Topic:Antibiotics
Antibiotics are medications used to treat bacterial infections in horses. They work by either killing bacteria or inhibiting their growth, aiding the horse's immune system in overcoming the infection. Commonly used antibiotics in equine medicine include penicillin, trimethoprim-sulfamethoxazole, and gentamicin. The selection of an antibiotic depends on factors such as the type of bacteria, the site of infection, and the horse's health status. Responsible use of antibiotics is essential to minimize the risk of resistance. This page compiles peer-reviewed research studies and scholarly articles that explore the efficacy, administration, and impact of antibiotics on equine health.
Headshaking associated with a unique presentation of guttural pouches infection and otitis media in a Quarter Horse stallion: diagnosis, medical treatment and outcome. A 3-year-old Quarter Horse stallion was referred for headshaking (HS) syndrome of one month duration. The horse underwent complete HS workup. Physical examination revealed up-and-down head movements associated with nose snorting during lunging and riding, in the absence of other abnormalities at rest or in motion. Lameness, neurologic and behavioural evaluations were unremarkable. Endoscopic examination of the upper respiratory tract showed bilateral guttural pouches (GPs) inflammation. The mucosal surface was altered by the presence of areas of microbullous appearance coalescing into some bul...
Pharmacokinetics of Chloramphenicol and Chloramphenicol Glucuronide in Horses Following Administration Per Rectum or via Nasogastric Intubation. Chloramphenicol is a broad-spectrum antibiotic used in equine practice. It is known to produce adverse effects of hyporexia/anorexia after oral administration. Administration per rectum (PR) could mitigate the appetite suppression seen with oral administration and allow its use in horses unable to receive oral medications. The objectives of this study were to evaluate the relative bioavailability of chloramphenicol administered PR or via nasogastric tube (NGT) and determine relevant pharmacokinetic/pharmacodynamic parameters and metabolic ratios. Ten healthy, adult horses were administered chl...
Identification and molecular characteristics of Staphylococcus aureus isolated from horses in Lichuan, China. 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...
Understanding antimicrobial use by equine owners in Wales: Using cross-sectional survey and semi-structured interviews. Antimicrobial resistance (AMR) is an increasingly serious threat to human and animal health. Antimicrobial use (AMU) in horses is gathering research interest, although there remain significant evidence gaps. Currently, there is scant qualitative research into equine owners' use of antimicrobials, specifically antibiotics, hindering the design of evidence-based stewardship interventions and policies. Objective: To understand Welsh equine owners' views and behaviours relating to antimicrobial usage. Methods: Cross sectional survey and qualitative data collection and analysis. Methods: An online ...
Equine epiglottitis: Diagnosis, treatment and outcome. Epiglottitis is an uncommon upper airway pathology manifested endoscopically by mucosal oedema, reddening and thickening of the epiglottic mucosa. Literature on epiglottitis in horses is sparse. Objective: To describe the diagnosis, treatment and outcome of Thoroughbred and Standardbred racehorses diagnosed with epiglottitis at a single centre. A secondary objective is to demonstrate the efficacy of inhaled and topical anti-inflammatories for this condition. Methods: Retrospective case series. Methods: Medical records (2009-2023) were reviewed for racehorses treated for epiglottitis. Data coll...
Penicillin and Gentamicin Concentrations in the Uterine Fluid of Non-Pregnant Mares Following a Single Intrauterine Infusion. Despite their widespread clinical use, there is limited pharmacokinetic data for many equine intrauterine antimicrobials. This study aimed to measure the concentration of gentamicin and penicillin in the uterine fluid of mares following infusion of either a standard (PPGent) or long-acting (LA-PPGent) compounded formulation. We hypothesized that both formulations would result in therapeutic concentrations, with total concentrations sustained for longer using the long-acting formulation. Mares were administered 2400 mg of procaine penicillin and 200 mg of gentamicin via a single intrauterin...
Presumptive Lyme disease-associated eosinophilic synovitis in a horse. A 1-year-old American Quarter horse was presented with acute onset of right hind lameness. On physical examination, there was synovial effusion of the right tarsocrural joint. Synovial fluid cytology revealed a marked eosinophilic synovitis. Serology indicated evidence of acute and chronic infection with Borrelia burgdorferi, although PCR of the synovial fluid was negative. The filly was treated with phenylbutazone and oxytetracycline, and repeated synovial cytology indicated improvement. The filly was discharged with a prescription of minocycline for 30 days. Despite initial improvement, recu...
