Penicillin is a widely used antibiotic in equine medicine, primarily employed to treat bacterial infections in horses. It functions by inhibiting the synthesis of bacterial cell walls, thereby preventing bacterial growth and proliferation. Penicillin is effective against a range of gram-positive and some gram-negative bacteria, making it a common choice for treating conditions such as respiratory infections, skin infections, and soft tissue infections in horses. The administration of penicillin can be oral, injectable, or intramuscular, depending on the specific formulation and the clinical scenario. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacokinetics, efficacy, and safety of penicillin use in equine patients, as well as its role in managing bacterial infections in horses.
Piché CA.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...
Ducharme NG, Dill SG, Shin SJ, Schwark WS, Ducharme GR, Beilman WW.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 ...
Love DN, Rose RJ, Martin IC, Bailey M.Twelve geldings were used to evaluate serum levels of penicillin following the intravenous (iv) and intramuscular (im) injection of benzylpenicillin, im procaine penicillin and im fortified benzathine penicillin, at a variety of dose rates. Blood samples were collected up to 7 h after iv and im benzylpenicillin, up to benzathine penicillin. Results were analysed using an analysis of variance and regression analyses were used to calculate the time taken for the serum penicillin concentration to decline to 0.5 micrograms/ml. As a result of the experiments the following dosage regimes could be re...
Ayliffe TR, Allen WE.PREVIOUS studies have shown that instillation of sodium benzylpenicillin into the uterine lumen of ponies in small volumes is followed by peak plasma concentrations of the antibiotic in 10to 15 mins (Allen 1978; Allen and Clarke 1978). However, the assumption that the circulating penicillin is absorbed only through the endometrium is questionable because Allen, Kessy and Noakes (1979) concluded that the intrauterine instillation of phenolsulphonphthalein was followed by absorption of the dye from the peritoneal cavity, after passage along the uterine tubes.
The present investigation was carri...
Smith BP, Robinson RC.Five out of 6 foals between 2 and 4 months old, on a ranch in northern California, developed pneumonia within a 3 week period in June and July 1978. Corynebacterium equi was recovered from each of the 5 foals by transtracheal aspiration. Clinical signs were variable but included increased respiratory rate, fever, cough, nasal discharge, harsh airway sounds over middle sized airways and wheezing over small airways. Cyanosis was present in the most severely affected foal. Radiographic findings included diffusely increased interstitial and peribronchial densities, areas of consolidation and, in 3...
Kirchhoff H, Heitmann J, Bisping W.Mycoplasmas were isolated from 11 (=#6,8%) of 161 cervix swabs from infertile mares. A total of 17 strains was isolated and characterized by indirect immunofluorescent test and metabolic inhibition test as Mycoplasma equigenitalium (11 strains), Mycoplasma subdolum (2 strains), Acholeplasma laidlawii (3 strains) and Acholeplasma equifetale (1 strain). In addition cervix swabs of the mares were investigated for bacteria. There was no specific correlation between presence of mycoplasmas and bacteria (table 1). In clinical investigations 5 of the 11 mares which harboured mycoplasmas showed a pneu...
Timoney PJ, O'Reilly PJ, Harrington AM, McCormack R, McArdle JF.The ability of Haemophilus equigenitalis, the causal agent of contagious equine metritis 1977, to survive in various antibiotic-containing semen extenders was studied at different environmental temperatures. Gentamicin sulphate was found to be markedly superior to ampicillin or a combination of sodium benzyl penicillin and polymyxin B sulphate, Semen treated with the former antibiotic was either sterile at cultural examination or else yielded appreciably fewer colonies of H. equigenitalis than the untreated semen control. Ampicillin had no observable effect on the survival of this organism. Ge...
Allen WE.Plasma concentrations of sodium benzylpenicillin were measured following intrauterine infusion at a dose rate of 22,000 u/kg (250,000 u/ml). The reproductive status of the mare at the time of infusion did not appear to influence plasma concentrations of penicillin, but preswabbing the endometrium for bacteriological culture resulted in peak plasma concentrations which were nearly twice those found in unswabbed mares.
Rumbaugh GE, Smith BP, Carlson GP.internal abdominal abscesses in 25 horses, including 8 horses that died or were euthanatized, were found to be caused by Streptococcus equi, Streptococcus zooepidemicus, or Corynebacterium pseudotuberculosis. Breed or sex predilection was not found. Although horses of all ages were affected, those under 5 years of age were more commonly affected. Nearly all of the horses had a history of respiratory catarrh or lymphadenitis. Horses with internal abdominal abscesses also had intermittent, prolonged colic or chronic weight loss. Most horses had increased rectal temperature, increased heart and r...
