Limits...
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

OD570 nm values from biofilm formation assay at various temperatures for EAEC strains 17-2 (■) and 042 (□).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4555238&req=5

ijerph-12-08631-f004: OD570 nm values from biofilm formation assay at various temperatures for EAEC strains 17-2 (■) and 042 (□).

Mentions: We next studied biofilm formation to investigate the adherence ability of EAEC, and to determine whether these results confirmed those of the Adherence assay at the same temperature points. Biofilm formation by EAEC strains 17-2 and 042 under different temperatures was determined by light absorbance at OD570 nm. Although we observed a similar biofilm formation trend for both EAEC strains, EAEC strain 17-2 showed a distinct increase particularly at 33 °C which significantly different from biofilm formation at 29 °C (p-value < 0.05). Other temperature observed to be significantly different from biofilm formation at 29 °C of EAEC strain 17-2 included 30 °C, 32 °C, 33 °C, 34 °C, 36 °C, 37 °C, 38 °C and 40 °C. In a different manner, EAEC strain 042 showed a less distinct trend with the highest formation detected at 40 °C. But biofilm formation at 31 °C–40 °C of EAEC strain 042 was significantly different from that of 29 °C (p-value < 0.05). Both EAEC strains showed low biofilm formation at 34 °C and 38 °C, which represented the lowest levels for EAEC strain 042 and 17-2, respectively (Figure 4). Significant difference of biofilm formation between both EAEC strains was observed at 29 °C, 32 °C, 33 °C, 34 °C, 36 °C, 37 °C, 38 °C and 40 °C (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)

OD570 nm values from biofilm formation assay at various temperatures for EAEC strains 17-2 (■) and 042 (□).
© Copyright Policy
Related In: Results  -  Collection

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

ijerph-12-08631-f004: OD570 nm values from biofilm formation assay at various temperatures for EAEC strains 17-2 (■) and 042 (□).
Mentions: We next studied biofilm formation to investigate the adherence ability of EAEC, and to determine whether these results confirmed those of the Adherence assay at the same temperature points. Biofilm formation by EAEC strains 17-2 and 042 under different temperatures was determined by light absorbance at OD570 nm. Although we observed a similar biofilm formation trend for both EAEC strains, EAEC strain 17-2 showed a distinct increase particularly at 33 °C which significantly different from biofilm formation at 29 °C (p-value < 0.05). Other temperature observed to be significantly different from biofilm formation at 29 °C of EAEC strain 17-2 included 30 °C, 32 °C, 33 °C, 34 °C, 36 °C, 37 °C, 38 °C and 40 °C. In a different manner, EAEC strain 042 showed a less distinct trend with the highest formation detected at 40 °C. But biofilm formation at 31 °C–40 °C of EAEC strain 042 was significantly different from that of 29 °C (p-value < 0.05). Both EAEC strains showed low biofilm formation at 34 °C and 38 °C, which represented the lowest levels for EAEC strain 042 and 17-2, respectively (Figure 4). Significant difference of biofilm formation between both EAEC strains was observed at 29 °C, 32 °C, 33 °C, 34 °C, 36 °C, 37 °C, 38 °C and 40 °C (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