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.
Gerhauser I, Geburek F, Wohlsein P.Perosomus elumbis represents a rare congenital anomaly characterized by aplasia of the lumbosacral spinal cord and vertebrae. This anomaly is often associated with arthrogryposis and malformations of the urogenital and intestinal tract. This report describes the first case of perosomus elumbis in an aborted Thoroughbred foal associated with cerebral aplasia with meningocele, cranioschisis, spina bifida, a fused urogenital and intestinal tracts lined by a cutaneous mucosa without uterine glands, atresia ani, and arthrogryposis of the hind legs. Immunohistochemistry detected no abnormalities in ...
Lanka S, Borst LB, Patterson SK, Maddox CW.The objective of the present investigation was to differentiate between strains of Streptococcus equi subspecies equi implicated in abscess formation in vaccinated horses. Streptococcus equi isolates recovered from clinical specimens associated with equine strangles cases submitted to the University of Illinois Veterinary Diagnostic Laboratory were compared with S. equi isolates representing at least 12 lots of a commercial modified live vaccine (MLV) to determine whether the isolates obtained from the abscesses were vaccine or wild type. Genotyping techniques evaluated included enterobacteria...
Kim TI, Chung CP, Heo MS, Park YJ, Rhee SH.This study was performed to evaluate the periodontal wound healing effect of particulate equine bone mineral on canine alveolar bone defects. Methods: Twelve adult male beagle dogs were used as study subjects. The mandibular second and fourth premolars were extracted prior to the experimental surgery, and the extraction sites were allowed to heal for 8 weeks. After periodontal probing, two-walled defects were created at the mesial and distal sides of the mandibular third premolars bilaterally, and the defects were filled with equine particulate bone with collagen membrane or bovine particulate...
Carlson KL, Kuskie KR, Chaffin KM, Libal MC, Giguère S, Lawhon SD, Cohen ND.This study determined the antimicrobial activity of tulathromycin against Rhodococcus equi in vitro. Ninety-eight virulent isolates of R. equi from equine clinical cases were examined, of which 20 isolates were macrolide resistant. A custom 96-well antimicrobial susceptibility testing plate was used, allowing 14 additional antimicrobials to be tested against R. equi. Isolates were cultured with various concentrations of antimicrobials, and minimal inhibitory concentration (MIC) values were determined. Tulathromycin was found to have poor activity in vitro against R. equi isolates susceptible o...
Gorman JK, Gabriel M, MacLachlan NJ, Nieto N, Foley J, Spier S.This pilot study evaluated protection of an equine autogenous bacterin-toxoid vaccine against Corynebacterium pseudotuberculosis infection. Twenty-four BALB/c mice were inoculated with two doses of bacterin-toxoid vaccine or two injections of a placebo. Clinical, microbiologic, and pathologic outcomes were assessed after intradermal infection with one of two equine-origin C. pseudotuberculosis strains. Mice receiving bacterin-toxoid from fast-growing C. pseudotuberculosis showed significant protection from challenge infection, as evidenced by a higher survival rate, fewer gross and histopathol...
David DE, Lynne AM, Han J, Foley SL.Escherichia coli has been used as an indicator organism for fecal contamination of water and other environments and is often a commensal organism in healthy animals, yet a number of strains can cause disease in young or immunocompromised animals. In this study, 281 E. coli isolates from bovine, porcine, chicken, canine, equine, feline, and other veterinary sources were analyzed by BOXA1R PCR and by virulence factor profiling of 35 factors to determine whether they had utility in identifying the animal source of the isolates. The results of BOXA1R PCR analysis demonstrated a high degree of dive...
Viana D, Blanco J, Tormo-Más MA, Selva L, Guinane CM, Baselga R, Corpa J, Lasa I, Novick RP, Fitzgerald JR, Penadés JR.Staphylococci adapt specifically to various animal hosts by genetically determined mechanisms that are not well understood. One such adaptation involves the ability to coagulate host plasma, by which strains isolated from ruminants or horses can be differentiated from closely related human strains. Here, we report first that this differential coagulation activity is due to animal-specific alleles of the von Willebrand factor-binding protein (vWbp) gene, vwb, and second that these vwb alleles are carried by highly mobile pathogenicity islands, SaPIs. Although all Staphylococcus aureus possess c...
