Persistence of biofilm-associated Escherichia coli and Pseudomonas aeruginosa in groundwater and treated effluent in a laboratory model system
Persistence of biofilm-associated Escherichia coli and Pseudomonas aeruginosa in groundwater and treated effluent in a laboratory model system
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DOI：
10.1099/mic.0.25938-0
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发表时间：
2003-01-01
期刊：
影响因子：
2.8
通讯作者：
Mee, BJ
中科院分区：
文献类型：
--
作者：
Banning, N;Toze, S;Mee, BJ
这项研究基于这样的假设：地下水来源的生物膜可能为大肠菌群或病原菌提供储存库，正如在饮用水分配系统中观察到的那样。人们发现，用绿色荧光蛋白标记的大肠杆菌能够在实验室规模的反应器中与本地地下水微生物相关的混合群体生物膜的所有层中定殖。在连续流动状态下，与生物膜相关的大肠杆菌从反应器烧瓶中去除的速度比浮游大肠杆菌慢。在地下水流过期间，与没有盖玻片的对照烧瓶相比，在含有盖玻片以增强生物膜发育的烧瓶中，浮游大肠杆菌的去除速度较慢。相反，在处理后的流出物流过期间，与没有盖玻片的烧瓶相比，带盖玻片的烧瓶中浮游大肠杆菌的去除速度更快。在带有流出液流过的盖玻片烧瓶中，去除附着的大肠杆菌也是最快的。这表明，由于营养物质的竞争加剧或本地微生物种群的拮抗作用增强，可用营养物质的增加可能会降低大肠杆菌的生存潜力。在相同条件下，发现 GFP 标记的铜绿假单胞菌在生物膜中的存留时间比大肠杆菌长，尤其是当暴露于处理后的废水流过时。然而，废水中铜绿假单胞菌的长期存在不能归因于与生物膜的关联。这项研究表明，在某些条件下，混合群体生物膜的存在可能会限制引入地下水的肠道细菌病原体的生存潜力。
This study was based on the hypothesis that groundwater-derived biofilms may provide a reservoir for coliform or pathogenic bacteria as has been observed in drinking water distribution systems. Escherichia coli, labelled with green fluorescent protein, was found to colonize all layers of mixed-population biofilms developed in association with indigenous groundwater micro-organisms in a laboratory-scale reactor. Biofilm-associated E coli was removed at a slower rate from the reactor flasks than planktonic E coli under a continuous flow regime. During flow-through of groundwater, planktonic E coli removal was slower in flasks containing coverslips for enhanced biofilm development compared to a control flask without coverslips. Conversely, during flow-through of treated effluent, planktonic E coli removal was faster in flasks with coverslips compared to without. Removal of attached E coli was also fastest in the coverslip-containing flasks with effluent flow-through. This suggests that an increase in available nutrients may reduce E coli survival potential due to either enhanced competition for nutrients or enhanced antagonism by the indigenous microbial population. Under identical conditions, GFP-labelled Pseudomonas aeruginosa was found to persist in the biofilms for longer than E coli, most notably when exposed to flow-through of treated effluent. However, prolonged persistence of P. aeruginosa in the effluent could not be attributed to an association with the biofilms. This study has shown that under certain conditions the presence of mixed-population biofilms may limit the survival potential of enteric bacterial pathogens introduced into groundwater.