 1.32–4.46), feeding of raw meat (p = 0.011, OR = 2.28; 95% CI: 1.21–4.31), food residues (p = 0.0151, OR = 2.31; 95% CI: 1.18–4.53) and food supplements (p = 0.0487, OR = 0.426; 95% CI: 0.18–0.96), and antibiotic treatments of dogs (p = 0.0005, OR = 3.030; 95% CI: 1.62–5.68) or owners (p = 0.041, OR = 2.74; 95% CI: 1.04–7.19) prior to the study. These factors refer to the animals themselves as well as to the owners and their habits or medical treatments. Although the causality and direction of transmission from owners to their dogs cannot be proven, the factor of antibiotic treatment of the owner is clearly associated with the dog’s status.