Poultry litter as potential source of pathogens and other contaminants in groundwater and surface water proximal to large-scale confined poultry feeding operations.

Manure from livestock production has been associated with the contamination of water resources. To date, research has primarily focused on runoff of these contaminants from animal operations into surface water, and the introduction of poultry-derived pathogenic zoonoses and other contaminants into groundwater is under-investigated. We characterized pathogens and other microbial and chemical contaminants in poultry litter, groundwater, and surface water near confined poultry feeding operations (chicken layer, turkey) at 9 locations in Iowa and one in Wisconsin from May and June 2016. Results indicate that poultry litter from large-scale poultry confined feeding operations is a likely source of environmental contamination and that groundwater is also susceptible to such poultry-derived contamination. Poultry litter, groundwater, and surface water samples had detections of viable bacteria growth (Salmonella spp., enterococci, staphylococci, lactobacilli), multi-drug resistant Salmonella DT104 flost and int genes, F+ RNA coliphage (group I and IV), antibiotic resistance genes (ARGs; blaDHA, blaOXA-48, blaTEM, blaCMY-2, tetM), phytoestrogens (biochanin A, daidzein, formononetin), and a progestin (progesterone). In addition, mcr-1 (a colistin ARG), was detected in a groundwater sample and in another groundwater sample, antibiotic resistant isolates were positive for Brevibacterium spp., a potential signature of poultry in the environment. Detectable estrogenicity was not measured in poultry litter, but was observed in 67% of the surface water samples and 22% were above the U.S. Environmental Protection Agency trigger level of 1 ng/L. The transport of microbial pathogens to groundwater was significantly greater (p < 0.001) than the transport of trace organic contaminants to groundwater in this study. In addition to viable pathogens, several clinically important ARGs were detected in litter, groundwater, and surface water, highlighting the need for additional research on sources of these contaminants in livestock dominated areas.

Occurrence and distribution of Vibrio vulnificus and Vibrio parahaemolyticus--potential roles for fish, oyster, sediment and water.

UNLABELLED: Vibrio vulnificus and Vibrio parahaemolyticus are Gram-negative marine bacteria naturally found in estuaries such as the Gulf of Mexico and can be pathogenic to humans. We quantified both of these organisms in fish, oyster, sediment, and water using culture-independent (quantitative PCR; qPCR) and culture-dependent (direct plating-colony hybridization; DP-CH) techniques during the transition period between winter and spring. We correlated these levels to environmental conditions and to abundance of total bacteria and total vibrio. By qPCR, fish intestine samples had the highest V. vulnificus densities and were 2·7, 3·5, and 4·2 logs greater than oyster, sediment and water samples, respectively. Densities of V. parahaemolyticus in fish samples by qPCR were 1·0, 2·1, and 3·1 logs greater than oyster, sediment and water samples, respectively. Similar differences between sample types were also observed by DP-CH. The difference between the more favourable and less favourable environmental conditions identified in this study was small (mean salinity 4·3 vs. 13 ppt). However, V. vulnificus and V. parahaemolyticus were consistently detected in fish intestines, but infrequently detected and at lower levels in oysters and during the less favourable period. This trend was observed by qPCR and DP-CH, indicating fish intestines are a significant source of pathogenic vibrios in the environment. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to report the densities of Bacteria 16S rRNA, Vibrio 16S rRNA, Vibrio vulnificus, and V. parahaemolyticus in fish intestine, oyster, sediment and water samples, as well as compare these values through culture-dependent and culture-independent methodology. Vibrio vulnificus and V. parahaemolyticus were detected in samples of fish intestines by qPCR and colony hybridization when conditions were less favourable for their occurrence in the environment. In contrast, V. vulnificus and V. parahaemolyticus were infrequently detected and at lower levels in other niches examined. These results indicate that fish intestinal tracts are a significant source of these pathogens.