Influence of bacterial communities based on 454-pyrosequencing on the survival ofEscherichia coliO157:H7 in soils

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.