Leptospirosis. Leptospirosis is a zoonotic bacterial infection that is prevalent across all continents and is caused by pathogenic spirochaetes of the genus Leptospira. Although infection can be asymptomatic, symptomatic disease can vary in severity from mild to severe illness, the latter characterized by icterus and/or multi-organ dysfunction and potentially death. An estimated one million cases of leptospirosis occur globally each year, resulting in ~60,000 deaths. The pathogenesis of severe leptospirosis is poorly understood but is believed to involve an interplay between genetic predisposition, pathogen ...
Minimal disruption of equine gut microbiota by intravenous cephalothin treatment. In horses, the gut microbiota plays a critical role in maintaining intestinal homeostasis and overall health, but antimicrobial administration can disrupt its balance, resulting in dysbiosis, which can cause antibiotic-associated diarrhea. This study assessed the impact of intravenous cephalothin sodium administration on the equine gut microbiota by using microbial amplicon sequencing targeting the 16S-ITS-23S rRNA operon. Fecal samples from 39 clinically normal horses, 16 antibiotic-treated horses (cephalothin, n=5; minocycline, n=5; metronidazole, n=6, each administered for 5 days), and seve...
Intra- and Post-Operative Bacteriological Surveys of Surgical Site in Horses: A Single-Centre Study. Bacterial contamination of the surgical site in horses is a major risk factor for the development of surgical site infections (SSIs), which increase morbidity, mortality, the hospitalisation period, antibiotic use, and management costs. While contamination is a prerequisite for infection, its progression to clinical infection depends on additional factors that compromise host defences. The present study, conducted at the Veterinary Teaching Hospital of the University of Perugia over an 11-month period, investigated bacterial contamination in 70 surgeries (53 clean and 17 clean-contaminated) at...
A Laboratory Protocol for Routine Therapeutic Drug Monitoring of Beta-Lactams Antimicrobials in Horses and Dogs. Background: Although antibiotic resistance is a well-known issue in veterinary medicine, studies proposing real-time therapeutic monitoring (TDM) are lacking. The objective of the present study was to develop a simple and rapid protocol for the real-time therapeutic monitoring of antibiotics in horses and dogs. Methods: A reliable TDM protocol should encompass guidelines for the definition of plasma/serum collection time points, sample management by the clinical staff, transportation to the laboratory, and the availability of robust and swift analytical technologies. Ampicillin and sulbactam w...
Survey of the antimicrobial susceptibility of Escherichia coli isolated from horses admitted to the Western College of Veterinary Medicine, Saskatoon, Saskatchewan. Antimicrobial resistance is a serious threat in human and veterinary medicine. Among the most problematic resistant organisms are the extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, which are resistant to the 3rd-generation cephalosporins. The purpose of this study was to determine the frequency of colonization of horses admitted to the Western College of Veterinary Medicine with resistant Escherichia coli. Unassigned: Rectal swabs were collected from 60 horses admitted between November 2021 and March 2022. Swabs were selectively cultured for E. coli, which was identified usi...
Influence of antimicrobial prophylaxis in horses undergoing sutured castrations. To investigate the influence of surgical antimicrobial prophylaxis (SAP) on complication rates and surgical site infections (SSI) in horses undergoing sutured castration in a hospital setting. Methods: Retrospective chart review of a convenience sample. Methods: A total of 220 colts and stallions admitted for sutured castration. Methods: Medical records of sutured castration were assessed for patient characteristics, perioperative and postoperative medications, and postoperative complications within 6 weeks after surgery. The effect of these variables on the occurrence of complications was a...
Antibiotic resistance in equine dermatology: what should we do? 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...
Misidentification of Raoultella spp. (R. terrigena, R. planticola) and Klebsiella spp. (K. variicola, K. grimontii) as Klebsiella pneumoniae: Retrospective study of a necropsy-associated bacterial collection from horses. Misidentifications as Klebsiella pneumoniae were observed during a French retrospective study of a necropsy-associated K. pneumoniae bacterial collection from horses. Accordingly, the present study aimed to further characterise the 12 Raoultella spp. and Klebsiella spp. strains involved in these misidentifications. The strains were identified and characterised using the Api 20E system, K. pneumoniae PCR detection, matrix-assisted laser desorption/ionisation time-of-flight mass spectroscopy and whole-genome sequencing. Antimicrobial susceptibilities were tested by the disc diffusion method with...
