Research Interests
Our research focuses on the cellular, molecular, and ultrastructural aspects of the interaction of pathogenic bacteria with host cells. Specifically, we study structure-function mechanisms of novel adherence factors that mediate the adherence of pathogenic E. coli strains including, enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC), enterohemorrhagic (EHEC), and uropathogenic (UPEC) E. coli to host epithelial cells. We have recently identified 3 new pili types in EHEC O157:H7 and defining their role in human and bovine colonization is the central objective of our research. The new pili include the E. coli common pilus (ECP), a type IV pilus called hemorrhagic coli pilus (HCP) and the E. coli laminin-binding fimbriae (ELF). We are interested in understanding how these new pili are synchronized during human or bovine colonization, how they are regulated and if their expression if coupled to expression of other virulence factors.
Of interest as well, is to study the molecular mechanisms of pili biogenesis. Recent outbreaks of intestinal disease in the USA associated to consumption of tainted spinach stimulated us to study the interaction of leafy greens with E. coli O157:H7. We have found that this human pathogen establishes a niche on the produce leaves where they can survive in the environment and gain access to the human host.
We also expand our study to other human and animal pathogenic bacteria such as Shigella, Vibrio cholera, Klebsiella pneumoniae, Brucella, and Mycobacterium tuberculosis.
We have studied the adherence properties of Brucella spp., a human and animal pathogenic microorganism classified as a potential bioterrorism agent and we are interested in pursuing the study of the role of surface proteins as adhesins in this organism. Recently, we discovered that M. tuberculosis is capable of assembling pili structures and their role in the pathogenesis scheme of this organism remains elusive. Future studies will aim at determine the biological and immunological relevance of pili in the mycobacteria.
An exciting and innovative aspect of our research is the relationship between the assembly machineries of type 3 secretion systems, flagella, and type IV pili. We hope to provide useful information regarding their coordinate regulation and function within the context of the interaction of the pathogen with host cells.
Our long-term goal is the understanding of how bacterial pathogens interact with host epithelial cells aiming at proposing new strategies for prevention of infectious diseases.
Recent
Peer-Reviewed Publications
1.
Rendón, MA,
Saldaña, Z,
Monteiro-Neto, V, Erdem, AL, Vázquez, A, Kaper, JB, Puente, JL,
and Girón, JA.2007.
Commensal and pathogenic Escherichia
coli use a common adherence factor for epithelial cell colonization.
Proc. Natl. Acad. Sci. USA. 104:10637-10642.
2.
Xicohtencatl-Cortes, Z, Monteiro-Neto, V, Francetic, O, Rendón, MA,
Ledesma, MA, Kaper, JA, Puente, JL, and Girón, JA. 2007.
Intestinal adherence
associated with type IV pili of enterohemorrhagic Escherichia
coli O157:H7. J. Clin Invest.
117(11):
3519–3529.
3.
Alteri, C., Xicohtencatl, J., Hess, S., Caballero, G., Girón, JA,
and Friedman, RL. 2007. Mycobacterium tuberculosis
produces pili during human infection. Proc. Natl. Acad. Sci.
USA 104 (12) 5145-50.
4.
Saldaña Z,
Erdem AL, Okeke IN, Lucas, M., Phillips AD, Kaper JB, Puente, JL,
Girón JA. 2009. The
Escherichia coli
common pilus and the bundle-forming pilus act in concert during the
formation of localized adherence by enteropathogenic
E. coli.
J Bacteriol.
Jun;191(11):3451-61.
5.
Saldaña Z, Xicohtencatl-Cortes J, Avelino F, Phillips AD, Kaper JB,
Puente JL, Girón JA. 2009.
Synergistic role of curli and cellulose in cell adherence and
biofilm formation of attaching and effacing
Escherichia coli and
identification of Fis as a negative regulator of curli.
Environ Microbiol. 11(4):992-1006.
6.
Blackburn, D., Husband A., Saldana, Z., Rana, NA, Klena, J., Qadri,
F., and Girón JA. 2009.
Distribution of the
Escherichia coli Common Pilus (ECP) among Diverse Strains of
Human Enterotoxigenic E. coli.
J. Clin. Microbiol. 47(6):1781-4.
7.
Xicohtencatl-Cortes, J., M.E.Sánchez, Saldaña, Z., E. Freer,, and
Girón, JA. 2009. The interaction of enterohemorrhagic
Escherichia coli with
leafy green produce.
J Food Prot.
2009 Jul;72(7):1531-7.
8.
8.
Avelino,F., Saldaña, Z., Islam, S., Monteiro-Neto, V.,
Dall’Agnol, M., Eslava, CA., Girón, JA. 2010..
The majority of enteroaggregative
Escherichia coli strains produce the E. coli common pilus
when adhering to cultured epithelial cells. Int. J. Med. Microbiol.
2010 May
6. [Epub ahead of print]PMID:
20452276.
9.
Xicohtencatl-Cortes, J,
Saldaña, Z, Deng, W., Castaneda, E., Freer, E., Tarr, PI, Finlay,
BB., Puente, JL, Girón,
JA.
Bacterial macroscopic rope-like fibers with cytopathic and adhesive
properties.
J Biol Chem.
2010 Aug 5. Epub ahead of print.
10.
Ledesma MA, Ochoa SA, Cruz A, Rocha-Ramírez LM, Mas-Oliva J, Eslava
CA, Girón JA, Xicohtencatl-Cortes J.
The Hemorrhagic Coli
Pilus (HCP) of Escherichia coli O157:H7 is an inducer of
proinflammatory cytokine secretion in intestinal epithelial cells.
PLoS One. 2010 Aug
12;5(8). pii: e12127.
