Survival of Escherichia coli O157:H7 in wastewater from dairy lagoons

Abstract

Aim: To determine the survival of Escherichia coli O157:H7 in dairy wastewater from on‐site holding lagoons equipped with or without circulating aerators. Methods and Results: Survival was monitored in dairy lagoon microcosms equipped with or without scale‐size circulators. Both laboratory strains of E. coli O157:H7 and an isolate of E. coli H7 from wastewater had poor survival rates and none proliferated in water from waste lagoons with or without circulators. Furthermore, the decline of E. coli O157:H7 was not enhanced in those microcosms equipped with circulators. Strain variation in survival was observed in both circulated and settling waters. The decline rate of E. coli O157:H7 Odwalla strain increased proportionately with the inoculum load. Escherichia coli failed to establish itself in wastewater even after four sequential inoculations simulating continuous faecal input into the lagoon. The native aerobic bacteria survived longer with a decimal reduction time of 21·3 days vs either introduced or native E. coli, which declined rapidly with decimal reduction time of 0·5–9·4 days. Conclusions: Escherichia coli O157:H7 failed to establish and proliferate in dairy wastewater microcosms equipped with or without circulating aerators. Significance and Impact of the study: This study furthers our knowledge of pathogen survival in wastewater, and suggests that proper management of wastewater before its use in irrigation is essential to reduce pathogen transfer to crops.

Extractable Organic Components and Nutrients in Wastewater from Dairy Lagoons Influence the Growth and Survival of Escherichia coli O157:H7

“…The pathogen is known to be shed in manure by cattle and survives in animal waste and wastewater (2,11,14,22,25). Owing to its low prevalence (13,14,25), the pathogen could not be detected in manure and wastewater from dairies in the central valley of California (27,31). It is likely that the pathogen could escape detection at low cell numbers or as nonculturable cells (32).…”

“…Although E. coli O157:H7 can be isolated even after 21 months (24) by selective enrichments from a manure pile from inoculated sheep, the pathogen failed to grow and decline rapidly in manure, manure slurries, and wastewater from dairy lagoons (2,17,31). In addition, feeding cattle with a straw-rich diet (12), silage made with bacteriocin-producing bacteria (3), and competitive exclusion products using lactic acid bacteria (7), colicinogenic E. coli (8,33) and O157-specific bacteriophages (35) has the potential to inhibit pathogen replication inside the animals.…”

Quantification of Bacterial Indicators and Zoonotic Pathogens in Dairy Wastewater Ponds

“…paratuberculosis, Salmonella spp., Yersinia spp., Giardia lamblia, and Cryptosporidium parvum (38,39,40). While numerous studies have measured the occurrence of these zoonotic pathogens in cattle manures and assessed their fate and transport in the environment (41,48,55), to our knowledge, no comprehensive studies have been conducted to quantify pathogens in dairy wastewaters. In addition, only a few studies to date have quantified a wide range of pathogens within cattle manures (20,21,26).…”

“…While the greatest number of detections for all organisms occurred in that first month of analysis, the number of positive pond results generally decreased during each subsequent month. The decrease in the number of detections may have been affected by the pathogen-shedding rate of the cattle, environmental variables (e.g., solar irradiation, temperature), pond characteristics (e.g., solids content), or competition from other indigenous microorganisms leading to a reduction of pathogen survival in the ponds (29,41,42). The fact that Leptospira spp.…”

The Impact of Enterohemorrhagic <i>Escherichia coli</i> (EHEC) on Ciliate Protozoan Populations in Municipal Sewage

“…EHEC can be transmitted from contaminated cattle manure and irrigation water to agricultural products, such as lettuce [11] [12]. Ravva et al [10] showed that E. coli O157:H7 failed to proliferate in dairy lagoon wastewater microcosms, indicating that EHEC could be removed from wastewater system. Some ciliate protozoa were found to be resistant to E. coli O157:H7 and also able to reduce E. coli populations in dairy lagoon wastewater [13].…”