TITLE:
The Impact of Enterohemorrhagic Escherichia coli (EHEC) on Ciliate Protozoan Populations in Municipal Sewage
AUTHORS:
Zhen Li, Peter P. Sheridan, Malcolm S. Shields
KEYWORDS:
18S rDNA, Activated Sludge, Protozoa, Enterohemorrhagic E. coli, T-RFLP
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.9,
August
27,
2015
ABSTRACT: Enterohemorrhagic Escherichia coli strains (EHEC) have caused many foodborne outbreaks. Bacterivorous protozoa
could remove bacteria from aquatic systems. We analyzed the ciliate protozoan
population changes influenced by EHEC co-culture in activated sludge. EHEC and
non-EHEC control E. coli cells were
added to activated sludge samples in microcosms. The ciliate population changes
were monitored by terminal restriction fragment length polymorphism (T-RFLP)
analysis. EHEC and non-EHEC fed ciliate protozoan populations were different
from each other and the no bacteria added controls based on the additive main
effects and multiplicative interaction model (AMMI) analysis. Ciliate species
were identified by 18S rDNA clone libraries. The 18S rDNA clones from the
original sludge sample were identified as Epistylis
wenrichi (70%) and Prorodon teres (30%), while clones from EHEC treated sludge sample were identified as P. teres (52%), Vorticella fusca (41%), Dexitrichides
pangi (5%), and Opisthonecta
henneguyi (2%). This study could provide helpful information about ciliate
protozoan population changes caused by different E. coli strains in wastewater treatment plants, which could be
useful for preventing and tracking E.
coli outbreaks.