Gentamicin is an aminoglycoside antibiotic commonly used in equine medicine to treat bacterial infections. It is effective against a broad spectrum of Gram-negative bacteria and some Gram-positive bacteria. In horses, gentamicin is frequently administered for conditions such as respiratory infections, uterine infections, and septicemia. The drug is typically delivered via intravenous or intramuscular injection, and its use requires careful dosage management due to potential nephrotoxic effects. Monitoring serum levels and renal function is important during treatment to minimize the risk of toxicity. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacokinetics, therapeutic applications, and safety considerations of gentamicin in equine medicine.
Parker RA, Bladon BM, McGovern K, Smith KC.To describe and discuss previously unreported complications associated with intraosseous perfusion with gentamicin in horses. Methods: Case report. Methods: Ten-year-old Warmblood gelding. Methods: Intraosseous perfusion with gentamicin into the proximal phalanx (P1) was used as part of the treatment regimen for distal interphalangeal joint and navicular bursa synovial sepsis. Although the sepsis responded favorably complications developed at the perfusion site, including persistent osteomyelitis, progressive osteonecrosis, and ultimately pathologic fracture of P1. Results: The progression of ...
Kaartinen MJ, Pang DS, Cuvelliez SG.CASE 1: A two-year old, 462 kg Standard bred horse was anesthetized for arthroscopy and castration. During anesthesia, hyperemia of the mucosal membranes and urticaria were noticed. During 5 hours of anesthesia subcutaneous edema of the eyelids and neck region developed. In the recovery box, the orotracheal (OT) tube was left in situ and secured in place with tape. Following initial attempts to stand, the horse became highly agitated and signs consistent with pulmonary edema developed subsequently. Arterial hypoxemia (PaO(2): 3.7 kPa [28 mmHg]) and hypocapnia (PaCO(2): 3.1 kPa [23 mmHg]) were ...
Winther L, Andersen RM, Baptiste KE, Aalbæk B, Guardabassi L.Stenotrophomonas maltophilia is being reported with increasing frequency as a human nosocomial pathogen, especially among immuno-compromised patients. To the authors' knowledge, this pathogen has not previously been associated with lower airway disease in the horse. In this paper the clinical findings, laboratory diagnosis and response to treatment of seven cases of respiratory infection with S. maltophilia in horses, presented at three equine referral hospitals in Denmark in 2007, are described. In all cases there was a clinical history of chronic coughing and abundant mucopurulent exudate wa...
Anderson ME, Lefebvre SL, Rankin SC, Aceto H, Morley PS, Caron JP, Welsh RD, Holbrook TC, Moore B, Taylor DR, Weese JS.Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging veterinary and zoonotic pathogen, associated with increasing reports of disease in horses. Objective: To provide an overview of the characteristics of clinical MRSA infections in horses. Methods: A retrospective case study was performed on 115 horses admitted to 6 participating veterinary teaching hospitals in Canada and the United States between 2000 and 2006, and diagnosed with clinical MRSA infection. Descriptive statistics, univariate and multivariable analyses for community- (CA) vs. hospital-associated (HA) MRSA infections...
Nourian AR, Mills PC, Pollitt CC.Intraosseous (i.o.) infusion of the distal phalanx (IOIDP) as a delivery route targeting hoof lamellar tissue of standing, conscious horses was evaluated. Following sedation and regional nerve blockade in six Standardbred horses, a microdialysis (MD) probe was implanted into the hoof lamellar tissue of one forelimb. A purpose designed cannulated bone screw was introduced into the body of the distal phalanx, approximately 6 cm from the MD probe. Gentamicin solution (25 mg/mL) was infused at 20 microL/min through the bone screw for 2 h without the application of a tourniquet. MD and blood sample...
Nourian AR, Mills PC, Pollitt CC.Microdialysis (MD) was used for continuous monitoring of the lamellar extracellular fluid (ECF) in six mature healthy Standardbred horses. MD probes were introduced into the lamellar tissue under local anaesthesia. Following intravenous injection of gentamicin (5mg/kg), MD and serum samples were collected for 24h and analysed using a sensitive ELISA test for gentamicin and fluorescence polarization immunoassay for urea concentrations. Calibration of probes was performed through in vivo urea recovery and in vitro gentamicin and urea recovery. Data obtained from different body compartments were ...
Price S, Aurich J, Davies-Morel M, Aurich C.This study was undertaken to investigate the effects of storage of stallion semen in a defined milk protein extender at 5 and 15 degrees C under either anaerobic or aerobic conditions, with or without addition of the antibiotic gentamicin. Semen samples were collected from eight fertile stallions and stored for 96 h (day 0-4) and assessed daily for motility, velocity and membrane integrity (viability) using a CASA system. Samples for bacteriology assessment were taken on day 2 of storage. No significant (p > 0.05) differences in motility, velocity or viability were observed between treatmen...
Schwarz S, Alesík E, Grobbel M, Lübke-Becker A, Werckenthin C, Wieler LH, Wallmann J.A total of 500 streptococci from two indications of swine (beta-haemolytic streptococci from infections of the urinary/genital tract including strains from the mastitis metritis agalactia syndrome as well as S. suis from infections of the central nervous system and the musculoskeletal system), two indications of horses (S. equi from respiratory tract infections and beta-haemolytic streptococci from infections of the genital tract), as well as three indications of dogs and cats (beta-haemolytic streptococci from infections of the respiratory tract, the urinary/genital tract, and skin/ear/mouth)...
Gasthuys F, Pockelé K, Vervaet C, Weyenberg W, De Prijck K, Pille F, Vlaminck L, Nelis H, Remon JP.The in vivo behaviour of 5% gentamicin sulphate ocular mini-tablets (2-mm diameter, 6.525 mg weight) was compared with gentamicin eye drops in six ponies. Two mini-tablets were inserted on the bulbar conjunctiva of the right eye while a similar dose of gentamicin was administered via eye drops in the left eye. Irritation induced by the mini-tablets and the eye drops was evaluated using a visual analogue scale (0-10). Tears were sampled with ophthalmologic absorption triangles for 1 min for the determination of the concentration of gentamicin sulphate using a microbiological plate diffusion met...
Lorenzo-Figueras M, Pusterla N, Byrne BA, Samitz EM.To evaluate the effectiveness of a commercial conventional blood culture system (BCS), a commercial resin-containing BCS, and a commercial lysis-centrifugation-based BCS for the recovery of Escherichia coli from equine blood samples inoculated with that organism. Methods: Samples of blood obtained from a clinically normal horse that were inoculated with E coli. Methods: Blood samples were aseptically collected and inoculated with an E coli specimen (50 CFUs/mL) that had been previously isolated from a foal with sepsis. Subsequently, samples were spiked with gentamicin at a concentration of 30 ...
Aurich C, Spergser J.This study investigated effects of bacteria from the genital tract of horses and the effect of gentamicin in semen extender on spermatozoal function in cooled-stored stallion semen. Semen was collected from healthy stallions and processed with a milk-based extender with or without gentamicin (1g/l). Pseudomonas (Ps.) aeruginosa, Staphylococcus (St.) aureus, Streptococcus (Sc.) equi subsp. equi (Sc. equi), Sc. equi subsp. zooepidemicus (Sc. zooepidemicus), Sc. dysgalactiae subsp. equisimilis (Sc. equisimilis) or culture medium alone (control) were added. Immediately after addition of bacteria a...
Murchie TA, Macpherson ML, LeBlanc MM, Luznar S, Vickroy TW.Most current treatments for placentitis in mares are empirical with few control studies to evaluate their effectiveness. Objective: To monitor drug concentrations in allantoic fluid of pregnant pony mares using in vivo microdialysis and establish if this method would be useful for determining allantoic concentrations of drugs in normal mares and those with placentitis. Methods: Five late gestational pony mares had microdialysis probes inserted into the allantoic fluid using transabdominal ultrasound-guided allantocentesis. Single injections of penicillin G (22,000 u/kg), gentamicin (6.6 mg/kg ...
Ivester KM, Adams SB, Moore GE, Van Sickle DC, Lescun TB.To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge. Methods: 6 healthy adult mares. Methods: A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of ...
Båverud V, Nyström C, Johansson KE.Contagious equine metritis (CEM), caused by Taylorella equigenitalis, is a widely known highly contagious genital equine disease that is transmitted venereally. A new bacterium, Taylorella asinigenitalis resembling T. equigenitalis was recently isolated from three American donkey jacks, at routine testing for CEM. The purpose of this study was to identify and characterize a strain of Taylorella sp. from the genital tract of a stallion. Swab samples for culture of T. equigenitalis were taken from urethral fossa, urethra and penile sheath of a 3-year-old stallion of the Ardennes breed when it wa...
