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Stephen D. Allen, MD

James W. Smith Professor of Clinical Microbiology

Indiana University School of Medicine 
IU Health Pathology Laboratory
350 West 11th Street, Room 6027
Indianapolis, IN 46202-4108

Telephone: (317) 491-6643
FAX: (317) 491-6419
email: sallen@iupui.edu

My research interests are in the following areas:

  1. Diagnostic and public health microbiology
  2. Roles of:
    1. free-living amoebae
    2. anaerobic bacteria in diseases
  3. Human microbial ecology.

In diagnostic (clinical) microbiology, on-going research projects are focused on the activities of new antibiotics against clinically encountered aerobic bacteria, anaerobic bacteria, and free-living amoebae, and the emergence of resistance to antimicrobics that we are now encountering in Enterococcus species, Streptococcus pneumoniae, and in anaerobes.  Our laboratory also has a major interest in rapid diagnostic methods, and in developing and evaluating new or improved methods for diagnosing infections caused by anaerobic and non-anaerobic enteric bacteria.

Roles of free-living amoebae and anaerobic bacteria in diseases: In the Amoeba Research Laboratory, currently we are studying certain small, soil and water, free-living amoebae (e.g., Acanthamoeba spp., Naegleria spp., and others); we are studying the epidemiologic, clinical, pathologic, and laboratory diagnostic features of amoebic infections.  In the Anaerobe Laboratory, we are studying the roles of certain anaerobes (including Clostridium septicum, C. difficile, and C. perfringens) in intestinal diseases, and we are especially interested in mechanisms of pathogenesis of diseases caused by the clostridia.

We are highly interested in the growth of, and in limiting factors that influence the growth of, mixed populations of microorganisms (e.g., Acanthamoeba spp. with bacteria in amoebic keratitis, or with Legionella spp. in Legionnaires' Disease).  Last but not least, we are especially interested in the fatty acid and steroid metabolism of intestinal microorganisms, the effects of fatty acids and biliary steroids on host cells and tissues, and how the indigenous microbiota is influenced by diet, and how diet and metabolic products of the intestinal microbiota could play a role in the pathogenesis of certain neoplasms (e.g., breast cancer; colorectal cancer).

Publications:

Books and Chapters:

Allen, S.D. and C.G. Culbertson. 1992. Naegleria and Acanthamoeba Chapter 182, pp. 2020-2032. In: Feigin, R. and J. Cherry. Textbook of Pediatric Infectious Diseases. Edition 3. W. B. Saunders Co., Philadelphia, PA.

Allen, S.D. and B.I. Duerden. 1998. Infections due to non-sporing anaerobic bacilli and cocci. Chapter 38, pp. 743-776. In: L. Collier, A. Balows, M. Sussman, and W.J. Hausler (eds.), Topley & Wilson's Microbiology and Microbial Infections, 9th ed., vol. 3. Edward Arnold Publisher.

Lyerly, D.M., and S.D. Allen. 1997. The Clostridia. Chapter 19a, pp. 599-623. In: Emmerson, P. Hawkey, and S. Gillespie (eds.), Principles and Practice of Clinical Bacteriology. John Wiley & Sons, New York.

Journal Articles:

Kahi CJ. Wheat LJ. Allen SD. Sarosi GA; Gastrointestinal histoplasmosis; American Journal of Gastroenterology; 100(1):220-31, 2005 Jan.

Hudson JD. Danis RP. Chaluvadi U. Allen SD; Posttraumatic exogenous Nocardia endophthalmitis. American Journal of Ophthalmology; 135(6):915-7, 2003 Jun.