Bergan T, Versland I.To be active, antimicrobials must reach the bacteria in the infectious foci in adequate concentrations. Direct measurements of levels in the various foci are difficult to perform, but a number of animal models with artificial extravascular foci have been developed. In many ways, the physiology of pigs resemble that of humans. Consequently, it was thought that pigs might also parallel humans in the handling of penicillins. General pharmacokinetics of ampicillin and flucloxacillin and the penetration of the substances to subcutaneously implanted teflon tistisue chambers were investigated. Ampici...
Dinev D, Koĭchev K, Kolev K, Gerganova E.A total of 24 horses and 42 cattle with a variety of local suppurative processes (wounds, abscesses, phlegmons, tendovaginitis, etc.) were studied under conditions of the clinic with regard to the most commonly found microbial species and the opportunity to work out antibioticogrammes in terms of the effectiveness of 11 of the chemotherapeutic agents widely used in the practice. It was found that prevailing in horses were staphylococci and streptococci. In cattle Corynebacterium pyogenes was predominantly established. Besides, there was a rising trend in the part played by representative agent...
Kendall A, Mayhew IG, Petrovski K.Treatment of subclinical carriers of Streptococcus equi subsp. equi with a gelatine-penicillin formulation deposited in the guttural pouch has been empirically proposed, but data on local tissue penicillin concentrations after treatment are lacking. Methods: We analysed tissue levels of penicillin after administration into the guttural pouches of four healthy horses. Two horses received local treatment with gelatine-penicillin and two horses received local treatment with an intramammary formulation of penicillin. Tissues were harvested for analysis either 12 or 24 h later. Conclusions: Resul...
Bernard W, Divers TJ, Whitlock RH, Messick J, Tulleners E.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.
van Spijk JN, Beckmann K, Wehrli Eser M, Stirn M, Steuer AE, Saleh L, Schoster A.Neuro- and nephrotoxicity of polymyxins are known but clinical studies in horses are lacking. The aim of this study was to describe neurogenic and nephrogenic side effects of hospitalized horses receiving Polymyxin B (PolyB) as part of their treatment plan. Twenty horses diagnosed with surgical colic ( = 11), peritonitis ( = 5), typhlocolitis ( = 2), pneumonia, and pyometra (each = 1) were included. Antimicrobial treatment was randomized to GENTA (gentamicin 10 mg/kg bwt q24 h IV, penicillin 30.000 IU/kg q6 h IV) or NO GENTA (marbofloxacin 2 mg/kg bwt q24 h IV, penicillin 30.000 IU/kg q6 h IV...
Higgins R, Biberstein EL, Jang SS.Of 24 isolates of nutritionally variant streptococci recovered from equine corneal ulcers, 22 were tested for growth requirements, physiological and biochemical reactions, and susceptibility to different antimicrobial agents. Satisfactory growth was obtained by supplementing blood agar and Todd-Hewitt broth with pyridoxal hydrochloride, and all of the media for the culture and the biochemical testing were supplemented with 0.002% of this substance. Biochemical patterns of 12 of the isolates resembled those of two viridans streptococcal species, Streptococcus intermedius and Streptococcus const...
Raidal SL, Taplin RH, Bailey GD, Love DN.To evaluate the administration of procaine penicillin prior to or during confinement with head elevation as a means of reducing the associated accumulation of inflammatory lower respiratory tract secretions and increased numbers of bacteria within the lower respiratory tract of confined horses. Methods: Two experiments were conducted to evaluate the efficacy of different dose rates and dosing frequencies. In experiment A a single low dose (15,000 IU/kg) of procaine penicillin was administered to four horses immediately prior to confinement with head elevation for 48 hours. The systemic leucocy...
Jaeschke G, Wintzer HJ.This is a review on Morbus maculosus equorum (purpura haemorrhagica) on the base of literature data and of a case report on 13 own patients. It is shown, that the clinical picture of this disease has not changed within the last 150 years. Clinical main symptoms are haemorrhagic diathesis (petechiae, ecchymosis, suggillations) as well as peripheral edema and fever. The main haematological findings are neutrophilia, mostly going along with shift to the left and lymphopenia. In the last few years thrombocytopenia was also described in some cases. Basic therapeutics are glucocorticoids and penicil...
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...
Tirosh-Levy S, Solomovich-Manor R, Comte J, Nissan I, Sutton GA, Gabay A, Gazit E, Steinman A.Envenomation by venomous snakes is life threatening for horses. However, the efficacy of available treatments for this occurrence, in horses, has not yet been adequately determined. The aim of this study was to describe the treatments provided in cases of Daboia palaestinae envenomation in horses and to evaluate the safety and efficacy of antivenom administration. Data regarding 123 equine snakebite cases were collected over four years from 25 veterinarians. The majority of horses were treated with procaine-penicillin (92.7%), non-steroidal anti-inflammatory drugs (82.3%), dexamethasone (81.4%...
