CS6 is the predominant colonization factor of enterotoxigenic (ETEC). We report the existence of multiple CS6 subtypes caused by natural point mutations in and , the structural genes for CS6. The subtype AIBI was mostly associated with ETEC isolated from diarrhoeal cases, whereas AIIBII was mostly found in asymptomatic controls. Here we explore the rationale behind this association. ETEC isolates expressing AIIBII showed weaker adherence to intestinal epithelial cells compared with ETEC expressing AIBI. AIIBII expression on the ETEC cell surface was threefold less than AIBI. We found that alanine at position 37 in CssAII, in conjunction with asparagine at position 97 in CssBII, was responsible for the decreased levels of AIIBII on the bacterial surface. In addition, purified AIIBII showed fourfold less mucin binding compared with AIBI. The asparagine at position 97 in CssBII was also accountable for the decreased mucin binding by AIIBII. Reduced fluid accumulation and colonization occurred during infection with ETEC expressing AIIBII in animal models. Together these results indicate that the differential adherence between AIBI and AIIBII was a cumulative effect of decreased surface-level expression and mucin binding of AIIBII due to two specific amino acid variations. As a consequence, ETEC expressing these two subtypes displayed differential pathogenicity. We speculate that this might explain the subjective association of AIBI with ETEC from diarrhoeal cases and AIIBII with asymptomatic controls.


Article metrics loading...

Loading full text...

Full text loading...