Donabedian SM, Perri MB, Abdujamilova N, Gordoncillo MJ, Naqvi A, Reyes KC, Zervos MJ, Bartlett P.Vancomycin-resistant enterococci are a major cause of nosocomial infections but are rarely found in humans in the community and have not been identified in food animals in the United States. We evaluated a total of 360 fecal specimens from humans and their animals being raised for exhibit at three county fairs in Michigan. Fecal samples from 158 humans, 55 swine, 50 cattle, 25 horses, 57 sheep, 14 goats, and 1 llama were obtained and plated onto Enterococcosel agar containing 16 μg/ml of vancomycin. Vancomycin-resistant Enterococcus faecium (VREF) was isolated from six pigs but not from human...
Lin Y, Barker E, Kislow J, Kaldhone P, Stemper ME, Pantrangi M, Moore FM, Hall M, Fritsche TR, Novicki T, Foley SL, Shukla SK.Not much is known about the zoonotic transmission of methicillin-resistant Staphylococcus aureus (MRSA) in companion animals in the United States. We report the rate of prevalence of S. aureus and MRSA recovered from clinical samples of animals requiring treatment at veterinary clinics throughout the upper midwestern and northeastern United States. Methods: We compared phenotypes, genotypes, and virulence profiles of the MRSA isolates identified in companion animals, such as cats, dogs, horses, and pigs, with typical human nosocomial and community-associated MRSA (CA-MRSA) genotypes to assess ...
Dumoulin M, Pille F, van den Abeele AM, Boyen F, Boussauw B, Oosterlinck M, Pasmans F, Gasthuys F, Martens A.Standard methods for culturing equine synovial fluid (SF) are often unrewarding. Evidence-based information on the relative efficiency of different systems used for optimisation of isolation of microorganisms from equine SF is lacking. Objective: To compare the results of different culture systems performed in parallel on SF samples from horses clinically diagnosed with synovial sepsis. Methods: Synovial fluid specimens were collected between February 2007 and October 2008 from all horses admitted to a referral hospital that were clinically diagnosed with synovial sepsis and from control horse...
Ramsay JD, Leib SR, Orfe L, Call DR, Tallmadge RL, Fraser DG, Mealey RH.Development of an accurate and efficient molecular-based equine MHC class I typing method would facilitate the study of T lymphocyte immune responses in horses. Here, a DNA microarray was designed to detect expressed classical MHC class I genes comprising serologically defined equine leukocyte antigen (ELA)-A haplotypes represented in a closed Arabian horse breeding herd. Initially, cloning and sequencing of RT-PCR products were used to identify sequences associated with the ELA-A1, A4, and W11 haplotypes, and one undefined haplotype, in six horses. Subsequently, sequence-specific, conserved (...
Javsicas LH, Giguère S, Womble AY.The objectives of this study were to determine the serum and pulmonary disposition of telithromycin in foals and to determine the minimum inhibitory concentration (MIC) of telithromycin against macrolide-susceptible and macrolide-resistant Rhodococcus equi isolates. A single dose of telithromycin (15 mg/kg of body weight) was administered to six healthy 6-10-week-old foals by the intragastric route. Activity of telithromycin was measured in serum, pulmonary epithelial lining fluid (PELF), and bronchoalveolar lavage (BAL) cells using a microbiological assay. The broth macrodilution method was u...
Bolton T, Kuskie K, Halbert N, Chaffin K, Healy M, Lawhon S, Jackson A, Cohen N.Rhodococcus equi is an important pathogen of foals aged 1-6 months. Evidence exists that foals are exposed to a wide diversity of R. equi strains in their environment. However, limited data are available regarding the extent to which genotypic variation exists among isolates infecting individual foals. Therefore, electrophoresis of repetitive sequence-based polymerase chain reaction (rep-PCR) amplicons in an automated microfluidics chip format was used to genotype 9 virulent R. equi isolates obtained from distinct anatomic locations in a single foal. Four of the isolates were obtained from dif...
