The increase of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) causes a threat to human health. LA-MRSA can be transmitted from animals to animal caretakers, which may further spread MRSA to communities and health care facilities. The objective of this work was to study the efficacy of phage treatment in the eradication of LA-MRSA from healthy carrier pigs. A total of 19 MRSA -positive weanling pigs were assigned to a test (n = 10) and a control group (n = 9). A phage cocktail containing three Staphylococcus phages, or a control buffer was administered to the nares and skin of the pigs three times every two days, after which the phage and MRSA levels in nasal and skin swab samples were monitored for a three-week period. The sensitivity of the strains isolated during the follow-up period to the phage cocktail and each phage individually was analyzed and the pig sera were tested for antibodies against the phages used in the cocktail. The phage treatment did not cause any side effects to the pigs. Phages were found in the skin and nasal samples on the days following the phage applications, but there was no reduction in the MRSA levels in the sampled animals. Phage-resistant strains or phage-specific antibodies were not detected during the experiment. The MRSA load in these healthy carrier animals was only 10–100 CFU/swab or nasal sample, which was likely below the replication threshold of phages. The effectiveness of phage treatment to eradicate MRSA from the pigs could thus not be (reliably) determined.

中文翻译：

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从健康载体猪中根除 LA-MRSA 的噬菌体治疗试验

与家畜相关的耐甲氧西林金黄色葡萄球菌(LA-MRSA) 的增加对人类健康构成威胁。LA-MRSA 可以从动物传播给动物看护人，这可能会进一步将 MRSA 传播到社区和医疗机构。这项工作的目的是研究噬菌体治疗从健康携带猪身上根除 LA-MRSA 的功效。总共 19 头 MRSA 阳性断奶猪被分配到测试组（n = 10）和对照组（n = 9）。含有三种葡萄球菌的噬菌体混合物每两天向猪的鼻孔和皮肤施用噬菌体或对照缓冲液 3 次，然后监测鼻腔和皮肤拭子样本中的噬菌体和 MRSA 水平，为期三周。在随访期间分离的菌株对噬菌体混合物的敏感性以及单独分析每个噬菌体，并测试猪血清中针对混合物中使用的噬菌体的抗体。噬菌体处理不会对猪造成任何副作用。在噬菌体应用后的几天里，在皮肤和鼻腔样本中发现了噬菌体，但采样动物的 MRSA 水平没有降低。实验期间未检测到噬菌体抗性菌株或噬菌体特异性抗体。这些健康携带动物的 MRSA 载量仅为 10-100 CFU/拭子或鼻腔样本，这可能低于噬菌体的复制阈值。因此不能（可靠地）确定噬菌体治疗从猪中根除 MRSA 的有效性。