Impact of GeneXpert MTB/RIF on patients and tuberculosis programs in a low-burden setting. a hypothetical trial.

RATIONALE: Guidelines recommend routine nucleic-acid amplification testing in patients with presumed tuberculosis (TB), but these tests have not been widely adopted. GeneXpert MTB/RIF (Xpert), a novel, semiautomated TB nucleic-acid amplification test, has renewed interest in this technology, but data from low-burden countries are limited. OBJECTIVES: We sought to estimate Xpert's potential clinical and public health impact on empiric treatment, contact investigation, and housing in patients undergoing TB evaluation. METHODS: We performed a prospective, cross-sectional study with 2-month follow-up comparing Xpert with standard strategies for evaluating outpatients for active pulmonary TB at the San Francisco Department of Public Health TB Clinic between May 2010 and June 2011. We calculated the diagnostic accuracy of standard algorithms for initial empiric TB treatment, contact investigation, and housing in reference to three Mycobacterium tuberculosis sputum cultures, as compared with that of a single sputum Xpert test. We estimated the incremental diagnostic value of Xpert, and the hypothetical reductions in unnecessary treatment, contact investigation, and housing if Xpert were adopted to guide management decisions. MEASUREMENTS AND MAIN RESULTS: A total of 156 patients underwent Xpert testing. Fifty-nine (38%) received empiric TB treatment. Thirteen (8%) had culture-positive TB. Xpert-guided management would have hypothetically decreased overtreatment by 94%, eliminating a median of 44 overtreatment days (interquartile range, 43-47) per patient and 2,169 total overtreatment days (95% confidence interval, 1,938-2,400) annually, without reducing early detection of TB patients. We projected similar benefits for contact investigation and housing. CONCLUSIONS: Xpert could greatly reduce the frequency and impact of unnecessary empiric treatment, contact investigation, and housing, providing substantial patient and programmatic benefits if used in management decisions.

A tuberculosis outbreak in a private-home family child care center in San Francisco, 2002 to 2004.

BACKGROUND: Child care facilities are well known as sites of infectious disease transmission, and California child care facility licensure requirements include annual tuberculosis (TB) screening for on-site adults. In April 2004, we detected an adult with TB living in a private-home family child care center (child care center A). METHODS: We reviewed patient medical records and conducted a contact investigation. The investigation included all persons at the child care center, the workplace and leisure contacts of the adult patient with TB, and the household contacts of secondary case patients. Contact names were obtained through patient interviews. A positive tuberculin skin test result was defined as induration of > or =5 mm. DNA fingerprints of Mycobacterium tuberculosis isolates were analyzed. Outbreak cases were those that had matching DNA fingerprint patterns or were linked epidemiologically, if DNA fingerprint results were not available. RESULTS: Between August 2002 and July 2004, we detected 11 outbreak cases, including 9 (82%) among children (<18 years of age). All 11 outbreak patients lived or were cared for at child care center A. The 9 pediatric TB patients were young (<7 years of age), United States-born children of foreign-born parents, and 4 (44%) had positive cultures for M tuberculosis. Including isolates recovered from the 2 adult patients, all 6 M tuberculosis isolates shared identical, 7-band, DNA fingerprint patterns. The contact investigation identified 3 (33%) of the 9 pediatric cases; 2 (22%) presented with illness and 4 (44%) were detected by primary care providers during routine TB screening. Excluding case subjects, 36 (54%) of 67 named contacts had latent TB infection. CONCLUSIONS: Provider adherence to locally adapted pediatric TB screening recommendations proved critical to outbreak control. TB screening compliance by the child care center and more aggressive source-case investigation by the TB program might have prevented or abated this large pediatric TB outbreak.