  1. Baker K. K., Levine M. M., Morison J., Phillips A., Barry E. M. (2009). CfaE tip mutations in enterotoxigenic Escherichia coli CFA/I fimbriae define critical human intestinal binding sites. Cell Microbiol 11, 742754. [View Article][PubMed] [Google Scholar]
  2. Baselski V., Briggs R., Parker C. (1977). Intestinal fluid accumulation induced by oral challenge with Vibrio cholerae or cholera toxin in infant mice. Infect Immun 15, 704712.[PubMed] [Google Scholar]
  3. Black R. E. (1990). Epidemiology of travelers’ diarrhea and relative importance of various pathogens. Rev Infect Dis 12 ( Suppl 1), S73S79. [View Article][PubMed] [Google Scholar]
  4. Black R. E. (1993). Epidemiology of diarrhoeal disease: implications for control by vaccines. Vaccine 11, 100106. [View Article][PubMed] [Google Scholar]
  5. Boddicker J. D., Ledeboer N. A., Jagnow J., Jones B. D., Clegg S. (2002). Differential binding to and biofilm formation on, HEp-2 cells by Salmonella enterica serovar Typhimurium is dependent upon allelic variation in the fimH gene of the fim gene cluster. Mol Microbiol 45, 12551265. [View Article][PubMed] [Google Scholar]
  6. Elder B. L., Boraker D. K., Fives-Taylor P. M. (1982). Whole-bacterial cell enzyme-linked immunosorbent assay for Streptococcus sanguis fimbrial antigens. J Clin Microbiol 16, 141144.[PubMed] [Google Scholar]
  7. Gaastra W., Svennerholm A. M. (1996). Colonization factors of human enterotoxigenic Escherichia coli (ETEC). Trends Microbiol 4, 444452. [View Article][PubMed] [Google Scholar]
  8. Ghosal A., Bhowmick R., Nandy R. K., Ramamurthy T., Chatterjee N. S. (2007). PCR-based identification of common colonization factor antigens of enterotoxigenic Escherichia coli . J Clin Microbiol 45, 30683071. [View Article][PubMed] [Google Scholar]
  9. Ghosal A., Bhowmick R., Banerjee R., Ganguly S., Yamasaki S., Ramamurthy T., Hamabata T., Chatterjee N. S. (2009). Characterization and studies of the cellular interaction of native colonization factor CS6 purified from a clinical isolate of enterotoxigenic Escherichia coli . Infect Immun 77, 21252135. [View Article][PubMed] [Google Scholar]
  10. Grange P. A., Mouricout M. A., Levery S. B., Francis D. H., Erickson A. K. (2002). Evaluation of receptor binding specificity of Escherichia coli K88 (F4) fimbrial adhesin variants using porcine serum transferrin and glycosphingolipids as model receptors. Infect Immun 70, 23362343. [View Article][PubMed] [Google Scholar]
  11. Helander A., Hansson G. C., Svennerholm A. M. (1997). Binding of enterotoxigenic Escherichia coli to isolated enterocytes and intestinal mucus. Microb Pathog 23, 335346. [View Article][PubMed] [Google Scholar]
  12. Jansson L., Tobias J., Jarefjäll C., Lebens M., Svennerholm A. M., Teneberg S. (2009). Sulfatide recognition by colonization factor antigen CS6 from enterotoxigenic Escherichia coli . PLoS ONE 4, e4487. [View Article][PubMed] [Google Scholar]
  13. Kisiela D., Sapeta A., Kuczkowski M., Stefaniak T., Wieliczko A., Ugorski M. (2005). Characterization of FimH adhesins expressed by Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum: reconstitution of mannose-binding properties by single amino acid substitution. Infect Immun 73, 61876190. [View Article][PubMed] [Google Scholar]
  14. Lowry O. H., Rosebrough N. J., Farr A. L., Randall R. J. (1951). Protein measurement with the Folin phenol reagent. J Biol Chem 193, 265275. [Google Scholar]
  15. Mondal M., Nag D., Koley H., Saha D. R., Chatterjee N. S. (2014). The Vibrio cholerae extracellular chitinase ChiA2 is important for survival and pathogenesis in the host intestine. PLoS ONE 9, e103119. [View Article][PubMed] [Google Scholar]
  16. Qadri F., Svennerholm A. M., Faruque A. S. G., Sack R. B. (2005). Enterotoxigenic Escherichia coli in developing countries: epidemiology, microbiology, clinical features, treatment, and prevention. Clin Microbiol Rev 18, 465483. [View Article][PubMed] [Google Scholar]
  17. Roy S. P., Rahman M. M., Yu X. D., Tuittila M., Knight S. D., Zavialov A. V. (2012). Crystal structure of enterotoxigenic Escherichia coli colonization factor CS6 reveals a novel type of functional assembly. Mol Microbiol 86, 11001115. [View Article][PubMed] [Google Scholar]
  18. Sabui S., Ghosal A., Dutta S., Ghosh A., Ramamurthy T., Nataro J. P., Hamabata T., Chatterjee N. S. (2010). Allelic variation in colonization factor CS6 of enterotoxigenic Escherichia coli isolated from patients with acute diarrhoea and controls. J Med Microbiol 59, 770779.[PubMed][CrossRef] [Google Scholar]
  19. Sabui S., Dutta S., Debnath A., Ghosh A., Hamabata T., Rajendran K., Ramamurthy T., Nataro J. P., Sur D. et al. (2012). Real-time PCR-based mismatch amplification mutation assay for specific detection of CS6-expressing allelic variants of enterotoxigenic Escherichia coli and its application in assessing diarrheal cases and asymptomatic controls. J Clin Microbiol 50, 13081312. [View Article][PubMed] [Google Scholar]
  20. Sokurenko E. V., Courtney H. S., Ohman D. E., Klemm P., Hasty D. L. (1994). FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes. J Bacteriol 176, 748755.[PubMed] [Google Scholar]
  21. Sokurenko E. V., Courtney H. S., Maslow J., Siitonen A., Hasty D. L. (1995). Quantitative differences in adhesiveness of type 1 fimbriated Escherichia coli due to structural differences in fimH genes. J Bacteriol 177, 36803686.[PubMed] [Google Scholar]
  22. Tobias J., Lebens M., Källgård S., Nicklasson M., Svennerholm A. M. (2008). Role of different genes in the CS6 operon for surface expression of Enterotoxigenic Escherichia coli colonization factor CS6. Vaccine 26, 53735380. [View Article][PubMed] [Google Scholar]
  23. Trevelyan W. E., Harrison J. S. (1952). Studies on yeast metabolism. 1. Fractionation and micro determination of cell carbohydrates. Biochem J 50, 298303. [Google Scholar]
  24. Wajima T., Sabui S., Fukumoto M., Kano S., Ramamurthy T., Chatterjee N. S., Hamabata T. (2011). Enterotoxigenic Escherichia coli CS6 gene products and their roles in CS6 structural protein assembly and cellular adherence. Microb Pathog 51, 243249. [View Article][PubMed] [Google Scholar]
  25. Wajima T., Sabui S., Kano S., Ramamurthy T., Chatterjee N. S., Hamabata T. (2013). Entire sequence of the colonization factor coli surface antigen 6-encoding plasmid pCss165 from an enterotoxigenic Escherichia coli clinical isolate. Plasmid 70, 343352. [View Article][PubMed] [Google Scholar]
  26. WHO (2006). Future directions for research on enterotoxigenic Escherichia coli vaccines for developing countries. Wkly Epidemiol Rec 81, 97104.[PubMed] [Google Scholar]
  27. Wolf M. K. (1997). Occurrence, distribution, and associations of O and H serogroups, colonization factor antigens, and toxins of enterotoxigenic Escherichia coli . Clin Microbiol Rev 10, 569584.[PubMed] [Google Scholar]
  28. Wolf M. K., de Haan L. A., Cassels F. J., Willshaw G. A., Warren R., Boedeker E. C., Gaastra W. (1997). The CS6 colonization factor of human enterotoxigenic Escherichia coli contains two heterologous major subunits. FEMS Microbiol Lett 148, 3542. [View Article][PubMed] [Google Scholar]

Data & Media loading...


Supplementary Data


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error