Microbiology and horses explores the interactions between microorganisms and equine hosts, focusing on the role of bacteria, viruses, fungi, and other microbes in horse health and disease. This field examines the microbial flora present in various equine environments, including the gastrointestinal tract, skin, and respiratory system, and investigates how these microorganisms influence equine physiology and pathology. Research in this area includes studies on microbial infections that affect horses, the development of antimicrobial resistance, and the impact of probiotics and prebiotics on equine health. This page compiles peer-reviewed research studies and scholarly articles that investigate the diversity, dynamics, and implications of microbial communities in horses, as well as the strategies for managing microbial-related diseases.
Clayton YM, Fox EC.The research article aims to investigate the mycology of dental calculus (tartar) and its potential to harbor fungal organisms that could lead to ocular infections, particularly in those involved in […]
Fong CK, Hsiung GD.Development of equine herpesvirus strain 82A was studied in cells from primary horse kidney (HOK) cultures and an equine dermis (ED) cell strain. HOK and ED cells are equally susceptible to the 82A virus infection and yield about the same amount of infectious virus. Intranuclear inclusions were present in both cell systems, but a ring-shaped syncytial formation was observed only in infected ED cells. Ultrastructural studies revealed the presence of dense granules 30 nm in diameter and characteristic star-like clusters of granules in the infected HOK cells, but these granules were rarely seen i...
Fulton RE, Doane FW, Macpherson LW.Combined light and electron microscopy were used to follow the sequence of virus development in equine papillomas. The deepest layer in which virus was observed was the stratum spinosum of the epidermis. In this layer virus was scattered throughout the nuclei and was occasionally found in association with the nucleolus. In the stratum granulosum virus particles were more numerous, often forming isolated nuclear aggregates. Virus inclusions observed in the stratum granulosum by electron microscopy were correlated with nuclear inclusions seen by light microscopy. In the stratum corneum closely p...
Tajima M, Nakajima H, Ito Y.Equine infectious anemia (EIA) virus was observed in thin sections of infected cultured horse leukocytes by electron microscopy. The virus particles had a spherical shape and were between 80 and 120 nm in diameter. Most of them contained an electron-dense nucleoid 40 to 60 nm in diameter. They were observed to form by a process of budding from the plasma membrane and appeared to have thin surface projections. The particles described were not detected in uninfected cultured cells, and their appearance could be prevented by adding EIA immune serum to the inoculum. The implications of these findi...
Rogers HJ.Under a variety of conditions of concentration, Eh, and pH, horse anti- serum and normal horse serum exerted similar bacteriostatic effects against Type A. Ferric iron abolished the bacteriostatic effect when added during the first 2 hours of incubation at Eh+60 mV. Ferrous iron abolished the bacteriostatic effect when added after 3 hours. Ferric iron abolished the bacteriostatic effect at—140 mV. A mixture consisting of horse β- and γ-globulins together with human transferrin exerted a bacteriostatic effect similar to that of whole serum. This system responded in the same way as whole se...
Haque RU.A technique for identifying and characterizing staphylococcal hemolysins by first separating them electrophoretically in barbital-buffered agar gel (pH 8.4) at 5 ma/cm for 2 hr and then determining their hemolytic activities by exposing them to human, horse, rabbit, and sheep erythrocytes is described. The alpha-hemolysin produced by a White variant of the Wood 46 strain of Staphylococcus aureus migrated 18 mm towards the cathode, and it lysed horse, rabbit, and sheep erythrocytes, whereas a Clear variant of the Wood 46 strain of S. aureus produced a lysin which migrated similarly to the alpha...
Stolle LM, Oltmanns H, Meißner J, Heun F, Schieder AK, Wolff HT, Ohnesorge B, Busse C.To determine the in vitro antimicrobial activity of specific antiseptics against common equine ocular surface pathogens. Methods: Staphylococcus aureus (S. aureus) (n = 12), Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) (n = 9), Enterobacter hormaechei (E. hormaechei) (n = 6), and Bacillus cereus (B. cereus) (n = 5) were collected from corneal samples of horses with ulcerative keratitis. Reference strains were included. Minimum bactericidal concentrations (MBC) of polyhexanide, povidone-iodine, and hypochlorous acid were tested using the microdilution method. ...
To date, there is extensive scientific evidence affirming that physical exercise plays a fundamental role in both the prevention and treatment of various pathological conditions in humans as well as in animals. It is understood that the advantages of movement and exercise have a multifactorial origin and they depend on a category of bioactive molecules vehicolated by extracellular microvesicles known as exosomes. The exosomes act as potential delivery systems for messages within the organism. These findings have drawn significant attention, leading researchers to further investigate the role o...
