In vitro efficacy of iodine in the pre and post dipping against coagulase negative Staphylococcus isolated in milk of cows with subclinical mastitis

ABSTRACT: The efficiency of the disinfectants used in the milking management is fundamental to the success in the dairy activity, being a critical point to the control of mastitis. The objective was to evaluate the in vitro efficacy of iodine used in pre and post-dipping against coagulase negative Staphylococcus (CNS). Thus, 53 CNS isolates were studied for the action of the 1.0% disinfectant and their serial dilutions of 0.5%, 0.375% and 0.25%, in addition to two commercial presentations of iodine in concentrations of 0.5% and 0.25%. The rate of CNS inhibition achieved by iodine at 0.375%, 0.5% and 1.0% for 60 seconds, was 60.4%. In 30 seconds, iodine at 0.5% and 1.0% showed a microbial inhibition rate of 52.8% and 56.6%, respectively. The other protocols tested were less efficient. It is concluded that the greatest in vitro disinfectant activity for CNS was demonstrated by iodine at 0.375%, 0.5% and 1.0%, for 60 seconds. Microbial susceptibility tests should be carried out periodically, as well as health education practices and corrective training on the property, in order to ensure udder health and mastitis control.

摘要：挤奶管理中所用消毒剂的效能对乳品生产活动的成败至关重要，亦是乳腺炎防控的关键环节。本研究旨在评估用于挤奶前、后乳头药浴的碘制剂，对凝固酶阴性葡萄球菌（coagulase negative Staphylococcus，CNS）的体外抑菌效果。为此，我们针对53株CNS分离株，测试了1.0%浓度碘消毒剂及其系列稀释液（0.5%、0.375%、0.25%）的抑菌效果，同时还纳入了两种市售的0.5%与0.25%浓度碘制剂进行测试。当作用时长为60秒时，0.375%、0.5%及1.0%浓度的碘制剂对CNS的抑菌率可达60.4%；当作用时长为30秒时，0.5%和1.0%浓度的碘制剂抑菌率分别为52.8%与56.6%，其余受试方案的抑菌效果均较差。研究结论表明，作用时长60秒的0.375%、0.5%及1.0%浓度碘制剂，对CNS展现出最优的体外抑菌活性。为保障奶牛乳房健康、有效防控乳腺炎，应定期开展药敏试验，并在牧场开展健康宣教与操作规范矫正培训。