Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, 1870, Denmark.
Vet Microbiol. 2011 Sep 28;152(3-4):420-3. doi: 10.1016/j.vetmic.2011.05.025. Epub 2011 May 20.
An in vivo experiment was conducted to evaluate the effects of tetracycline and zinc on pig colonization and transmission of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398. Eight piglets naturally colonized with MRSA ST398 and 8 MRSA-negative piglets of the same age and breed were assigned to three groups treated with tetracycline and zinc (Group 1), zinc (Group 2) or tetracycline alone (Group 3) and one non-treated group (Group 4), each containing two MRSA-positive and two MRSA-negative animals. Two additional non-treated control groups composed of only MRSA-positive (Group 5) and MRSA-negative (Group 6) animals were used to check for stability of MRSA carriage status. Nasal swabs and environmental wipes were collected on Days 0, 7, 14, and 21, and the occurrence of MRSA in each sample was quantified by bacteriological counts on Brilliance™ MRSA agar. Significantly higher nasal MRSA counts were observed in the zinc-treated (p=0.015) and tetracycline-treated (p=0.008) animals compared to the non-treated animals. Environmental MRSA counts appeared to increase over time in Groups 1 and 2 but such an increase was not statistically significant. MRSA-negative animals housed with MRSA-positive animals became positive in all groups, whereas the carriage status of the animals in Groups 5 and 6 did not change. This study demonstrates that feed supplemented with tetracycline or zinc increases the numbers of MRSA ST398 in the nasal cavity of pigs. Transmission of MRSA from positive to negative animals housed within the same pen was not influenced by exposure to these agents.
进行了一项体内实验，以评估四环素和锌对猪定植和传播耐甲氧西林金黄色葡萄球菌（MRSA）序列型（ST）398 的影响。8 头自然定植 MRSA ST398 的仔猪和 8 头同年龄和品种的 MRSA 阴性仔猪被分配到三个用四环素和锌（第 1 组）、锌（第 2 组）或单独用四环素（第 3 组）处理的组和一个未处理的组（第 4 组），每组包含 2 头 MRSA 阳性和 2 头 MRSA 阴性动物。另外两个仅由 MRSA 阳性（第 5 组）和 MRSA 阴性（第 6 组）动物组成的非处理对照组用于检查 MRSA 定植状态的稳定性。在第 0、7、14 和 21 天采集鼻拭子和环境拭子，并通过在 Brilliance™MRSA 琼脂上进行细菌计数来定量每个样品中的 MRSA 存在。与未处理的动物相比，锌处理（p=0.015）和四环素处理（p=0.008）的动物的鼻腔 MRSA 计数明显更高。在第 1 组和第 2 组中，环境 MRSA 计数似乎随着时间的推移而增加，但这种增加没有统计学意义。与 MRSA 阳性动物一起饲养的 MRSA 阴性动物在所有组中均变为阳性，而第 5 组和第 6 组动物的携带状态没有变化。本研究表明，饲料中添加四环素或锌会增加猪鼻腔中 MRSA ST398 的数量。在同一围栏中暴露于这些药物不会影响 MRSA 从阳性动物向阴性动物的传播。
