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.
Omphalophlebitis and osteomyelitis associated with Klebsiella septicemia in a premature foal. Gram-negative neonatal septicemia was diagnosed in a premature Standardbred colt. Clinical signs included lethargy, weakness, loss of suckle reflex, tachypnea, and injected mucous membranes. Sequelae included pneumonia, omphalophlebitis, septic arthritis, and osteomyelitis. Prepartum maternal uterine infection, premature delivery, abnormal parturition with premature fetal membrane separation, and failure of passive transfer of colostral immunoglobulins increased the foal's risk for developing sepsis. Treatment included administration of moxalactam disodium and cefadroxil. The clinical efficacy...
A method for reproducing fatal idiopathic colitis (colitis X) in ponies and isolation of a clostridium as a possible agent. Severe colitis was induced in two ponies after oral pretreatment with clindamycin and lincomycin, followed by intestinal content from two horses which had died from naturally-occurring idiopathic colitis. Two ponies treated with antibiotic alone, and two ponies treated with intestinal content alone, were unaffected. In a further study, three ponies treated on separate occasions with lincomycin, administered orally, died or were destroyed 67 to 72 h after initial treatment. No established salmonella, yersinia or campylobacter pathogens were isolated from these ponies, but a clostridium closely ...
Keratomas in horses: seven cases (1975-1986). The diagnosis of keratoma in 7 horses and their treatment and outcome were evaluated. Horses were 2 to 20 years old, of various breeds, and were intact or castrated males. All were lame, and 6 horses had had previous injuries of the affected hoof that had not responded to prior treatments. Only 1 hoof was affected in each horse. Keratomas were beneath the hoof wall (6 horses) or sole (1 horse). Radiographically, a circular or semicircular defect with a discrete margin was present in the distal portion of the third phalanx in 3 horses. Grossly, keratomas were firm solitary masses (1.5 to 5 cm d...
Serum and synovial fluid steady-state concentrations of trimethoprim and sulfadiazine in horses with experimentally induced infectious arthritis. The tarsocrural joints of 11 horses were inoculated with 1.2 to 2.16 x 10(6) viable Staphylococcus aureus organisms susceptible to a trimethoprim-sulfadiazine (TMP-SDZ) combination with minimal inhibitory concentration (MIC) of 0.25 micrograms of TMP/ml and 4.75 micrograms of SDZ/ml. Antimicrobial treatment consisted of oral administration of a TMP-SDZ combination--30 mg/kg of body weight given once daily (group-1 horses) or 60 mg/kg given as 30 mg/kg every 12 hours (group-2 horses). Paired serum and synovial fluid samples were obtained before intra-articular inoculation with the S aureus, aft...
Pharmacokinetics and estimated bioavailability of amoxicillin in mares after intravenous, intramuscular, and oral administration. The pharmacokinetics and estimated bioavailability of amoxicillin were determined after IV, intragastric, and IM administration to healthy mares. After IV administration of sodium amoxicillin (10 mg/kg of body weight), the disposition of the drug was best described by a 2-compartment open model. A rapid distribution phase was followed by a rapid elimination phase, with a mean +/- SD half-life of 39.4 +/- 3.57 minutes. The mean volume of distribution was 325 +/- 68.2 ml/kg, and the mean body clearance was 5.68 +/- 0.80 ml/min.kg. It was concluded that frequent IV administration of sodium amoxic...
Treatment of Fasciola hepatica infection in horses with triclabendazole. Thirteen thoroughbred foals with an adult infection and a presumed immature infection with Fasciola hepatica were treated with 12 mg triclabendazole/kg bodyweight. The absence of eggs from samples of faeces examined at intervals up to 110 days after treatment showed that all the animals were cured. In a second trial the same dose of triclabendazole cured 11 of 12 foals whereas nitroxynil at 7 mg/kg cured only six of 12 foals. No side effects were observed after treatment.
Management of a severely comminuted fracture of the third metacarpal bone in a horse. A 4-year-old Standardbred stallion sustained a severely comminuted fracture involving the second, third, and fourth metacarpal bones. The fracture was repaired using two 14-hole broad dynamic compression plates positioned at 90 degrees to one another, allowing one plate to protect the other in the bending mode. An autologous cancellous bone graft obtained from the tuber coxae was added at the site of the defect in the mid- to upper third of the third metacarpal bone. Complications associated with the fixation included a Staphylococcus aureus infection 5 months after surgery, laminitis that dev...
Biochemical and toxigenic characteristics of Aeromonas spp. isolated from diseased mammals, moribund and healthy fish. In this study we describe biochemical, toxigenic and surface characteristics of 33 motile Aeromonas isolated from diseased mammals, 3 from moribund marine mammals, 24 from healthy fish and 4 from moribund fish. Aeromonas hydrophila, A. caviae and A. sobria were isolated from both mammals and fish but at a different incidence. Aeromonas hydrophila was the predominant species isolated from clinical specimens; it was isolated from pneumonia, wound infections, septicemia and abortion in horses, cattle and pigs. Aeromonas sobria was isolated from one mammal and 11 healthy fish. Aeromonas caviae was...