Giguère S, Lee E, Williams E, Cohen ND, Chaffin MK, Halbert N, Martens RJ, Franklin RP, Clark CC, Slovis NM.To determine the prevalence of antimicrobial resistance to macrolide antimicrobials or rifampin in Rhodococcus equi isolates and to describe treatment outcome in foals infected with antimicrobial-resistant isolates of R equi. Methods: Cross-sectional study. Methods: 38 isolates classified as resistant to macrolide antimicrobials or rifampin received from 9 veterinary diagnostic laboratories between January 1997 and December 2008. Methods: For each isolate, the minimum inhibitory concentration of macrolide antimicrobials (ie, azithromycin, erythromycin, and clarithromycin) and rifampin was dete...
Westgate SJ, Percival SL, Knottenbelt DC, Clegg PD, Cochrane CA.Wound research is an evolving science in the equine species. In particular, interest is growing regarding the role that microorganisms play in delaying both acute and chronic wound healing. Equine wounds, particularly lower limb wounds, frequently display delayed healing and infection is commonly the underlying reason. This review will summarize the current research and knowledge surrounding equine wound healing and wound care. Particular focus is placed on the role that microbes play in chronic equine wounds and the significance of associated bacterial biofilms. .
Bryan J, Leonard N, Fanning S, Katz L, Duggan V.The objective of this study was to examine the impact of hospitalisation and antimicrobial drug administration on the prevalence of resistance in commensal faecal E. coli of horses. Faecal samples were collected from ten hospitalised horses treated with antimicrobials, ten hospitalised horses not treated with antimicrobials and nine non-hospitalised horses over a consecutive five day period and susceptibility testing was performed on isolated E. coli. Results revealed that hospitalisation alone was associated with increased prevalence of antimicrobial resistance and multidrug resistance in com...
Coleman M, Kuskie K, Liu M, Chaffin K, Libal M, Giguère S, Bernstein L, Cohen N.The objective of this study was to determine the in vitro antimicrobial activity of gallium maltolate (GaM) against Rhodococcus equi. A total of 98 virulent bacterial isolates from equine clinical cases were examined, of which 19 isolates were known to be resistant to macrolides and rifampin. Isolates were cultured with various concentrations of GaM and minimal inhibitory concentration (MIC) values were determined after 24 and 48 h. Both the MIC(50) and the MIC(90) after 24h of growth were 558 ng/mL (8 μM) and after 48 h of growth were 2230 ng/mL (32 μM). There were no apparent differences b...
Shimizu C, Shibahara T, Takai S, Kasuya K, Chikuba T, Murakoshi N, Kobayashi H, Kubo M.A 26-month-old thoroughbred colt with a 4-month history of continuous diarrhoea and weight loss was subject to necropsy examination. The small intestinal mucosa was thickened and this change particularly affected the terminal ileum. Microscopical examination revealed multifocal epithelial hyperplasia, with multifocal granulomas and marked lymphocytic infiltration of the lamina propria. Numerous gram-negative argyrophilic curved bacilli were observed within the cytoplasm of affected enterocytes. Macrophages and epithelioid cells forming the granulomas had abundant, lightly eosinophilic, foamy c...
Wada S, Hobo S, Niwa H.To describe the number of cases, etiologies, healing times, and results of microbial culture and susceptibility testing of corneal ulcers in thoroughbred racehorses in Japan. Methods: Retrospective study of the medical records of racehorses belonging to the Japan Racing Association (JRA) from 1997 to 2008. Results: A total of 2846 horses suffered ulcerative keratitis. These horses accounted for 90.5% of all the corneal problems and 54.9% of the entire number of horses with ocular diseases. Running in races was the cause in 64.3% of the cases. The mean healing time of the ulcers developed in ra...
Boveland SD, Moore PA, Mysore J, Krunkosky TM, Dietrich UM, Jarrett C, Paige Carmichael K.Determine the effects of matrix metalloproteinases (MMPs)-2, -9, macrophage inflammatory protein-2 (MIP-2), tissue inhibitors of matrix metalloproteinase (TIMP)-1 and -2 by immunohistochemical expression in fungal affected and purulonecrotic corneas. Methods: Paraffin-embedded equine corneal samples; normal (n = 9), fungal affected (FA; n = 26), and purulonecrotic without fungi (PN; n = 41) were evaluated immunohistochemically for MMP-2, -9, MIP-2, TIMP-1 and -2. The number of immunoreactive inflammatory cells was counted and statistics analyzed. Western blot was performed to detect MMP-2, MMP...
