LA35 Poultry Fecal Marker Persistence Is Correlated with That of Indicators and Pathogens in Environmental Waters

Abstract

bDisposal 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.T he practice of applying poultry litter (bedding contaminated with feces) as fertilizer is the chosen method of disposal of several billion tons of litter per year in the United States (1, 2). Numerous studies have demonstrated the cause-and-effect relationship between land application of poultry litter and contamination of environmental waters and soils due to chemical and microbial pollution from runoff (3-6). The presence of pathogens such as Campylobacter jejuni, Salmonella enterica, and Staphylococcus aureus along with fecal indicator bacteria (FIB) such as enterococci and Escherichia coli in poultry litter is of particular concern from a public health perspective (7-10). The human disease risk associated with contamination of environmental water bodies with human fecal material is unambiguous; in contrast, the risk of disease from nonhuman fecal contamination (from animals and birds) is more variable and host dependent (11).Currently, water body contamination by fecal pollution is assessed by FIB levels. A body of literature has established that fecal coliforms, E. coli, and Enterococcus spp. can persist in environmental waters and in sediments (12-14), indicating the existence of extraintestinal reservoirs of FIB. The ability of enteric pathogens to persist in environmental waters and sediments is much less clear and almost certainly varies by pathogen type and species (13,15). A better ...

Pastured Poultry Production in the United States: Strategies to Balance System Sustainability and Environmental Impact

“…Agricultural production practices, both crop and animal, have been identified as sources of excess nutrients and microorganisms contributing to freshwater pollution (Nayak et al, 2015;Evans et al, 2019). In states such as Arkansas, the land application of manure generated by confined poultry operations has been identified as a source of both excess nutrients, especially phosphorous, and fecal indicator bacteria (FIB) in regional watersheds (Ismail et al, 2016;Sharpley et al, 2016).…”

Identification of Factors Affecting Fecal Pollution in Beaver Lake Reservoir

“…A study by Li et al (2015) reported relatively low sensitivity of the LA35 marker when applied to poultry litter samples, although the authors did not compare with the CL marker or any other poultry‐specific marker. Unfortunately, additional studies using the LA35 poultry marker did not apply the marker to environmental waters, but rather to experimental microcosms to evaluate persistence (Nayak et al, 2015; Mantha et al, 2017). Therefore, this is the first study to evaluate both poultry‐specific markers within a single watershed over a prolonged period of time.…”

Using Bacteroidales genetic markers to assess fecal pollution sources in coastal waters

“…; Nayak et al . ). As elevated fecal indicator bacteria (FIB) levels have been correlated with an increased human risk of illness (Prüss ), the microbiological quality of water has been assessed for decades by enumerating FIB such as Escherichia coli ( E. coli ) and enterococci in recreational waters (USEPA ).…”