Nahm-2012-in-Hospital-3Professor of Pulmonary, Allergy, and Critical Care
Director, NIH Bacterial Respiratory Pathogen Reference Laboratory

Director, WHO Pneumococcal Reference Laboratory

Address: 845 19th Street South
Bevill Research Bldg, room 614
Birmingham, AL 35294
Telephone: (205) 934-0163



Members of the Laboratory




B.A., Washington University in St. Louis MO
M.D., Washington University in St. Louis MO
Residency Training in Laboratory Medicine, Washington University in St. Louis MO
Postdoctoral fellow, Department of Microbiology, Washington University in St. Louis MO

Research Interests

Pneumococci are Gram-positive bacteria that are responsible for several important diseases such as pneumonia, meningitis, sepsis and ear infections. The most important virulence factor of pneumococci is their polysaccharide (PS) capsule. The main host defense against pneumococci is the production of anti-capsule antibodies. To study host-bacterial pathogen interactions and to improve pneumococcal vaccines, my laboratory studies the pneumococci's capsules and the hosts' anti-capsule antibodies. Pneumococci can evade host antibodies since they can produce many serologically distinct PS capsules (more than 90 serotypes). Out studies of diversity in pneumococcal PS capsules led us to discover new, previously unrecognized serotypes. One new serotype is 6C, which had previously been misclassified as serotype 6A. We have shown that 6C is chemically and genetically distinct from 6A, that its infection is not prevented by the currently available vaccine, and that its prevalence has been increasing worldwide. Based on our work on serotype 6C, we predicted and have discovered a new pneumococcal serotype 6D. These findings have had a great impact on pneumococcal vaccine developments and evaluations. Recent studies led us discover another new serotype, 11E. Serotype 11E is almost identical to serotype 11A, but 11E has inactive wcjE whereas 11A has a functional wcjE, a gene responsible for acetylating capsular PS. Our epidemiologic survey showed that 11E is rare among the isolates from the nasopharynx, but common among isolates from the blood. All isolates of serotype 11E are genetically distinct (i.e., have distinct wcjE inactivation patterns) and may have been derived from serotype 11A independently in each individual. These findings supports a hypothesis that innate immune factors present in the nasopharynx favors serotype 11A but innate immune factors in the blood favors serotype 11E. We are currently investigating this hypothesis. Our studies have also led us to develop various bio-technologies such as multiplexed assays for antibody function (MOPA) and automated serotyping of pneumococci (Multibead Assay). We are also investigating a new way to diagnose pneumococcal pneumonia based on the biochemical changes observed during pneumonia infections. These bio-technologies are of fundamental importance in developing pneumococcal vaccines and are widely used. Because of our development of these technologies and our expertise with pneumococcal antibodies, our laboratory is serving as the Reference Laboratory for both the NIH and the World Health Organization.