Objectives Determine the prevalence of MDR-TB among patients with new smear-positive pulmonary TB in Port au Prince, Haiti Methods Sputum samples were cultured from 1006 patients diagnosed with new tuberculosis in 2008. The core region of the rpoB gene that is associated with resistance to rifampin was sequenced. All isolates with rpoB mutations were sent to the NY State reference laboratory for conventional drug susceptibility testing (DST). All isolates were also tested with the GenoType MTBDRplus line probe assay. Results M.tubercuosis was isolated from 906 patients. 26 (2.9%) of the isolates had mis-sense mutations or deletions in rpoB and were resistant to rifampin by DST. All 26 were also resistant to isoniazid and classified as MDR-TB. 46 control isolates without rpoB mutations were all found to be rifampin-sensitive by DST. The GenoType MTBDRplus line probe assay correctly identified 26 MDR-TB strains. It misclassified 1 pansusceptible isolate as RIF-resistant. Conclusions This study shows an MDR-TB prevalence of 2.9% in newly diagnosed TB patients in Haiti and also suggests that rpoB sequencing or hybridization assays are good screening tools for early detection of MDR-TB.

SUMMARY:The procedure of ultra-rapid extraction (PURE) and loop-mediated isothermal amplification for tuberculosis (LAMP-TB) is a simple and rapid manual tuberculosis diagnostic with mediumthroughput capability. Because of its simplicity, this method could be useful in resource-limited conditions such as microscopy centers in developing countries. This study was conducted to evaluate the clinical performance of this method in a point-of-care setting. The performance was compared to that of smear microscopy and liquid culture in a hospital laboratory in Haiti, which is considered a representative facility for the implementation of this method. The sensitivity, based on culture-positivity, was 86z (95z confidence interval: 81.3-90.3z) and that based on the smear-negative and culturepositive results was 51z (38.7-63.5z). The specificity based on sample negativity for both smear and culture was 98.4z (96.8-99.2). These results are nearly equivalent to those of a clinical study performed in Japan and are comparable with those of other nucleic acid amplification methods. Thus, approximately 18z more tuberculosis patients could be identified by adding the LAMP-TB method to routine smear microscopy in field settings in Haiti. In addition, it is suggested that local technicians could perform LAMP-TB after only short-term training.