Busschers E, Richardson DW.A 16-year-old Thoroughbred gelding was examined because of chronic right forelimb lameness. Results: On radiographs of the right front foot, the distal interphalangeal (DIP) joint space was narrow, and osteophytes and periarticular bony proliferation indicative of severe osteoarthritis were seen. Arthrodesis of the right DIP joint was recommended to improve the horse's comfort on the limb. Results: The horse was anesthetized, and palmar and dorsal arthroscopic approaches were used to remove as much of the articular cartilage as was accessible. Holes were then drilled through the dorsal aspect ...
Lescun TB, Ward MP, Adams SB.To compare gentamicin concentrations achieved in synovial fluid and joint tissues during IV administration and continuous intra-articular (IA) infusion of the tarsocrural joint in horses. Methods: 18 horses with clinically normal tarsocrural joints. Methods: Horses were assigned to 3 groups (6 horses/group) and administered gentamicin (6.6 mg/kg, IV, q 24 h for 4 days; group 1), a continuous IA infusion of gentamicin into the tarsocrural joint (50 mg/h for 73 hours; group 2), or both treatments (group 3). Serum, synovial fluid, and joint tissue samples were collected for measurement of gentami...
Duijkeren EV, Box AT, Schellen P, Houwers DJ, Fluit AC.Integrons in gentamicin- and cotrimoxazole-resistant Enterobacteriaceae from dogs and horses with clinical infections were analyzed by conserved segment PCR-RFLP. Five distinct integron types were found, most of which have previously been reported in Enterobacteriaceae isolated from humans and farm animals, indicating that resistance genes are exchanged between the reservoirs in humans, farm animals, and companion animals.
van der Harst MR, Bull S, Laffont CM, Klein WR.The aminoglycoside gentamicin is often used in equine practice. Despite its clinical use, concerns remain regarding the potential toxic side-effects, such as nephrotoxicity, in equine patients, particularly after repeated dosing. The aim of the study was to investigate first in vitro the mechanisms contributing to the renal toxicity of gentamicin and to identify sensitive biomarkers indicating proximal tubule damage. To this end, the kidney-derived cell lines LLC-PKI and MDCK were treated with gentamicin at different concentrations. Toxicity was assessed by measuring the release of gamma-gluta...
van der Harst MR, Bull S, Laffont CM, Klein WR.The aminoglycoside antibiotic gentamicin is commonly used in equine medicine for the prevention and treatment of Gram-negative and staphylococcal bacteria in surgically treated colic patients. The pharmacokinetics of gentamicin in these patients might be altered by the disease status, and/or under the influence of fluid therapy. The purpose of this study was to investigate the effect of intravenous fluid treatment on gentamicin kinetics in colic patients. Colic patients subjected to laparotomy were given fluid infusions according to clinical status. Following gentamicin administration, blood s...
Al-Bagdadi FK, Eilts BE, Richardson GF.Scanning electron microscopy (SEM) was used to study the endometrium of nine 1-year-old thoroughbred mares after twice intrauterine infusions of gentamicin, on 2 consecutive days. Five mares were infused on 2 consecutive days with 40 ml gentamicin (50 mg/ml) mixed with 80 ml of normal saline. Four mares served as controls and were infused with 120 ml of saline on 2 consecutive days. Endometrial biopsies were obtained from all mares 3 days after the second intrauterine infusion. Each biopsy was processed for SEM by standard methods. The endometrial epithelium of the gentamicin-infused mares had...
Sullins KE, White NA, Lundin CS, Dabareiner R, Gaulin G.Treatments addressing variously theorised pathophysiological mechanisms of small intestinal adhesions have been reported. This study applied those classes of treatments to the most clinically relevant aetiology of post operative adhesions. Objective: Treatments addressing the pathophysiology of ischaemia-reperfusion induced adhesions would accordingly reduce the incidence of adhesions from this model. Methods: Four classes of treatments were administered for 72 h to 16 foals subjected to complete ischaemia followed by reperfusion to create peritoneal adhesions. These groups were: 1) FPG group-...
