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.
Absorption of neomycin from the equine uterus: effect of bacterial and chemical endometritis. Plasma concentrations of neomycin were measured after intrauterine infusion of 3.3 mg/kg neomycin sulphate. Mares infected two hours previously with an intra-uterine infusion of beta-haemolytic streptococci absorbed approximately 12 per cent of the neomycin in both the oestrous and the luteal phases of the cycle. Normal mares in oestrus absorbed 6 per cent of the neomycin infused and luteal mares absorbed 56 per cent. In infected mares the peak plasma concentrations occurred two hours after neomycin infusion, earlier than in healthy mares. Cervical flushings after neomycin infusion in infected...
Pharmacokinetics of intravenously and intramuscularly administered ticarcillin and clavulanic acid in foals. Serum concentrations of ticarcillin and clavulanic acid were measured in healthy foals (2 to 6 months old) given the drugs in combination by intravenous and intramuscular routes of administration. Five foals were administered 50 mg of ticarcillin/kg of body weight and 1.67 mg of clavulanic acid/kg, IV. Five foals were administered 100 mg of ticarcillin/kg and 3.33 mg of clavulanic acid/kg, IV, and 4 of those 5 were given the same combined dose IM. The elimination half-life of ticarcillin for intravenous administration was 0.83 hour for the low dosage and 0.96 hour for the high dosage. After in...
Effects of halothane anesthesia on the clearance of gentamicin sulfate in horses. Inhalation anesthetics decrease the clearance of some drugs that are eliminated by renal excretion. The purpose of the study reported here was to investigate the effects of halothane anesthesia on the pharmacokinetics and urinary excretion of gentamicin sulfate, using the horse as a model. Using a crossover design, pharmacokinetic values after a single IV dose of gentamicin (4 mg/kg) were compared in halothane-anesthetized and unanesthetized horses. Compared with unanesthetized horses, the anesthetized horses had significant decreases in total body clearance (P less than 0.01) and apparent vol...
Epidemiologic studies of Lyme disease in horses and their public health significance. A serologic survey of horses in the New Jersey-Pennsylvania area demonstrated that about 10% (6.2-14.2%) have significant levels of serum antibody to Borrelia burgdorferi. However, in a highly endemic area of central New Jersey, up to 60% of the mares and yearlings samples on one farm were seropositive. In 1983, sera from this same farm exhibited only 12% positives in mares and 35% positives in yearlings. Longitudinal studies of paired sera obtained from individual yearlings over a 6-month period in 1985 showed that 34% of them declined during the period. A new clinical syndrome associated wit...
Pancytopenia caused by bone marrow aplasia in a horse. Pancytopenia was evaluated in a mature Quarter Horse gelding. A diagnosis of bone marrow aplasia was made on the basis of bone marrow hypocellularity. History of drugs administered included penicillin, oxytetracycline, trimethoprim-sulfadiazine, phenylbutazone, dipyrone, flunixin meglumine, and isoxsuprine. Clinical remission was observed after treatment with glucocorticoids, androgens, and broad-spectrum antimicrobials.
[Isolation and purification of proteolytic enzymes on organo-silica sorbents with immobilized gramicidin S]. Biospecific sorbents for affinity chromatography of proteolytic enzymes have been synthesized by attaching cyclopeptide antibiotic gramicidin S to organo-silica supports. It is shown possible to attach gramicidin S to the organo-silica supports using glutaric aldehyde, p-benzoquinone, soluble and insoluble carbodiimides. The sorbents prepared by these methods were successfully applied for the purification of the crude pepsin from horse gastric juice and proteolytic complex produced by Acremonium chrysogenum.
Hematuria caused by abdominal abscessation in a foal. A 4.5-month-old Standard-bred filly was referred for evaluation of pigmenturia. Initially, the pigmenturia had resolved with the administration of antibiotics, only to recur after their withdrawal. A dark red urine sample contained numerous RBC, WBC, and gram-negative rods (Escherichia coli). Ultrasonography revealed the right kidney to be large, with multiple cystic structures and a dilated renal pelvis and calices. Cystoscopy revealed a large blood clot within the bladder and urine coming from the left ureteral opening. Urine was not observed coming from the right ureter. It was suspected th...
