Institute of Soil and Water Resources and Environmental Science, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, China.
Appl Environ Microbiol. 2014 Jan;80(1):70-6. doi: 10.1128/AEM.03046-13. Epub 2013 Oct 11.
The survival of Escherichia coli O157:H7 in soils can contaminate vegetables, fruits, drinking water, etc. However, data on the impact of E. coli O157:H7 on soil microbial communities are limited. In this study, we monitored the changes in the indigenous microbial community by using the phospholipid fatty acid (PLFA) method to investigate the interaction of the soil microbial community with E. coli O157:H7 in soils. Simple correlation analysis showed that the survival of E. coli O157:H7 in the test soils was negatively correlated with the ratio of Gram-negative (G(-)) to Gram-positive (G(+)) bacterial PLFAs (G(-)/G(+) ratio). In particular, levels of 14 PLFAs were negatively correlated with the survival time of E. coli O157:H7. The contents of actinomycetous and fungal PLFAs in the test soils declined significantly (P, <0.05) after 25 days of incubation with E. coli O157:H7. The G(-)/G(+) ratio declined slightly, while the ratio of bacterial to fungal PLFAs (B/F ratio) and the ratio of normal saturated PLFAs to monounsaturated PLFAs (S/M ratio) increased, after E. coli O157:H7 inoculation. Principal component analysis results further indicated that invasion by E. coli O157:H7 had some effects on the soil microbial community. Our data revealed that the toxicity of E. coli O157:H7 presents not only in its pathogenicity but also in its effect on soil microecology. Hence, close attention should be paid to the survival of E. coli O157:H7 and its potential for contaminating soils.
大肠杆菌 O157:H7 在土壤中的存活可能会污染蔬菜、水果、饮用水等。然而，有关大肠杆菌 O157:H7 对土壤微生物群落影响的数据有限。在本研究中，我们使用磷脂脂肪酸（PLFA）方法监测土著微生物群落的变化，以研究土壤微生物群落与土壤中大肠杆菌 O157:H7 的相互作用。简单相关分析表明，试验土壤中大肠杆菌 O157:H7 的存活与革兰氏阴性（G(-)）与革兰氏阳性（G(+)）细菌 PLFA 的比例（G(-)/G(+) 比值）呈负相关。特别是，有 14 种 PLFA 与大肠杆菌 O157:H7 的存活时间呈负相关。在接种大肠杆菌 O157:H7 25 天后，试验土壤中放线菌和真菌 PLFA 的含量显著下降（P，<0.05）。G(-)/G(+) 比值略有下降，而细菌与真菌 PLFA 的比值（B/F 比值）和正常饱和 PLFA 与单不饱和 PLFA 的比值（S/M 比值）增加。主成分分析结果进一步表明，大肠杆菌 O157:H7 的入侵对土壤微生物群落有一定的影响。我们的数据表明，大肠杆菌 O157:H7 的毒性不仅表现在其致病性，还表现在其对土壤微生态的影响上。因此，应密切关注大肠杆菌 O157:H7 的存活及其对土壤的潜在污染。
