Fate of non O157 Shiga toxigenic Escherichia coli in composted cattle manure

Abstract

To determine the fate of Shiga toxigenic Escherichia coli (STEC) non-O 157 in composted manure from naturally colonized cattle, fresh manure was obtained from three cows carrying non-O157 STEC strains possessing the stx2 gene. Two composting systems were used: a 0.6m deep cave opened in the soil and an one meter high solid manure heap in a pyramidal architecture. Every day, for the 10 first days, and every five days for a month, one manure sample from three different points in both systems was collected and cultured to determine the presence of E. coli and the presence of the stx 2 gene in the cells. The temperature was verified at each sampling. STEC non-O157 E. coli cells survived for 8, 25 and 30 days at 42, 40 and 38 o C, respectively, in the deep cave and 4, 4 and 7 days at 65, 58 and 52 o C, respectively, in the heap, during the composting manure. Temperature and indigenous microorganisms appear to contribute to pathogen disappearance in the composting system. It is concluded that both composting systems were efficient to eliminate STEC cells. Land application of composted manure should minimize environmental risk associated with the dissemination of the pathogen.

Compostagem dos dejetos da bovinocultura de corte: influência do período, do genótipo e da dieta

“…Temperatura baixa durante curto período de tempo pode não ser suficiente para higienizar o composto final. Dessa forma, seu uso como adubo pode levar a contaminação do alimento que será produzido e consequentemente contribuir para disseminação de doenças na propriedade (Gonçalves & Marin, 2007). No início do processo de compostagem, foi observado elevado NMP.g -1 , que sofreu drástica redução durante a compostagem a ponto de não ser mais detectada a presença de coliformes totais e termotolerantes ao final do processo (Tabela 4).…”

An evaluation of the use of probiotics and manure composting as strategies to reduce levels of Shiga toxin-producing Escherichia coli in sheep

“…The composting process helps to ensure the hygiene of the final compost product (Pourcher et al, 2005;Murkherjee et al, 2006;Gonçalves and Marin, 2007). Previous studies have shown a long-term survival of more than 21 months for E. coli O157:H7 in manure held under a variety of environmental conditions (Kudva et al, 1998).…”

“…The use of probiotic strains to supplement the ration of livestock (Lema et al, 2001;Chaucheyras-Durand et al, 2010) and the use of composting to decrease the population of pathogenic microbes (Pourcher et al, 2005;Murkherjee et al, 2006;Gonçalves and Marin, 2007) have both been reported as efficient alternatives to decrease the spread of pathogenic strains on a farm. However, these studies were done separately, and there is little information about the combined use of the two practices to decrease the STEC population present on a sheep farm.…”

Parâmetros microbiológicos e físico químicos em um sistema de compostagem experimental de carcaças e dejetos sólidos de suínos

“…Em um sistema que envolveu o tratamento de dejetos de bovino por compostagem com a presença de Escherichia coli Shigatoxigênica, o sistema foi capaz de eliminar o micro-organismo diminuindo o risco de contaminação ambiental e a disseminação do patógeno (GONÇALVES; MARIN, 2007).…”