Adland-Davenport P, Brown MP, Robinson JD, Derendorf HC.Fourteen foals less than four days of age were treated with the aminoglycoside, amikacin sulphate, and either penicillin or ampicillin for septicaemia, pneumonia, and/or failure of passive immunoglobulin transfer. Serum amikacin concentrations were determined at three times during an 8 or 12 h dosing interval. A 7.0 mg/kg bodyweight dose of amikacin every 8 h was appropriate. Prematurity did not influence mortality. All seven premature foals survived, whereas four of the seven full term foals died. Uraemia in three foals was caused by urinary bladder rupture; amikacin-induced nephrotoxicity wa...
Stevenson AJ, Weber MP, Todi F, Young L, Beaumier P, Kacew S.Plasma and urinary concentrations of procaine were examined in Standardbred mares after subcutaneous administration of various doses (80 mg to 1600 mg) of procaine hydrochloride. Regardless of dose, peak plasma procaine values occurred within 1 h, but remained detectable in a dose-dependent manner, with procaine present at 1 h with the 80 mg dose and 6 h at the 1600 mg dose. Similarly, peak urinary procaine concentrations were attained within 1.5 to 3 h, irrespective of dose, while detection time was dose-dependent, being 23 h for 80-200 mg doses but as long as 30-54 h with the 1600 mg dose. W...
Stanek C.A retrospective study (1984-1994) was made of 10 cases of septic arthritis of the distal interphalangeal joint in horses aged 7 months to 17 years. In 6 cases a hind limb was affected, in 4 cases a front limb. The arthritis was caused either by a puncture wound in the sole area (8 cases), by a perforating wound in the coronary region (1) or iatrogenic (1). All horses exhibited a severe lameness at the walk. Radiography showed no typical lesions in fresh cases, whilst later an increasing subluxation of the joint was observed followed by periosteal reactions. Therapy included partial resection o...
Dujardin CL.A Belgian draft horse stallion presented with classical signs of purpura haemorrhagica: oedema of the distal limbs, ventral abdomen and head, ecchymotic haemorrhage of mucous membranes, epistaxis, fever, lethargy, reluctance to move, and anorexia. Serum chemistry revealed a highly elevated gamma-globulin fraction. Streptococcal lymphadenitis (strangles) had been present on a neighbouring farm in the past few months. After an initial positive response to therapy with benzylpenicillin, flunixin and dexamethasone, the horse's condition deteriorated suddenly on day 4 of hospitalization, with signs...
Fenger CK, Kohn CW.A 20-month-old Quarter Horse stallion was admitted for evaluation of labored breathing, honking cough, and bilateral epistaxis that were caused by pneumonia and collapsed trachea. A transtracheal aspiration revealed highly cellular, serosanguineous fluid. Radiography revealed a patchy alveolar pattern and a narrowed tracheal lumen. Endoscopy confirmed narrowing of the tracheal lumen. Streptococcus zooepidemicus was isolated on culture of the transtracheal aspirate. The horse responded to penicillin treatment, and the tracheal collapse improved endoscopically after 4 days, with complete recover...
Younkin JT, Santschi EM, Kukanich B, Lubbers BV, Warner M.Penicillin is administered intravenously (IV) or intramuscularly (IM) to horses for the prevention and treatment of infections, and both routes have disadvantages. To minimize these shortcomings, a 24-hr hybrid administration protocol (HPP) was developed. Our objective was to determine penicillin plasma concentrations in horses administered via HPP. Venous blood was collected from seven healthy horses administered IV potassium penicillin G at 0 and 6 hr and IM procaine penicillin G at 12 hr. Blood was collected at 2-hr intervals from 0 to 20 hr and at 24 hr. Plasma penicillin concentration...
Ducharme NG, Dill SG, Shin SJ, Schwark WS, Ducharme GR, Beilman WW.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 ...
Horspool LJ, McKellar QA.The present study was designed to determine and compare the plasma disposition and pharmacokinetics of penicillin G sodium following intravenous (i.v.) administration to horses, ponies and donkeys. The plasma disposition and pharmacokinetics of penicillin G was similar in horses, ponies and donkeys (elimination half-lives--39.0, 27.3 and 31.5 min, respectively) and a dosage interval of 6-8 h would be suitable to treat infections caused by susceptible bacteria. Although penicillin G was absorbed rapidly following nasogastric administration, the systemic availability was low (0.12-0.34%), theref...
Grønvold AM, L'Abée-Lund TM, Strand E, Sørum H, Yannarell AC, Mackie RI.Antimicrobial treatment is associated with the spread of antimicrobial resistance and disturbances in the ecological balance of intestinal microbiota. In horses, the main adverse effect of antimicrobial treatment is colitis. We used culture and 16S rRNA gene based molecular methods to monitor the prevalence of antimicrobial resistance and changes in predominant fecal populations during penicillin treatment and general anesthesia of horses in the clinical setting. After 5 days of parenteral administration of penicillin, fecal Escherichia coli were resistant to multiple unrelated antimicrobial a...