Mattson S, Bouré L, Pearce S, Hurtig M, Burger J, Black W.To report tissue gentamicin concentrations after intraosseous (IO) perfusion in standing horses. Methods: In vivo study. Methods: Twelve horses. Methods: Sedated horses had a cannulated cortical bone screw inserted into the dorsolateral aspect of the treated metacarpus and a tourniquet applied proximally. Gentamicin (2.2 mg/kg) diluted in sterile saline solution (0.1 mL/kg) was infused through the screw. Two horses were euthanatized at each time interval: 0, 2, 6, 12, 24, and 36 hours. Synovial fluid and bone samples were collected distal to the screw from both forelimbs. Gentamicin concentrat...
McKenzie HC, Murray MJ.To assess gentamicin concentrations in serum and bronchial lavage fluid (BLF) of horses during a 24-hour period after once-daily aerosol administration of gentamicin (GAER) for 7 days and the pattern and degree of bronchial tree inflammation associated with repeated GAER. Methods: 13 healthy adult horses (9 geldings and 4 mares). Methods: The treatment group comprised 8 horses, and 5 horses were untreated control animals. Gentamicin (20 mL of gentamicin [50 mg/mL]) was administered via aerosol once daily for 7 days. Samples of serum and BLF were obtained from all horses before GAER and 0.5, 4,...
Werner LA, Hardy J, Bertone AL.To compare intra-articular (IA) and bone gentamicin concentrations achieved after intra-articular administration or regional intravenous perfusion (RIP). Methods: Experimental study. Methods: Twelve healthy adult horses. Methods: Horses were assigned to 2 treatment groups (n = 6/group): Group 1, 1 g gentamicin administered simultaneously in both left and right metacarpophalangeal joints and group 2, 1 g gentamicin administered simultaneously in both left and right lateral palmar veins. Serum, synovial fluid, and bone biopsy specimens were collected. Gentamicin concentrations were determined by...
McKenzie HC.A study was conducted to characterize the aerosols produced by a medical ultrasonic nebulizer using solutions containing antimicrobials appropriate for therapy of equine lower respiratory bacterial infections (gentamicin sulfate and ceftiofur sodium). Test aerosols were generated using an ultrasonic nebulizer and were analyzed using a laser diffraction aerosol particle analyzer. The aerosol was described in terms of the particle size distribution (volume median diameter), span (sample dispersion), and aerosol density (% volume). The particle size distribution and aerosol density of gentamicin ...
Abo El Sooud K.The pharmacokinetics of gentamicin was studied in lambs, calves and foals, respectively after single intravenous (i.v.) injections of 5 mg kg(-1) body weight. The plasma concentration-time curves of gentamicin sulphate were best fitted to follow a two-compartment open model in calves and foals and a three-compartment open model in lambs. Gentamicin showed high plasma level at 5 min post-injection. Then its concentration decreased gradually until its minimum detectable level at 10 and 12 h post-injection in foals and calves, respectively, was reached. In contrast, the plasma concentrations were...
Jacks SS, Giguère S, Nguyen A.The objective of this study was to determine in vitro activities of azithromycin (AZM), clarithromycin (CLR), and 20 other antimicrobial agents against Rhodococcus equi and other common equine bacterial pathogens. A total of 201 bacterial isolates from various equine clinical samples were examined. CLR was more active than AZM against R. equi, with MICs at which 90% of the isolates were inhibited of 0.12 and 1.0 micro g/ml, respectively. Other antimicrobial agents highly active against at least 90% of R. equi isolates in vitro included rifampin, gentamicin, and imipenem. Both AZM and CLR showe...
Smith MA, Ross MW.To determine features of postoperative wound infection caused by Actinobacillus spp in horses undergoing clean, elective surgery and to evaluate bacterial susceptibility profiles of bacteria isolated. Methods: Retrospective study. Methods: 10 horses. Methods: Data were retrieved from medical records and the microbiology laboratory database. Results: 1,604 horses underwent clean, elective surgical procedures during the study period. Of these, 23 (1.43%) had postoperative wound infections, and Actinobacillus spp was isolated from 10 of these 23 (43%). Surgical procedures in these 10 horses inclu...
