title: Effect of Temperature on Fimbrial Gene Expression and Adherence of Enteroaggregative Escherichia coli.
abstract: The influence of temperature on bacterial virulence has been studied worldwide from the viewpoint of climate change and global warming. The bacterium enteroaggregative Escherichia coli (EAEC) is the causative agent of watery diarrhea and shows an increasing incidence worldwide. Its pathogenicity is associated with the virulence factors aggregative adherence fimbria type I and II (AAFI and AAFII), encoded by aggA and aafA in EAEC strains 17-2 and 042, respectively. This study focused on the effect of temperature increases from 29 °C to 40 °C on fimbrial gene expression using real-time PCR, and on its virulence using an aggregative adherence assay and biofilm formation assay. Incubation at 32 °C caused an up-regulation in both EAEC strains 17-2 and strain 042 virulence gene expression. EAEC strain 042 cultured at temperature above 32 °C showed down-regulation of aafA expression except at 38 °C. Interestingly, EAEC cultured at a high temperature showed a reduced adherence to cells and an uneven biofilm formation. These results provide evidence that increases in temperature potentially affect the virulence of pathogenic EAEC, although the response varies in each strain.
authors.affiliation: Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. p_prem85@yahoo.com.
authors.forename: Woranich
authors.initials: W
authors.lastname: Hinthong
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. nitaya.ind@mahidol.ac.th.
authors.forename: Nitaya
authors.initials: N
authors.lastname: Indrawattana
authors.affiliation: Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. pannamthip.pit@mahidol.ac.th.|Center of Excellence for Antibody Research (CEAR), Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. pannamthip.pit@mahidol.ac.th.
authors.forename: Pannamthip
authors.initials: P
authors.lastname: Pitaksajjakul
authors.affiliation: Center of Excellence for Antibody Research (CEAR), Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. chonlatip.pip@mahidol.ac.th.
authors.forename: Chonlatip
authors.initials: C
authors.lastname: Pipattanaboon
authors.affiliation: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. thida.kon@mahidol.ac.th.
authors.forename: Thida
authors.initials: T
authors.lastname: Kongngoen
authors.affiliation: Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. prapin.tha@mahidol.ac.th.
authors.forename: Prapin
authors.initials: P
authors.lastname: Tharnpoophasiam
authors.affiliation: Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchadewee, Bangkok 10400, Thailand. suwalee.wor@mahidol.ac.th.
authors.forename: Suwalee
authors.initials: S
authors.lastname: Worakhunpiset
mesh_terms: D018830:Adhesins, Escherichia coli / Q000235:genetics*; D001422:Bacterial Adhesion / Q000235:genetics*; D018441:Biofilms; D057231:Climate Change; D003967:Diarrhea / Q000382:microbiology; D015536:Down-Regulation; D004926:Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics*; D036781:Fimbriae Proteins / Q000235:genetics*; D010861:Fimbriae, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D006358:Hot Temperature; D015854:Up-Regulation; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000378:metabolism
chemical_list: C108511:AafA protein, E coli; D018830:Adhesins, Escherichia coli; C079725:AggA protein, E coli; D029968:Escherichia coli Proteins; D037521:Virulence Factors; D036781:Fimbriae Proteins
keywords: EAEC; aggregative adherence; biofilms; fimbria; gene expression; temperature; virulence