Leonard F. Peruski, Jr., Ph.D.

Former Associate Professor of Microbiology and Immunology (Resigned)




Michigan Technological University, Department of Biological Sciences, Houghton, 1981, B.S. (Biology)
University of Michigan Medical School, Ann Arbor, 1983, M.S. (Microbiology); 1988, Ph.D. (Microbiology)


National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado, Postdoctoral Fellow
Staff Microbiologist, National Center for Human Genome Research, National Institutes of Health, Bethesda, Maryland
Head, Enteric Microbiology Program, Naval Medical Research Unit No. 3, Cairo, Egypt
Chief Scientist, Biological Defense Research Directorate, Naval Medical Research Center, Silver Spring, Maryland


Former Associate Professor, Microbiology and Immunology
Former Lecturer, Step 6 Invasion and Defense


American Society for Microbiology
American Association for the Advancement of Science

Research Description:

Discovery of Novel Virulence Factors in Enterotoxigenic E. coli

The bacterial pathogen, enterotoxigenic Escherichia coli (ETEC) is the leading causative agent of acute infectious diarrheal disease in deployed military forces and remains a major public health problem in the developing world, affecting young children that are residents and travelers visiting from developed nations. The cholera-like disease caused by ETEC is usually only an inconvenience to the latter group but is often life-threatening to local children, resulting in significant morbidity and mortality. Two virulence attributes that define ETEC are adhesins called colonization factors (CF), and two enterotoxins, a heat-labile toxin (LT) and a heat-stable toxin (ST). Enterotoxins and CFs work in concert to cause diarrhea. Both LT and individual CFs have been implicated as protective antigens and have accordingly become the focus of ETEC vaccine development efforts. As the role of CFs in the pathogenesis of ETEC has been well described, control strategies for ETEC have focused on the 20 known CFs of ETEC. But as up to 60% ETEC strains do not express one of these antigens, it is believed that many CFs remain undiscovered. Because of these observations, three years ago we began screening of ETEC strains for CFs that remain undetected by current methods. Our proposed study has three aims: (1) identify and characterize novel colonization factors (CF) from diarrhea-causing ETEC strains; (2) produce polyclonal and monoclonal antibodies reactive against these novel CFs for the use as diagnostic reagents; and (3) clone, characterize, and express genes encoding the novel CFs of greatest epidemiological and biological relevance.

In recent work, we identified an ETEC strain (serotype O39:H ) that expressed LT enterotoxin and while negative for known CFs, it adhered to the enterocyte-like cell line Caco-2, suggesting that it may elaborate a novel adhesin. Purification of surface antigens yielded two protein bands with apparent molecular masses (Mr) of 21,000 and 26,000. A mouse polyclonal antibody (PAb) raised against this crude protein fraction reacted with original strain and also with other ETEC strains that expressed CFA/I, CFA/III, CS1, CS2, CS6, CS19, PCFO159, and PCFO166. Serial absorption of the PAb eliminated this cross-reactivity, yielding sera that was highly specific. Using electrospray mass-spectrometric analysis the Mr of the putative CF was determined to be 18,280. A monoclonal antibody (MAb) specific for the putative fimbriae was made and used to screen a type collection of ETEC strains isolated from Africa and originally identified as CF-negative. Of these strains, 8% reacted with the MAb. All expressed LT and had originally been identified as CF-negative. Serotypes identified among these strains included O39:H-, O44:H18, and O60:H5. Our findings suggest that this putative CF is both novel and biologically relevant in ETEC pathogenesis and human disease.

Selected Bibliography:

Books , Chapters and Journals

Peruski, L.F., B.E. Wadzinski, and G.L. Johnson. 1993. Analysis of the multiplicity, structure, and function of protein serine/threonine phosphatases, in Adv. Prot. Phosphatases, Vol. 7, pp. 9-30. W. Merlevede (ed.), Leuven University Press, Leuven, Belgium

Peruski, L.F., and A.H. Peruski. 1997. The Internet and the New Biology: Tools for Genomic and Molecular Research. ASM Press, American Society for Microbiology, Washington D.C., 314 pp.

Peruski, L.F. Jr., and A. Harwood Peruski (editors). Special Section: Rapid Detection and Identification of Infectious Disease Agents. BioTechniques, Vol. 35, No. 4 (October 2003).


Oyofo, B.A., Z.S. Mohran, S.H. El-Etr, M.O. Wasfy, and L.F. Peruski Jr. 1996. Detection of enterotoxigenicEscherichia coli, Shigella and Campylobacter by multiplex PCR assay. J. Diarr. Dis. Res. 14:207-210.

Ismail, T.F., M.O. Wasfy, B.A. Oyofo, M.M. Mansour, H.M. El-Berry, A.M. Churilla, S.S. Eldin, and L.F. Peruski Jr. 1997. Evaluation of antibodies reactive with Campylobacter jejuni in Egyptian diarrhea patients. Clin. Diag. Lab. Immunol. 4:536-539.

