Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America.
PLoS One. 2012;7(1):e30092. doi: 10.1371/journal.pone.0030092. Epub 2012 Jan 19.
In order to examine the prevalence of Staphylococcus aureus on retail pork, three hundred ninety-five pork samples were collected from a total of 36 stores in Iowa, Minnesota, and New Jersey. S. aureus was isolated from 256 samples (64.8%, 95% confidence interval [CI] 59.9%-69.5%). S. aureus was isolated from 67.3% (202/300) of conventional pork samples and from 56.8% (54/95) of alternative pork samples (labeled "raised without antibiotics" or "raised without antibiotic growth promotants"). Two hundred and thirty samples (58.2%, 95% CI 53.2%-63.1%) were found to carry methicillin-sensitive S. aureus (MSSA). MSSA was isolated from 61.0% (183/300) of conventional samples and from 49.5% (47/95) of alternative samples. Twenty-six pork samples (6.6%, 95% CI 4.3%-9.5%) carried methicillin-resistant S. aureus (MRSA). No statistically significant differences were observed for the prevalence of S. aureus in general, or MSSA or MRSA specifically, when comparing pork products from conventionally raised swine and swine raised without antibiotics, a finding that contrasts with a prior study from The Netherlands examining both conventional and "biologic" meat products. In our study spa types associated with "livestock-associated" ST398 (t034, t011) were found in 26.9% of the MRSA isolates, while 46.2% were spa types t002 and t008--common human types of MRSA that also have been found in live swine. The study represents the largest sampling of raw meat products for MRSA contamination to date in the U.S. MRSA prevalence on pork products was higher than in previous U.S.-conducted studies, although similar to that in Canadian studies.
为了检测零售猪肉中金黄色葡萄球菌的流行情况，从爱荷华州、明尼苏达州和新泽西州的 36 家商店共采集了 395 份猪肉样本。从 256 份样本（64.8%，95%置信区间[CI]59.9%-69.5%）中分离出金黄色葡萄球菌。从 67.3%（202/300）的常规猪肉样本和 56.8%（54/95）的替代猪肉样本（标有“无抗生素饲养”或“无抗生素生长促进剂饲养”）中分离出金黄色葡萄球菌。230 份样本（58.2%，95%CI53.2%-63.1%）携带甲氧西林敏感金黄色葡萄球菌（MSSA）。从 61.0%（183/300）的常规样本和 49.5%（47/95）的替代样本中分离出 MSSA。26 份猪肉样本（6.6%，95%CI4.3%-9.5%）携带耐甲氧西林金黄色葡萄球菌（MRSA）。从常规饲养的猪和无抗生素饲养的猪的猪肉产品中比较金黄色葡萄球菌的总体流行率、MSSA 或 MRSA 的流行率时，未观察到统计学上的显著差异，这与荷兰的一项先前研究结果形成对比，该研究同时检测了常规和“生物”肉类产品。在我们的研究中，与“牲畜相关”ST398（t034、t011）相关的 spa 型在 26.9%的 MRSA 分离株中被发现，而 46.2%的 spa 型为 t002 和 t008--常见的人类 MRSA 类型，也在活猪中被发现。该研究代表了迄今为止美国对生肉产品进行的最大规模的 MRSA 污染抽样。猪肉产品中 MRSA 的流行率高于美国之前进行的研究，但与加拿大的研究相似。