Ousey JC, Palmer L, Cash RS, Grimes KJ, Fletcher AP, Barrelet A, Foote AK, Manning FM, Ricketts SW.Standard bacteriological methods for identifying Taylorella equigenitalis in cervical smears are time consuming. Therefore, a more rapid real-time PCR assay was evaluated for its suitability in screening swabs. Objective: To compare the results of a commercially available real-time PCR assay with routine microbiological culture for the identification of T. equigenitalis, the causative organism of contagious equine metritis, in equine genital swab samples, under 'field trial' conditions. Methods: Routine prebreeding genital swabs (n=2072) collected from Thoroughbred mares and stallions during 2...
Milinovich GJ, Klieve AV, Pollitt CC, Trott DJ.Equine laminitis is the most serious foot disease of the horse, often resulting in death or euthanasia. Laminitis has long been recognized as an affliction of horses, as has the association of this condition with the ingestion of carbohydrates. Research into the pathophysiology of this condition has been facilitated by the development of reliable models for experimentally inducing laminitis, and DNA-based techniques for profiling complex microbiomes have dramatically increased the knowledge of the microbiology of this disease. Recent studies have provided substantial evidence showing equine hi...
Grønvold AM, L'Abée-Lund TM, Strand E, Sørum H, Yannarell AC, Mackie RI.Antimicrobial treatment is associated with the spread of antimicrobial resistance and disturbances in the ecological balance of intestinal microbiota. In horses, the main adverse effect of antimicrobial treatment is colitis. We used culture and 16S rRNA gene based molecular methods to monitor the prevalence of antimicrobial resistance and changes in predominant fecal populations during penicillin treatment and general anesthesia of horses in the clinical setting. After 5 days of parenteral administration of penicillin, fecal Escherichia coli were resistant to multiple unrelated antimicrobial a...
Ahmed MO, Clegg PD, Williams NJ, Baptiste KE, Bennett M.Escherichia coli isolates of equine faecal origin were investigated for antibiotic resistance, resistance genes and their ability to perform horizontal transfer. Methods: In total, 264 faecal samples were collected from 138 horses in hospital and community livery premises in northwest England, yielding 296 resistant E. coli isolates. Isolates were tested for susceptibility to antimicrobial drugs by disc diffusion and agar dilution methods in order to determine minimum inhibitory concentrations (MIC). PCR amplification was used to detect genes conferring resistance to: ampicillin (TEM and SHV b...
Husted L, Jensen TK, Olsen SN, Mølbak L.The equine glandular stomach is commonly affected by erosion and ulceration. The aim of this study was to assess whether bacteria, including Helicobacter, could be involved in the aetiology of gastric glandular lesions seen in horses. Results: Stomach lesions, as well as normal appearing mucosa were obtained from horses slaughtered for human consumption. All samples were tested for urease activity using the Pyloritek assay, while mucosal bacterial content was evaluated using Fluorescence In Situ Hybridisation. In selected sub samples, bacteria characterisation was pursued further by cloning an...
Meehan M, Burke FM, Macken S, Owen P.Streptococcus equi possesses a haem-uptake system homologous to that of Streptococcus pyogenes and Streptococcus zooepidemicus. The system consists of two ligand-binding proteins (Shr and Shp) and proteins (HtsA-C) with homology to an ABC transporter. The haem-uptake system of S. equi differs from that of S. pyogenes and S. zooepidemicus in that Shr is truncated by two-thirds. This study focused on the SeShr, SeShp and SeHtsA proteins of S. equi. Analysis of shr, shp and shphtsA knockout mutants showed that all three proteins were expressed in vitro and that expression was upregulated under co...
Preziuso S, Laus F, Tejeda AR, Valente C, Cuteri V.Streptococcus (S.) dysgalactiae subsp. equisimilis is responsible for severe diseases in humans, including primary bacteraemia, pneumonia, endocarditis, and toxic shock syndrome. Infection in some animal species can also occur, although a few studies have looked into cross-species infectivity. In horses, S. equisimilis is generally considered infrequent or opportunistic, but has recently been isolated from cases of strangles-like disease. Rapid and sensitive diagnostic techniques could enable epidemiological studies and effective investigation of outbreaks involving these bacteria. In this stu...
