|Ma, Jincai -|
|Yang, Ching-Hong -|
|Crowley, David -|
Submitted to: FEMS Microbiology Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 23, 2013
Publication Date: February 26, 2013
Repository URL: http://www.ars.usda.gov/SP2UserFiles/Place/53102000/pdf_pubs/P2414.pdf
Citation: Ma, J., Ibekwe, A.M., Yang, C., Crowley, D.E. 2013. Influence of bacterial communities based on 454-pyrosequencing on the survival of Escherichia coli O157:H7 in soils. FEMS Microbiology Ecology. 84(3):542-554. Interpretive Summary: Numerous studies have been done to investigate the fate of E. coli O157:H7 in different agricultural systems with major focus on the survival of E. coli O157:H7 in soils and manure-amended soils. In this study, survival of E. coli O157:H7 in 32 soils (16 organically, 16 conventionally managed) from California (CA) and Arizona (AZ) was investigated. Our goal was to correlate the survival time of E. coli O157:H7 in soils with total bacterial composition using deep sequencing. Our data showed that E. coli O157:H7 can survive for about 30 days before reaching the detection limit in soils from Salinas Valley CA and about 20 days in soils from Imperial Valley CA and Yuma AZ. The survival of E. coli O157:H7 in soils was related to bacterial groups that can degrade complex materials to simpler materials for E. coli to use as nutrient sources. The results of this research will be used by growers, researchers, FSIS, FDA, and different state agencies that are involved in leafy green production.
Technical Abstract: Shiga toxin-producing Escherichia coli O157:H7 has been implicated in many foodborne illnesses. In this study, survival of E. coli O157:H7 in 32 soils from California (CA) and Arizona (AZ) was investigated. Our goal was to correlate the survival time of E. coli O157:H7 in soils with 16S rRNA pyrosequencing based bacterial community composition. Kohonen self-organizing map of survival and associated soil chemical, physical and biological variables using artificial neural network analysis showed that survival of E. coli O157:H7 in soils was negatively correlated with salinity (EC), but positively correlated with total nitrogen (TN) and water soluble organic carbon (WSOC). Bacterial diversity as determined by the Shannon diversity index had no significant (P = 0.635) effect on ttd, but individual bacterial phyla had different effects. The survival of E. coli O157:H7 was positively correlated with the abundances of Actinobacteria (P < 0.001) and Acidobacteria (P < 0.05), and negatively correlated with those of Proteobacteria and Bacteroidetes (P < 0.05). Our data showed that specific groups of bacteria correlate with the persistence of E. coli O157:H7 in soils thus opening new ways to study the influence of certain bacterial phyla on persistence of this pathogen and other related pathogens in complex environments.