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Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a mucosal commensal of the lower genital tract in horses and is the most isolated bacterium causing endometritis in mares. The aim of this study was to determine the molecular diversity of S. zooepidemicus obtained from endometritis in mares in Buenos Aires province, Argentina. Thirty isolates obtained from the uterus of mares in 2005 and 2017 were studied. The MLST scheme was applied to identify the Argentinian genotypes and the clonal relationships and patterns of evolutionary descent were identified using the eBURST algorithm - goeBURST. Twenty six different Sequence types (STs) were identified, being only 11 of them previously reported in horses and also, from several host species and tissues. The other 15 STs were reported in Argentinian reproductive strains of mares in our study for the first time. The genotypes obtained from uterus in Argentina were not evenly distributed when all the published S. zooepidemicus STs were analysed, thus, it was not possible to establish that the same lineage circulates in our equine population. The fact that the identified genotypes were also reported in other countries, diverse samples and host species suggest that there is not a host, and an anatomical niche adaptation. Finally, the isolation of the same genotype in the vagina/clitoris and the uterus of the same mare highlights the versatility of S. zooepidemicus and its role as an opportunistic pathogen., Competing Interests: Declaration of competing interest None of the authors of this paper has a financial or personal relationship with other people or organisations that could inappropriately influence the content of this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Streptococcus dysgalactiae subsp. equisimilis (Sde) is a commensal bacterium of horses that causes opportunistic infections. The aim of the work was to study genotypic and phenotypic properties of the Sde strain related to equine neonatal mastitis. Sde was isolated from an 8 day-old filly and sequenced for genome analysis, antibiotic susceptibility tests and virulence factor (VF) assays. The Sde strain presented the novel emm-subtype stC839.12 and the novel multilocus-sequence type ST-670, which belonged to a specific equine genotype group. Although no specific genotypic mechanisms related to antibiotic resistance were found, it presented genes encoding efflux pumps and transporters pmrA, bmrC and lmrP. Genes encoding several putative VFs including emm, cpa, fbp-2, adcA, hyl, htrA, tig, slo, and ndk and loci-encoding phosphoenolpyruvate-protein phosphotransferase systems were identified. This is the first report of an equine neonatal mastitis case caused by a novel genotype and horse specific Sde strain., Competing Interests: Declaration of Competing Interest None of the authors has any financial or personal relationships that could inappropriately influence the content of the paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Strangles is a contagious bacterial disease of horses caused by Streptococcus equi subspecies equi (SEE) that occurs globally. Rapid and accurate identification of infected horses is essential for controlling strangles. Because of limitations of existing PCR assays for SEE, we sought to identify novel primers and probes that enable simultaneous detection and differentiation of infection with SEE and S. equi subsp. zooepidemicus (SEZ). Comparative genomics of U.S. strains of SEE and SEZ (n = 50 each) identified SE00768 from SEE and comB from SEZ as target genes. Primers and probes for real-time PCR (rtPCR) were designed for these genes and then aligned in silico with the genomes of strains of SEE (n = 725) and SEZ (n = 343). Additionally, the sensitivity and specificity relative to microbiologic culture were compared between 85 samples submitted to an accredited veterinary medical diagnostic laboratory. The respective primer and probe sets aligned with 99.7 % (723/725) isolates of SEE and 97.1 % (333/343) of SEZ. Of 85 diagnostic samples, 20 of 21 (95.2 %) SEE and 22 of 23 SEZ (95.6 %) culture-positive samples were positive by rtPCR for SEE and SEZ, respectively. Both SEE (n = 2) and SEZ (n = 3) were identified by rtPCR among 32 culture-negative samples. Results were rtPCR-positive for both SEE and SEZ in 21 of 44 (47.7 %) samples that were culture-positive for SEE or SEZ. The primers and probe sets reported here reliably detect SEE and SEZ from Europe and the U.S., and permit detection of concurrent infection with both subspecies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Strangles is a worldwide infectious disease caused by Streptococcus equi subsp. equi that affects the upper respiratory tract of horses. Streptococcus equi subsp. equi characterisation by seM-typing is internationally used for epidemiological studies and comparison