Oscar G. Gomez MD, PhD
Research Profile

At the present time we are studying a plasmid-encoded type IV pilus, designated longus, which has been identified in ETEC isolates from many countries. The major longus structural subunit (lngA) shares homology to major subunits of known colonization factors such as the toxin-co-regulated pilus of V. cholerae, CFA/III of ETEC, and the bundle-forming pilus of Enteropathogenic E. coli. Our research involves the identification and characterization of genes involved in the biosynthesis of longus. We are looking at the structural gene variation among many international isolates to determine if areas of conservation within the protein sequence may be used for vaccine development.

Molecular diagnostics for E. coli diarrheal disease. In addition to the bacterial pathogenesis project, my laboratory also works in a molecular epidemiology project with the goal of developing and implementing affordable and rapid diagnostic techniques for the identification of diarrheogenic bacterial pathogens from stool samples of children with diarrhea. This work is carried out in collaboration with international scientists and clinicians in Mexico and Colombia. The molecular-based techniques may facilitate diagnosis and management, and improve epidemiological surveillance in developing countries where the nature of the bacterial diarrheal diseases in children is unknown.

Recent Publications

1. Gomez-Duarte, O. G. 1987. Pseudomonas aeruginosa infection. Revista Facultad de Medicina. 30: 341-356.
2. Gomez-Duarte, O. G., and Kaper, J. B. 1995. A plasmid-encoded regulatory region activates chromosomal eaeA expression inenteropathogenic Escherichia coli. Infect. Immun. 63: 1767-1776.
3. Gomez-Duarte O. G., Galen J., Chatfield S., Rappuoli R., Eidels L., and Levine M. M. 1995.  Expression of fragment C of tetanus toxin fused to a carboxy-terminal fragment of diphtheria toxin in Salmonella typhi CVD 908 vaccine strain. Vaccine. 13: 1596-1602.
4. Giron J. A., Viboud G., Sperandio V., Gomez-Duarte O. G., Maneval D., Albert M., Levine M. M., and Kaper J. B. 1995. Prevalence and association of the Longus pilus structural gene (lngA) with colonization factor antigens, enterotoxin types and serotypes of Enterotoxigenic Escherichia coli. Infect. Immun. 63:4195-4198.
5. Barry E., Gomez-Duarte O. G., Chatfield S., Rappuoli R., Pizza M., Losonsky G., and Levine M. M. 1996. Expression and immunogenicity of pertussis toxin S1 subunit-tetanus toxin fragment C fusions in Salmonella typhi vaccine strain CVD908. Infect. Immun. 64:4172-4181.
6. Postnova T., Gomez-Duarte O. G., and Richardson K. 1996. Motility mutants of Vibrio cholerae O1 have reduced adherence in vitro to human small intestinal epithelial cells as demonstrated by ELISA. Microbiology. 142:2767-2776.
7. Kaper J. B., Gomez-Duarte O. G. 1997. The per regulator of enteropathogenic Escherichia coli. Mol. Microbiol. 23:179-181.
8. Gomez-Duarte O. G., Dehio M., Guzmán C., Chhatwal G., Dehio C. and Meyer T. F. 1997. Binding of Vitronectin to Opa-expressing Neisseria gonorrhoeae Mediates Invasion of HeLa Cells. Infect. Immun. 65:3857-3866.
9. Galen J., Gomez-Duarte O. G., Losonsky G., Halpern J., Lauderbaugh C., Kaintuk S., Reyman M., and Levine M. M. 1997. A murine model of intranasal immunization to assess the immunogenicity of attenuated Salmonella typhi live vector vaccines in stimulating serum antibody responses to expressed foreign antigens. Vaccine. 15:700-708.
10. Gomez-Duarte O. G., Lucas B., Yan Z., Panthel K., Haas R., and Meyer T. F. 1998 Urease subunits A and B delivered by attenuated Salmonella typhimurium vaccine strain protects mice against gastric colonization by Helicobacter pylori. Vaccine. 16:460-471.
11. Dehio M., Gomez-Duarte O. G., Dehio C. and Meyer T. F. 1998. Vitronectin-dependent invasion of epithelial cells by Neisseria gonorrhoeae involves alpha(v) integrin receptors. FEBS Let. 424:84-88.
12. Dehio C., Freissler E., Lanz C., Gomez-Duarte O. G., David G., Meyer T. F. 1998. Ligation of cell surface heparan sulfate proteoglycans by antibody- coated beads stimulates phagocytic uptake into epithelial cells: a model for cellular invasion by Neisseria gonorrhoeae. Exp. Cell Res. 242:528-539
13. Gomez-Duarte O. G., Ruiz-Tagle A., Gomez D. C., Vivoud G. I.,  Jarvis K. G., Kaper J. B., and Girón J. A 1999. Longus and colonization factor antigen III (CFA/III): two highly related but distinct type 4 pili produced by enterotoxigenic Escherichia coli. Microbiology. 145:1809-1816.
14. Wu S., Beier M., Sztein M. B., Galen J., Pickett T., Holder A., Gomez-Duarte O. G., Levine M. M. 2000. Construction and immunogenicity in mice of an attenuated Salmonella typhi expressing Plasmodium falciparum merozoite surface protein-1 (MSP-1) fused to Fragment C of tetanus toxin. J. Biotechnol. 83:125-135.
15. Gomez-Duarte O. G., Pasetti M., Santiago A., Sztein M. B., Hoffman S. L., Levine M. M. 2001. Expression, extra-cellular secretion, and immunogenicity of the Plasmodium falciparum sporozoite surface protein-2 in Salmonella vaccine strains. Infect. Immun. 69:1192-1198.
16. Chinchilla  M., Pasetti M. F., Medina-Moreno S., WangJ. W., Gomez-Duarte O. G., Rick Stout , Levine M. M., and Galen J. E. 2007. Enhanced immuny to Plasmodium falciparum circumsporozoite protein using Salmonella Typhi expressing PfCSP-encoding DNA vaccine in a heterologous prime-boost strategy. Infect. Immun.  75:3769-3779.
17. Gomez-Duarte O. G., Chattopadhyay S., Weissman S. J., Girón J. A, Kaper J. B., and E. V. Sokurenko. 2007. Genetic and evolutionary analysis of the operon encoding Longus type IV pilus of enterotoxigenic Escherichia coli. J. Bacteriol. In press.
18. Gomez-Duarte O. G., Bai J., and E. Newell. 2007. Multiple PCR assay for detection of E. coli and non-E. coli strains associated to diarrheal disease in children. Manuscript in preparation.
19. Gomez-Duarte O. G., Bai J., and P. A. Clavijo. 2007. Cloning and expression of Longus type IV pilus of enterotoxigenic Escherichia coli in K12 E. coli. 2007. J. Bacteriol. 189:9145-9149.
20. Rugeles-Garcia, L. C., M. C. Vanegas, and O. G. Gomez-Duarte. Evalutation of E. coli pathotypes from clinical and food isolates in Bogota, Colombia. Manuscript in preparation.
21. Gomez-Duarte, O. G., Bai, J., and E. Newel. 2008. Detection of E. coli,Salmonella spp., Shigella spp., Yersinia enterocolitica, Vibrio cholerae, and Campylobacter jejuni  enteropathogens by Multiplex PCR. Diag. Microbiol. Infect. Dis. Submitted for publication.
22. Rugeles, L., Bai J., Martinez, A., Gomez-Duarte, O. G., and M. Vanegas. 2008. Molecular characterization of diarrheogenic Escherichia coli isolated from food products and stools from children with diarrhea in Colombia. FEMS Microbiol. Submitted for publication.