Steinman A, Isoherranen N, Ashoach O, Soback S.Gentamicin pharmacokinetics has not been studied in horses. Pharmacokinetics of gentamicin C1, C1a and C2 components following i.v. administration of total gentamicin at 6.6 mg/kg bwt to 6 healthy mature horses was determined. Significant differences in clearance, half-life (t 1/2), and mean residence time (MRT) between the gentamicin Cia and the 2 other components were found. The total body clearance (CL) of gentamicin C1a was 1.62 +/- 0.50 ml/min x kg and similar to the glomerular filtration rate (GFR) reported for horses. The CL of gentamicin C1 and C2 were 1.03 +/- 0.08 ml/min x kg and 1.1...
Lehavi O, Aizenstien O, Katz LH, Hourvitz A.Infection with Burkholderia mallei (formerly Pseudomonas mallei) can cause a subcutaneous infection known as "farcy" or can disseminate to condition known as Glanders. It is primarily a disease affecting horses, donkeys and mules. In humans, Glanders can produce four types of disease: localized form, pulmonary form, septicemia, and chronic form. Necrosis of the tracheobronchial tree and pustular skin lesions characterize acute infection with B. mallei. Other symptoms include febrile pneumonia, if the organism was inhaled, or signs of sepsis and multiple abscesses, if the skin was the port of e...
Bertone AL, Davis DM, Cox HU, Kamerling SS, Roberts ED, Caprile KA, Gossett KA.To evaluate the clinical, laboratory, and histologic effects of 2 methods of treatment for infectious arthritis in horses, Staphylococcus aureus (3.4 to 3.9 x 10(3) colony-forming units) was inoculated into the tarsocrural joints of 8 horses on day 0. Each horse was treated with phenylbutazone (2 g, PO, q 24 h) and gentamicin sulfate (2.2 mg/kg of body weight, IV, q 8 h) for 14 days. On day 2, general anesthesia was induced, and each horse had 1 tarsocrural joint treated by arthrotomy, with removal of accessible fibrin and lavage with 3 L of sterile balanced electrolyte solution. An indwelling...
Orsini JA, Benson CE, Spencer PA, Van Miller E.Resistance of gram-negative bacteria to gentamicin has become an increasingly common problem among clinical isolates from human beings. Susceptibility of isolates from horses to gentamicin and amikacin was evaluated for the period from July, 1983 to June, 1985. All isolates of Escherichia coli, and species of Enterobacter, Klebsiella, Proteus, and Pseudomonas examined were susceptible to amikacin, except 2 of the 46 Pseudomonas isolates. In contrast, 13 to 50% of isolates were resistant to gentamicin. Escherichia coli, and Klebsiella, Proteus, and Enterobacter species isolates were highly sign...
Ivester KM, Adams SB, Moore GE, Van Sickle DC, Lescun TB.To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge. Methods: 6 healthy adult mares. Methods: A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of ...
Stover SM, Pool RR.Gentamicin sulfate (3 ml; 50 mg/ml) was administered intra-articularly into 30 normal equine radiocarpal joints after arthrocentesis. Arthrocentesis alone was performed on 10 normal radiocarpal joints. Synovial fluid evaluations and gross and microscopic examinations were performed on synovial fluid and synovial membrane of designated joints at selected daily intervals over a period of 10 days. Synovial fluid from gentamicin-injected joints had greater turbidity, higher RBC and WBC counts, and higher refractive indices than did joints not injected with gentamicin. The largest increases develop...
Hardefeldt LY, Crabb HK, Bailey KE, Gilkerson JR, Billman-Jacobe H, Browning GF.Appropriate dosing with antimicrobial agents is critical for effective treatment and to prevent the development of antimicrobial resistance. Methods: A review was undertaken of equine journal articles (Equine Veterinary Journal, Equine Veterinary Education, Australian Veterinary Journal, Australian Equine Veterinarian, Journal of Veterinary Internal Medicine and Journal of Equine Veterinary Science) between January 2015 and August 2018. Those with dosing regimens for procaine penicillin G, gentamicin or trimethoprim-sulfonamide in adult horses were examined and evaluated. Pharmacokinetics and ...
Kauter A, Brombach J, Lübke-Becker A, Kannapin D, Bang C, Franzenburg S, Stoeckle SD, Mellmann A, Scherff N, Köck R, Guenther S, Wieler LH....Horse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of peri-operative antibiotic prophylaxis (PAP) based on a combination of penicillin and gentamicin on the gut microbiota is limited. Unassigned: We collected fecal samples of horses from a non-hospitalized control group (CG) and from horses receiving either a pre-...
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 ...