of isolates., Objectives: To identify and to compare the seM-types of Argentinian isolates of Streptococcus equi subsp. equi., Study Design: Investigation of bacterial isolates using molecular and phylogenetic approaches., Methods: A total of 59 Argentinian isolates of Streptococcus equi subsp. equi obtained between 2007 and 2019 were studied by seM-typing. The sequence similarity of Argentinian seM-types and the other alleles available on the seM database was determined using BLAST and phylogenetic analysis was performed using the Neighbour-Joining algorithm. The amino acid sequences were predicted and compared with the predicted amino acid sequence of the reference strain 4047 using the MEGA 7 software and PROVEAN tool., Results: Eight seM-types were found among the isolates. Only one of them (seM-61) has been previously reported and the other seven alleles (seM-129, seM-130, seM-131, seM-132, seM-133, seM-134 and seM-135) were novel seM sequences. High genetic similarity was observed among the Argentinian seM-types, with the exception of seM-130. No functional effects of amino acid differences were predicted., Main Limitations: The number of related and unrelated isolates per year., Conclusions: Seven novel seM-types and seM-61 that were previously reported in Brazil were circulating in Argentina which were identified as circulating in Argentinian horses between 2007 and 2019. The high genetic similarity among the Argentinian and Brazilian seM-types suggests that there is a geographical distribution of strain types. The geographical restriction of strains is likely to reflect the movement of horses between different equine disciplines and neighbouring countries., (© 2021 EVJ Ltd.)

Equine salmonellosis is caused by several Salmonella serotypes, including Salmonella Newport, which cause enterocolitis and diarrhea. Treatment usually includes the administration of antibiotics. However, since multidrug-resistant Salmonella is commonly detected, alternative options to control the pathogen are needed. One of these options is the use of specific egg yolk antibodies (IgY) for passive immunotherapy. Thus, the aim of our work was to produce IgY antibodies against an equine S. Newport strain and assess their in vitro inhibitory activity. To this end, laying hens were immunized with an inactivated S. Newport strain by using either Freund's or Montanide adjuvant and egg yolk extracts were obtained. The levels of specific IgY antibodies against Salmonella in sera and egg extracts were determined by dot-blot and microagglutination. Besides, the IgY extracts were characterized by total protein analysis, SDS-PAGE, Western Blot, and inhibition of bacterial motility. IgY extracts showed high purity (87.7 to 91.8 %), high microagglutination titers, and the ability to inhibit the motility of the bacterium. The results using Montanide were similar to those using the traditional Freund's adjuvant. Thus, Montanide may also be a good adjuvant to produce IgY. IgY-technology represents a potential tool for the control of salmonellosis in horses., (Copyright © 2021. Published by Elsevier Inc.)

Wild bird species have commonly been implicated as potential vectors of pathogens to other species, humans included. However, the habitat where birds live could influence the probability to acquire these pathogens. Here, we evaluated if the characteristics of the environment used by obligate scavenging birds (vultures) influence their colonization by zoonotic pathogens. For this, we particularly focused on Salmonella spp., a zoonotic pathogen commonly present in bird species. The occurrence of this bacteria was evaluated in free ranging Andean condors ( Vultur gryphus ) using natural environments from Argentina and compared with those obtained from condors under human care. In addition, we compared our results with those reported for other wild vultures using natural and anthropized environments at a global scale. We did not find Salmonella spp. in samples of wild condors. Captive condor samples presented Salmonella spp. with an occurrence of 2.8%, and one isolate of Meticilin Resistant Staphylococcus aureus , among other potential pathogenic microorganisms. Moreover, some species of free ranging vultures from diverse geographical areas using anthropized environments tend to present higher occurrences of Salmonella spp. These results highlight the importance of pristine ecosystems to protect vultures' health toward pathogenic microorganisms that can produce disease in these birds, but also in other species. We call for more studies evaluating differences in occurrence of zoonotic pathogens in vultures according to the quality of the environment they use. Even when vultures have not been implicated in zoonotic pathogen spread, our results add information to evaluate potential events of pathogen spillover between vultures and from these birds to other species.

