Persistence of microbial and chemical pig manure markers as compared to faecal indicator bacteria survival in freshwater and seawater microcosms

Abstract

Natural seawater and freshwater microcosms inoculated with pig manure were set up to determine the persistence of pig faecal microbial and chemical markers in these two types of surface water. The concentrations of Lactobacillus amylovorus, the Bacteroidales Pig-2-Bac 16S rRNA genetic marker, five stanols and the evolution of two ratios of stanols, R1 (coprostanol to the sum of coprostanol and 24-ethylcoprostanol) and R2 (sitostanol to coprostanol) were analyzed during two months along with the concentration of Faecal Indicator Bacteria (FIB). Pig manure was inoculated to unfiltered water microcosms incubated aerobically at 18 °C in the dark. The faecal contamination load represented by the concentrations of culturable Escherichia coli and/or enterococci remained for two months in the freshwater and seawater microcosms water column. These concentrations followed a biphasic decay pattern with a 97% reduction of the initial amount during a first rapid phase (<6 days) and a remaining proportion undergoing a slower or null second decline. The L. amylovorus marker and five stanols persisted as long as the indicators in both treatments. The Pig-2-Bac marker persisted 20 and 27 days in seawater and freshwater, respectively. The ratios R1 and R2 were in the range specific to pig manure until day 6 in both types of water. These results indicate that Pig-2-Bac, L. amylovorus and stanol ratios might be used in combination to complement FIB testing to determine the pig source of fecal pollution. However, stanol ratios are to be used when the time point of the discharge is known.

Persistence of mitochondrial DNA markers as fecal indicators in water environments

“…The environmental conditions influencing the decay of mtDNA markers may be complex because other environmental factors (e.g., salinity and dissolved oxygen) can also affect the persistence of microbial genetic markers (Jeanneau et al, 2012;Marti et al, 2011;Okabe and Shimazu, 2007). For example, the Bacteroides and Bifidobacterium genetic markers can persist longer in salt water than in fresh water (Green et al, 2011;Jeanneau et al, 2012;Solecki et al, 2011), whereas oxygen can accelerate the decay of the markers (Marti et al, 2011).…”

Decay of Fecal Indicator Bacterial Populations and Bovine-Associated Source-Tracking Markers in Freshly Deposited Cow Pats

“…The shorter survival times (2 to 15 days) reported in these studies can be attributed to various physical and biological factors, including dissolved oxygen and predation, which have been implicated in shortening the persistence of strictly anaerobic Bacteroidales spp. (16,(19)(20)(21)(22)(53)(54)(55). Balleste and Blanch (22) suggested that environmental Bacteroides strains may be more sensitive to dissolved oxygen than pure cultures of Bacteroidales spp.…”

Relevance of Bacteroidales and F-Specific RNA Bacteriophages for Efficient Fecal Contamination Tracking at the Level of a Catchment in France

“…Separately, Lactobacillus amylovorus GE39/GE40, another pig-associated marker (19), was quantified at concentrations ranging from 4.6 to 6.5 log 10 copies/100 ml in 5 out of the 5 water samples collected downstream of the accidental spillage monitored in the present study (Olivia Solecki, Irstea, Rennes, France, personal communication). This marker has a greater persistence than Pig2Bac in fresh and marine waters (32) and might be considered for pig manure tracking at the catchment level. Correlation between the general Bacteroidales marker AllBac and the fecal indicators E. coli and enterococci has been previously reported (11).…”