Reviews

1. Gomez-Duarte, O. G., Yan Z., Haas R., Lucas B., and Meyer T. F. 1996. Helicobacter pylori live vaccine. European patent registration number 96116337.5. Max-Planck Gesellschaft.
2. Kaper J. B., McDaniel T. K., Jarvis K. G., Gomez-Duarte O. G. 1997. Genetics of virulence of enteropathogenic E. coli. Adv Exp Med Biol 1997; 412:279-287.
3. Giron J. A., Gomez-Duarte O. G., Jarvis K., Kaper J. B. 1997. Longus pilus of enterotoxigenic Escherichia coli and its relatedness to other type 4 pili. Gene. 192:39-43.
4. Gomez-Duarte, O. G., Bumann, D., and Meyer T. 1999. The Attenuated Salmonella Vaccine Approach for the Control of Helicobacter pylori-Related Diseases. Vaccine. 171667-1673.
5. Gomez-Duarte, O. G. 2000. Attenuated Salmonella vaccine as a vector for heterologous antigens. Biomédica. 20:131-143.
6. Levine, M. M., Galen, J., Barry, E., Tacket, C. C., Gomez-Duarte, O. G., Passeti, M. F. Sztein, M. B. 2000. Live vectors: have they delivered? In fighting infection. Blackwells, London.
7. Sanchez-Vargaz F. M., and O. G. Gomez-Duarte. 2008. Mycoplasma pneumoniae an emergent extrapulmonary pathogen. Clin. Microbiol. Infec. 14: 105–115.

Patent:
Helicobacter pylori live vaccine. World International Patent Organization. Patent No. PCT/EP1997/004744