Franzan BC, da Silva Coelho I, Ramos EM, de Souza ARP, de Almeida FQ, Silva VP.This study aimed to investigate the gradual adaptation of the fecal bacterial community and in vitro fermentative capacity of horses fed a complete extruded diet (CED). Twelve geldings weighing 370 kg were removed from a native pasture and fed coastcross hay (Cynodon spp) for 7 days. In the second week, horses were assigned to two groups: one group was fed exclusively with coastcross hay (HAY) for 28 days and the other group fed with weekly increases of CED (30%, 60%, and 100%) to replace HAY. Fecal samples were collected on Days 7, 14, 21, and 28 for microbiota and in vitro fermentati...
Nowicka B, Łopuszyński W, Krajewska-Wędzina M, Biazik A, Sobuś M, Polkowska I, Szacawa E.Gastrointestinal mycobacteriosis in horses is difficult to diagnose because of the pathogen's intracellular nature and the non-specific clinical symptoms. Effective accurate diagnosis facilitates prognosis and treatment. Current diagnostic procedures and methods of collecting material do not permit definitive antemortem diagnosis. However, culturing, acid-fast bacilli staining, histopathology, PCR and immunological marker evaluation may prove useful. Unassigned: Three horses were admitted to a clinic for intensive care and a final diagnosis. Physical examination and additional tests were perfo...
He H, Han L, Ni W, Yu J, Liu K, Li W, Li C, Hu S, Li C, Li X.Herbivores represent crucial subjects for mining highly efficient carbohydrate-active enzymes (CAZymes) from gut microbiomes. Here, we analyzed 12,763 metagenome-assembled genomes (MAGs) from the horse gut, revealing that its microbial community as a rich reservoir of CAZymes diversity, with 5,204,848 glycoside hydrolases (GHs) and 4,596,191 glycosyl transferases (GTs) identified. Our findings demonstrate that Bacteroidota (5,479,287 CAZymes) and Bacillota_A (2,987,684 CAZymes) serve as the primary functional phyla for plant polysaccharide degradation. A total of 17,250 polysaccharide utilizat...
Petry S, Tapprest J, Maillard K, Barbut F, Duquesne F, Kozak S, Foucher N, Bernez-Romand M, Bridoux L, Poquet I. an anaerobic, spore-forming enteropathogen, is less studied in animals than in humans despite its importance in One Health. We evaluated occurrence, diversity, circulation, and virulence in French Equidae ( = 100) after their necropsy in northwestern France, from 2019 to 2021. We systematically recovered all cecal contents and any watery intestinal contents. We isolated strains, determined their toxin gene profile by PCR, and established their PCR-ribotype according to the WEBRIBO database. We also performed free toxin detection. Twenty-seven Equidae were positive for and 20 had a toxigeni...
Wang C, Wang J, Ma B, Liu T, Yuan X, Meng J, Zeng Y.: This study investigated the effects of dietary bamboo leaf extract (BLE) on milk parameters and intestinal microbiota in lactating mares. : Twenty-four mares of similar age (10 ± 2 years), weight (360.62 ± 15.23 kg) and body condition were selected for this study and randomly divided into four groups of six mares each: an untreated control group (CG) and three experimental groups (EG1, EG2, EG3) were fed a basal diet supplemented with 0, 10, 20, or 30 g/day of BLE, respectively, for 60 days. Then, horse milk composition, antioxidant activity, and immunoglobulin levels along with the rela...
Hoerdemann M, Sahoo DK, Allbaugh RA, Kubai MA.To assess if an inexpensive, commercially available ultraviolet C (UV-C) light device with a peak emission of 275 nm can inhibit equine keratomycosis-associated pathogens located at different corneal depths in an ex vivo model. Methods: A controlled, randomized experimental design. Aspergillus fumigatus and Fusarium solani isolates were inoculated in fresh bovine corneoscleral transplants, superficially or at 450 μm of stromal depth for the ulcerative keratomycosis or stromal abscess model, respectively. After a minimum of 18 h of incubation, treatment groups received 15 s of UV-C li...
Barber C, McGlennon A, Whitlock F, Grewar J, Spalding S, Newton R, Dewé T.Charlotte Barber, Abigail McGlennon, Fleur Whitlock, John Grewar, Sophie Spalding, Richard Newton and Tamsin Dewé introduce a new government-funded initiative to strengthen the surveillance of antimicrobial resistance in the equine sector.
