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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.
Esophageal anastomosis in two foals. Esophageal anastomosis was performed on 2 foals after resecting a midcervical stricture. Nasogastric tube alimentation and antibiotic therapy allowed these foals to recover, and they matured to useful performing horses. These cases demonstrated a feasible and successful surgical management regimen for the strictured esophagus.
Ivermectin and an ivermectin-penicillin combination: a comparison of anthelmintic efficacy in horses. Ivermectin given IM at 200 micrograms/kg, alone or in combination with procaine penicillin G at 600 IU/kg, to 20 randomly selected young horses of various breeds reduced fecal strongyle egg counts from 400-4100 epg (avg greater than 1000) pretreatment to zero 7 days posttreatment. There were no systemic or injection-site reactions, either immediate or delayed, in any of the horses.
Serum concentration of penicillin in the horse after repeated intramuscular injections of procaine penicillin G alone or in combination with benzathine penicillin and/or phenylbutazone. Twenty-one adult horses were randomly assigned into 7 groups of 3 and were treated for 5 days with procaine penicillin G, benzathine penicillin , or phenylbutazone in various combinations and dosage schedules. Serum concentration of penicillin was measured serially over a 7-day period. The highest mean peak serum concentration was 2.06 micrograms/ml. Comparable peak values were seen 2 to 4 hours after administration of 22,000 IU of procaine penicillin G/kg of body weight given once or twice daily. A minimum serum concentration of 0.25 micrograms/ml was selected as adequate for efficacy against...
Uterine culture in mares. A guarded, sterile swab is used to obtain samples for uterine culture. With the mare in stocks, the tail bandage and the perineum washed, the culture rod is introduced into the vagina with a gloved hand. After the rod is guided through the cervix, the guard cap is dislodged and the swab is rubbed along the endometrium, after which the rod is extracted. Samples for uterine culture should only be obtained during full estrus. Swabs should be directly plated onto agar within 2 hours of collection. Blood agar is appropriate for initial screening, but use of specialized types of agar expedites ident...
The effects of combinations of selected antibiotics on the growth of Corynebacterium equi. The minimal inhibitory concentrations of penicillin G, ampicillin, gentamicin, erythromycin and rifampicin were determined for nine strains of Corynebacterium equi. The effect of combinations of any two of these antibiotics on the killing of these strains was determined at antibiotic concentrations achievable in horses using recommended drug dosages (ampicillin 4.0 microgram/ml, gentamicin 1.0 microgram/ml using recommended drug dosages (ampicillin 4.0 microgram/ml, gentamicin 1.0 microgram/ml and erythromycin 0.25 microgram/ml). Penicillin G was used at 4.0 microgram/ml and rifampicin at 0.06...
Chloramphenicol sodium succinate in the horse: serum, synovial, peritoneal, and urine concentrations after single-dose intravenous administration. Six healthy adult mares were given a single IV dose (25 mg/kg of body weight) of chloramphenicol sodium succinate. Chloramphenicol concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The highest measured serum chloramphenicol concentration was 6.21 micrograms/ml at 0.5 hour. Chloramphenicol was detected in synovial and peritoneal fluids, with mean peak concentrations of 3.89 micrograms/ml and 3.50 micrograms/ml, respectively, at 0.5 hour. Serum and synovial concentrations declined rapidly and were not measurable at 3 hours. Chloram...
Clinical observations on an outbreak of strangles. An outbreak of strangles, which occurred during the spring, summer and fall of 1980 on a Standardbred stud farm in eastern Alberta is described. The infective organism, Streptococcus equi, may have been introduced by an outside mare that was brought to the stud for breeding. All of the groups of horses on the farm were affected. For the most part, the disease was allowed to run its natural course. Only severely affected individuals were treated. During the outbreak, the foals were prophylactically treated with penicillin to prevent them from contracting the disease. Ten horses died of complica...
Facial and vestibulocochlear nerve disease in six horses. In 6 horses, clinical signs of illness implicated a lesion involving the facial and vestibulocochlear nerves. One horse had signs of otitis externa. Five horses had radiographic changes primarily involving periosteal bony proliferation of the stylohyoid bone at its articulation with the temporal bone. Five horses improved with antibiotic therapy. Otitis media-interna was found at necropsy of one horse.
Absorption and distribution patterns of oral phenoxymethyl penicillin (penicillin V) in the horse. Serum levels of phenoxymethyl penicillin (penicillin V; Pen V) were measured following oral administration of two different formulations of the drug to five healthy horses. The mean serum concentration profile was described by a two-compartment model with a first order rate of absorption. Half-lives of the absorption, distribution and elimination phases were, respectively, 0.199 +/- 0.035, 0.362 +/- 0.060 and 3.650 +/- 0.575 hours. The distribution of the drug to body fluid compartments other than serum was examined. Mean peak levels of Pen V in serum, synovial fluid, peritoneal fluid and urin...
