Staphylococcus is a genus of bacteria commonly found on the skin and mucous membranes of horses. These bacteria can be part of the normal flora but may also act as opportunistic pathogens, leading to infections under certain conditions. In horses, Staphylococcus species can cause a range of infections, including skin infections, wound infections, and more severe conditions such as septicemia. The most frequently identified species in equine infections is Staphylococcus aureus, known for its ability to resist certain antibiotics, complicating treatment efforts. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenic mechanisms, and treatment strategies of Staphylococcus infections in horses.
McLaughlin SA, Brightman AH, Helper LC, Manning JP, Tomes JE.In 123 cases of external ocular disease in the horse, pathogenic microorganisms isolated with greatest frequency were Streptococcus sp (43.9%), Staphylococcus sp (24.2%), and Pseudomonas sp (13.8%). Fungi were isolated in 4.8% of the cases. In vitro testing showed that most of the Streptococcus sp isolants were sensitive to ampicillin, cephalothin, and carbenicillin. Most of the Staphylococcus sp isolants were sensitive to gentamicin, cephalothin, and bacitracin. Most of the Pseudomonas sp isolants were sensitive to polymyxin B and gentamicin.
Barber SM.A three year old Thoroughbred filly was examined because of bilateral nasal discharge and external swelling of the left laryngeal area. Endoscopy revealed an enlarged left arytenoid cartilage, left laryngeal hemiplegia and drainage of purulent material into the lumen of the larynx. Radiographs showed a large fluid and gas filled cavity overlying the caudal larynx and cranial trachea. Surgical drainage and debridement of the abscess led to complete healing by secondary intention. Laryngeal ventriculectomy was performed as a treatment for left laryngeal hemiplegia, but a grave prognosis for resp...
Love DN, Rose RJ, Martin IC, Bailey M.Amoxycillin trihydrate was administered orally to 6 foals at dose rates of 13 mg/kg (low), 20 mg/kg (medium) and 30 mg/kg (high) and serum concentrations determined at intervals up to 8 h. Therapeutic serum levels of 1 microgram/ml persisted for 268 mins at a dose rate of 13 mg/kg, for 339 mins at 20 mg/kg and for 381 mins at 30 mg/kg. A 2 micrograms/ml serum level persisted for 198 mins at a dose rate of 13 mg/kg, for 268 mins at 20 mg/kg and for 311 mins at 30 mg/kg. To determine the spectra of its antibacterial activity, the minimum inhibitory concentrations of amoxycillin against 8 genera ...
Turner WH, Pickard DJ.A new haemolysin from Staphylococcus aureus produced opaque zones of haemolysis on horse blood agar but did not lyse equine erythrocytes suspended in phosphate-buffered saline. The haemolysin was not neutralized by normal rabbit serum and was distinct from alpha-, beta- and delta-haemolysins as well as human leucocidin. Partially purified preparations produced erythema when injected intradermally into rabbit skin.
Jahrling PB, Hesse RA, Metzger JF.A radioimmunoassay (RIA) procedure is described for measuring antibodies to alphaviruses in human and other mammalian sera. The test employed protein Abearing Staphylococcus aureus as a solid-phase immunoadsorbent for (3)H-labeled viruses complexed with immunoglobulin G. Using antibodies produced in humans and guinea pigs, the RIA procedure clearly differentiated among antibodies to Venezuelan, western, and eastern equine encephalomyelitis viruses. Sensitivity of the RIA depended on the concentrations of labeled viruses employed. The dilution of serum that effected binding of 50% of the (3)H-l...
Cattabiani F, Cabassi E, Allodi C, Gianelli F.The AA. report the results of taxonomic research conducted on the conjunctival sac of 59 horses for identification of the present bacterial flora. In the controlled animals, it was observed, at the level of the considered niche, a community constituted of normal bacterial populations, but not autochtonous in the significance they attributed from DUBOS et al., relative to the characterization of the indigenous microbiota of the intestine. The isolated normal bacterial flora seems to be constituted of: Micrococcus (subgroup 6 of Baird-Parker, M. luteus, Micrococcus spp.) isolated in 49,15% of th...