Conservative treatment of a minimally displaced fracture of the radius of a horse. The successful conservative treatment of an open, displaced fracture of the radius of a horse suggests that conservative treatment should not be ignored when surgery is not an option. The importance of proper soft-tissue management and the use of broad-spectrum antimicrobial treatment in the management of orthopedic injuries is emphasized.
Preputial hematoma in a stallion. An 8-year-old Quarter Horse stallion was admitted with a swelling involving the prepuce, dorsal part of the scrotum, and root of the penis. The swelling was first noticed 10 days after breeding, with no evidence that it had resulted from a kick by the mare. The penis was retracted into the prepuce, except for a 10- to 15-cm protrusion of the glans penis. Treatment included warm hydrotherapy, massage, stockinette compression, antidiuretics, antibiotics, penile support, and exercise, without success. At necropsy, a massive preputial hematoma was found extending forward from the root of the penis...
Distribution of cephapirin into a tissue chamber implanted subcutaneously in horses. The pharmacokinetics of cephapirin sodium and its distribution into a tissue chamber implanted subcutaneously in the neck of mature horses are described. Cephapirin was administered as an intravenous bolus dose of 20 mg/kg. The serum concentration vs time curve was best described by a two-compartment open model. Cephapirin disappeared from serum rapidly (t1/2 beta = 18.8 min), and had only a modest volume of distribution (Vd(area) approximately equal to 346 mg/kg, Vd(ss) approximately equal to 204 ml/kg). Total clearance was also rapid (approximately equal to 13 ml/min.kg). Concentrations of t...
Preservation of skin by refrigeration for autogenous grafting in the horse. Eighteen stored split thickness meshed skin grafts were applied to surgically created lesions on the metacarpal and metatarsal regions of six horses. Donor skin was harvested from the sternal region, meshed and stored at 4 degrees C in a cell culture medium containing 10% serum. Stored grafts were applied to the wounds at 1, 2, and 3 week intervals. Acceptance of the grafts stored for 1 week was generally poor (1 of 6 grafts), whereas that of the 2 and 3 week old grafts was generally excellent (10 of 12 grafts). Poor acceptance of the 1 week old grafts was attributed to streptococcal infection...
Use of erythromycin-rifampin combination in treatment of Rhodococcus equi pneumonia. The selection of lipid-soluble antibiotics capable of intracellular penetration is considered critical for the successful treatment of Rhodococcus equi pneumonia and lung abscesses in foals. Two such antibiotics: erythromycin (25 mg kg-1, three times daily) and rifampin (5 mg kg-1 twice daily) have been used in combination for this purpose at the University of Florida since 1981. Positive evidence of R. equi was present on culture of tracheal aspirates in 57 foals, most of which exhibited radiographic evidence of extensive lung abscessation. The duration of therapy ranged from 4 to 9 weeks. Mi...
Marsupialization of an abdominal abscess caused by Serratia marcescens in a mare. An intra-abdominal abscess was diagnosed in a 7-year-old mare by palpation per rectum and from abnormal clinicopathologic findings. Initial treatment with procaine penicillin for 21 days was unsuccessful in halting the deterioration of the physical condition of the mare. Surgical exploration of the abdomen revealed a mass in the wall of the left ventral colon. Drainage was achieved by marsupialization. Serratia marcescens was isolated from the abscess. Recovery appeared complete, and the mare has resumed broodmare capability.