Treatment of bacterial endocarditis in a horse. Using echocardiography, mitral valve bacterial endocarditis was diagnosed in a yearling Thoroughbred filly with a history of periodic fever and intermittent hind limb lameness. Streptococcus sp were isolated from blood, and the filly was treated with penicillin, resulting in a bacteriologic cure. Severe mitral regurgitation developed secondary to scarring of the valve, which resulted in the filly's death. A poor prognosis usually is indicated in horses with bacterial endocarditis, as bacteriologic cures are infrequent and severe valvular insufficiency often develops.
Corynebacterium folliculitis in a horse. A 7-year-old Thoroughbred was examined for evaluation of mildly pruritic multiple skin lesions that had progressed from nodules to alopecia and crusts. Folliculitis caused by Corynebacterium pseudotuberculosis was diagnosed by bacterial culture. Oral treatment with a trimethoprimsulfadiazine paste resulted in resolution of all lesions, with normal hair regrowth.
The effects of corticosteroid administration on the migration, phagocytosis and bactericidal capacity of equine neutrophils. Neutrophil function was evaluated in six clinically normal adult horses, immediately before and 3-6 hours after they were given one dose of hydrocortisone sodium succinate (1 mg/kg body weight). Random migration, stimulated migration to zymosan-activated serum, bacterial phagocytosis and bactericidal capacity of neutrophils were determined in vitro. The mean indices of stimulated migration (net migration and migration ratio) were significantly greater after CS administration (net migration = 62 +/- 23 micron; migration ratio = 11.5 +/- 6.7) than before CS administration (net migration = 44 +/-...
The effect of various antibacterial preparations on the in vitro morphology and chemotactic response of equine neutrophils. Two independent assay systems were used to study the effect of three antibacterial preparations on in vitro morphology and chemotaxis of equine neutrophils. Incubation of neutrophils with high (200 micrograms/ml) and medium (20 micrograms/ml) concentrations of neomycin impaired their response to standard chemoattractants. Trimethoprim/sulfadoxine (0.4/2.0 micrograms/ml-40/200 micrograms/ml) and benzylpenicillin (0.25-25 micrograms/ml) had no effect. Neutrophils collected from geldings 2 and 24 h after neomycin (5 mg/kg) administration had impaired responses to standard chemoattractants. Benzyl...
A-equi-2 influenza in horses in the Republic of South Africa. In early December 1986 A-equi-2 influenza virus was isolated for the first time in the Republic of South Africa. All horses were susceptible to the highly contagious aerosol-borne orthomyxovirus resulting in widespread outbreaks of equine influenza with typical primary respiratory symptoms. Treatment consisted of rest, anti-inflammatory drugs, antibiotics and good nursing. Future protection can be obtained by vaccination.
Nonsurgical management of ruptured urinary bladder in a critically ill foal. A small tear in the urinary bladder of a severely debilitated 4-day-old foal was managed with an indwelling urinary catheter connected to a urine collecting system. Fluid therapy, parenteral nutrition, and antimicrobial agents were used during the initial management of the ruptured bladder. Aseptic technique for catheter care and systemic administration of antimicrobial agents prevented the development of bacterial cystitis. Catheter management required constant monitoring, but the bladder defect was sealed within 5 days. Fungal arthritis caused by Candida tropicalis, immune-mediated anemia, d...
Pharmacokinetics and body fluid and endometrial concentrations of trimethoprim-sulfamethoxazole in mares. Six healthy adult mares were each given a single IV injection of trimethoprim (TMP)-sulfamethoxazole (SMZ) at a dosage of 2.5 mg of TMP/kg of body weight and 12.5 mg of SMZ/kg. Serum concentrations of each drug were measured serially over a 24-hour period. For TMP, the mean overall elimination rate constant (K) was 0.43/hr and the elimination half-life (t1/2) was 1.9 hours. The apparent volume of distribution (at steady state) was 1.62 L/kg and TMP clearance was 886 ml/hr/kg. For SMZ, K was 0.22/hr and t1/2 was 3.53 hours. The apparent volume of distribution at steady state was 0.33 L/kg and S...
Response of pony peritoneum to four peritoneal lavage solutions. Peritoneal lavage was performed on ponies to determine the effect on peritoneal surfaces. Lavage solution (20 L) was introduced into each pony's peritoneal cavity through catheters placed in the paralumbar fossa, and the solution was removed by drainage from the ventral portion of the abdomen. Six ponies each were lavaged with sterile saline (0.9% NaCl) solution, sterile saline solution containing 5 X 10(6) U of potassium penicillin and 3 g of neomycin or povidone-iodine diluted to 3% by volume with sterile saline solution, and 3 ponies were lavaged with povidone-iodine diluted to 10% with ste...