Salmonella spp. causes digestive clinical signs in horses. Foals and hospitalized animals are more susceptible to the disease. Nowadays, the report of multidrug-resistant Salmonella spp. producer of extended-spectrum β-lactamases, is more frequent. The aim of this work was to study the clonal relationship and antimicrobial susceptibility profiles among Salmonella ser. Typhimurium isolates, obtained during a salmonellosis outbreak in an Argentinian equine hospital. Thus, in 2017, we studied the genotypic profiles and the susceptibility to antimicrobials of the strains isolated from three animals with diarrhea in an equine hospital of Argentina. The pulsotype identified by pulsed-field gel electrophoresis was the same among the isolates. Also, this pulsotype had been previously detected in human and porcine isolates, suggesting the circulation of the same strains in different species. Multidrug-resistant isolates with different β-lactam susceptibility profiles were identified and bla CTX-M-14 was detected for the first time from an isolate of equine-origin in Argentina. Salmonella ser. Typhimurium is an important pathogen in public and veterinary health, so our results emphasize the relevance of appropriate measures to prevent and control this disease. Furthermore, routine antibiotic susceptibility tests of local strains are needed to improve the empiric treatment of equine salmonellosis., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Salmonella enterica subsp. enterica serovar Abortusequi (S. Abortusequi) is a serotype restricted to equines, which produces abortion outbreaks. Nowadays the disease is being reported in different countries including Argentina thus generating an important impact in the equine industry. Molecular characterization of the 95 kb virulence plasmid and the spvC gene of S. Abortusequi demonstrated their importance in the pathogenicity of the serotype. In the last decades, high clonality of S. Abortusequi was identified in Japan, Mongolia and Croatia., Objectives: The aim of this work was to characterize S. Abortusequi isolates obtained in Argentina between 2011 and 2016 by virulence-gene profiling and pulsed-field gel electrophoresis., Study Design: Case report., Methods: S. Abortusequi isolates were studied by virulence-gene profiling and pulsed-field gel electrophoresis., Results: Four virulence profiles and nine pulsed-field gel electrophoresis pulsotypes were identified among the 27 isolates included in the study. Different strains were found in the same outbreak and/or farm suggesting the presence of different sources of infection or mutation of isolates., Main Limitations: The number of related and nonrelated strains. More isolates may be necessary for a more intensive study., Conclusions: Most strains presented the same virulence profile, being positive for all the studied genes except gipA and sopE1, which are involved in intestinal virulence. Only few isolates showed different results in the same outbreak or farm. Unlike other studies, our results demonstrate a considerable diversity of S. Abortusequi pulsed-field gel electrophoresis pulsotypes, which suggests that different sources of infection may be involved within the same outbreak., (© 2019 EVJ Ltd.)

Streptococcus equi subsp. equi is the etiologic agent of strangles, an infectious disease affecting the upper respiratory tract and head and neck lymph nodes of equines. Routine antimicrobial therapy includes penicillin (PEN) as antibiotic of first choice. Streptococci are usually susceptible to PEN and only a few antimicrobial studies had been performed. The aim of this work was to study the antimicrobial susceptibility profile of S. equi from Buenos Aires, Argentina. Ninety-two isolates were studied by the single disk method to PEN, cefotaxime, erythromycin (ERY), tetracycline, enrofloxacin (ENR), trimethoprim sulfamethoxazole (TMS), ciprofloxacin, clindamycin (CLI), streptomycin (STR) and florfenicol. Minimum inhibitory concentration (MIC) to PEN and antibiotics with resistance and intermediate susceptibility were tested. High percentages of susceptibility were obtained by the disk diffusion method and MIC values of PEN, TMS and CLI were found to be under the breakpoint values. Resistant strains of ENR and STR with MIC 50 , MIC 90 and MIC ranges above breakpoints were identified. These findings confirm that PEN may be used empirically because resistant strains were not found in Buenos Aires. Emphasis is placed on the rational use of antibiotics to achieve therapeutic success, to prevent chronicity, recurrence of infections and the emergence of resistance., (Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)