Luxation of the metacarpophalangeal and metatarsophalangeal joints in horses. Lateral or medial luxation of the metacarpophalangeal or metatarsophalangeal (fetlock) joint in 10 horses is presented. Closed and open fetlock luxation each occurred in five horses. Horses were treated by cast immobilisation after debridement of soft tissue and joint lavage in cases of open luxations. Suture apposition of a ruptured collateral ligament was attempted in three cases. Antibiotic therapy was used in all cases of open fetlock luxation but non-steroidal anti-inflammatory medication was used inconsistently. Whether closed or open, fetlock luxations had a good prognosis for return to...
Actinobacillus suis-like organisms in horses. Actinobacillus suis-like organisms have been recognized in equine specimens at the University of California Veterinary Medical Teaching Hospital since 1975. The most common source (65%) of the organism was transtracheal washings. The organism was gram-negative, produced hemolysis on blood agar, and gave a positive reaction for oxidase, urease, o-nitrophenyl-beta-D-galactopyranoside, and esculin. Carbohydrate reactions were variable, consisting of 4 main patterns. Actinobacillus suis-like organisms were (90%) sensitive to therapeutic concentrations of amikacin, cephalothin, chloramphenicol, gen...
Botulism as a sequel to open castration in a horse. Clostridium botulinum and type-B C botulinum toxin were isolated from a necrotic wound that developed subsequent to castration in a 2-year-old Thoroughbred gelding. The horse had clinical signs of botulism and was successfully treated with wound debridement, C botulinum type-B antitoxin, potassium penicillin, and supportive care.
Immune-mediated hemolytic anemia induced by penicillin in horses. Three horses developed severe, immune-mediated hemolytic anemia after treatment with penicillin. The horses had positive direct antiglobulin (Coombs) tests and high titers of IgG antibody that agglutinated penicillin-coated equine red cells. Two of the horses were tested for antibodies to autologous red cell antigens; autoantibodies were not present. Titers of antipenicillin antibody decreased after penicillin was discontinued but IgG antibody was detectable months after recovery. One of the horses was challenged with penicillin; antibody titer increased slightly, but anemia did not develop. A...
Cellulitis and subcutaneous abscesses caused by Rhodococcus equi infection in a foal. Cellulitis and subcutaneous abscess formation was diagnosed in a 3-month-old Thoroughbred filly. Clinical signs consisted of a large ulcerated plaque, with satellite pustules on the medial aspect of the right hock and subcutaneous abscesses in the right inguinal and mammary gland areas. Laboratory analysis revealed mature neutrophilia. Rhodococcus equi was isolated from the cellulitis and the subcutaneous abscess. Oral administration of erythromycin and rifampin for 35 days resulted in a clinical cure.
Antimicrobial susceptibility of microorganisms isolated from equine orthopedic patients. Positive cultures were obtained from 60 equine orthopedic cases during a 12 year period (1974-1985). These cases consisted of 34 long or cuboidal bone fractures, 13 arthrotomy/arthroscopy procedures for removal or internal fixation of a fracture, 7 proximal splint bone fractures, and 6 facial or mandibular fractures. Excluding the 13 arthrotomies, only 10 (21%) of the 47 were open fractures. Multiple organisms were isolated from 36 cases (20 long or cuboidal bone fractures, 7 splint bone fractures, 5 mandibular fractures, and 4 intra-articular fractures). Of the 142 isolates, 35 (24%) were mem...
Absorption of neomycin from the equine uterus: effect of stage of oestrous cycle and volume of vehicle. Plasma concentrations of neomycin were measured following intrauterine infusion of 3.3 mg/kg bodyweight neomycin sulphate. Mares in oestrus absorbed approximately 6 per cent of neomycin infused whereas mares in a luteal phase absorbed 56 per cent. The volume of infusate also affected absorption as increased volume resulted in decreased absorption. The decreased absorption both during oestrus and when large volumes were used was probably due to reflux of antibiotic through the cervix.
