Research Updates: Single-injection antibiotic treatment for cats with abscesses and infected wounds


Research Updates: Single-injection antibiotic treatment for cats with abscesses and infected wounds

Oct 01, 2009

Erika Meler, DVM, MS
Cephalosporins are often used as first-line antibiotics for superficial skin infections in dogs and cats. However, subcutaneous abscesses in cats are more commonly treated with broader-spectrum second-line antibiotics such as amoxicillin-clavulanic acid despite results that suggest that penicillins may be ineffective in many cases.1

Barrak Pressler, DVM, PhD, DACVIM
The purpose of this multicenter, randomized, double-blinded, controlled clinical study was to compare the efficacy of a new cephalosporin option (single subcutaneous injection of cefovecin) with that of a positive control cephalosporin (once-daily orally administered cefadroxil) for the treatment of abscesses and infected skin wounds in cats. In this study, 177 cats with moderate to severe cutaneous abscesses or infected wounds were included in the antimicrobial effectiveness analysis. Swabs of affected areas obtained at initial presentation were submitted for aerobic and anaerobic bacteriologic culture; a positive culture result of pathogenic bacteria was required for inclusion.

Cats were randomly assigned on the day of admission to receive either a single dose of cefovecin (89 cats; 8 mg/kg subcutaneously), followed by owner administration of placebo drops for two weeks, or one subcutaneous placebo injection, followed by owner administration of cefadroxil (88 cats; 22 mg/kg orally every 24 hours) for two weeks. Concurrent wound management, including clipping and drainage of the abscess or surgical d├ębridement of the skin wound but no concurrent topical antiseptic was allowed. Additional topical or systemic antibiotics or glucocorticoids were not permitted.

Cats with abscesses made up 71% of the study group, while those with infected wounds made up 27%. Pasteurella multocida was the most common pathogen recovered from culture specimens. Other pathogenic bacteria commonly isolated included Prevotella species, Streptococcus canis, coagulase-negative Staphylococcus species, Staphylococcus intermedius, Fusobacterium species, Escherichia coli, and Porphyromonas species.

After 14 days, 98% of the cats treated with cefovecin had resolution or significant improvement in skin infections vs. 95% of the cats treated with cefadroxil; no significant difference was seen in the efficacy of these two drug regimens. At the final assessment (28 days after diagnosis), 2% vs. 9% of the cefovecin- and cefadroxil-treated cats, respectively, were considered treatment failures. Cefovecin-associated side effects reported by owners were similar to those of other cephalosporins and were usually related to the gastrointestinal tract. Although no statistical analysis was performed, the number of cats with vomiting or diarrhea was higher in those administered cefadroxil (14 with vomiting and 26 with diarrhea) than in those receiving cefovecin (10 with vomiting and seven with diarrhea).