Tuberculosis is the major infectious cause of mortality among AIDS patients in the developing world, and HIV infection has been shown to increase mortality from tuberculosis five-fold in parts of Subsaharan Africa. Increasingly, HI V-infected children in developing countries are becoming infected with Mycobacterium tuberculosis (Mtb) and dying at an early age, presenting new dilemmas that differ from those facing adults with HIV-Mtb coinfection. The diagnosis of pediatric TB is complicated by inefficient and expensive methods to recover Mtb and vague diagnostic criteria. This project will evaluate novel approaches to the diagnosis of AIDS-related pediatric TB in a hyperendemic setting using 1) rapid, cost-effective Mtb culture and susceptibility methods based on direct microscopic observation techniques and 2) alternative non-invasive specimens such as nasopharyngeal aspirates (NPA) and stool to detect Mtb. An optional component will assess improved rapid detection of Mtb by a semi-nested polymerase chain reaction assay (N2 PCR), a technique appropriate for regional reference laboratories in developing countries. Our preliminary data show a high correlation between culture results and N2 PCR results in adults (sputum PCR) and children (stool and NPA PCR) with tuberculosis, and mean time to detection of Mtb by our microscopic observation method was 9 days (at a fraction of the cost of rapid methods used in the U.S.). This is a collaborative effort between PRISMA, a Peruvian private voluntary organization, two U.S. universities (Tulane and Johns Hopkins), and a Peruvian university (Cayetano Heredia). Two hundred-sixty children with pulmonary disease meeting clinical criteria for TB disease (including at least 100 HIV-infected) from the Hospital del Nino, Lima, Peru, and 260 age-matched controls from both high- and low-risk communities will be enrolled. Mtb will be detected in gastric aspirates (cases only), NPAs, and stool by new and traditional culture methods and by N2 PCR. Children with a positive N2 PCR but without clinical evidence of TB requiring antituberculous therapy will be followed longitudinally. These new diagnostic methods have tremendous potential to improve and simplify the diagnosis of pediatric tuberculosis in low-income countries with limited laboratory resources.