Clinical use of antimicrobial regional limb perfusion in adult horses diagnosed with synovial sepsis or penetrating synovial wounds at a single equine referral hospital in the Midwest United States-163 cases (2010-2020). The clinical outcomes in horses diagnosed with established synovial sepsis (SS) or minimally contaminated synovial wounds (SW)/non-established sepsis, following intravenous regional limb perfusion (IVRLP) treatment, have not been reported since 2010. Additionally, previous reports on this subject were confined to just two clinical retrospective reports. This study aimed to provide an update on the short-term (hospital discharge) and long-term (≥1 year) survival rates in adult horses diagnosed with SS or SW treated with IVRLP at a single institution in the USA from 2010-2020. The study also...
Cutaneous non-tuberculous Mycobacterium ulcerans infection: A serious cause for concern. Mycobacterium ulcerans infection in horses is under-reported. Objective: To document the successful multimodal treatment of M. ulcerans and highlight the need for further investigation due to the zoonotic nature of M. ulcerans with its related potential public health concerns. Methods: Case report CASE DESCRIPTION: A 14-year-old gelding in the Southeastern region of Australia was diagnosed with M. ulcerans infection, initially presenting as a non-healing wound of the right flank progressing to extensive necrotic ulceration. Ziehl-Neelsen and Wade-Fite stained incisional biopsies revealed large...
A single-centre retrospective study of surgical site infection following equine colic surgery (2013‒2021). Surgical site infection (SSI) is a significant cause of postoperative morbidity following equine laparotomy. Therefore, if risk factors for SSI can be identified, morbidity may consequently be reduced. The objectives of this study were to determine the prevalence of SSI in horses undergoing exploratory laparotomy at a single hospital over an 8-year period (2013‒2021), investigate the risk factors associated with SSI and report on the bacterial isolates identified. Methods: The medical records of horses that had an exploratory laparotomy performed at the teaching hospital due to colic were r...
Ex Vivo Pharmacokinetic/Pharmacodynamic Integration Model of Cefquinome Against Escherichia coli in Foals. Cefquinome is used to treat septicemia caused by () and respiratory infections caused by subsp. in foals. However, studies reporting the use of cefquinome to target as pathogens of sepsis are lacking. Therefore, this study aimed to determine the optimal dosage regimen for cefquinome against using a PK/PD model. After the administration of 1 mg/kg cefquinome (intramuscularly or intravenously), blood samples were collected at different time points to determine the serum concentration of cefquinome via HPLC. The pharmacokinetic parameters were evaluated via NCA (WinNonlin 5.2.1 software). Th...
Concurrent intravenous regional limb perfusion and systemic amikacin administration achieves variable synovial fluid amikacin concentrations in healthy neonatal foals. To evaluate plasma and synovial fluid amikacin concentrations following cephalic or saphenous IV regional limb perfusion (IVRLP) with a dosing protocol of 25 mg of amikacin/kg, divided into 16.7 mg/kg systemically and 8.3 mg/kg regionally. We hypothesized that plasma amikacin concentrations observed at 30 minutes after systemic administration would exceed a therapeutic target of 53 μg/mL and that synovial fluid concentrations would exceed a therapeutic target of 80 μg/mL. Unassigned: Over a 5-month period (spring/summer of 2023), 8 healthy neonatal foals were administered each protocol at le...
It is not always what it seems: allantochorion cervical pole necrosis. A 286-day pregnant mare was referred for signs of impending abortion. The ultrasonographic evaluation revealed a high normal combined thickness of the utero-placental unit (CTUP), oligohydroallantois and a living fetus. No vulvar discharge was observed, and the cervical swab culture was negative. After a choke, the mare received NSAIDs and antibiotics and then developed systemic inflammatory response syndrome (SIRS) and aborted. The amniotic portion of the umbilical cord was excessively long and twisted and the chorionic side of the placenta showed a brown discoloration and rough surface area....
The prevalence, serotypes and antibiograms of Salmonella isolates on Thoroughbred stud farms in New South Wales and Victoria. Salmonella enterica subsp. enterica is responsible for substantial morbidity and mortality within horse populations, worldwide. The prevalence of Salmonella shedding in faeces has largely been reported in hospital settings, with limited information from general horse populations. Further, there is little understanding of the serotypes and antibiograms of Salmonella isolates from horses in Australia. The objectives of this study were to (1) estimate the prevalence of Salmonella in stud farm horse populations, (2) determine serotypes and antibiograms for isolates, and (3) determine whether seaso...