Chaucheyras-Durand F, Durand H.The use of probiotics for farm animals has increased considerably over the last 15 years. Probiotics are defined as live microorganisms which can confer a health benefit for the host when administered in appropriate and regular quantities. Once ingested, the probiotic microorganisms can modulate the balance and activities of the gastrointestinal microbiota, whose role is fundamental to gut homeostasis. It has been demonstrated that numerous factors, such as dietary and management constraints, can strongly affect the structure and activities of the gut microbial communities, leading to impaired...
Murakami S, Otaki M, Hayashi Y, Higuchi K, Kobayashi T, Torii Y, Yokoyama E, Azuma R.Recently, submandibular abscesses associated with Actinomyces denticolens have been reported in horses. The actinomycotic clumps have been observed in the tonsillar crypts. The aim of this study was to demonstrate colonisation of A denticolens in equine tonsils. Twelve equine tonsils obtained from a slaughterhouse were divided into two parts for histopathological examination and for isolation of A denticolens. When actinomycotic clumps were found in these tonsillar crypts, immunohistochemistry using hyperimmune serum against A denticolens (DMS 20671) was performed on the serial sections. To de...
Harlow BE, Lawrence LM, Harris PA, Aiken GE, Flythe MD.Cereal grains are often included in equine diets. When starch intake exceeds foregut digestion starch will reach the hindgut, impacting microbial ecology. Probiotics (e.g., lactobacilli) are reported to mitigate GI dysbioses in other species. This study was conducted to determine the effect of exogenous lactobacilli on pH and the growth of amylolytic and lactate-utilizing bacteria. Feces were collected from 3 mature geldings fed grass hay with access to pasture. Fecal microbes were harvested by differential centrifugation, washed, and re-suspended in anaerobic media containing ground corn, whe...
Morris ERA, Wu J, Bordin AI, Lawhon SD, Cohen ND.Streptococcus equi subsp. (SEE) is a host-restricted equine pathogen considered to have evolved from Streptococcus equi subsp. (SEZ). SEZ is promiscuous in host range and is commonly recovered from horses as a commensal. Comparison of a single strain each of SEE and SEZ using whole-genome sequencing, supplemented by PCR of selected genes in additional SEE and SEZ strains, was used to characterize the evolution of SEE. But the known genetic variability of SEZ warrants comparison of the whole genomes of multiple SEE and SEZ strains. To fill this knowledge gap, we utilized whole-genome sequenci...
Proietto L, Beatty SS, Plummer CE.To compare corneal cytology samples from three common sampling techniques: cytobrush (CB), Kimura platinum spatula (KS), and the handle edge of a scalpel blade (SB). Methods: Equine patients presenting to the University of Florida College of Veterinary Medicine with ulcerative keratitis were included. Following diagnosis of corneal ulcer and sampling for microbial culture, two cytology samples per technique were collected with sterile CB, KS, and SB in a randomized order. Cytologic evaluation was performed by two observers masked to collection method. Objective measures of sample cellularity, ...
Steward KF, Robinson C, Maskell DJ, Nenci C, Waller AS.The Gram-positive bacterium subspecies () is the causative agent of strangles, among the most frequently diagnosed infectious diseases of horses worldwide. Genome analysis of strain 4047 (4047) identified a putative operon, Fim1, with similarity to the pilus loci of other Gram-positive bacteria. The Fim1 locus was present in all strains of and its close relative subspecies () that have been studied to date. In this study we provide evidence that the putative structural pilus proteins, SEQ_0936 and CNE, are produced on the cell surface during growth and infection. Although the proteins ...
Sá e Silva M, da Costa MM, de Avila Botton S, Barretta C, Groff AC, de Vargas AC.Strangles is an acute and contagious disease characterized by inflammation of the upper respiratory tract of horses. The etiological agent of strangles is the bacteria S. equi subsp. equi, which belongs to the Lancefield group C. Opportunistic agents from the same group are frequently isolated from horses with strangles and may induce mistaken diagnoses. Among the subspecies of S. equi, the phenotypic features are almost undistinguishable; however, the pathogenic potential is widely differentiated. The aim of this study was to characterize S. equi isolates obtained from clinical samples of str...