Barvelink M, Brok B, Djajadiningrat-Laanen SC, Vernooij JCM, Broens EM, Slenter IJM.To assess the antibacterial activity of manuka honey against bacterial isolates commonly associated with infected corneal ulcerations in horses, and to investigate possible combined effects of manuka honey and commonly prescribed topical antibiotics. Methods: Four Staphylococcus aureus, including three methicillin-resistant (MRSA), two methicillin-resistant coagulase-negative staphylococci (S. sciuri and S. haemolyticus), and two Streptococcus equi subspecies zooepidemicus isolates from horses with stromal ulcerative keratitis were selected. Minimum inhibitory concentrations (MICs) and minimu...
Gamage C, Graves A, Li G, Thieulent CJ, Balasuriya UBR, Morrow J, Vissani A, Parreño V, Matthijnssens J, Carossino M.Equine rotavirus B (ERVB) has caused foal diarrhea in central Kentucky since 2021. Coding-complete genome sequences from 14 strains circulating in 2024 revealed >99% nucleotide identity to the 2021 prototype ERVB strain RVB/Horse-wt/USA/KY1518/2021, with a conserved genomic constellation (G3-P[3]-I3-R3-C3-M3-A4-N3-T3-E3-H3).
Accorroni L, Dini F, Pilati N, Marchegiani A, Bazzano M, Spaterna A, Laus F.Wound management is a fundamental skill for veterinarians, requiring a systematic approach to wound care and a deep understanding of the biological principles underlying healing. Sucralfate, widely known as a mucoprotective agent for gastroduodenal ulcers, has recently shown promising topical effects in human skin lesions by binding and protecting growth factors from proteolytic degradation, thereby enhancing their local availability. This action promotes angiogenesis, chemotaxis and cell proliferation, while reducing oxidative stress and exerting bacteriostatic and bactericidal effects agains...
Wei L, Wei J, Liu X, Chen W, Wang C, Khan MZ, Zhang Z.Donkeys () remain nutritionally understudied despite their critical roles in agriculture across developing regions, with current feeding practices inappropriately extrapolating horse standards without accounting for species-specific digestive physiology. No comprehensive synthesis has integrated how dietary modifications systematically alter gut microbial communities to drive measurable health outcomes in donkeys, preventing development of evidence-based feeding strategies. This review critically synthesizes current evidence on donkey nutritional requirements and gut microbiota dynamics to est...
Roy CN, Wiechmann CE, Dev A, Walther BK, Musser JM, Olsen RJ, Beres SB, Axell-House DB. subsp. (SESZ) are zoonotic group C streptococci primarily acquired from contact with horses and other animals, such as llamas. They are unusual causes of infection in humans and rarely cause infective endocarditis. Unassigned: A 58-year-old woman presented with fever, malaise, and polyarthritis. Clinical evaluation diagnosed native tricuspid valve SESZ endocarditis. The SESZ isolate was genetically closely related to a clone causing an outbreak of post-streptococcal glomerulonephritis linked to the consumption of unpasteurized cheese in Brazil. The patient had no exposure to unpasteurized ch...
Beshir A, Kemal J, Abraha B, Tola EH.Wounds on the skin are a common health issue affecting working equines. This study aimed to evaluate the in-vitro antibacterial properties of crude methanolic extracts from selected medicinal plants against pathogens isolated from equine skin wounds in Merti district. Agar well and disc diffusion tests were used to determine the mean zone of inhibition, while broth dilution methods were used to determine the minimum inhibitory concentrations and minimum bactericidal concentrations (MBCs), further confirming the potent antibacterial effects of the selected medicinal plant extracts. One way anal...
Wottlin LR, Anderson RC, Bhatta R, Leatherwood J, Olson EG, Callaway TR, Ricke SC.Environmental impacts of animal agriculture are under intense scrutiny, thus strategies to decrease greenhouse gas emissions and volatile nitrogen waste are valuable. As dietary inclusion of tannins has been shown to decrease methanogenesis and improve nitrogen retention in ruminants, this study was designed to determine the effects of graded levels of hydrolysable tannin (chestnut) and condensed tannin (mimosa) on equine in vitro cecal fermentation. Methods: Two in vitro experiments were conducted, each with three replications per treatment. Treatments were 0.2 g alfalfa without or with 5, 1...