Oeding P, Hájek V, Marsálek E.Out of 70 S. aurew strains isolated from the anterior nares of horses, 48 (69 per cent)
belonged to the E biotype. Approximately one third of these isolates were typed with factor
sera, the 6 (35 per cent) that were typable showing 5 different patterns. All strains but one
were non-typable with the basic sets of phages for typing human and bovine staphylococci
even at RTD x 100. Without any exception the equine staphylococci of the E biotype
contained polysaccharide Aa. Sixteen biochemically different strains belonged to the biotype A, B or C. A number of different serological patterns an...
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...
To investigate predictors of survival and athletic function in adult horses with infection of a synovial structure. Objective: Increasing duration from contamination to referral, bone or tendon involvement and positive microbial culture decreases short-term survival. Synovitis and/or sepsis at 5 days post-admission and involvement of Staphylococcus spp. decreases long-term athletic function. Methods: Retrospective study. Methods: Records over 4 years of adult horses with synovial sepsis were reviewed. A two-tailed Fisher's exact test, Mann-Whitney U test or t-test was used to examine whether v...
A 3-year-old Thoroughbred gelding was examined because of clinical signs of pneumonia and shock. Mucous membrane petechiation and ventral edema were observed and considered to be a result of vasculitis. Epidermal necrosis developed on the distal portions of the limbs. The horse had a persistent high fever that was unresponsive to nonsteroidal anti-inflammatory treatment, and Staphylococcus aureus was isolated from a nasal swab specimen and 2 transtracheal wash fluid samples. Antimicrobial, anti-inflammatory, and supportive treatment resulted in clinical improvement. However, resolution of the ...
Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging problem in horses; however, the epidemiology of infection and colonization is poorly understood. This study evaluated factors associated with MRSA colonization at the time of admission to a veterinary teaching hospital. A case-control study evaluating historical factors was performed. Previous colonization of the horse, previous identification of colonized horses on the farm, antimicrobial administration within 30 days, admission to the neonatal intensive care unit, and admission to a service other than the surgical service were...
Köhne M, Hegger A, Tönissen A, Heusinger A, Hader C, Görgens A, Sieme H.Antimicrobial-resistant bacteria pose a serious threat to the wellbeing of animals and humans. In equine reproduction, endometritis caused by facultative microbial pathogens is a condition, which is usually treated with antibiotics. Data from Germany on prevalence of facultative pathogenic microorganisms cultured in samples from the equine uterus and the frequency of multi-drug resistant (MDR) bacteria is lacking. The aim of the study was to provide representative numbers for both. Microbiological culture results (n = 28,887) of endometrial samples submitted to a large veterinary diagnostic ...
Olivo G, Zakia LS, Ribeiro MG, da Cunha MLRS, Riboli DFM, Mello PL, Teixeira NB, de Araújo CET, Oliveira-Filho JP, Borges AS.Staphylococci are well-known opportunistic pathogens associated with suppurative diseases in humans and animals. Antimicrobial resistance is an emergent threat to humans and animals worldwide. This study investigated the prevalence of methicillin-resistant Staphylococcus spp. (MRS) in hospitalized horses and contacting personnel (veterinarians and staff), and assessed possible interspecies transmission in a teaching veterinary hospital. Nasal swabs from horses (n = 131) and humans (n = 35) were collected. The microorganisms were identified by traditional biochemical tests and genotypic methods...
Kannekens-Jager MM, Duim B, der Graaf-van Bloois LV, Zomer AL, Broekhuizen-Stins MJ, Boswinkel M, Wagenaar JA, Broens EM.In 2020 and 2022, nine cases of surgical site infections with a methicillin-resistant Staphylococcus aureus (MRSA) were diagnosed in horses in an equine referral clinic. Sixteen isolates (horses, n=9; environment, n=3; and staff members, n=4) were analysed retrospectively using Nanopore whole-genome sequencing to investigate the relatedness of two suspected MRSA outbreaks (2020 and 2022). The MRSA isolates belonged to ST398 and ST612. ST398 genomes from 2020 and 2022 formed three phylogenetic clusters. The first ST398 cluster from 2020 consisted of isolates from five horses and one staff membe...
