Using PCR-based assays to identify individual serotypes of Streptococcus pneumoniae (pneumococcus) in respiratory tract specimens, Lorry Rubin, MD, is interested in understanding how the bacteria colonize nasopharyngeal tissue. This colonization is the source of respiratory tract infections such as pneumonia and acute otitis media as well as invasive pneumococcal infections. The infected tissue also serves as the reservoir for person-to-person transmission. Routine vaccination of infants with heptavalent pneumococcal conjugate since 2000 has resulted in a large decrease in the incidence of invasive pneumococcal infections in young children in the United States.

Invasive disease was also reduced in adults. But vaccination has also led to an apparent increase in the prevalence of colonization with non-vaccine serotypes. As a result, there is a need for sensitive tests for detection of colonization with S. pneumoniae including detection of the occurrence of simultaneous colonization with more than one serotype. Dr. Rubin and his colleagues have developed polymerase chain reaction nucleic acid amplification-based tests that amplify and detect S. pneumoniae DNA in respiratory tract specimens. They are now validating their test.