Godoi APDS, Sobral GG, da Silva Vieira JC, Carneiro GF, Conceição FR, da Silva ER, Mendonça M.Equine rhodococcosis is caused by Rhodococcus equi, an intracellular coccobacillus whose main virulence factor is a plasmid that harbors genes encoding proteins from the Vap family, with the vapA gene being the most important in equine isolates. Furthermore, other factors observed in R. equi strains, such as antimicrobial resistance and biofilm production, may represent significant challenges in the treatment of affected animals. The objective of this study was to characterize four isolates of R. equi from foals in the state of Pernambuco, Brazil. All isolates were identified as R. equi throug...
Arai N, Niwa H, Uchida-Fujii E, Sawa Y, Tamamura-Andoh Y, Kinoshita Y, Momoki A, Watanabe-Yanai A, Iwata T, Kubo M, Kusumoto M.Sequence type 34 (ST34) Salmonella enterica serovar Typhimurium and its monophasic variant (Salmonella 4,[5],12:i:-) are the most prevalent clones among humans and animals worldwide, including in Japan. Although cross-species transmission may have occurred in the background of global spread, the matter remains unresolved. Here, we conducted high-resolution phylogenetic analysis using whole-genome sequencing data of Salmonella Typhimurium and 4,[5],12:i:- obtained from a horse and cattle breeding district in Japan and identified cases of cross-species transmission of ST34 Salmonella 4,[5],12:i:...
Pereira Lopes A, Emanuel da Silva R, Sousa Santos L, de Morais Nobre ML, de Araujo Sousa PS, Almeida Rocha J, Veras Quelemes P, de Araujo-Nobre AR....The aim of this study was to investigate the antibacterial, antibiofilm and modulating activities of trans-trans-farnesol (tt-farnesol) on two strains of Streptococcus equi subsp. equi and two strains of S. equi subsp. zooepidemicus, pathogenic or commensal bacteria of horses. Tt-farnesol showed bactericidal activity against all tested strains, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) between 8 and 4 μg/mL. The sesquiterpene caused significant damage to the bacterial membrane, and its antibacterial activity did not appear to depend on oxidat...
Liu J, Huang X, Wang Y, Wang Y, Luo R, Lu X, Cao K, Xing J, Tu Y, Zheng W.Antibiotic resistance genes (ARGs) are emerging contaminants threatening public health, yet their transmission risk via mare milk products remains understudied. Using metagenomics, we analyzed lactic acid bacteria (LAB)-inoculated fermented, naturally fermented, raw, and pasteurized mare milk to investigate the effect of LAB inoculation on the distribution and transmission pathways of ARGs in mare milk. The results showed that naturally fermented, raw, and pasteurized mare milk had the highest number of pathogens, relative abundance of ARGs, and relative abundance of mobile genetic elements (M...
He L, Khine NO, Song J, Loubière C, Butaye P.Strangles, caused by the host-adapted subsp. (. ), imposes significant welfare and economic losses on the equine industry worldwide. Understanding its genomic features, virulence-associated genes (VAGs), antimicrobial resistance (AMR) and mobile genetic elements (MGEs) is essential for disease control and vaccine development. This study aimed to characterize the accessory genome composition, geographic distribution of VAGs and MGEs, and AMR profiles of . by a large-scale genomic analysis of global publicly available . sequences. All publicly available . sequences in the Sequence Read Arch...
Harel B, Sévin C, Le Hello S, Moreau P, Giard JC, Petry S, Gravey F.Enterobacteriaceae are opportunistic pathogens responsible for local or systemic infections in both human and veterinary medicine. To monitor circulating strains in stud farms in Normandy (France), we investigated a collection of Enterobacteriaceae isolated from necropsied equids performed in the region between 1997 and 2020. These strains were initially identified using MALDI-TOF; however, as this method failed to identify some isolates, whole genome sequencing followed by rMLST analysis was subsequently performed. Different genera were identified: Enterobacter spp., Huaxiibacter spp., Lellio...
Mota RA, Silito IS, Martins MP, Oliveira PRF, Melo RPB, Vieira da Silva V, Jorge FR, Martins TF, Labruna MB.Tick-borne diseases are among the most widespread vector-borne infections, including zoonoses caused by bacterial and protozoal microorganisms. This study consisted of a serosurvey for Rickettsia spp. in 270 horses from 11 farms in the coastal region of Pernambuco, Brazil. Through the indirect immunofluorescence assay (IFA) based on antigens of five Rickettsia species, 164 (60.7%) horses were seroreactive to Rickettsia spp., with seroreactivity among farms ranging from 10 to 100%. Through molecular analysis, all 270 horse blood DNA samples tested negative by PCR assays targeting Anaplasmatacea...
