Efficacy of extended pirlimycin hydrochloride therapy for treatment of environmental Streptococcus spp and Staphylococcus aureus intramammary infections in lactating dairy cows.
Fifty-one chronically infected lactating dairy cows were used to evaluate the efficacy of extended pirlimycin therapy regimens for treatment of intramammary infections by environmental Streptococcus spp and Staphylococcus aureus. Cows (n = 47) with one or more infected mammary quarters were blocked by parity and randomly allocated to one of three groups for treatment with pirlimycin (50 mg/mammary quarter) as follows: one treatment per day for 2 days (n = 36 infected mammary quarters); one treatment per day for 5 days (n = 36 infected mammary quarters); and one treatment per day for 8 days (n = 20 infected mammary quarters). Four cows with nine infected mammary quarters were included as untreated controls. Milk samples from each mammary quarter were collected 7 days before treatment, immediately before treatment, and weekly for 4 weeks after the final treatment for microbiological evaluation. A bacteriologic cure was defined as a treated, infected quarter that was bacteriologically negative for the presence of previously identified bacteria at weekly intervals after treatment. Efficacy of pirlimycin therapy against intramammary infections caused by environmental Streptococcus spp and S. aureus was 44.4%, 61.1%, and 95.0% for the 2-, 5-, and 8-day treatment regimens, respectively. None of the infections in the untreated control quarters was cured. Significant differences in efficacy were detected between all pirlimycin groups and the untreated control group, between the 8- and 2-day treatment regimens, and between the 8-day and 5-day treatment regimens (P < or = .05). Results of this study indicate that extended pirlimycin therapy was effective in eliminating intramammary infections caused by environmental streptococci and S. aureus in lactating dairy cows.
Gillespie
Barbara E
BE
The University of Tennessee, Food Safety Center of Excellence, 2640 Morgan Circle, Knoxville, TN 37996, USA.
Moorehead
Hugh
H
Lunn
Phillip
P
Dowlen
Henry H
HH
Johnson
David L
DL
Lamar
Ken C
KC
Lewis
Mark J
MJ
Ivey
Susan J
SJ
Hallberg
John W
JW
Chester
S Ted
ST
Oliver
Stephen P
SP
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002417:Cattle; D002981:Clindamycin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D003612:Dairying; D004334:Drug Administration Schedule; D005260:Female; D007774:Lactation; D008414:Mastitis, Bovine / Q000188:drug therapy* / Q000382:microbiology; D008892:Milk / Q000382:microbiology; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013290:Streptococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D013291:Streptococcus / Q000302:isolation & purification; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D002981:Clindamycin; C034093:pirlimycin