Inactivation of indicators and pathogens in cattle feedlot manures and compost as determined by molecular and culture assays

Abstract

Accurate and conservative information about pathogen inactivation rates is needed as the basis for safe manure management on beef cattle feedlots. The survival of indicators and pathogens in faecal pen manure, stockpiled manure and manure compost was measured with autochthonous indicator bacteria (Escherichia coli, Clostridium perfringens, enterococci, total coliforms) and pathogens (Listeria monocytogenes, Campylobacter jejuni) using culture and/or real-time quantitative PCR (qPCR) methods. Additionally, the manures were incubated at 20, 37, 50 and 60 °C in microcosms to quantify the persistence of autochthonous microorganisms and selected process performance surrogates (Clostridium sporogenes, green fluorescent protein-labelled E. coli and L. monocytogenes). Estimated qPCR cell counts indicated that up to four orders of magnitude more target cells were present compared with the culturable counts. Corresponding T(90) estimates were up to sixfold higher. This study demonstrates the benefits of nucleic acid-based quantification of pathogen inactivation in cattle manures and concludes that the concurrent analysis of microorganisms by molecular and culture methods provides complementary value.

Quantification of Bacterial Indicators and Zoonotic Pathogens in Dairy Wastewater Ponds

“…The qPCR method was specifically designed to detect E. faecalis, which is one of the most common enterococcus species found in the gastrointes- tinal tract of cattle (14,32). qPCR values were about 3 logs greater than those determined by the MPN technique (a statistically significant difference; P Ͻ 0.0001), which indicated that the majority of enterococci might have gone into a VBNC state such as was seen in earlier studies involving bovine feces and manure (28,30). However, since the DNA could also have been extracted from damaged or dead cells, qPCR analysis may have resulted in overestimation of actual titer values in the samples (7,31,37).…”

“…It should be noted that changes in the levels of fecal indicators in the wastewater ponds may not be seasonal in nature and could be related to the manure aging process or nutrient status of the pond. In general, it has been reported that levels of bacterial indicators and zoonotic agents in stored livestock wastes decline over time (22,28,34,57). However, regrowth of indicator bacteria to some extent, due to the nutrient-rich conditions, has also been reported (13,28).…”

Molecular Detection of Campylobacter spp. and Fecal Indicator Bacteria during the Northern Migration of Sandhill Cranes (Grus canadensis) at the Central Platte River

“…Also, while Bacteroidetes markers have been used to identify human and cattle fecal contamination, the group may not be useful for evaluating waterfowl fecal contamination (35,47). Finally, while both viable and dead cells are detected, the interpretion of qPCR results in risk management decision making provides a conservative estimate that is suitable for an initial-screening-level assessment (36).…”

Fate and Survival of Campylobacter coli in Swine Manure at Various Temperatures

“…Livestock wastes such as manure or slurry from intensive animal production may contain pathogenic microorganisms including viruses, bacteria ( Escherichia coli , Campylobacter spp., and Salmonella ), and protozoa (Mawdsley et al, 1995; Semenov et al, 2009; Klein et al, 2011). There has been an increasing concern about which effect of pathogens in animal manure may have on human and animal health (Bicudo and Goyal, 2003).…”