Savarino, S.J., F.M. Brown, E.R. Hall, S. Bassily, F. Youseff, T.F. Wierzba, L.F. Peruski Jr., N.A. El-Masry, M. Safwat, M. Rao, A.L. Bourgeois, M. Jertborn, A.-M. Svennerholm, Y.J. Lee, and J.D. Clemens. 1998. Safety and immunogenicity of an oral, killed enterotoxigenic Escherichia coli-cholera toxin B subunit vaccine in Egyptian adults. J. Inf. Dis. 177:796-799.

El-Gendy, A., N. El-Ghorab, E.M. Lane, R. Abu-Elyazeed, N.I. Carlin, M.M. Mitry, B.A. Kay, S.J. Savarino, andL.F. Peruski Jr. 1999. Identification of Shigella flexneri subserotype 1c in rural Egypt. J. Clin. Microbiol.37:873-874.

Khalil, S.B., F.J. Cassels, H.I. Shaheen, L.K. Pannell, N. El-Ghorab, K. Kamal, M. Mansour, S.J. Savarino, andL.F. Peruski Jr. 1999. Characterization of an enterotoxigenic E. coli strain from Africa expressing a putative colonization factor. Infect. Immun. 67:4019-4026.

Peruski, L.F., B.A. Kay, R. Abu-Elyazeed, S.H. El-Etr, A. Cravioto, T.F. Wierzba, N. El-Ghorab, H. Shaheen, S.B. Khalil, K. Kamal, M.O. Wasfy, M. Rao, J.D. Clemens, A.-M. Svennerholm, and S.J. Savarino. 1999. Phenotypic diversity of enterotoxigenic Escherichia coli (ETEC) from a community-based study of pediatric diarrhea in rural Egypt. J. Clin. Microbiol. 37:2974-2978.

Wasfy, M.O., B.A. Oyofo, J.C. David, T.F. Ismail, A.M. El-Gendy, Z.S. Mohran, Y. Sultan, and L.F. Peruski Jr.2000. Isolation and antibiotic susceptibility of Salmonella, Shigella, and Campylobacter from acute enteric infections in Egypt. J. Health Popul. Nutr. 18:33-38.

Callahan, J.D., S-J. L. Wu, A. Dion-Schultz, B.E. Mangold, L.F. Peruski Jr., D.M. Watts, K.R. Porter, G.R. Murphy, W. Suharyono, C.-C. King, C.G. Hayes, and J.J. Temenak. 2001. Development and evaluation of serotype- and group-specific fluorogenic reverse transcriptase PCR (TaqMan) assays for dengue virus. J. Clin. Microbiol. 39:4119-4124.

Savarino, S.J., D.R. Hall, S. Bassily, T.F. Wierzba, F. Youssef, L.F. Peruski Jr., R. Abu-Elyazeed, M. Rao, W.M. Francis, H. El-Mohamady, M. Safwat, A.B. Naficy, A.M. Svennerholm, J. Jertborn, Y.J. Lee, and J.D. Clemens. 2002. Introductory evaluation of an oral, killed whole cell Escherichia coli plus cholera toxin B subunit vaccine in children under two years of age. Ped. Infect. Dis. J., 21: 3220330.

Peruski, A.H., L.H. Johnson III, and L.F. Peruski Jr. 2002. Rapid and sensitive detection of biological warfare agents using time resolved fluorescence (TRF) assays. J. Immunol. Methods, 263:35-41.*

Heller,H.B., M.L. Bunning, M.E.B. France, D.M. Niemeyer, L.F. Peruski Jr., T. Naimi, P. Talboy, P.H. Murray, H.W. Pietz,J. Kornblum, W. Oleszko, S.T. Beatrice, Joint Microbiological Rapid Response Team, and New York City Anthrax Investigation Working Group. 2002. Laboratory response to anthrax bioterrorism, New York City, 2001. Emerg. Infect. Dis. 8:1096-1102.

Shaheen, H.I., K.A. Kamal, M.O. Wasfy, N.M. El-Ghorab, B. Lowe, R. Steffen, N. Kodkani, L. Amsler, J.C. David, W. Jefferson, S.B. Khalil, and L.F. Peruski Jr. 2003 Phenotypic diversity of enterotoxigenicEscherichia coli (ETEC) from travelers diarrhea in Kenya. Int. J. Infect. Diseases, 7:35-41.

Peruski, L.F., and A.H. Peruski. 2003 Rapid diagnostic assays in the genomic biology era: detection and identification of infectious disease and biological weapon agents. BioTechniques 35:840-846.*

Andreotti P.E., G.V. Ludwig, A.H. Peruski, J.J. Tuite, S.S. Morse, and L.F. Peruski Jr. 2003. Immunoassay of infectious agents. BioTechniques 35:850-859.*

*Click on Link to download an Adobe PDF reprint.

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