Timoney PJ, O'Reilly PJ, Harrington AM, McCormack R, McArdle JF.The ability of Haemophilus equigenitalis, the causal agent of contagious equine metritis 1977, to survive in various antibiotic-containing semen extenders was studied at different environmental temperatures. Gentamicin sulphate was found to be markedly superior to ampicillin or a combination of sodium benzyl penicillin and polymyxin B sulphate, Semen treated with the former antibiotic was either sterile at cultural examination or else yielded appreciably fewer colonies of H. equigenitalis than the untreated semen control. Ampicillin had no observable effect on the survival of this organism. Ge...
Zetterström S, Groover E, Lascola K, Cole R, Velloso A, Boone L.A five-year-old Thoroughbred mare was evaluated because of chronic, malodorous, unilateral nasal discharge, and suspected maxillary cheek tooth root abscess. Skull radiographs revealed bilateral sinusitis suspected secondary to tooth root abscessation of 109 and 210. Following oral extraction of 109, bilateral conchofrontal sinus trephination and lavage; fever, tachycardia, and cervical stiffness developed. A lumbosacral cerebrospinal fluid tap was performed, and a presumptive diagnosis of bacterial meningitis was made. Targeted therapy consisted of antibiotic treatment with penicillin, enrofl...
Lawhon SD, Taylor A, Fajt VR.Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). Th...
Sweeney CR, Sweeney RW, Divers TJ.Case records of 48 foals with pneumonia due to Rhodococcus equi were reviewed. Twenty of the 48 foals survived and 28 died or were euthanized. There was no significant difference between the survivors and non-survivors in the age of onset of illness, duration of illness prior to admission, the mean white blood cell (WBC) count, or the mean plasma fibrinogen content. All foals had R. equi isolated from a tracheobronchial aspirate or lung specimens obtained at necropsy. All organisms were susceptible in vitro (Kirby-Bauer) to erythromycin and gentamicin. Susceptibilities to other drugs were: tri...
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 ...
Rasheed H, Ijaz M, Ahmed A, Javed MU, Shah SFA, Anwaar F.Antimicrobial resistance is a global issue that limits therapeutic options for infections. S. aureus being a member of the ESKAPE group is capable of "escaping" the biocidal action of antimicrobial agents. There are phenotypic and genotypic methods used for the identification of antibiotic resistant genes harboring S. aureus but these methods do not always show concordant results. To address these discrepancies, a total of 335 equine nasal swab samples from four districts of Punjab were collected using a convenient sampling technique. These samples were first subjected to common microbial tech...
Braga PRC, Dos Santos CA, Bertani AMJ, Vieira T, Amarante AF, Reis AD, Sacchi CT, Camargo CH, Ribeiro MG, Borges AS, Tiba-Casas MR.This study reports the genomic characterization of the multidrug resistant Salmonella Newport strain 195_20 recovered from the diarrheic faeces of a foal in Brazil and co-harbouring the mcr-9, blaCMY-2 and qnrB19 antibiotic resistance genes. Bacterial isolate positive for mobile colistin resistance gene (mcr-9) was submitted to antimicrobial susceptibility testing by disk diffusion and broth microdilution for colistin and polymyxin B. The isolate was submitted to whole genome sequencing by Illumina technology and Nanopore Sequencing. Conjugation assays, plasmid sizes determined by S1-PFGE and ...
Rockow M, Griffenhagen G, Landolt G, Hendrickson D, Pezzanite L.Recognition of antimicrobial resistance in equine practice has increased over the past decade. The objective of this study was to provide an updated retrospective review of antimicrobial regimens in one tertiary referral hospital and to evaluate the association with postoperative complications. A secondary objective was to evaluate other perioperative factors including surgical procedure, anesthetic and recovery parameters, and the effect of perioperative medications on complications and outcomes. A computerized search of medical records was performed to identify horses undergoing exploratory ...
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-...
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);...
Köhne M, Hegger A, Tönissen A, Hofbauer L, Görgens A, Sieme H.Bacterial endometritis is a major problem in equine reproduction usually treated with antibiotics, however reports of success rates are scarce. This study collected data from mares diagnosed with intrauterine bacterial growth and compared the outcome of different therapies for bacterial endometritis in German stud farm practice. Data on mares with positive uterine culture results were collected retrospectively in veterinary practices (n = 5; 2018-2022). Information relating to 30 factors (mare, diagnostics, therapy, pregnancy rate) of bacterial endometritis cases (n = 772) were recorded an...