Phenoxymethyl penicillin in the horse: an alternative to parenteral administration of penicillin. This preliminary study evaluated phenoxymethyl penicillin (Penicillin V) as an alternative to parenteral administration of penicillin in horses. Penicillin V was administered orally to five horses at two different doses and plasma levels of the drug were determined at timed intervals. The results were evaluated by regression analysis. Following the administration of penicillin V at a dose of 66,000 IU/kg or 110,000 IU/kg, the mean peak plasma levels obtained were 1.55 micrograms/mL and 2.34 micrograms/mL respectively. A plasma level two to four times above the minimal inhibitory concentration ...
[An inventory of the castration of stallions based on a survey among Dutch veterinarians]. To gain an insight into the procedures adopted in castrating stallions in the Netherlands, a questionnaire was sent to 670 Dutch veterinary practitioners. The 176 veterinary practitioners who replied performed 1850 castrations. Castration of the recumbent horse was preferred by 88 per cent of the veterinary surgeons. Fifty per cent preferred the open method of castration and 44 per cent the half-closed technique. A local anaesthetic was given by 65 per cent of the practitioners; 84 per cent administered antibiotics in an attempt to prevent wound infection. Postoperative complications were obse...
[Primary closure of the scrotal wound in the castration of stallions]. A method of castration in stallions is reported on, in which primary closure of the wound caused by castration was attempted. Primary wound-healing occurred in 90 per cent of 110 stallions showing normally descended testicles, whereas this proportion was 97.4 per cent in thirty-eight unilaterally cryptorchid stallions in which the normally descended testicle was removed using the method described. It is concluded that the present method of castration will only be successful when surgery is carried out under strictly aseptic conditions.
Pharmacokinetics of chloramphenicol in the neonatal horse. Chloramphenicol sodium succinate was administered as an intravenous bolus (50 mg/kg) to eight foals which weighed 49-57 kg (mean +/- 1 standard deviation = 53.19 +/- 2.66) each, and were 1-9 days (4.5 +/- 2.56) of age. The drug was rapidly distributed and followed first-order elimination. Mean pharmacokinetic values were: zero-time serum concentration (C0) = 36.14 microgram/ml (+/- 14.80); apparent specific volume of distribution (Vd) = 1.614 1/kg (+/- 0.669); and elimination rate constant (K) = 0.7295 h-1 (+/- 0.3066) which corresponds to a biological half-life (t1/2) = 0.95 h. These values d...
Gentamicin pharmacokinetics in horses given small doses of Escherichia coli endotoxin. The pharmacokinetics of gentamicin (3 mg/kg of body weight) were evaluated in 6 healthy horses and in 6 horses after they were given Escherichia coli endotoxin (0.113 microgram/kg). In the horses given endotoxin, there were a maximum temperature increase of 1.97 +/- 0.44 degrees (C) and a fever index (between the 2 groups) of 8.754 units. Other mild signs of endotoxemia also occurred. Statistically significant changes were not observed in the rate constants for distribution (alpha) or elimination (beta) or in body clearance (ClB) of gentamicin in the 2 groups of horses. In the horses given end...
The in vitro effects of EDTA-tris, EDTA-tris-lysozyme, and antimicrobial agents on equine genital isolants of Pseudomonas aeruginosa. Five isolants of Pseudomonas aeruginosa collected from clinical cases of equine genital infection and one standard strain of P. aeruginosa were exposed to various concentrations of ethylene-diaminetetraacetic acid (EDTA) and tris (hydroxymethyl) aminomethane (tris buffer pH 8) and EDTA-tris lysozyme. Colony forming units of the isolants and minimal inhibitory concentrations for 11 antimicrobial agents were determined with each isolant before and after exposure to the EDTA solutions. Decreased cellular viability was found with all six isolants after exposure to the EDTA-tris solutions. Reversal...
Successful bacterin therapy in a case of chronic equine staphylococcal infection. A Staphylococcus aureus infection in a mature horse, resulting from trauma, is described, which proved refractory to antibiotic therapy directed by the results of antibiotic sensitivity testing. After a prolonged course, rapid resolution of the infection was achieved with the administration of an autogenous formalized bacterin.
