Survival of Host-Associated Bacteroidales Cells and Their Relationship with Enterococcus spp., Campylobacter jejuni, Salmonella enterica Serovar Typhimurium, and Adenovirus in Freshwater Microcosms as Measured by Propidium Monoazide-Quantitative PCR
Survival of Host-Associated Bacteroidales Cells and Their Relationship with Enterococcus spp., Campylobacter jejuni, Salmonella enterica Serovar Typhimurium, and Adenovirus in Freshwater Microcosms as Measured by Propidium Monoazide-Quantitative PCR
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DOI：
10.1128/aem.05157-11
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发表时间：
2012-02-01
影响因子：
4.4
通讯作者：
Wuertz, Stefan
中科院分区：
文献类型：
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作者：
Bae, Sungwoo;Wuertz, Stefan
理想的宿主相关遗传粪便标记将能够预测特定病原体的存在。将含有混合粪便和病原体空肠弯曲杆菌、肠道沙门氏菌血清型鼠伤寒沙门氏菌和腺病毒接种物的流通淡水微宇宙置于环境温度下，在存在和不存在日间阳光的情况下。总肠球菌DNA增加在早期（23小时）在阳光照射下，即使可培养的肠球菌和DNA在完整的细胞，作为测量的单叠氮丙啶（PMA），在整个期间的一级动力学下降。我们发现，在阳光暴露和黑暗条件下，宿主相关拟杆菌目细胞的衰变存在显著差异（P值< 0.05），而宿主相关拟杆菌目DNA的持久性相当。腺病毒的2-log减少时间为72小时的阳光照射和99小时的黑暗条件下具有相似的衰减速率常数（P值= 0.13）。粪便类杆菌细胞和弯曲杆菌细胞暴露于阳光下的持久性相似，宿主相关的类杆菌DNA和水传病原体DNA以相当的速率降解（P值> 0.05）。总体而言，有和没有PMA处理的定量PCR（qPCR）循环阈值（C-T）值的比值指示了自接种（i）基于宿主相关拟杆菌目的不同动物来源的粪便材料和（ii）细菌病原体的纯培养物以来所经过的时间。PMA-qPCR和qPCR的使用可能会产生更真实的信息，最近的粪便污染源，并导致改善预测的水传播病原体和健康风险评估。
The ideal host-associated genetic fecal marker would be capable of predicting the presence of specific pathogens of concern. Flowthrough freshwater microcosms containing mixed feces and inocula of the pathogens Campylobacter jejuni, Salmonella enterica serovar Typhimurium, and adenovirus were placed at ambient temperature in the presence and absence of diurnal sunlight. The total Entero coccus DNA increased during the early periods (23 h) under sunlight exposure, even though cultivable Enterococcus and DNA in intact cells, as measured by propidium monoazide (PMA), decreased with first-order kinetics during the entire period. We found a significant difference in the decay of host-associated Bacteroidales cells between sunlight exposure and dark conditions (P value < 0.05), whereas the persistence of host-associated Bacteroidales DNA was comparable. The 2-log reduction times of adenovirus were 72 h for sunlight exposure and 99 h for dark conditions with similar decay rate constants (P value = 0.13). The persistences of fecal Bacteroidales cells and Campylobacter cells exposed to sunlight were similar, and host-associated Bacteroidales DNA and waterborne pathogen DNA were degraded at comparable rates (P values > 0.05). Overall, the ratio of quantitative PCR (qPCR) cycle threshold (C-T) values with and without PMA treatment was indicative of the time elapsed since inoculation of the microcosm with (i) fecal material from different animal sources based on host-associated Bacteroidales and (ii) pure cultures of bacterial pathogens. The use of both PMA-qPCR and qPCR may yield more realistic information about recent sources of fecal contamination and result in improved prediction of waterborne pathogens and assessment of health risk.