Persistant Bacteria

Contributed by Bart C. Weimer, Ph.D.

Food microbiologists have wrestled with the concept of non-culturable bacteria (NCB). It is well accepted in environmental microbiology the NCB are common. The expanded importance of the gut microbiome has raised this issue to the forefront. The implications of NCB for food safety are extensive. If bacteria become NC in food there is room for extraction from the zombie state to cause disease. My group has long had interest in NCB. It first started with bacteria used in fermentation where we conclusively demonstrated that lactococci produce branched chain fatty acids only after entry in NC. A recent search produced only 6 papers for Salmonella NC and virulence. I was surprised. The data are not at all convincing that link NC in pathogens to virulence. The link between survival in the food supply and emergence of outbreaks is yet to be proven. This is an important link that needs attention!

Additional reading:

Shah, Jigna, Prerak T. Desai, & Bart C. Weimer. 2014. Genetic mechanisms underlying pathogenicity of cold-stressed Salmonella Typhimurium in cultured intestinal epithelial cells. Appl. Environ. Microbiol. 80:6943-53. (PMID: 25192993)

Shah, J., Prerak Desai, Dong Chen, John Stevens, and Bart C. Weimer. 2013. Proteomics of cold stress in Salmonella enterica sv Typhimurium LT2. Appl. Environ. Microbiol. 79:7281-7289. (PMID: 24056458)

Ganesan, B., M. Stuart, and Bart C. Weimer. 2007. Carbohydrate starvation causes a metabolically active but nonculturable state in Lactococcus lactis. Appl. Environ. Microbiol. 73:2498-2512.

Persistent Ganesan, B., P. Dobrowolski, and B. C. Weimer. 2006. Identification of the Leucine-to-2-Methylbutyric Acid Catabolic Pathway of Lactococcus lactis. Appl. Environ. Microbiol. 72:4264-73.

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