Riviere JE, Traver DS, Coppoc GL.Three clinical cases of toxic nephropathy in young horses were ascribed to gentamicin toxicity. Criteria for defining gentamicin-induced nephrotoxicosis were a serum urea nitrogen value greater than the pretreatment value or cylindruria, hematuria, and proteinuria in the absence of pyuria and bacteriuria. Recommended doses of gentamicin had been given in all cases. The nephropathy was reversible in 1 case in which the toxicosis was detected early and was treated by volume diuresis and drug withdrawal.
Godber LM, Walker RD, Stein GE, Hauptman JG, Derksen FJ.Once-daily administration of aminoglycosides may be a safe and effective therapeutic regimen, on the basis of the microbiologic and pharmacokinetic characteristics of these antibiotics. This study was designed to determine serum and tissue concentrations following i.v. administration of gentamicin, at dosages of 6.6 mg/kg of body weight, every 24 hours, and 2.2 mg/kg, every 8 hours, for 10 days in adult horses. Nephrotoxicosis from these dosage regimens also was compared, and microbiologic effects, including postantibiotic effects, were determined with various concentrations of gentamicin agai...
van Spijk JN, Beckmann K, Wehrli Eser M, Boxler M, Stirn M, Rhyner T, Kaelin D, Saleh L, Schoster A.Polymyxin B (PolyB) is used to treat endotoxemia in horses; neurologic and nephrogenic adverse effects occur in humans. Objective: To describe PolyB adverse effects in horses. Methods: Five healthy horses (ataxia 0/5), 1 horse with cervical osteoarthritis (ataxia 1/5). Methods: Prospective blinded randomized cross-over trial; 3-weeks wash out. Horses received PolyB (PolyB 6000 IU/kg IV, 7 doses q12h, n = 6) and PolyB/gentamicin (PolyB 6000 IU/kg IV, q12h 7 doses; gentamicin 10 mg/kg IV q24h 4 doses n = 4, or q12-24 h 5 doses because of an additional erroneous dose, n = 2). Daily n...
Brashier MK, Geor RJ, Ames TR, O'Leary TP.To determine whether supplemental i.v. calcium administration would attenuate or prevent gentamicin-induced acute renal failure, defined as an increase in serum creatinine concentration > or = 50% above baseline. Methods: 10 healthy pony mares. Methods: Pony mares were randomly assigned to receive calcium at a dosage of 20 mg/kg of body weight or saline solution i.v., twice daily for 14 days. All pony mares received gentamicin at a dosage of 20 mg/kg i.v. every 8 hours for 14 days. Gentamicin pharmacokinetic, serum biochemical, and urinalysis data were measured every other day for the 14-da...
van der Harst MR, Bull S, Laffont CM, Klein WR.The aminoglycoside antibiotic gentamicin is commonly used in equine medicine for the prevention and treatment of Gram-negative and staphylococcal bacteria in surgically treated colic patients. The pharmacokinetics of gentamicin in these patients might be altered by the disease status, and/or under the influence of fluid therapy. The purpose of this study was to investigate the effect of intravenous fluid treatment on gentamicin kinetics in colic patients. Colic patients subjected to laparotomy were given fluid infusions according to clinical status. Following gentamicin administration, blood s...
Cohen ND, Giguère S, Burton AJ, Rocha JN, Berghaus LJ, Brake CN, Bordin AI, Coleman MC.Adverse effects of, and bacterial resistance to, macrolides used to treat Rhodococcus equi infections have prompted search for clinically effective alternative antimicrobials. Liposomal gentamicin (LG) is effective against R. equi in vitro and decreases tissue concentrations of R. equi in experimentally infected mice. Effectiveness of LG treatment of foals with R. equi pneumonia, however, has not been described. Objective: Liposomal gentamicin is safe and effective for treating foals with R. equi pneumonia. Methods: Ten foals with experimentally induced R. equi pneumonia. Methods: Pilot treatm...
Travers CW, van den Berg JS.This paper describes the case histories of two Thoroughbred horses, a 2-year-old colt in training and a 7-year-old broodmare, that were presented with histories of weight loss, exercise intolerance, intermittent fever, limb oedema and anaemia. Vegetative endocarditis of the mitral and tricuspid valves was diagnosed in the colt by means of echocardiography. Pseudomonas sp. endocarditis of the mitral valve was diagnosed in the mare using echocardiography and bacterial culture. The colt had secondary congestive heart failure and was euthanased on humane grounds. Pseudomonas cepacia was isolated f...
