Mollenkopf Dixie F, Mathys Dimitria A, Feicht Sydnee M, Stull Jason W, Bowman Andrew S, Daniels Joshua B, Wittum Thomas E
1 Department of Veterinary Preventive Medicine, The Ohio State University College of Veterinary Medicine , Columbus, Ohio.
2 Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine , Columbus, Ohio.
Foodborne Pathog Dis. 2018 Jun;15(6):372-376. doi: 10.1089/fpd.2017.2355. Epub 2018 Mar 15.
Carbapenemase-producing Enterobacteriaceae (CPE) threaten both agriculture and public health. While carbapenems are restricted in food-producing animals, other β-lactams, such as ceftiofur, are frequently applied in livestock. While the relationship is not fully elucidated, ceftiofur use may provide selective pressure that promotes carbapenem resistance. Recently reported in U.S. livestock, plasmid-mediated CPE are also present in livestock in Europe and Asia. We previously reported the rare carbapenemase gene, bla, in the environment of a large farrow-to-finish swine operation. To better understand CPE in this swine production system, in 2016 we followed a cohort of 350+ pigs over 5 months from late sow gestation to the final finishing phase. We screened both environmental and fecal samples for CPE using our selective enrichment protocol, with resulting phenotypic CPE isolates further characterized. Of 55 environmental and 109 sow fecal samples collected from a farrowing barn on our initial visit, 35 (64%) environmental and 15 (14%) sow fecal samples yielded isolates of multiple Enterobacteriaceae species carrying the metallo-β-lactamase gene bla on an IncQ plasmid. The frequency of IMP-64-positive environmental (n = 32), sow fecal (n = 30), and piglet fecal swab (n = 120) samples was highest for all groups when the market pig cohort was between 1 and 10 days, with observed prevalence of 97%, 28%, and 18%, respectively. After weaning, bla was detected in a single environmental sample from a nursery pen, with no CPE recovered in the finishing phase. Used in U.S. swine production to treat and control disease, ceftiofur is administered to piglets on this farm at birth, with males receiving a second dose at castration (≈day 7). Once introduced into animal agriculture, the common use of ceftiofur may provide the selection pressure required for CPE dissemination throughout large, intensively managed food animal populations housed in animal-dense environments.
产碳青霉烯酶肠杆菌科细菌（CPE）对农业和公共卫生都构成威胁。虽然碳青霉烯类药物在食用动物中受到限制，但其他β-内酰胺类药物，如头孢噻呋，却经常用于家畜。虽然这种关系尚未完全阐明，但使用头孢噻呋可能会提供选择压力，促进对碳青霉烯类药物的耐药性。美国家畜中最近报告了质粒介导的CPE，欧洲和亚洲的家畜中也存在这种情况。我们之前在一个大型的从产仔到育肥的养猪场环境中报告了罕见的碳青霉烯酶基因bla。为了更好地了解这个养猪生产系统中的CPE，2016年我们跟踪了350多头猪，历时5个月，从母猪妊娠后期到最终育肥阶段。我们使用选择性富集方案对环境和粪便样本进行CPE筛查，并对产生表型的CPE分离株进行进一步鉴定。在我们首次访问时从一个产仔栏收集的55份环境样本和109份母猪粪便样本中，3（64%）份环境样本和15（14%）份母猪粪便样本产生了携带金属β-内酰胺酶基因bla的多种肠杆菌科细菌分离株，该基因位于IncQ质粒上。当上市猪群在1至10日龄时，IMP-64阳性的环境样本（n = 32）、母猪粪便样本（n = 30）和仔猪粪便拭子样本（n = 120）的频率在所有组中最高，观察到的患病率分别为97%、28%和18%。断奶后，在一个保育栏的单个环境样本中检测到bla，育肥阶段未回收CPE。头孢噻呋在美国养猪生产中用于治疗和控制疾病，该农场的仔猪在出生时就接受头孢噻呋治疗，雄性仔猪在阉割时（约第7天）接受第二剂。一旦引入动物养殖业，头孢噻呋的普遍使用可能会提供CPE在密集管理的大型食用动物群体中传播所需的选择压力，这些动物群体饲养在动物密集的环境中。
