Secondary Fate of Pathogenic Bacteria in Livestock Mortality Biopiles.

Prominent bacterial pathogens, such as E. coli O157:H7 and Salmonellae sp. (SA), reside in multiple hosts, exist in animal-borne wastes, and are excreted by animals in large volumes. They have also been linked to increasing incidence of mammalian infections. Emerging zoonoses cause ≈12-24% of global infectious diseases, thus human and animal exposure to bacterial pathogens embodies a health risk. Livestock, for example, represent vectors for and defenses in bio- or agri-terrorism situations. It is impractical, however, to monitor for all bacterial pathogens due to difficulty, time, expense, virulence, and their ubiquity in nature. Indicator micro-organisms are therefore used to equate bacterial pathogen presence. Choosing a universal indicator is therefore a foremost concern that is continuously debated in academic and public circles. Escherichia coli (EC) and Streptococcus fecalis (SF) have historically been used as indicators of pathogens inherent in the gut of humans and warm-blooded animals. Since EC is the prominent species in the total (TC), fecal coliform (FC), and the Family Enterobacteriaceae (EB) groups, EC detection should coincide with detection of EB and TC. Likewise, TC or SA presence should elicit EB detection. Theoretically, since SF is not an EB member, no similarities in detection or ultimate fate should be observed. The crux of this research was to assess the fate of indicator bacteria fate in solid and liquid media associated with slaughterhouse-residual biopiles during the secondary composting phase. Traditional (membrane filtration; MF) and rapid (PetriFilm™) enumerative methods, and classical (TC, EC, SF) and non-classical (EB, SA, EC NAR) indicator bacteria, were used. This presentation will focus on the re-growth potential of these micro-organisms.