Biofilm Formation and Sanitizer Resistance of Escherichia coli O157:H7 Strains Isolated from "High Event Period" Meat Contamination
Biofilm Formation and Sanitizer Resistance of Escherichia coli O157:H7 Strains Isolated from "High Event Period" Meat Contamination
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DOI：
10.4315/0362-028x.jfp-14-253
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发表时间：
2014-11-01
影响因子：
2
通讯作者：
Arthur, Terrance M.
中科院分区：
文献类型：
--
作者：
Wang, Rong;Kalchayanand, Norasak;Arthur, Terrance M.
在肉类行业，“高事件期”(HEP) 被定义为商业肉类工厂遭受大肠杆菌 O157:H7 污染率高于平常水平的时间段。遗传分析表明，在 REP 内，大多数大肠杆菌 O157:117 菌株属于单一优势菌株类型。这与当前的牛肉污染模型不一致，该模型指出，当动物皮上传入的病原体负载（由不同类型的大肠杆菌 O157:117 组成）超过干预能力时，就会发生污染。因此，我们假设 IMP 污染可能是由于某些植物内定植的大肠杆菌 O157:H7 菌株造成的，这些菌株能够通过生物膜形成更好地在消毒过程中生存。为了检验我们的假设，对从 HEP 牛肉污染事件中分离出的 45 株大肠杆菌 O157:H7 菌株和一组具有不同遗传背景的 47 株大肠杆菌 O157:H7 菌株进行了生物膜形成和消毒剂耐药性的比较。在 96 孔聚苯乙烯板上测试生物膜形成 1 至 6 天。使用常见消毒剂（包括氯化季铵、氯和亚氯酸钠）对两个菌株集合进行消毒后的生物膜细胞存活率和恢复生长进行比较。在 22 至 25 摄氏度孵育 1 或 2 天后，两个菌株集合之间没有观察到“早期”生物膜的差异。然而，在孵育 4 至 6 天后，REP 菌株表现出显着更高的“成熟”生物膜形成能力。 REP 菌株的生物膜还表现出明显更强的消毒耐受性。这些数据表明，生物膜的形成和消毒阻力可能在大肠杆菌 O157:H7 污染 REP 牛肉的过程中发挥作用，这凸显了对商业肉类工厂中的食品接触表面和食品加工设备进行适当和彻底消毒的重要性。
In the meat industry, a "high event period" (HEP) is defined as a time period during which commercial meat plants experience a higher than usual rate of Escherichia coli O157:H7 contamination. Genetic analysis indicated that within a REP, most of the E. coli O157:117 strains belong to a singular dominant strain type. This was in disagreement with the current beef contamination model stating that contamination occurs when incoming pathogen load on animal hides, which consists of diverse strain types of E. coli O157:117, exceeds the intervention capacity. Thus, we hypothesize that the IMP contamination may be due to certain in-plant colonized E. coli O157:H7 strains that are better able to survive sanitization through biofilm formation. To test our hypothesis, a collection of 45 E. coli O157:H7 strains isolated from HEP beef contamination incidents and a panel of 47 E. coli O157:H7 strains of diverse genetic backgrounds were compared for biofilm formation and sanitizer resistance. Biofilm formation was tested on 96-well polystyrene plates for 1 to 6 days. Biofilm cell survival and recovery growth after sanitization were compared between the two strain collections using common sanitizers, including quaternary ammonium chloride, chlorine, and sodium chlorite. No difference in "early stage" biofilms was observed between the two strain collections after incubation at 22 to 25 degrees C for 1 or 2 days. However, the REP strains demonstrated significantly higher potency of "mature" biofilm formation after incubation for 4 to 6 days. Biofilms of the REP strains also exhibited significantly stronger resistance to sanitization. These data suggest that biofilm formation and sanitization resistance could have a role in REP beef contamination by E. coli O157:H7, which highlights the importance of proper and complete sanitization of food contact surfaces and food processing equipment in commercial meat plants.