Plasma and synovial fluid concentrations of gentamicin in horses after intra-articular administration of buffered and unbuffered gentamicin. The concentration of gentamicin in plasma and synovial fluid of normal adult horses was measured periodically for 24 hours after IV (2.2 mg/kg of body weight), intra-articular (IA; 150 mg), and simultaneous IV and IA administrations. Gentamicin also was buffered with sodium bicarbonate (3 mEq) and then was administered IA and simultaneously IV and IA. Synovial fluid specimens were obtained via an indwelling catheter placed into the antebrachiocarpal joint. The peak mean plasma gentamicin concentration (8.30 micrograms/ml) after IV administration was significantly (P less than 0.05) greater tha...
Consolidating pneumonia and pneumothorax in a horse. A 3-year-old Thoroughbred mare with signs of acute abdominal pain and chronic pneumonia was found to have pneumothorax. A single application of suction was successful in resolving the pneumothorax. The underlying pneumonia was treated with long-term antibiotic administration selected on the basis of results of bacteriologic culture and antimicrobial susceptibility testing of a transtracheal aspirate. The pneumonia resolved, and the mare returned to competition as a show hunter.
Prevention and management of peritonitis in horses. Peritonitis and adhesions in the horse are best managed through prevention. Perioperative antimicrobial therapy, nonsteroidal anti-inflammatory therapy, experienced personnel, and good surgical techniques should minimize complications after surgery. Despite preventative measures, some horses still develop peritonitis after surgery. Immediate, intensive treatment is necessary to enhance their chances for survival.
Pharmacokinetics of sodium amoxicillin in horses. The pharmacokinetics of sodium amoxicillin were investigated after intravenous and intramuscular administration of a single dose of 15 mg kg-1 body-weight to five horses. A rapid distribution phase was noted after intravenous administration (t1/2 alpha about 20 minutes). The t1/2 beta values obtained after the intravenous and the intramuscular administration were significantly different (P less than 0.05). The bioavailability obtained was about 67 per cent. Plasma protein binding, evaluated in vitro, showed that the percentage of bound fraction was 37 to 38 per cent. It was concluded that sodi...
Pharmacokinetics of ticarcillin and clavulanic acid given in combination to adult horses by intravenous and intramuscular routes. The pharmacokinetics of ticarcillin and clavulanic acid following administration by the intravenous (i.v.) and intramuscular (i.m.) routes were investigated in six normal adult horses. Following i.v. administration, the ticarcillin disposition data conformed to a two-compartment model with an elimination half-life of 1.0 h. The disposition of clavulanic acid was described by a one-compartment model with an elimination half-life of 0.40 h. Following i.m. administration, the half-lives of both drugs were prolonged (ticarcillin 1.8 h, clavulanic acid 1.2 h). The bioavailability of ticarcillin was...
Effect of induced synovial inflammation on pharmacokinetics and synovial concentration of sodium ampicillin and kanamycin sulfate after systemic administration in ponies. Single doses of sodium ampicillin (10 mg/kg) and kanamycin sulfate (5 mg/kg) were administered intramuscularly (i.m.) separately, and then together, to five pony mares. The plasma antibiotic concentration-time curves were constructed. The pharmacokinetic parameters of the antibiotics given separately were not altered by concurrent administration. Four of the five pony mares were then given the i.m. kanamycin/ampicillin combination 4 h after acute synovitis and fever had been induced by injection of lipopolysaccharide into the left intercarpal joint. The plasma concentration-time curves and the...
Bilateral seminal vesiculitis and ampullitis in a stallion. A Thoroughbred stallion suspected of having venereal disease was found to have an infection of the accessory sex glands. Purulent debris, blood, and Pseudomonas aeruginosa were recovered from all ejaculates. Treatment with gentamicin sulfate, tobramycin, and amikacin sulfate was unsuccessful in eliminating the infection. The stallion's seminal plasma, collected during treatment with gentamicin sulfate, did not contain any appreciable antibacterial activity. Apparently, negligible amounts of gentamicin diffused across the mucosal cell borders of the accessory sex glands into the seminal plasma....
Septicemic salmonellosis and suspected phenylbutazone toxicosis in an aged pony. A 16-year-old pony with signs of intermittent abdominal pain was treated with phenylbutazone in excess of the recommended dosage. Endoscopy revealed ulceration of the esophagus, stomach, and proximal portion of small intestine. The pony developed diarrhea. Salmonella typhimurium was isolated from the blood and feces. Treatment included fluids, trimethoprim-sulfadiazine, sucralfate, and ranitidine hydrochloride. The diarrhea resolved, as did the gastrointestinal ulceration. This case was unusual because septicemia with salmonellosis is an uncommon finding in adult equids. Also, complications co...