Singha H, Malik P, Saini S, Khurana SK, Elschner MC, Mertens K, Barth SA, Tripathi BN, Singh RK.Burkholderia mallei is a Gram-negative coccobacillus which causes glanders-a fatal disease of equines that may occasionally be transmitted to humans. Several cases of outbreaks have been reported from India since 2006. This paper presents draft genome sequences of two B. mallei strains isolated from equines affected by glanders in India.
de Sousa ME, Araújo MA, Mota RA, Porto WJ, Souza AK, Dos Santos JL, da Silva PP.Normal fungal conjunctiva microbiota of horses remains stable in healthy animals, free from ocular and/or systemic diseases which may, eventually, cause ocular alterations. The knowledge of the fungal microbiota is of great importance due to the reduced number of studies reported in the literature and also to the large occurrence of ocular alterations, mainly keratomycosis, in these animals. The aim of this study was to isolate and to identify the fungi present in the ocular conjunctiva of healthy horses belonging to the Military Police Cavalry of Alagoas. Samples from both conjunctival sacks ...
Mathewson JJ, Simpson RB, Roush DA.Six isolations of Salmonella krefeld were made from clinical veterinary specimens. These isolates were multiply resistant to several antimicrobial agents commonly used to treat salmonellosis.
Allombert J, Vianney A, Laugier C, Petry S, Hébert L.Taylorella equigenitalis is the causative agent of contagious equine metritis, a sexually-transmitted infection of Equidae characterised in infected mares by abundant mucopurulent vaginal discharge and a variable degree of vaginitis, cervicitis or endometritis, usually resulting in temporary infertility. The second species of the Taylorella genus, Taylorella asinigenitalis, is considered non-pathogenic, although mares experimentally infected with this bacterium can develop clinical signs of endometritis. To date, little is understood about the basic molecular virulence and persistence mechanis...
Vanniasinkam T, Barton MD, Das TP, Heuzenroeder MW.This chapter describes a strategy for mapping linear B-cell epitopes of proteins using synthetic biotinylated peptides in an ELISA.A set of overlapping peptides were designed based upon a known amino acid sequence of the target protein, VapA (Virulence-associated Protein A) of the bacterium Rhodococcus equi, an important pulmonary pathogen in foals. The peptides synthesized as biotinylated peptides were coated directly onto micro titer plates which had been pre-coated with NeutrAvidin™ and used to screen sera from foals confirmed to have R. equi disease. A linear B-cell epitope was identifie...
Simmons DR, Letcher PM, Powell MJ, Longcore JE.The order Lobulomycetales contains chytrids from soil, freshwater and marine habitats; environmental DNA sampling has indicated that representatives of this order might be found in deep ocean localities. We describe Alogomyces tanneri as the first lobulomycetalean chytrid isolated from horse manure; A. tanneri is also the first species in the order to possess a rumposome in its zoospore. This species widens the range of habitats, ultrastructural variation and thallus morphology for Lobulomycetales.
Rudi K.Mainly due to the lack of time-series data, we know very little about the underlying interactions leading to adverse states in the gut. I therefore investigate the host-bacteria dynamic interactions in a recently published acidotic state induction time-series experiment. Too high levels of fermentation in the hindgut may lead to elevated serum lactate levels, which is a characteristic of the acidotic state. The acidotic state was induced through injection of oligofructose directly into the caecum of five horses, with subsequent temporal measurements of host serum lactate, and a range of caecum...
Hisey EA, Martins BC, Donnelly CG, Cassano JM, Katzman SA, Murphy CJ, Thomasy SM, Leonard BC.This study aimed to define the antimicrobial peptide (AMP) expression pattern of the equine ocular surface and amniotic membrane using a targeted qPCR approach and 3'Tag-sequencing. It will serve as a reference for future studies of ocular surface innate immunity and amniotic membrane therapies. Methods: A targeted qPCR approach was used to investigate the presence of orthologs for three of the most highly expressed beta-defensins (DEFB1, DEFB4B, and DEFB103A) of the human ocular surface and amniotic membrane in equine corneal epithelium, conjunctiva, and amniotic membrane. 3'Tag-sequencing wa...
