鸡舍环境金黄色葡萄球菌气溶胶产生及其传播的REP-PCR鉴定

REP-PCR Identification of Airborne Staphylococcus aureus Isolated from Chicken Houses and Their Spreading around the Farms

采用ANDERSEN-6级空气微生物样品收集器和RCS离心式采样器在山东泰安4个鸡场舍内空气、舍外环境上风向10、50m和下风向10、50、100、200、400m不同距离处收集金黄色葡萄球菌，计算每个采样点的金黄色葡萄球菌浓度；与此同时，收集鸡的粪便，分离金黄色葡萄球菌。利用金黄色葡萄球菌DNA基因外重复一致回文序列聚合酶链式反应（Repetitive extragenic palindromic elements PCR，REP—PCR）鉴定技术，扩增不同测量点和粪便分离的金黄色葡萄球菌的DNA图谱。通过每个采样点的金黄色葡萄球菌的浓度变化以及金黄色葡萄球菌遗传相似性分析确认动物舍微生物气溶胶向舍外环境的传播。结果显示：4个鸡场舍内空气中金黄色葡萄球菌的浓度远远高于舍外上风和下风向的金黄色葡萄球菌浓度（P〈0．05或P〈0．01），但是舍外下风不同距离间的金黄色葡萄球菌浓度差异并不显著（P〉0．05）。REP-PCR结果表明，从鸡的粪便中分离的金黄色葡萄球菌与从舍内空气中分离的部分金黄色葡萄球菌（38．7％）相似性可达100％，从鸡场舍外下风方向分离到的多数金黄色葡萄球菌（55．9％）与舍内空气或粪便中分离的金黄色葡萄球菌相似性可达100％。可见，它们分别是由粪便中遗传基因完全相同的菌株繁殖而来。而从鸡舍上风分离到的金黄色葡萄球菌与舍内空气或粪便中分离的金黄色葡萄球菌相似性仅在60％～87％。结果显示，鸡粪便中的金黄色葡萄球菌能够形成气溶胶，进入气悬状态，不仅能在舍内传播，而且还能够借助舍内外气体交换，传播到舍外下风一定的距离。从而说明，来自动物体的金黄色葡萄球菌既能污染舍内空气，对本舍鸡群构成传染威胁，又能传播一定的距离，对周边社区环境空气造成生物污染。

In order to study the transmission of S. aureus in chicken houses to their ambient air, the air samples, including indoor, upwind （10, 50 m） and downwind air （10, 50, 100, 200, 400 m） of 4 chicken houses were collected using Andersen-6 stages sampler and RCS. The S. aureus concentration of every sampling site was calculated. Chicken feces samples were collected according to the standard method and S. aureus was isolated. S. aureus was used as an indicator in this study. The repetitive extragenic palindromic elements PCR （REP-PCR） method was applied to generate genomic amplification products of S. aureus isolated from the chicken feces and the air. By analyzing the different concentration and genetic similarity of S. aureus in every sampling site,the transmission of bioaerosol from chicken houses to their ambient can be identified. The results showed that the S. aureus indoor concentration in 4 chicken houses were higher than those of upwind and downwind sites（P〈0. 05 or P〈0. 01）, but there were no significantly differences of S. aureus concentration among every downwind site （P〉0.05）. The fingerprints and the phylogenetic tree indicated that a part of the S. aureus （38. 7%） isolated from indoor air had the same REP-PCR fingerprints with those isolates isolated from feces, the most of S. aureus isolated （55.9%） from downwind 10, 50, 100, 200 even 400 m had the same REP-PCR fingerprints with those isolated from indoor air or feces too, which indicated that some isolates isolated from downwind air and indoor air originated from the chicken feces. However, those isolated from upwind air had the low similarity coefficients （60%-87%） with those isolated from indoor air or feces. It was concluded that the isolates isolated from upwind air didn＇t come from the chicken feces or indoor air. In a word, the S. aureus in chicken feces can be aerosolized and transmitted into the indoor and outdoor air, especially the downwind air of the chicken houses with the air exchange. This study revealed the transmitting rule of airborne S. aureus bioaerosol to the ambience.