COMPARISON OF THE EFFICACY OF EXTENDED PIRLIMYCIN THERAPY ALONE OR IN COMBINATION WITH LYSIGIN IN THE TREATMENT OF STAPHYLOCOCCUS A UREUS MASTITIS ON A LARGE COMMERCIAL DAIRY

摘要

In a recent pilot study we evaluated the efficacy of Lysigin (Boehringer Ingelheim Vetmedica, Inc.) to potentiate extended pirlimycin HC1 (Pirsue, Pfizer, Inc.) therapy for Staphylococcus aureus intramammary infection (IMI) in a small group of dairy cattle infected with a diverse population of S. aureus strains (n = 8 strains) (Luby and Middleton, 2004). Cow and mammary quarter cure rates were 43% and 50%, respectively, for extended pirlimycin therapy alone (n = 7 cows, 10 quarters) and 60% and 66%,respectively, for vaccination with extended pirlimycin therapy (n = 5 cows, 6 quarters) with no significant differences between groups (P > 0.633). However, the overall cure rate for S. aureus IMI, regardless of whether cows were vaccinated, were generally higher than previous studies which evaluated autogenous bacterins in combination with extended pirlimycin therapy (Sears and Belschner, 1999; Timms et al., 2000). Given our small sample size and the diversity of S. aureus strains identified in our initial study, we undertook the following study on a large commercial dairy with a high prevalence of S. aureus mastitis to further evaluate extended pirlimycin therapy with or without vaccination.