Data from: Detection of <i>Salmonella enterica </i>and <i>Listeria monocytogenes</i> in alternative irrigation water by culture and qPCR-based methods in the Mid-Atlantic U.S.

Alternative irrigation waters (rivers, ponds, and reclaimed water) can harbor bacterial foodborne pathogens like <i>Salmonella enterica</i> and <i>Listeria monocytogenes</i>, potentially contaminating fruit and vegetable commodities. Detecting foodborne pathogens using qPCR-based methods may accelerate testing methods and procedures compared to culture-based methods. This study compared detection of <i>S. enterica</i> and <i>L. monocytogenes</i> by qPCR (real-time PCR) and culture methods in irrigation waters to determine the influence of water type (river, pond, and reclaimed water), season (winter, spring, summer, and fall), or volume (0.1, 1, and 10 L) on sensitivity, accuracy, specificity, and positive (PPV), and negative (NPV) predictive values of these methods. Water samples were collected by filtration through modified Moore swabs (MMS) over a 2-year period at 11 sites in the Mid-Atlantic U.S. on a bi-weekly or monthly schedule. For qPCR, bacterial DNA from culture-enriched samples (n = 1,990) was analyzed by multiplex qPCR specific for S. enterica and L. monocytogenes. For culture detection, enriched samples were selectively enriched, isolated, and PCR confirmed. PPVs for qPCR detection of <i>S. enterica</i> and <i>L. monocytogenes</i> were 68% and 67%, respectively. The NPV were 87% (S. enterica) and 85% (L. monocytogenes). Higher levels of qPCR/culture agreement were observed in spring and summer compared to fall and winter for <i>S. enterica</i>; for <i>L. monocytogenes</i>, lower levels of agreement were observed in winter compared to spring, summer, and fall. Reclaimed and pond water supported higher levels of qPCR/culture agreement compared to river water for both <i>S. enterica</i> and <i>L. monocytogenes</i>, indicating that water type may influence the agreement of these results.

替代灌溉用水（河流、池塘水与再生水）可携带肠炎沙门氏菌（Salmonella enterica）、单核细胞增生李斯特菌（Listeria monocytogenes）等食源性细菌致病菌，存在污染果蔬类农产品的潜在风险。相较于传统培养法，基于定量聚合酶链式反应（qPCR，即实时荧光定量PCR）的食源性致病菌检测方案可显著优化检测流程、缩短检测周期。本研究针对灌溉用水中的肠炎沙门氏菌（S. enterica）与单核细胞增生李斯特菌（L. monocytogenes），分别采用qPCR与培养法开展检测，旨在探究用水类型（河流、池塘、再生水）、采样季节（冬、春、夏、秋）及过滤体积（0.1、1、10 L）对两种检测方法的灵敏度、准确度、特异性，以及阳性预测值（Positive Predictive Value, PPV）、阴性预测值（Negative Predictive Value, NPV）的影响。本研究于2年周期内，以双周或月度采样频率，在美国中大西洋地区11处采样点，通过改良莫氏拭子（modified Moore swab, MMS）过滤法采集水样。针对qPCR检测组，研究人员对1990份培养富集后的水样提取细菌DNA，采用针对肠炎沙门氏菌与单核细胞增生李斯特菌的多重qPCR体系进行分析；针对培养法检测组，富集后的水样依次经选择性增菌、分离培养，再通过PCR验证确认目标致病菌。qPCR检测肠炎沙门氏菌与单核细胞增生李斯特菌的PPV分别为68%与67%，NPV分别为87%与85%。对于肠炎沙门氏菌，春季与夏季的qPCR与培养法检测结果一致性显著高于秋冬两季；而对于单核细胞增生李斯特菌，冬季的检测结果一致性显著低于春、夏、秋三季。针对两种致病菌，再生水与池塘水的qPCR与培养法检测结果一致性均高于河水，提示用水类型可能对两种检测方法的结果一致性存在影响。