Werle J, Nunes GT, Machado CS, Silva CBD, Vogel FSF, Vargas APC, Cargnelutti JF.The genus Corynebacterium encompasses versatile bacteria that act as natural microbiota or pathogens, causing infections in humans and animals, including equine reproductive disorders. Corynebacterium uterequi (C. uterequi) is a potential pathogen in mares, associated with reproductive disorders including endometritis, embryonic loss, and infertility, raising concerns for equine reproductive health. This study aimed to characterize C. uterequi isolates from mares in southern Brazil and deepen the understanding of this species. Phenotypic, molecular, and phylogenetic analyses were performed on ...
Snedden K, Frye E, Conklin R, Aprea M, Rishniw M, Lejeune M, Goodrich E.To analyze the results and metadata of canine, feline, and equine respiratory PCR panel assays performed at the New York State Animal Health Diagnostic Center and inform veterinary diagnostic sample submission. Unassigned: This retrospective study reviewed laboratory data from routine sample submissions to the Animal Health Diagnostic Center for canine, feline, and equine respiratory PCR panels from January 1 through December 31, 2023. Associations were compared between variables using χ2 tests of independence or Fisher exact tests. Unassigned: A total of 1,902 canine, feline, and equine resp...
Nakajima K, Kasuya K, Senba H, Tagami K, Kinoshita Y, Niwa H.Strangles is a globally widespread, commonly diagnosed and important infectious disease of equids caused by Streptococcus equi subsp. equi. We performed whole genome sequencing of 19 S. equi isolates collected from imported horses at the Japanese border. Of these isolates, 15 isolates were obtained from clinical cases and 4 were from subclinical cases. The 19 isolates were grouped into 3 Bayesian analysis of population structure (BAPS) groups by the core genome single nucleotide polymorphism analysis corresponding to exporting country, SeM typing, or exporter of the horses. The 19 isolates pos...
Hu B, Gao S, Zhang H, Li Q, Li G, Zhang S, Xing Y, Huang Y, Han S, Tian Y, Zhang W, He H.Rhodococcus equi (R. equi) is a Gram-positive zoonotic pathogen that frequently leads to illness and death in young horses (foals). This study presents the complete genome sequence of R. equi strain BJ13, which was isolated from a thoroughbred racehorse breeding farm in Beijing, China. Results: The BJ13 genome has a length of 5.30 Mb and consists of a complete chromosome and a plasmid measuring 5.22 Mb and 0.08 Mb, respectively. We predicted 4,929 coding gene open reading frames, along with 52 tRNAs and 12 rRNAs. Through analysis of mobile genetic elements, we identified 6 gene islands and ...
Molazadeh S, Tukmechi A, Hadian M, Dalir-Naghadeh B.This study aimed to determine the prevalence and phylogenetic analysis of Ehrlichia spp. in horses and dogs in Iran. Blood samples were collected from 400 animals, including 200 horses and 200 dogs, from five different provinces in Iran. Polymerase chain reaction (PCR) was used to detect Ehrlichia spp. based on amplification of the 16S rRNA gene. The semi-nested PCR method was used to amplify the dsb, TRP36, and gltA genes. The results showed that 4.5 % of the samples (3 % horses and 6 % dogs) were positive for Ehrlichia sp. The highest prevalence was observed in Kerman and Khuzestan, while th...
To provide some glimpses on the possibility of shaping the human gut microbiome (GM) through probiotic exchange with natural ecosystems, here we explored the impact of 15 days of daily interaction with horses on the GM of 10 urban-living Italian children. Specifically, the children were in close contact with the horses in an "educational farm", where they spent almost 10 h/day interacting with the animals. The children's GM was assessed before and after the horse interaction using metabarcoding sequencing and shotgun metagenomics, along with the horses' skin, oral and fecal microbiomes. Targ...
Zhang Y, Zhang M, Zhao Z, Peng Y, Deng F, Jiang H, Zhang M, Song B, Kim JK, Pan JH, Chai J, Li Y.Unique skin microbial communities have been shaped by the harsh climatic conditions in high-altitude areas, such as intense ultraviolet radiation and low oxygen concentration. However, it is unknown whether high altitude contributes to shaping common microbiota inhabiting the skin across different mammals. The skin microbial communities of humans and horses living in high-altitude (Tibetan) and low-altitude areas were analyzed using full-length 16S rRNA sequencing technology. Alpha diversity differed between high- and low-altitude groups ( < 0.01). Skin microbial community composition also dif...