Haddad NS, Pedersoli WM, Ravis WR, Fazeli MH, Carson RL.Healthy mature pony mares (n = 6) were given a single dose of gentamicin (5 mg/kg of body weight) IV or IM 8 days apart. Venous blood samples were collected at 0, 5, 10, 20, 30, and 45 minutes and at 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 18, 24, 30, 36, 40, and 48 hours after IV injection of gentamicin, and at 10, 20, 30, and 45 minutes and at 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 18, 24, and 30 hours after IM injection of gentamicin. Gentamicin serum concentration was determined by a liquid-phase radioimmunoassay. The combined data of IV and IM treatments were analyzed by a nonlinear least-square...
Haddad NS, Pedersoli WM, Ravis WR, Fazeli MH, Carson RL.Gentamicin (GT) was administered IM to 6 healthy mature mare ponies at a dosage of 5 mg/kg of body weight every 8 hours for 7 consecutive days (total, 21 doses). Two venous blood samples were collected before (trough) and at 1 hour (peak) after the 5th, 10th, 14th, and 19th doses. An endometrial biopsy was done of each mare on days 4 and 7. On the 7th day, just before the 21st administration of GT, base-line blood samples were collected, and 22 blood samples were collected over a period of 48 hours after GT was given. The mares were catheterized on the 7th day, and urine was collected for 24 h...
Murchie TA, Macpherson ML, LeBlanc MM, Luznar S, Vickroy TW.Most current treatments for placentitis in mares are empirical with few control studies to evaluate their effectiveness. Objective: To monitor drug concentrations in allantoic fluid of pregnant pony mares using in vivo microdialysis and establish if this method would be useful for determining allantoic concentrations of drugs in normal mares and those with placentitis. Methods: Five late gestational pony mares had microdialysis probes inserted into the allantoic fluid using transabdominal ultrasound-guided allantocentesis. Single injections of penicillin G (22,000 u/kg), gentamicin (6.6 mg/kg ...
Kleinpeter A, Göpfert A, Köhler E, Brehm W.Aim of the study was the retrospective evaluation regarding vision and recurrence in equine recurrent uveitis (ERU)-affected horses treated by intravitreal low-dose gentamicin injection in Tierklinik Alt Sammit during the years 2006-2013. Methods: The study included 50 equine patients (61 ERU-affected eyes) of different age and breed with different stages of ERU. The solution for the injection contained 4.0 mg sterile gentamicin per eye. The injection was performed according to the procedure described by Pinard et al. in 2005 under general anaesthesia in lateral recumbency of the patient and...
Johnston GCA, Lumsden JM.To describe the prevalence and antimicrobial susceptibility of bacterial isolates cultured from surgical specimens of infected arytenoid cartilage and granulomas. Methods: Retrospective cohort study. Methods: Thirty-three thoroughbred horses. Methods: Hospital records were retrieved for all horses admitted to a referral hospital for arytenoid chondropathy surgery that had samples submitted for culture and sensitivity between 2005 and 2019. Descriptive analyses were performed. Results: In total, 56 bacterial isolates were obtained. Gram-positive bacteria (58%), Gram-negative bacteria (54%), and...
Nostrandt AC, Pedersoli WM, Marshall AE, Ravis WR, Robertson BT.Ototoxicosis was evaluated in 6 healthy ponies given 5 mg of gentamicin/kg of body weight, q 8 h, IM. Ponies 1, 2, and 3 were dosed for 7 days and ponies 4, 5, and 6 were dosed for 14 days. Serum peak and trough concentrations of gentamicin were measured by radioimmunoassay at regular intervals. Brain stem auditory-evoked responses were recorded every 5 days up to 60 days after the first dose to monitor auditory function. Although serum gentamicin concentrations were within or above the accepted clinical therapeutic range, loss of auditory function was not observed at the frequency range (1 to...
Von Dollen KA, Jones M, Beachler T, Harris TL, Papich MG, Lyle SK, Bailey CS.The use of antimicrobials for the management of equine uterine disease is commonplace, with antibiotic selection generally based on empirical evidence or in vitro sensitivity results. However, the potential disconnect between these laboratory results and clinical efficacy in the mare raises concern for antibiotic failure and subsequent development of resistant organisms. In this work, we attempt to bridge this gap by using an ex vivo model of the equine postpartum uterus to quantitatively evaluate the antimicrobial activity of two commonly used antibiotic treatments in the mare (ceftiofur an...
