Survival of a Shiga toxin-encoding bacteriophage in a compost model

Johannessen, Gro, James, Chloe, Allison, Heather, Smith, Darren, Saunders, Jon and McCarthy, Alan (2005) Survival of a Shiga toxin-encoding bacteriophage in a compost model. FEMS Microbiology Letters, 245 (2). pp. 369-375. ISSN 03781097

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Abstract

Bacteriophages that carry the Shiga toxin gene (stx) represent an additional hazard in cattle manure-based fertilizers in that their survival could lead to toxigenic conversion of Escherichia coli and other bacteria post-composting. A Stx-phage in which the Shiga toxin (stx2) gene was inactivated by insertion of a chloramphenicol resistance gene was used in combination with a rifampicin-resistant E. coli host where RecA is constitutively activated so that all infectious phage particles could be enumerated by plaque assay. PCR-based confirmation methods and the additional application of a host enrichment protocol ensured that very low numbers of surviving bacteriophage could be detected and unequivocally identified. Stx-bacteriophage numbers declined rapidly over the first 48 h and none could be detected after 3 days. The host enrichment method was applied after 6 days and no bacteriophages were recovered. While addition of fresh E. coli cells at intervals after the compost temperature had reduced below 40 °C demonstrated that E. coli growth could be supported in the compost, Stx-phages or their lysogens were never detected. Here, we demonstrate that composting animal manure for 40 days during which a temperature of >60 °C is maintained for at least 5 days is effective at removing both E. coli and a model infectious Stx-encoding bacteriophage.

Item Type:	Article
Uncontrolled Keywords:	Compost, shiga toxin, bacteriophage, Escherichia coli, manure
Subjects:	B200 Pharmacology, Toxicology and Pharmacy
Department:	Faculties > Health and Life Sciences > Applied Sciences
Depositing User:	Becky Skoyles
Date Deposited:	15 Nov 2013 15:48
Last Modified:	12 Oct 2019 17:30
URI:	http://nrl.northumbria.ac.uk/id/eprint/14622

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