Attempted reconstitution of a foal with primary severe combined immunodeficiency. A foal with primary severe combined immunodeficiency, diagnosed within the first two weeks of life, was maintained with its dam in semi-isolation. The foal received continuous prophylactic antibiotic therapy, plasma from a sibling hyperimmunised with equine adenovirus vaccine, and intensive general nursing care. A full sibling female was selected as a bone marrow donor on the basis of red blood cell cross-matching and mixed lymphocyte reactions. Cyclophosphamide was given before two bone marrow transfusions at 35 and 73 days of age. To prevent graft versus host disease graft versus host diseas...
Staphylococcus hyicus in skin lesions of horses. Staphylococcus hyicus (subspecies hyicus) was isolated as the only pathogenic organism from two independent cases of dermatitis of the lower parts of the limbs (grease heel) in horses. The organism was recovered together with other pathogenic staphylococci from similar conditions in two other horses of different origins. These conditions were characterised by epidermolysis, alopecia and crust formation. They responded quickly to antibiotic treatment. The organism was also isolated from a long standing case of "summer eczema" which healed without antibiotic treatment, and from a horse with derm...
Secondary closure of infected abdominal incisions in cattle and horses. Infected abdominal incisions in 7 cattle and 3 horses were resutured with monofilamentous stainless steel retention sutures. After debridement of devitalized and infected tissue, wound edges were apposed with simple interrupted vertical (5 cattle, 3 horses) or horizontal (2 cattle) mattress sutures, placed through all layers of the body wall. Sutures were placed 2 to 3 cm apart over rubber tubing, 3 to 5 cm from wound edges. In 5 of the 10 operations, skin and subcutaneous tissue were left unsutured. The repaired wounds were supported with an encircling elastic roll bandage and sterile compres...
Bacterial and fungal isolates from Equidae with ulcerative keratitis. Gram-negative bacteria were the most common microbial isolates from 38 eyes of 37 horses with ulcerative keratitis. Pseudomonas sp, Enterobacter group, and Acinetobacter sp were the most prevalent. Fungi were cultured from 15 eyes and included 7 genera, with Aspergillus sp being the most prevalent. Ten of the eyes with fungal keratitis had been treated with corticosteroids. Eleven of 38 eyes had mixed bacterial and fungal infections. Clinically, the most severe cases were those in which Aspergillus and gram-negative bacteria existed in a mixed infection. On the basis of susceptibility testing,...
Pharmacokinetics of erythromycin in foals and in adult horses. The pharmacokinetic parameters of erythromycin in foals were determined following intravenous administration of 5.0 mg/kg to animals aged 1, 3, 5 and 7 weeks. The distribution of the drug was described by a two-compartment open model, and no significant differences were observed between coefficients on which the parameters were based. Pharmacokinetic values were also determined for four mares given 5.0 mg/kg intravenously and for six 10-12-week-old foals given 20.0 mg/kg intravenously. The half-life of erythromycin for all groups of animals (foals less than 7 weeks, mares, foals 10-12 weeks) w...
Ticarcillin administration to the equine: Intrauterine and intramuscular. Serum levels of ticarcillin disodium, a semi-synthetic penicillin (Beecham Laboratories, Bristol, Tennessee, 37620), were measured at various time intervals up to and including 24 h after intrauterine and intramuscular administration in adult female horses. Three separate studies were conducted in Part I: in the first and second studies, serum levels were measured after intrauterine administration of 1 and 3 g of ticarcillin, respectively, and in the third study, levels were measured after intramuscular administration of 6 g of ticarcillin. In Part II, serum levels of ticarcillin were measured...
Clostridium perfringens cellulitis and immune-mediated hemolytic anemia in a horse. A 10-year-old Quarter Horse mare was referred for evaluation and treatment of a large pectoral skin slough and hemoglobinuria. The skin slough was secondary to Clostridium perfringens cellulitis and associated gas gangrene. Cold hemagglutinin disease was diagnosed and was suspected to be secondary to C perfringens septicemia. The autoimmune hemolytic anemia, severe intravascular hemolysis, and hemoglobinuria were treated with dexamethasone and hydrocortisone. The infection was treated with 20 X 10(6) units of sodium penicillin, IV, 4 times daily, and the wound was debrided. When the mare relap...
Pathogenic bacteria and fungi associated with extraocular disease in the horse. In 123 cases of external ocular disease in the horse, pathogenic microorganisms isolated with greatest frequency were Streptococcus sp (43.9%), Staphylococcus sp (24.2%), and Pseudomonas sp (13.8%). Fungi were isolated in 4.8% of the cases. In vitro testing showed that most of the Streptococcus sp isolants were sensitive to ampicillin, cephalothin, and carbenicillin. Most of the Staphylococcus sp isolants were sensitive to gentamicin, cephalothin, and bacitracin. Most of the Pseudomonas sp isolants were sensitive to polymyxin B and gentamicin.