Papouskova A, Drabkova Z, Brajerova M, Krutova M, Cizek A, Tkadlec J.We performed a retrospective analysis of MRSA isolates collected at the university equine clinic including clinical isolates from 2008 to 2021 and screening environmental, equine and personnel isolates from 2016. Screening and clinical samples were cultured on Brilliance MRSA 2 and Columbia agar (Oxoid), respectively, with enrichment for environmental samples. Antimicrobial susceptibility was assessed by disc diffusion. All the isolates were characterized by spa typing. Eighteen selected isolates were subjected to WGS with subsequent wgMLST clonal analysis. Among 75 MRSA isolates, five spa typ...
Mazzuchini MP, Lisboa FP, de Castro JI, Alvarenga MA, Segabinazzi LGTM, Canisso IF.Endometritis is the leading cause of subfertility in horses, and it is a clinical problem where historically antibiotics have not always been used with prudent justification. Because of this, alternative therapies to treat endometritis are necessary for the rational use of antibiotics. Objective: To assess the in vitro antimicrobial activity of non-traditional therapies commonly used in clinical practice against microorganisms causing infectious endometritis in mares. Methods: In vitro experiments. Methods: A microdilution technique was performed to determine the minimum inhibitory concentrati...
Khatibzadeh SM, Dahlgren LA, Caswell CC, Ducker WA, Werre SR, Bogers SH.Biofilms reduce antibiotic efficacy and lead to complications and mortality in human and equine patients with orthopedic infections. Equine bone marrow-derived mesenchymal stromal cells (MSC) kill planktonic bacteria and prevent biofilm formation, but their ability to disrupt established orthopedic biofilms is unknown. Our objective was to evaluate the ability of MSC to reduce established S. aureus or E. coli biofilms in vitro. We hypothesized that MSC would reduce biofilm matrix and colony-forming units (CFU) compared to no treatment and that MSC combined with the antibiotic, amikacin sulfate...
Haenni M, Murri S, Drapeau A, Rafidinarivo I, Gilles S, Keck N, Léon A, Sulter A, Tricaud MC, François P, Madec JY.Staphylococcus aureus is an important zoonotic pathogen that has often been seen in animals through the prism of the MRSA clonal complex (CC) 398 in pigs and in-contact humans. The goal of this study was first to assess the prevalence of MRSA, and second to look for MSSA CC398 in cats, dogs and horses in France. Methods: Clinical S. aureus isolates (n = 479) were collected from 186 cats, 143 dogs and 150 horses during 2022-2023 all over the French territory. Antibiograms were performed on all isolates. MRSA and MSSA CC398 isolates were subject to WGS. Core genome (cg) MLST-based and SNP-ba...
Caddey B, Fisher S, Barkema HW, Nobrega DB.SUMMARYNumerous questions persist regarding the role of companion animals as potential reservoirs of antimicrobial-resistant organisms that can infect humans. While relative antimicrobial usage in companion animals is lower than that in humans, certain antimicrobial-resistant pathogens have comparable colonization rates in companion animals and their human counterparts, which inevitably raises questions regarding potential antimicrobial resistance (AMR) transmission. Furthermore, the close contact between pets and their owners, as well as pets, veterinary professionals, and the veterinary clin...
Styková E, Valocký I, Kačírová J, Fecskeová LK.Equine pastern dermatitis (EPD) is a multifactorial disease with a change in the skin microbiome. The present study monitored the influence of Weissella cibaria Biocenol™ 4/8 D37 CCM 9015 stabilized on alginite on the skin microbiota of healthy horses and model patients with EPD. Based on clinical signs, EPD lesions were identified as exudative or proliferative forms. A comparison of the initial microbial community based on 16S rRNA amplicon sequencing revealed that there was a statistically significant difference between healthy vs. exudative (R = 0.52, p = 0.003) and exudative vs. ...