Different methods of perfusate administration do not have an effect on synovial concentrations of amikacin following intravenous regional limb perfusion. To determine if different methods of perfusate instillation influence synovial amikacin concentrations in the radiocarpal joint (RCJ) after IV regional limb perfusion (IVRLP). Unassigned: 6 healthy horses received an IVRLP using 2 different methods: (1) 2 g amikacin followed by 52 mL 0.9% NaCl (60 mL total; perfusate-A) and (2) 2 g amikacin diluted to 60 mL with 0.9% NaCl (perfusate-D). For both methods, the perfusion was administered over 5 minutes. Joint fluid from the RCJ was sampled at 10, 15, 20, 25, and 30 minutes after instillation of the perfusate. Systemic concentrations of amikacin w...
Phenotypical and molecular characterization of Rhodococcus equi isolated from foals in the Agreste region of Pernambuco – Brazil. 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...
Antimicrobial use and prescribing practices by equine veterinarians in Australia: Insights into reproduction, dentistry, compounding and use for nonbactericidal effects. Antimicrobial resistance (AMR) is a problem for equine practitioners in Australia, but antimicrobial use in practice has been largely understudied. We aimed to evaluate equine veterinarians' intentions of prescribing antimicrobials in areas where we perceived there to be wide ranges of practice - dentistry, reproduction and for nonbactericidal effects. Methods: An online cross-sectional survey of veterinarians working in equine practice was conducted over 4 months in 2023 and 2024. Antimicrobial use, including compounding practices, for reproductive and dental disorders, and nonbactericidal...
Infections caused by extended-spectrum beta-lactamase-producing Enterobacterales in hospitalized neonatal foals: Can colonization predict infection? Infections with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) contribute to morbidity and mortality in human neonates. In foals, data are scarce. Objective: Determine the association between ESBL-PE gastrointestinal colonization on hospital admission and infections in hospitalized neonates. Methods: Sixty-seven foals. Methods: Prospective study of foals admitted to a veterinary hospital. Foals were screened for ESBL-PE colonization and for infections. Risk factors and clinical outcomes were analyzed. Results: Seventy-six percent of foals suffered from at least 1 bacteri...
Prospective randomised comparison of different antimicrobial protocols for the prevention of surgical site infections in horses undergoing emergency exploratory celiotomy. Surgical site infection (SSI) is an important complication following emergency celiotomy in the horse. Judicious antimicrobial use is important for the prevention of antimicrobial resistance and the limitation of antimicrobial-associated complications. Previous studies in horses have found no association between SSI and perioperative antimicrobial duration, but the ideal duration of antimicrobial administration in horses undergoing exploratory celiotomy remains unclear. Objective: To compare SSI and describe post-operative complications, survival, duration and cost of hospitalisation in horses...
Local anesthetics and antibiotics display synergistic and antagonistic drug interactions against pathogens causing septic arthritis in horses. To investigate the in vitro efficacy of antibiotics (amikacin, ceftiofur, and gentamicin) in combination with local anesthetics (LAs; bupivacaine hydrochloride, lidocaine hydrochloride, and mepivacaine hydrochloride), a combination commonly performed for IA injectate and regional limb perfusion (RLP) in horses. Unassigned: 17 equine clinical isolates were tested by the checkerboard method for their minimum inhibitory concentration (MIC) against a combination of concentrations of LAs and antibiotics from August 2020 through December 2023. Unassigned: For the majority of combinations, the antibi...
Antagonistic activity of butanamine 2,2-dinitro-N-methyl- synthesized by endosymbiotic Bacillus amyloliquefaciens VITAPRJS1 acquired from horse milk. Endosymbiotic bacteria are known to synthesize bioactive compounds which have biotechnological potentials that enhance immune responses by stimulating the production of immune cells. Horse milk is widely known to have nutraceutical and antimicrobial activities; however, there are no scientific reports on its inhibitory effects. VITAPRJS1, isolated from horse milk, showed non-hemolytic properties and was significantly tolerant to bile salt and NaCl. The isolate also exhibited potent antibacterial activity against pathogenic bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Sta...
Whole-genome sequencing of Salmonella serovars isolated from diarrheic and non-diarrheic foals. spp. are important pathogens of foals, causing clinical enterocolitis and sepsis. We characterized the resistance, virulence, and stress response genes in isolates from foals with or without diarrhea. isolates ( = 23) recovered from fecal samples of 16 diarrheic and 7 non-diarrheic <1-y-old foals were subjected to whole-genome sequencing. The most common serovars detected in diarrheic foals were subsp. serovars Infantis and Minnesota. Multidrug resistance was observed in 9 of 23 isolates, with 8 of the 9 from diarrheic foals. All of the isolates contained at least 2 resistance genes, ...