Open AccessSurvival characteristics of diarrheagenic E scherichia coli pathotypes and H elicobacter pylori during passage through the free‐living ciliate, T etrahymena sp.
Author(s) -
Smith Charlotte D.,
Berk Sharon G.,
Brandl Maria T.,
Riley Lee W.
Publication year - 2012
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2012.01428.x
Subject(s) - biology , ciliate , tetrahymena , microbiology and biotechnology , helicobacter pylori , tetrahymena pyriformis , escherichia coli , protozoa , genetics , gene
Free‐living protozoa have been implicated in the survival and transport of pathogens in the environment, but the relationship between non‐Shiga toxin‐producing E scherichia coli or H elicobacter pylori and ciliates has not been characterized. Six diarrheagenic pathotypes of E . coli and an isolate of H . pylori were evaluated for their susceptibility to digestion by T etrahymena , an aquatic ciliate. T etrahymena strain MB 125 was fed E . coli or H . pylori , and the ciliate's egested products examined for viable bacterial pathogens by the B ac L ight ™ LIVE / DEAD ™ assay, a cell elongation method, and by colony counts. All six diarrheagenic E . coli pathotypes survived digestion, whereas H . pylori was digested. Growth of E . coli on agar plates indicated that the bacteria were able to replicate after passage through the ciliate. Transmission electron micrographs of E . coli cells as intact rods vs. degraded H . pylori cells corroborated these results. Scanning electron microscopy revealed a net‐like matrix around intact E . coli cells in fecal pellets. These results suggest a possible role for T etrahymena and its egested fecal pellets in the dissemination of diarrheagenic E . coli in the environment. This bacterial–protozoan interaction may increase opportunities for transmission of diarrheagenic E . coli to mammalian hosts including humans.