Sweeney RW, Divers TJ, Rossier Y.Plasma concentration of gentamicin was measured 1, 4, and 6 hours after IV administration in 35 hospitalized adult horses on days 1, 3, 5, and 10 of treatment. The mean apparent elimination rate constant beta was 0.53 +/- 0.10 h-1 on day 1 for horses with normal plasma creatinine concentration and 0.41 +/- 0.13 h-1 for horses with abnormally high plasma creatinine concentration. There was no significant difference between beta of the hospitalized horses and of 6 healthy horses treated with gentamicin, but total clearance for the hospitalized horses with normal plasma creatinine concentration w...
Parker JL, Page A, Jacob O, Stanton V, Davis B, Flythe M, Adam EN.Though generally safe, research continues to demonstrate negative side effects of antibiotic administration on the gastrointestinal (GIT) microbiota across species. In horses, antibiotic associated diarrhea (AAD) is a life-threatening condition linked to the GIT microbiota. This study tested the hypothesis that short term antibiotic administration to healthy horses would negatively impact the fecal microbiota as measured by their ability to digest nutrients and through fecal shedding of disease-associated-bacteria. Twenty-four horses were assigned to one of four treatment groups: control (CO);...
Bacci S, Meucci V, Sgorbini M, De Marchi L, Pirone A, Pretti C, Tognetti R, Intorre L.Antimicrobial prescriptions of the University of Pisa and their compliance with prudent use recommendations were investigated over 11 years (2011-2021). At least one antimicrobial was always prescribed in surgical prophylaxis for the suture of wounds and in 33% of horses with signs of disease of a body system. Antimicrobials were administered in monotherapy (48%) in fixed dose combinations (21%) and empirical combinations (31%). Antimicrobials were mostly (63%) administered by parenteral route, while oral and topical antimicrobials accounted for 14% and 23% of prescriptions, respectively. Gen...
Verdenius CY, Slenter IJM, Hermans H, Broens EM, Djajadiningrat-Laanen SC.Ulcerative keratitis is a common ophthalmic disease in horses which can be complicated by microbial infection and requires immediate, accurate treatment to prevent loss of visual function or the eye. Objective: To report the results of microbial cultures, antibiotic susceptibility tests and corneal cytology in horses with ulcerative keratitis presented to a referral clinic, to assess agreement between cytology and culture results, to investigate whether previous topical treatment affected microbial culture results and whether the incidence of antimicrobial resistance changed during the study p...
Hobbs KJ, Davis JL, Cooper BL, Ueda Y, Burke MJ, Sheats MK.Plasma cytokine adsorption has shown benefit as an adjunctive therapy in human sepsis but has yet to be investigated in horses. We hypothesized that ex vivo filtration of equine plasma with a novel cytokine adsorption device would significantly reduce concentrations of lipopolysaccharide-stimulated cytokines. We also hypothesized that the device would adsorb medications commonly used to treat sepsis. Methods: 8 horses owned by North Carolina State University. Methods: Four liters of heparinized whole blood was collected from healthy adult horses (n = 8) and stimulated with lipopolysaccharide (...
Schwarz S, Alesík E, Grobbel M, Lübke-Becker A, Werckenthin C, Wieler LH, Wallmann J.A total of 500 streptococci from two indications of swine (beta-haemolytic streptococci from infections of the urinary/genital tract including strains from the mastitis metritis agalactia syndrome as well as S. suis from infections of the central nervous system and the musculoskeletal system), two indications of horses (S. equi from respiratory tract infections and beta-haemolytic streptococci from infections of the genital tract), as well as three indications of dogs and cats (beta-haemolytic streptococci from infections of the respiratory tract, the urinary/genital tract, and skin/ear/mouth)...
Summerhays GE.Eight horses with synovial sepsis induced by trauma were treated by arthroscopic/tenoscopic debridement and lavage followed by the implantation of a gentamicin-impregnated collagen sponge. Seven of them responded favourably and were sound six months after treatment. The other underwent a further surgical procedure and recovered. Gentamicin-impregnated collagen sponges appear to be a safe and useful adjunct in the treatment of septic joints and tendon sheaths, and have the advantage of being bioabsorbable.