Tannahill VJ, Cogan T, Allen K, Acutt E, Busschers E.To determine the efficacy and dermal tolerance of a novel alcohol-based skin antiseptic (ABSA) in horses. Methods: Experimental study. Methods: Systemically healthy horses (n = 25) with no history or clinical signs of skin disease. Methods: Four clipped sites on the abdomen were randomly assigned to a skin preparation protocol: saline (negative control; NC), chlorhexidine gluconate followed by isopropyl alcohol (positive control; PC), saline followed by the ABSA (ABSA A), or a commercially available horse shampoo followed by the ABSA (ABSA B). Microbiological swabs were obtained from each ...
Srivastava SK, Barnum DA.Streptococcus equi was found to adhere to tongue, cheek and nasal epithelial cells of ponies, in vitro. Maximum adherence was observed at pH 7.5 after one hour of incubation of bacteria with epithelial cells. This adherence was more on epithelial cells from adult animals than from foals. Streptococci exposed to heat (60 degrees C for 10 min) or treated with pepsin or trypsin showed a reduced adherence, whereas an increase occurred on treatment with hyaluronidase. Antibodies against whole S. equi cells or M-like protein blocked the adherence, whereas antibodies against group-specific carbohydra...
Bustos CP, Marfil MJ, Lanza NS, Guida N.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 ...
Sukmawinata E, Sato W, Uemura R, Kanda T, Kusano K, Kambayashi Y, Sato T, Ishikawa Y, Toya R, Sueyoshi M.In this study, the occurrence of antimicrobial-resistant (AMR) enterococci was evaluated in Thoroughbred (TB) racehorses in Japan. Fecal samples were collected from 212 healthy TB racehorses at the Miho and Ritto Training Centers of the Japan Racing Association from March 2017 to August 2018. Isolation and identification were performed by enterococcus selective medium and confirmed to the species using MALDI-TOF MS. Enterococcus faecium and E. faecalis isolates were subjected to antimicrobial susceptibility test against 11 antimicrobials by minimum inhibitory concentration based on recommenda...
Hoffman AM, Viel L, Muckle CA, Tesarowski DB.A novel method to reduce contamination of the bronchoscope during microbial sampling of the lower airways of foals was evaluated. Methylene blue (MB) was used as a nasopharyngeal dye marker to assess the relative contamination from the upper airways of bronchoalveolar lavage (BAL) specimens obtained by standard bronchoscopy (SB) and a "guarded" bronchoscopic method (GB). For GB, a clear sterile cellulose sheath was fitted over the bronchoscope in an effort to protect the endoscope tip and channel from contamination. Methylene blue was detected visually in seven of eight BAL samples from foals ...
Al-Ghamdi GM, Kapur V, Ames TR, Timoney JF, Love DN, Mellencamp MA.To determine whether repetitive sequence-based polymerase chain reaction (rep-PCR) could be used to differentiate Streptococcus equi isolates, to examine S equi isolates from throughout the world, and to determine whether a horse had > 1 subtype of S equi during an outbreak of disease. Methods: An initial group of 32 S equi isolates, 63 S equi isolates from various geographic areas, and 17 S equi isolates obtained during outbreaks of disease. Methods: An aliquot of S equi genomic DNA was amplified, using enterobacterial repetitive intergenic consensus primers. Gel electrophoresis was perfor...
Pacyńska JA.Horses are characterized by a very high incidence of mycoses in comparison with most livestock and companion animals. They are highly susceptible to asymptomatic infections caused by yeast-like fungi, but the carrier state may be disrupted under the influence of autogenic and allogenic factors. The above leads to severe organ mycoses, often with an acute form of infection. "Carrier horses" may also act as vectors which transmit potential pathogens between individuals and species. The aim of this study was to identify yeast-like fungi and yeast colonizing the ontocenoses of healthy horses and t...
Massa KL, Murphy CJ, Hartmann FA, Miller PE, Korsower CS, Young KM.To determine the diagnostic value of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis (IUK). Methods: Prospective study. Methods: 48 animals (26 dogs, 13 horses, 7 cats, 1 bird, and 1 llama) with corneal ulcers. Methods: Scrapings from corneal ulcers were examined cytologically. Corneal swab specimens were submitted for microbial culture. Animals were grouped according to whether they had been receiving antimicrobials at the time of admission. Results: Of the 38 animals receiving antimicrobials, 19 had positive results ...