Marsella R.Information on skin barrier in horses is limited. A study on the epidermal ultrastructure of normal and allergic horses documented disorganized amorphous intercellular lipids in the stratum corneum of allergic samples. These findings are similar to atopic canine and human skin. Currently, there is no published study comparing skin barrier function parameters between normal and allergic horses; thus, the functional implications of the ultrastructural changes are unknown. In normal horses, body location, gender, breed, and ambient conditions affect skin barrier parameters, such as Transepidermal...
Allano M, Arsenault J, Archambault M, Fairbrother JH, Sauvé F.Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infections, including in veterinary settings. Objective: To investigate the prevalence, risk factors for Staphylococcus aureus (SA) and MRSA colonization, and the duration of MRSA colonization. Methods: Elective cases admitted to the Veterinary Teaching Hospital were recruited (228 horses). Methods: A cross-sectional study was conducted over 3 years. Nasal swabs were collected at admission and cultured for SA. Methicillin-resistant isolates were identified using matrix-assisted laser desorption/ionization-time-...
Marsella R.Antibiotic resistance is a growing concern worldwide and across species. This is especially important in horses with skin infections, as many of them are infected with Staphylococcus aureus, which can also colonize people. An increasing body of literature has documented colonization of horses with methicillin-resistant S aureus (MRSA) and transmission of MRSA between horses and veterinarians and vice versa. Colonization with MRSA does not always result in disease but has a potential impact on other horses, owners, handlers, and especially veterinarians. The WHO has published criteria to determ...
Lin H, Deng D, Yan Z, Zou G, Shen Y.Staphylococcus aureus can transfer from animals to humans. Lichuan horse is an isolated breed living in a high-altitude area with limited use of antibiotics and is bred for use in tourism. To evaluate the risk of human-animal cross-transmission, the S. aureus was isolated from three horse farms in Lichuan, including healthy horses and horses with skin infections, farm workers and environment. From a collection of 111 samples, 18 S. aureus isolates were obtained. All the isolates were genome sequenced and their biological characteristics including antimicrobial susceptibility, virulence and bi...
Żychska M, Rzewuska M, Kizerwetter-Świda M, Chrobak-Chmiel D, Stefańska I, Kwiecień E, Witkowski L.The rise of antibiotic resistance is a global health crisis affecting human and veterinary medicine, highlighted within the One Health framework. Horses, classified as both meat and companion animals, play a crucial role in facilitating resistant bacteria spread to humans. Despite increased awareness and reduced antibiotic use in livestock, data on equine antibiotic use and resistance remain limited. This retrospective study examines antimicrobial resistance in 978 bacterial isolates from horses in Poland over 12 years (2010-2022), utilizing data from the Microbiological Diagnostic Laboratory ...
Clarysse M, Bertier P, Verpaele S, Madsen AM, Vlaminck L.Equine dental disorders, such as sharp enamel points and focal overgrowths, are common in horses and are often treated with motorized dental grinding tools. These tools, while effective, produce dust and aerosols that may pose health risks to veterinarians and nearby individuals. This study aimed to assess the health risks associated with dental dust and aerosols generated during equine odontoplasty. Using a realistic setup, air concentrations of inhalable and respirable dust, crystalline silica, and airborne microorganisms and endotoxins were measured in 12 groups of horses undergoing odontop...
Saraiva MMS, Rodrigues HLS, Benevides VP, de Leon CMCG, Santos SCL, Stipp DT, Givisiez PEN, Vieira RFC, Oliveira CJB. () is a major cause of opportunistic infections in humans and animals, leading to severe systemic diseases. The rise of MDR strains associated with animal carriage poses significant health challenges, underscoring the need to investigate animal-derived . Objective: This study examined the genotypic relatedness and phenotypic profiles of antimicrobial resistance in . , previously sampled from nostril swabs of healthy horses from two geographically distant Brazilian states (Northeast and South), separated by over 3700 km. The study also sought to confirm the presence of methicillin-resistant (M...