Cardiovascular effects of intravenous sodium penicillin, sodium cefazolin, and sodium citrate in awake and anesthetized horses. Sodium penicillin, sodium cefazolin, and sodium citrate were administered to six adult horses on separate occasions, when awake and during anesthesia. The order of administration was randomized and studies were separated by a minimum of 7 days. Arterial blood pressure decreased significantly (less than 0.05) from control 5 minutes after intravenous (IV) sodium penicillin in awake and anesthetized horses. Systolic arterial blood pressure remained significantly (less than 0.05) decreased 10 minutes after IV sodium penicillin in anesthetized horses. Sodium cefazolin and sodium citrate did not sig...
Group C streptococcal arthritis. A case report of equine transmission. Presented is the third known case of a group C streptococcal arthritis, this case documented in a healthy 42-year-old horse trainer, apparently transmitted by a mare. After a delayed diagnosis, the patient responded favorably to surgical drainage and parenteral penicillin G, but required a manipulation of his knee under general anesthesia. Although rare, group C streptococcal arthritis can occur in hosts with no apparent predisposing factors. Frequent exposure to farm animals may increase the risk.
Rational selection of antimicrobial drugs for treatment of infections of horses. The goal of antimicrobial drug use is quite specific. Consideration of many microbe-related, host-related, and drug-related factors is necessary for appropriate selection and use of antimicrobial drugs in equine patients. The concepts and data presented in this article demonstrate that fact. At the risk of oversimplification, "The bug denotes the drug, and the horse directs the course."
Antimicrobic susceptibility of bacterial pathogens from horses. Rational choice of an antimicrobial agent requires that the condition for which the drug is prescribed contain an infectious agent and, if so, knowledge of the susceptibility of the microorganism to antimicrobial drugs. Unfortunately, most infectious conditions necessitate the use of an antimicrobic drug before data from the microbiology laboratory are available. The data presented are meant to serve as a guide in the choice of antimicrobic drugs for treatment of infectious processes of the horse before knowledge of the nature of the microorganism isolated as well as its susceptibility to anti...
Pharmacologic considerations in drug therapy in foals. Rational drug therapy in the foal requires a sound knowledge of the pharmacodynamics and pharmacokinetics of various drugs as well as a thorough understanding of the physiologic differences that exist between the neonate and the adult and that may serve to alter drug disposition and, therefore, drug response. A summary of these physiologic factors with emphasis on the foal is presented and is followed by recommendations regarding the applied therapeutics of various antimicrobial agents.
Drug therapy of respiratory disorders. The emphasis of this article is on the clinical application of drugs in therapy for treatment of disorders of the lower respiratory tract. Medications discussed include those used to enhance clearance of secretions and those employed to prevent and/or alleviate bronchoconstriction. Antimicrobial agents and respiratory stimulants are briefly mentioned.
Povidone-iodine lavage treatment of experimentally induced equine infectious arthritis. Both tarsocrural joints of 4 horses were inoculated with 1.5 X 10(5) colony-forming units of Staphylococcus aureus. On days 1, 3, and 6, each horse had one tarsocrural joint lavaged with a balanced electrolyte solution and had the contralateral tarsocrural joint lavaged with 0.1% povidone-iodine solution. All horses were orally administered trimethoprim (5 mg/kg)/sufadiazine (25 mg/kg) combination twice daily and phenylbutazone (2 g) once daily for the duration of the study (21 days). On days 0, 1, 3, 6, 9, 14, and 21, synovial fluid specimens were collected and analyzed for color, clarity, to...
Anti-pseudomonas activity of anti-lipopolysaccharide hyperimmune equine plasma. Passive immunotherapy with anti-lipopolysaccharide hyperimmune equine plasma (Anti-LPS) is effective in treating experimental Gram-negative bacterial infections. The bactericidal activity of anti-LPS towards five different Pseudomonas species, including two multiresistant Pseudomonas aeruginosa isolates was tested here, as well as the ability of anti-LPS to inhibit the quantitative chromogenic limulus amoebocyte lysate (LAL) assay. Anti-LPS caused a mean reduction of 84.4 +/- 3.2% (P less than 0.001) in the number of colony forming units (cfu) of all isolates, whereas saline and complement ina...