TY - JOUR
T1 - Effect of lactation therapy on Staphylococcus aureus transmission dynamics in two commercial dairy herds
AU - Barlow, John W.
AU - Zadoks, Ruth N.
AU - Schukken, Ynte H.
N1 - Funding Information:
The authors acknowledge the support of field and laboratory staff at Quality Milk Production Services, Cornell University, including the technical contributions of Brad Rauch, Cameron Nightingale, and Sharinne Sukhnanand. The contributions of participating farm owners and farm staff are appreciated. The general support of Dr. John Bramley is gratefully acknowledged. This project was supported in part by funding from Pfizer Animal Health, USDA Cooperative State Research, Education, and Extension Service (CSREES), National Research Initiative award # 2005-35204-15651, USDA-CSREES Vermont Agricultural Experiment Station Animal Health and Disease award # VT-AH01011, and the Multi-State Mastitis Research Project USDA CSREES NE-1028 (formerly NE-1009).
Funding Information:
YHS and Cornell University received unrestricted funding from Pfizer Animal Health to conduct a portion of this research. JWB, RNZ and YHS have received travel reimbursements from Pfizer Animal Health for presentations they have given on mastitis control in dairy herds.
PY - 2013/2/11
Y1 - 2013/2/11
N2 - Background: Treatment of subclinical mastitis during lactation can have both direct (individual animal level) and indirect (population level) effects. With a few exceptions, prior research has focused on evaluating the direct effects of mastitis treatment, and to date no controlled field trials have been conducted to test whether beneficial indirect effects of lactation treatment strategies targeting subclinical mastitis can be demonstrated on commercial dairy farms. Furthermore, there is limited knowledge on the impact of such interventions on the population dynamics of specific bacterial strains. The purpose of this study was to test the hypothesis that lactation therapy targeting S. aureus subclinical intramammary infection reduces transmission of S. aureus strains within dairy herds. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to determine strain specific infection dynamics in treated and control groups in a split herd trial conducted on 2 commercial dairy farms.Results: The direct effect of 8 days intramammary lactation therapy with pirlimycin hydrochloride was demonstrated by an increased proportion of cure and a reduction in duration of infection in quarters receiving treatment compared to untreated controls. The indirect effect of lactation therapy was demonstrated by reduction of new S. aureus intramammary infections (IMI) caused by the dominant strain type in both herds. Strain typing of representative isolates taken over the duration of all IMI, including pre- and post-treatment isolates, provided more precise estimates of new infection, cure, and re-infection rates. New S. aureus infections in recovered susceptible quarters and the emergence of a new strain type in one herd influenced incidence measures.Conclusion: In addition to demonstrating positive direct effects of lactation therapy, this study provides evidence that treatment of subclinical S. aureus mastitis during lactation can have indirect effects including preventing new IMI and reducing incidence of clinical mastitis within dairy herds. Strain specific transmission parameter estimates for S. aureus MLST clonal complexes 5, 97 and 705 in 2 commercial dairy herds are also reported.
AB - Background: Treatment of subclinical mastitis during lactation can have both direct (individual animal level) and indirect (population level) effects. With a few exceptions, prior research has focused on evaluating the direct effects of mastitis treatment, and to date no controlled field trials have been conducted to test whether beneficial indirect effects of lactation treatment strategies targeting subclinical mastitis can be demonstrated on commercial dairy farms. Furthermore, there is limited knowledge on the impact of such interventions on the population dynamics of specific bacterial strains. The purpose of this study was to test the hypothesis that lactation therapy targeting S. aureus subclinical intramammary infection reduces transmission of S. aureus strains within dairy herds. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to determine strain specific infection dynamics in treated and control groups in a split herd trial conducted on 2 commercial dairy farms.Results: The direct effect of 8 days intramammary lactation therapy with pirlimycin hydrochloride was demonstrated by an increased proportion of cure and a reduction in duration of infection in quarters receiving treatment compared to untreated controls. The indirect effect of lactation therapy was demonstrated by reduction of new S. aureus intramammary infections (IMI) caused by the dominant strain type in both herds. Strain typing of representative isolates taken over the duration of all IMI, including pre- and post-treatment isolates, provided more precise estimates of new infection, cure, and re-infection rates. New S. aureus infections in recovered susceptible quarters and the emergence of a new strain type in one herd influenced incidence measures.Conclusion: In addition to demonstrating positive direct effects of lactation therapy, this study provides evidence that treatment of subclinical S. aureus mastitis during lactation can have indirect effects including preventing new IMI and reducing incidence of clinical mastitis within dairy herds. Strain specific transmission parameter estimates for S. aureus MLST clonal complexes 5, 97 and 705 in 2 commercial dairy herds are also reported.
KW - Lactation therapy
KW - Mastitis
KW - Molecular diagnostics
KW - Staphylococcus aureus
UR - http://www.scopus.com/inward/record.url?scp=84873514442&partnerID=8YFLogxK
U2 - 10.1186/1746-6148-9-28
DO - 10.1186/1746-6148-9-28
M3 - Article
C2 - 23398676
AN - SCOPUS:84873514442
SN - 1746-6148
VL - 9
JO - BMC Veterinary Research
JF - BMC Veterinary Research
M1 - 28
ER -