Mazet I, Pendland J, Boucias D.In this study, the phagocytic ability of Spodoptera exigua hemocytes was compared to horse neutrophils. In vitro assays showed that the insect granulocytes and horse neutrophils actively phagocytose FITC-labeled Paecilomyces farinosus blastospores opsonized with S. exigua hemolymph lectin or horse serum, respectively. Killing of fungal cells by the neutrophils and hemocytes was analyzed under in vitro conditions. Neutrophils reduced the growth of P. farinosus up to 65% whereas no fungicidal activity was observed with hemocyte monolayers. The production of oxygen metabolites by both phagocytic ...
Sheahan BJ, Atkins GJ, Russell RJ, O'Connor JP.Two aged mares with histiolymphocytic lymphosarcoma had multiple rapidly proliferating tumours in the subcutis. Consistent haematological changes were absent. One mare had lymph node involvement but no neoplastic lesions in the viscera. Microbiological examination of tumour tissue showed coryneform bacteria; there was no evidence of C-type or lytic viruses or of reverse transcriptase. Prominent intramitochondrial crystalline inclusions were in histiocytic tumour cells.
Velineni S, Timoney JF.Streptococcus zooepidemicus causes opportunist respiratory and other infections in the horse. Capsule expression is highly variable and known to affect resistance to phagocytosis. Most clinical isolates producing small, dry colonies at 37°C produce mucoid colonies at temperatures below 35°C. Objective: The aim was to understand the molecular basis of increased capsule expression by equine isolates of S. zooepidemicus at temperatures lower than 35°C. Methods: Cross-sectional observational study. Methods: Capsule production by groups of equine S. zooepidemicus strains was determined at 23, ...
Scotty NC, Brooks DE, Schuman Rose CD.To evaluate the in vitro efficacy of an ophthalmic drug combination against common corneal pathogens of horses. Methods: Representative isolates of 3 bacterial and 2 fungal corneal pathogens of horses. Methods: Pathogens were subjected to minimum inhibitory concentration (MIC) testing of a drug combination that consisted of equal volumes of natamycin 3.33%, tobramycin 0.3%, cefazolin 5.5%, and equine serum. Proteinase inhibitory activity of the drug combination was assessed by use of a fluorescence microplate assay with gelatin and collagen I as substrates. The MICs of the drug combination wer...
Fouché N, Gerber V, Thomann A, Perreten V.We report blood culture results of 43 foals admitted to an equine hospital for medical or surgical disorders and determine minimal inhibitory concentrations (MIC) of different antibiotics. Eleven foals had a positive blood culture result despite prior administration of antibiotics in 10 of these animals. MIC values above EUCAST and/or CLSI breakpoints were identified in coagulase-negative staphylococci, methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium. Gram-negative isolates were less frequently identified and did not appear to exhibit increased MIC values. This stud...
Dart AJ, Snyder JR, Julian D, Hinds DM.The microvascular anatomic features of the small intestine was described by correlating results of microangiography, light microscopy, gross studies, and scanning electron microscopy of vascular replicas in 14 horses. After heparinization, the horses were euthanatized, a length of jejunum was transected, and blood was flushed free of the circulation, using isotonic NaCl solution. In six horses, the circulatory system was perfused with a modified radiopaque medium and evaluated radiographically. These sections were then evaluated by standard histologic methods. Sections from 8 horses were perfu...
MacLeay JM, Kohn CW.Quantitative urine cultures were performed on 11 male and 11 female healthy adult horses. Urine was collected by free catch and catheterization using standard methods. Results showed that all samples collected by free catch contained less than 20,000 colony-forming units (CFU)/mL. All samples collected by catheterization contained 500 CFU/mL or less. A significant difference was found between collection methods (P < .005), with catheterization having less contamination. In samples collected by free catch, females had significantly greater contamination than did males (P < .03). Predominant bac...
Goni JI, Hendrix K, Kritchevsky J.It is important to determine if a horse is shedding Salmonella spp., but a complete culture series can be cost prohibitive. Objective: Determine the optimal pooling technique to maintain high sensitivity of Salmonella spp. culture using spiked samples, and then demonstrate the efficacy of this protocol on clinical submissions. Objective: Pooled fecal samples are as sensitive as 5 individual cultures for the detection of Salmonella shedding. Methods: A single Salmonella-negative horse from the university herd, and 19 hospitalized horses. Methods: Salmonella-free fecal samples were spiked with d...
