ABSTRACT
The occurrence of antibiotic-related enterocolitis in guinea pigs restricts the use of many common antibiotics in this species. Cephaloridine, an antibiotic frequently recommended for this species, is no longer available and a substitute has yet to be explored. In this study, the potential therapeutic efficacy of cefazolin, also a first generation cephalosporin, was evaluated in guinea pigs by assessing pharmacokinetics, toxicity and the minimal inhibitory concentration for selected animal pathogens. Pharmacokinetics and toxicity were evaluated in four phases: single intramuscular injections, multiple intramuscular injections over 30 hours, multiple intramuscular injections over 5 days, and serum-protein binding studies. Antibiotic-related enterocolitis and irritation at the injection site occurred following high (100 mg/kg) repeated doses. At all dose levels, blood values exceeded the minimum inhibitory concentration for Bordetella bronchiseptica for only 1 hour postinjection. For Streptococcus and Staphylococcus sp., the drug half-life was 0.5 hours with peak concentrations occurring within 0.25 hours of injection. The volume of distribution of 0.5 l/kg indicated that there was extensive tissue distribution. Serum protein binding was approximately 85%. The short half-life and rapid plasma clearance rate (10.4 ml/min/kg) indicated that cefazolin is eliminated very rapidly from the guinea pig and may be of questionable therapeutic value.
Subject(s)
Cefazolin/pharmacokinetics , Guinea Pigs/metabolism , Animals , Bordetella/drug effects , Cefazolin/pharmacology , Cefazolin/toxicity , Female , Kinetics , Microbial Sensitivity Tests , Staphylococcus aureus/drug effects , Streptococcus/drug effectsABSTRACT
An aged wild-caught male rhesus monkey (Macaca mulatta), maintained in a research facility for 10 years, developed bilateral pelvic limb paralysis without other signs of disease. Unresponsive to therapy, the monkey was killed and necropsied. Chronic inflammation with osteolysis of thoracic vertebrae 10-13 was observed. Pseudomonas pseudomallei was cultured and identified from cerebrospinal fluid obtained at the site of the thoracic lesion. This Gram-negative bacterium can cause infection in animals and man and may remain latent for years before the appearance of clinical signs.
