University of California Berkeley, School of Public Health, 101 Haviland, MC# 7358, Berkeley, CA 94720-7358, USA.
Water Res. 2012 May 1;46(7):2176-86. doi: 10.1016/j.watres.2012.01.033. Epub 2012 Feb 2.
Traditional fecal indicator bacteria (FIB) measurement is too slow (>18 h) for timely swimmer warnings.
Assess relationship of rapid indicator methods (qPCR) to illness at a marine beach impacted by urban runoff.
We measured baseline and two-week health in 9525 individuals visiting Doheny Beach 2007-08. Illness rates were compared (swimmers vs. non-swimmers). FIB measured by traditional (Enterococcus spp. by EPA Method 1600 or Enterolert™, fecal coliforms, total coliforms) and three rapid qPCR assays for Enterococcus spp. (Taqman, Scorpion-1, Scorpion-2) were compared to health. Primary bacterial source was a creek flowing untreated into ocean; the creek did not reach the ocean when a sand berm formed. This provided a natural experiment for examining FIB-health relationships under varying conditions.
We observed significant increases in diarrhea (OR 1.90, 95% CI 1.29-2.80 for swallowing water) and other outcomes in swimmers compared to non-swimmers. Exposure (body immersion, head immersion, swallowed water) was associated with increasing risk of gastrointestinal illness (GI). Daily GI incidence patterns were different: swimmers (2-day peak) and non-swimmers (no peak). With berm-open, we observed associations between GI and traditional and rapid methods for Enterococcus; fewer associations occurred when berm status was not considered.
We found increased risk of GI at this urban runoff beach. When FIB source flowed freely (berm-open), several traditional and rapid indicators were related to illness. When FIB source was weak (berm-closed) fewer illness associations were seen. These different relationships under different conditions at a single beach demonstrate the difficulties using these indicators to predict health risk.
传统的粪便指示菌（FIB）检测速度太慢（>18 小时），无法及时发出游泳者警告。
评估快速指示物方法（qPCR）与受城市径流影响的海洋海滩发病的关系。
我们在 2007-08 年期间测量了 9525 名访问多尼海滩的个体的基线和两周健康状况。比较了发病率（游泳者与非游泳者）。通过传统方法（EPA 方法 1600 或 Enterolert™测量粪肠球菌，粪便大肠菌群，总大肠菌群）和三种快速 qPCR 检测方法（Taqman，Scorpion-1，Scorpion-2）测量 FIB，并与健康状况进行比较。主要细菌源是一条未经处理就流入海洋的小溪；当形成沙堤时，小溪不会到达海洋。这为在不同条件下检查 FIB-健康关系提供了一个自然实验。
与非游泳者相比，游泳者观察到腹泻（OR 1.90，95%CI 1.29-2.80 用于吞咽水）和其他结果的显著增加。暴露（身体浸泡，头部浸泡，吞咽水）与胃肠道疾病（GI）的风险增加有关。每日 GI 发病模式不同：游泳者（2 天高峰）和非游泳者（无高峰）。当堤岸开放时，我们观察到 GI 与传统和快速 Enterococcus 方法之间的关联；当不考虑堤岸状态时，发生的关联较少。
我们发现，在这个受城市径流影响的海滩上，GI 的风险增加。当 FIB 源自由流动（堤岸开放）时，几种传统和快速指标与疾病有关。当 FIB 源较弱（堤岸关闭）时，观察到的疾病关联较少。在单个海滩的不同条件下，这些不同的关系表明，使用这些指标预测健康风险存在困难。
