Projahn Michaela, Daehre Katrin, Roesler Uwe, Friese Anika
Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, Berlin, Germany
Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, Berlin, Germany.
Appl Environ Microbiol. 2016 Dec 15;83(1). doi: 10.1128/AEM.02364-16. Print 2017 Jan 1.
Antimicrobial resistance through extended-spectrum beta-lactamases (ESBLs) and transferable (plasmid-encoded) cephamycinases (pAmpCs) represents an increasing problem in human and veterinary medicine. The presence of ESBL-/pAmpC-producing commensal enterobacteria in farm animals, such as broiler chickens, is considered one possible source of food contamination and could therefore also be relevant for human colonization. Studies on transmission routes along the broiler production chain showed that 1-day-old hatchlings are already affected. In this study, ESBL-/pAmpC-positive broiler parent flocks and their corresponding eggs, as well as various environmental and air samples from the hatchery, were analyzed. The eggs were investigated concerning ESBL-/pAmpC-producing enterobacteria on the outer eggshell surface (before/after disinfection), the inner eggshell surface, and the egg content. Isolates were analyzed concerning their species, their phylogroup in the case of Escherichia coli strains, the respective resistance genes, and the phenotypical antibiotic resistance. Of the tested eggs, 0.9% (n = 560) were contaminated on their outer shell surface. Further analyses using pulsed-field gel electrophoresis showed a relationship of these strains to those isolated from the corresponding parent flocks, which demonstrates a pseudo-vertical transfer of ESBL-/pAmpC-producing enterobacteria into the hatchery. Resistant enterobacteria were also found in environmental samples from the hatchery, such as dust or surfaces which could pose as a possible contamination source for the hatchlings. All 1-day-old chicks tested negative directly after hatching. The results show a possible entry of ESBL-/pAmpC-producing enterobacteria from the parent flocks into the hatchery; however, the impact of the hatchery on colonization of the hatchlings seems to be low.
ESBL-/pAmpC-producing enterobacteria occur frequently in broiler-fattening farms. Recent studies investigated the prevalence and possible transmission route of these bacteria in the broiler production chain. It seemed very likely that the hatcheries play an important role in transmission and/or contamination events. There are only few data on transmission investigations from a grandparent or parent flock to their offspring. However, reliable data on direct or indirect vertical transmission events in the hatchery are not available. Therefore, we conducted our study and intensively investigated the broiler hatching eggs from ESBL-/pAmpC-positive broiler parent flocks as well as the hatchlings and the environment of the hatchery.
通过超广谱β-内酰胺酶（ESBLs）和可转移（质粒编码）头孢菌素酶（pAmpCs）产生的抗菌药物耐药性在人类医学和兽医学中是一个日益严重的问题。农场动物，如肉鸡中产生ESBLs/pAmpCs的共生肠杆菌的存在被认为是食物污染的一个可能来源，因此也可能与人类定植有关。对肉鸡生产链中传播途径的研究表明，1日龄雏鸡已经受到影响。在本研究中，分析了ESBLs/pAmpCs阳性的肉鸡亲本种群及其相应的蛋，以及孵化场的各种环境和空气样本。对鸡蛋进行了调查，检测了蛋壳外表面（消毒前后）、蛋壳内表面和蛋内容物中产生ESBLs/pAmpCs的肠杆菌。对分离株进行了分析，确定了它们的种类、大肠杆菌菌株的系统发育群、各自的耐药基因以及表型抗生素耐药性。在检测的鸡蛋中，0.9%（n = 560）的蛋壳外表面受到污染。使用脉冲场凝胶电泳进行的进一步分析表明，这些菌株与从相应亲本种群中分离出的菌株有关，这表明产生ESBLs/pAmpCs的肠杆菌向孵化场进行了假垂直传播。在孵化场的环境样本中也发现了耐药肠杆菌，如灰尘或表面，这些可能是雏鸡的潜在污染源。所有1日龄雏鸡在孵化后直接检测均为阴性。结果表明，产生ESBLs/pAmpCs的肠杆菌可能从亲本种群进入孵化场；然而，孵化场对雏鸡定植的影响似乎较低。
产生ESBLs/pAmpCs的肠杆菌在肉鸡育肥场中频繁出现。最近的研究调查了这些细菌在肉鸡生产链中的流行情况和可能的传播途径。孵化场似乎很可能在传播和/或污染事件中起重要作用。关于从祖代或亲本种群到其后代的传播调查的数据很少。然而，关于孵化场中直接或间接垂直传播事件的可靠数据并不存在。因此，我们开展了本研究，并深入调查了来自ESBLs/pAmpCs阳性肉鸡亲本种群的肉鸡孵化蛋以及雏鸡和孵化场环境。
