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Effect of Temperature on Fimbrial Gene Expression and Adherence of Enteroaggregative Escherichia coli.

Hinthong W, Indrawattana N, Pitaksajjakul P, Pipattanaboon C, Kongngoen T, Tharnpoophasiam P, Worakhunpiset S - Int J Environ Res Public Health (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus

Attachment of EAEC strains 17-2 and 042 to Hep-2 cells in an Adherence assay. (A) 17-2 at 37 °C; (B) 042 at 37 °C; (C) 17-2 at 33 °C; and (D) 042 at 33 °C. Magnification ×20.
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ijerph-12-08631-f003: Attachment of EAEC strains 17-2 and 042 to Hep-2 cells in an Adherence assay. (A) 17-2 at 37 °C; (B) 042 at 37 °C; (C) 17-2 at 33 °C; and (D) 042 at 33 °C. Magnification ×20.

Mentions: The ability of EAEC strains 17-2 and 042 to adhere to intestinal epithelial cells was determined by their ability to adhere to Hep-2 cells in an Adherence assay. For EAEC strain 17-2, the highest level of adherence was found in bacteria cultured at 33 °C and, while strain 042 showed the highest adherence at 30 °C (Figure 2). The lowest adherence of EAEC strain 17-2 was at 38 °C, and 32 °C in EAEC strain 042. At the same temperatures, a qualitative Adherence assay showed that EAEC strain 17-2 had higher numbers of bacteria adhering to Hep-2 cells than strain 042, especially at 33 °C (Figure 3). Nevertheless, the adherence between 29 °C and other temperatures and adherence of EAEC strain 17-2 and strain 042 were not significantly different (p-value > 0.05).


Effect of Temperature on Fimbrial Gene Expression and Adherence of Enteroaggregative Escherichia coli.

Hinthong W, Indrawattana N, Pitaksajjakul P, Pipattanaboon C, Kongngoen T, Tharnpoophasiam P, Worakhunpiset S - Int J Environ Res Public Health (2015)

Attachment of EAEC strains 17-2 and 042 to Hep-2 cells in an Adherence assay. (A) 17-2 at 37 °C; (B) 042 at 37 °C; (C) 17-2 at 33 °C; and (D) 042 at 33 °C. Magnification ×20.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555238&req=5

ijerph-12-08631-f003: Attachment of EAEC strains 17-2 and 042 to Hep-2 cells in an Adherence assay. (A) 17-2 at 37 °C; (B) 042 at 37 °C; (C) 17-2 at 33 °C; and (D) 042 at 33 °C. Magnification ×20.
Mentions: The ability of EAEC strains 17-2 and 042 to adhere to intestinal epithelial cells was determined by their ability to adhere to Hep-2 cells in an Adherence assay. For EAEC strain 17-2, the highest level of adherence was found in bacteria cultured at 33 °C and, while strain 042 showed the highest adherence at 30 °C (Figure 2). The lowest adherence of EAEC strain 17-2 was at 38 °C, and 32 °C in EAEC strain 042. At the same temperatures, a qualitative Adherence assay showed that EAEC strain 17-2 had higher numbers of bacteria adhering to Hep-2 cells than strain 042, especially at 33 °C (Figure 3). Nevertheless, the adherence between 29 °C and other temperatures and adherence of EAEC strain 17-2 and strain 042 were not significantly different (p-value > 0.05).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus