Nayak Bina, Weidhaas Jennifer, Harwood Valerie J
Department of Integrative Biology, University of South Florida, Tampa, Florida, USA.
Civil and Environmental Engineering, West Virginia University, Morgantown, West Virginia, USA.
Appl Environ Microbiol. 2015 Jul;81(14):4616-25. doi: 10.1128/AEM.00444-15. Epub 2015 May 1.
Disposal of fecally contaminated poultry litter by land application can deliver pathogens and fecal indicator bacteria (FIB) into receiving waters via runoff. While water quality is regulated by FIB enumeration, FIB testing provides inadequate information about contamination source and health risk. This microbial source tracking (MST) study compared the persistence of the Brevibacterium sp. strain LA35 16S rRNA gene (marker) for poultry litter with that of pathogens and FIB under outdoor, environmentally relevant conditions in freshwater, marine water, and sediments over 7 days. Salmonella enterica, Campylobacter jejuni, Campylobacter coli, Bacteroidales, and LA35 were enumerated by quantitative PCR (qPCR), and Enterococcus spp. and E. coli were quantified by culture and qPCR. Unlike the other bacteria, C. jejuni was not detectable after 48 h. Bacterial levels in the water column consistently declined over time and were highly correlated among species. Survival in sediments ranged from a slow decrease over time to growth, particularly in marine microcosms and for Bacteroidales. S. enterica also grew in marine sediments. Linear decay rates in water (k) ranged from -0.17 day(-1) for LA35 to -3.12 day(-1) for C. coli. LA35 levels correlated well with those of other bacteria in the water column but not in sediments. These observations suggest that, particularly in the water column, the fate of LA35 in aquatic environments is similar to that of FIB, C. coli, and Salmonella, supporting the hypothesis that the LA35 marker gene can be a useful tool for evaluating the impact of poultry litter on water quality and human health risk.
通过土地施用处理受粪便污染的家禽粪便可能会使病原体和粪便指示菌（FIB）通过径流进入受纳水体。虽然水质是通过FIB计数来调节的，但FIB检测提供的关于污染源和健康风险的信息不足。这项微生物源追踪（MST）研究比较了在室外与环境相关的条件下，淡水、海水和沉积物中，家禽粪便的短杆菌属LA35菌株16S rRNA基因（标记物）与病原体和FIB在7天内的持久性。通过定量PCR（qPCR）对肠炎沙门氏菌、空肠弯曲菌、结肠弯曲菌、拟杆菌目和LA35进行计数，通过培养和qPCR对肠球菌属和大肠杆菌进行定量。与其他细菌不同，48小时后未检测到空肠弯曲菌。水柱中的细菌水平随时间持续下降，且物种间高度相关。在沉积物中的存活率从随时间缓慢下降到增长不等，特别是在海洋微宇宙和拟杆菌目中。肠炎沙门氏菌也在海洋沉积物中生长。水中的线性衰减率（k）范围从LA35的-0.17天⁻¹到结肠弯曲菌的-3.12天⁻¹。LA35水平与水柱中其他细菌的水平相关性良好，但与沉积物中的情况不同。这些观察结果表明，特别是在水柱中，LA35在水生环境中的命运与FIB、结肠弯曲菌和沙门氏菌相似，支持了LA35标记基因可作为评估家禽粪便对水质和人类健康风险影响的有用工具这一假设。
