Carlos Acuna-Villaorduna

Cost-Effectiveness Analysis of Introduction of Rapid, Alternative Methods to Identify Multidrug-Resistant Tuberculosis in Middle-Income Countries

BACKGROUND Resistance to commonly used antituberculosis drugs is emerging worldwide. Conventional drug-susceptibility testing (DST) methods are slow and demanding. Alternative, rapid DST methods would permit the early detection of drug resistance and, in turn, arrest tuberculosis transmission. METHODS A cost-effectiveness analysis of 5 DST methods was performed in the context of a clinical trial that compared rapid with conventional DST methods. The methods under investigation were direct phage-replication assay (FASTPlaque-Response; Biotech), direct amplification and reverse hybridization of the rpoB gene (INNO-LiPA; Innogenetics), indirect colorimetric minimum inhibitory concentration assay (MTT; ICN Biomedicals), and direct proportion method on Löwenstein-Jensen medium. These were compared with the widely used indirect proportion method on Löwenstein-Jensen medium. RESULTS All alternative DST methods were found to be cost-effective, compared with other health care interventions. DST methods also generate substantial cost savings in settings of high prevalence of multidrug-resistant tuberculosis. Excluding the effects of transmission, the direct proportion method on Löwenstein-Jensen medium was the most cost-effective alternative DST method for patient groups with prevalences of multidrug-resistant tuberculosis of 2%, 5%, 20%, and 50% (cost in US

Development of a clinical scoring system for the diagnosis of smear-negative pulmonary tuberculosis.

2004,

Outcomes of Multidrug-Resistant Tuberculosis among Binational Cases in El Paso, Texas

94,

Cough Aerosols of Mycobacterium tuberculosis in the Prediction of Incident Tuberculosis Disease in Household Contacts

36,

Evaluation of the performance of two liquid-phase culture media for the diagnosis of pulmonary tuberculosis in a national hospital in Lima, Peru

8, and

Evaluation of Clinical Prediction Rules for Respiratory Isolation of Inpatients with Suspected Pulmonary Tuberculosis

2 per disability-adjusted life year, respectively). CONCLUSION Alternative, rapid methods for DST are cost-effective and should be considered for use by national tuberculosis programs in middle-income countries.

Intensity of exposure to pulmonary tuberculosis determines risk of tuberculosis infection and disease

This study developed a clinical score based on clinical and radiographic data for the diagnosis of smear-negative pulmonary tuberculosis (SNPT). SNPT was defined as a positive culture in Ogawa in a patient with two negative sputum smears. Data from patients admitted to the emergency ward with respiratory symptoms and negative acid-fast bacilli (AFB) smears was analyzed by means of logistic regression to develop the predictive score.Two hundred and sixty two patients were included. Twenty patients had SNPT. The variables included in the final model were hemoptysis, weight loss, age > 45 years old, productive cough, upper-lobe infiltrate, and miliary infiltrate. With those, a score was constructed. The score values ranged from -2 to 6. The area under the curve for the ROC curve was 0.83 (95% CI 0.74-0.90). A score of value 0 or less was associated with a sensitivity of 93% and a score of more than 4 points was associated with a specificity of 92% for SNPT. Fifty-two point twenty-nine percent of patients had scores of less than one or more than four, what provided strong evidence against and in favor, respectively, for the diagnosis of SNPT. The score developed is a cheap and useful clinical tool for the diagnosis of SNPT and can be used to help therapeutic decisions in patients with suspicion of having SNPT.

High Mortality Associated with Retreatment of Tuberculosis in a Clinic in Kampala, Uganda: A Retrospective Study

In the United States, multidrug-resistant tuberculosis (MDR-TB) is more commonly seen among foreign-born patients. We report outcomes for 46 patients with MDR-TB who were born in Mexico and treated along the United States-Mexico border. According to our definition, 30 were cured, 3 showed treatment failure, 3 died, and 10 abandoned treatment. Multidrug-resistant tuberculosis can be successfully treated on an ambulatory basis.

Effect of Previous Treatment and Sputum Quality on Diagnostic Accuracy of Xpert(®) MTB/RIF

BACKGROUND Tuberculosis disease develops in only 5%-10% of humans infected with Mycobacterium tuberculosis The mechanisms underlying this variability remain poorly understood. We recently demonstrated that colony-forming units of M. tuberculosis in cough-generated aerosols are a better predictor of infection than the standard sputum acid-fast bacilli smear. We hypothesized that cough aerosol cultures may also predict progression to tuberculosis disease in contacts. METHODS We conducted a retrospective cohort study of 85 patients with smear-positive tuberculosis and their 369 household contacts in Kampala, Uganda. Index case patients underwent a standard evaluation, and we cultured M. tuberculosis from cough aerosols. Contacts underwent a standard evaluation at enrollment, and they were later traced to determine their tuberculosis status. RESULTS During a median follow-up of 3.9 years, 8 (2%) of the contacts developed tuberculosis disease. In unadjusted and adjusted analyses, incident tuberculosis disease in contacts was associated with sputum Mycobacterial Growth Indicator Tube culture (odds ratio, 8.2; 95% confidence interval, 1.1-59.2; P = .04), exposure to a high-aerosol tuberculosis case patient (6.0, 1.4-25.2; P = .01), and marginally, human immunodeficiency virus in the contact (6.11; 0.89-41.7; P = .07). We present data demonstrating that sputum and aerosol specimens measure 2 related but different phenomena. CONCLUSIONS We found an increased risk of tuberculosis progression among contacts of high-aerosol case patients. The hypothesis that a larger infectious inoculum, represented by high aerosol production, determines the risk of disease progression deserves evaluation in future prospective studies.

Active identification of patients who are methicillin-resistant Staphylococcus aureus colonized is not associated with longer duration of vancomycin therapy

OBJECTIVE To evaluate the diagnostic performance of two liquid-phase culture media for the diagnosis of pulmonary tuberculosis. PATIENTS AND METHODS From May to July 2003, sputum samples for culture were obtained from patients with respiratory symptoms attending the Hospital Nacional Cayetano Heredia. These were cultured in Ogawa medium, mycobacteria growth indicator tube (MGIT), and modified Middlebrook 7H9. Results were compared against a composite reference standard. RESULTS One hundred sputum specimens from 100 patients were included. Of these, 33 had culture-proven tuberculosis. The sensitivity of MGIT was found to be 100%. The modified Middlebrook 7H9 medium was found to have a sensitivity of 72.73%, while the sensitivity of Ogawa medium was found to be 69.70%. The mean growing time for MGIT was 12.18 days (95% confidence interval 10.24 to 14.12; p<0.01 vs. Ogawa and modified Middlebrook 7H9); for modified Middlebrook 7H9 was 16.65 days (95% confidence interval 14.85 to 18.80; p<0.01 vs. Ogawa), and for the Ogawa medium 25.74 days (95% confidence interval 22.22 to 29.6). CONCLUSIONS The liquid culture medium MGIT was superior to the modified Middlebrook 7H9 and the Ogawa media, both in terms of sensitivity and shorter growing time of colonies of Mycobacterium tuberculosis. The modified Middlebrook 7H9 medium is significantly faster but comparable in diagnostic performance to Ogawa. Costs remain an issue for MGIT.