The Delmarva Peninsula, a major agricultural and recreational region for the U.S. states of Delaware, Maryland and Virginia, experiences recurrent salmonellosis disease. Previous studies point to water environments as a potential persistent environmental reservoir of Salmonella enterica. To evaluate this hypothesis, water from the four main rivers of the Maryland Eastern Shore on the Delmarva Peninsula was tested for the presence of S. enterica, and recovered isolates were characterized for antimicrobial resistance. Sampling was performed in autumn and spring to evaluate temporal persistence at twenty four sites along the Choptank, Nanticoke, Pocomoke and Wicomico Rivers. Water (10 L) was filtered through sterile modified Moore swabs in situ. Swabs were selectively enriched for S. enterica and presumptive salmonellae were confirmed by PCR amplification of the Salmonella-specific invA and hilA genes. The serogroup of 402 isolates was determined, followed by serotype characterization for 157 isolates selected to represent all the identified serogroups across all samples. S. enterica was isolated from all the rivers in both seasons and was detected in 35/46 (65%) of surface water samples, with equivalent recovery in spring (70%) and fall (61%). The likelihood of isolating S. enterica was higher for the Nanticoke and Pocomoke Rivers, χ² (3, N = 46) = 12.75, p < 0.01. In total, 18 serotypes of S. enterica were identified, and serotype diversity differed between the fall and spring samplings. Newport was the most frequently isolated serotype, both overall and in the fall, identified in 8/46 samples (17%). Typhimurium was the predominant serotype in spring. Some temporal and biogeographic patterns were observed in S. enterica recovery, but 6/18 serotypes were identified in both seasons. The majority (84%) of isolates were pan-susceptible, including all those tested from the Wicomico River (N = 19). Twenty five isolates (16%) from 9 samples were resistant to at least one antimicrobial, including serotypes Typhimurium, Newport, Litchfield, III 17:z10: e,n,x,z15, III 60:I and IV_40:z4: z32: -. Of the isolates that were resistant to a single antimicrobial (N = 12), resistance was to streptomycin or sulfisoxazole. Thirteen isolates were multidrug resistant, nine exhibiting resistance to ampicillin, sulfisoxazole, tetracycline, amoxicillin/clavulanic acid, cefoxitin and ceftriaxone, and four to sulfisoxazole and tetracycline. The widespread presence and diversity of S. enterica in Delmarva rivers are concerning given the frequent use of rivers and tributaries as a source of irrigation and for recreation. Future research should seek to determine specific point sources of S. enterica for surface river waters, and risks associated with acquisition of antimicrobial resistance traits.

Delmarva半岛是美国特拉华州，马里兰州和弗吉尼亚州的主要农业和休闲区，经常发生沙门氏菌病。先前的研究指出水环境是肠沙门氏菌的潜在持久性环境储藏库。为了评估该假设，测试了德尔马瓦半岛马里兰东部海岸的四个主要河流中的水是否存在肠炎链球菌，并对分离出的分离物进行了抗药性鉴定。在秋季和春季进行了采样，以评估沿Choptank，Nanticoke，Pocomoke和Wicomico河的二十四个地点的时间持久性。通过无菌改良的摩尔拭子原位过滤水（10 L）。棉签被选择性富集用于肠道沙门氏菌和推定沙门氏菌是由PCR扩增证实沙门氏菌特异性invA的和HILA基因。确定了402个分离株的血清群，然后对157个分离株的血清型进行了表征，选择这些分离株代表所有样品中所有已鉴定的血清群。在两个季节中均从所有河流中分离出肠炎沙门氏菌，并在35/46（65％）的地表水样品中检出，春季（70％）和秋季（61％）的回收率相同。分离的可能性肠道沙门氏菌是为楠蒂科克和波科摩克河流更高，χ ²（3，N = 46）= 12.75，p  <0.01。总共18种血清型的肠道沙门氏菌被确定，并且血清型多样性在秋天和春天采样之间是不同的。在8/46个样本中，纽波特是整体和秋季最常见的血清型（17％）。鼠伤寒是春季的主要血清型。在小肠沙门氏菌中观察到一些时间和生物地理格局可以恢复，但在两个季节中均鉴定出6/18血清型。绝大多数（84％）的分离株是易感的，包括从威科米科河（N = 19）测试的所有分离株。来自9个样品的25个分离株（16％）对至少一种抗菌素具有抗药性，包括血清型鼠伤寒，纽波特，利奇菲尔德，III 17：z10：e，n，x，z15，III 60：I和IV_40：z4：z32： - 在对单一抗菌素（N = 12）有抗药性的菌株中，抗药性是对链霉素或磺胺异恶唑的抗药性。十三株分离株具有多药耐药性，其中九株对氨苄西林，磺胺异恶唑，四环素，阿莫西林/克拉维酸，头孢西丁和头孢曲松具有抗药性，四株对磺胺异恶唑和四环素具有抗药性。肠炎链球菌的广泛存在和多样性在德尔马瓦（Delmarva），河流和支流经常被用作灌溉和娱乐场所，因此河流令人担忧。未来的研究应寻求确定地表河水的肠炎沙门氏菌的特定来源，以及与获得抗菌素耐药性状相关的风险。