Preparation of mycobacteria-containing artificial sputum for TB panel testing and microscopy of sputum smears.

SETTING: Panel testing, blinded cross rechecking and on-site evaluation are the three methods for external quality assessment (EQA) of acid-fast bacilli (AFB) smear microscopy. Panel testing can provide data on laboratory capabilities prior to implementing a rechecking programme, assess the current status of laboratory performance and detect problems associated with diagnostic performance. Thus far, two methods for preparing panel test slides have been reported: these use real AFB-positive and -negative sputum treated with sodium hydroxide (NaOH) or N-acetyl-L-cysteine (NALC). OBJECTIVE: To evaluate the above methods and to develop a new method to prepare panel test slides with artificial sputum. DESIGN: Panel test slides were prepared using the NaOH and NALC methods. New artificial sputum preparation methods were developed and examined using a cultured monocyte cell line, cultured avirulent mycobacteria and methylcellulose or polyacrylamide gel as substrate. Smears prepared by the four methods were compared. RESULTS: Panel test slides prepared with NaOH and NALC methods are not macroscopically or microscopically similar to real smears. Our new artificial sputum is similar to real sputum in viscosity and macroscopic and microscopic appearance; it is also consistent in panel positivity grades. CONCLUSION: The artificial sputum described here could contribute to the EQA and training in tuberculosis laboratories or microscopy centres.

Tuberculosis drug resistance and treatment outcomes under DOTS settings in large cities in the Philippines.

SETTING: Two large cities in the Philippines. OBJECTIVES: To describe the problems of drug-resistant tuberculosis (TB) in an urban setting, with special emphasis on their potential impact on the treatment services provided by the National TB Control Programme. DESIGN: Cross-sectional survey and cohort analysis of treatment outcomes. METHODS: All patients with positive sputum smear examination results in Cebu and Mandaue cities during the survey period were included. The survey procedures of the World Health Organization and the International Union Against Tuberculosis and Lung Disease were strictly applied. Treatment outcome data were also collected. RESULTS: Of 306 cases enrolled, 255 were new cases, 28 were previously treated and for 23 treatment history was unknown. Of the new cases, 72.2% were pan-susceptible to all four first-line anti-tuberculosis drugs. Resistance in new cases was 16.9% to isoniazid (INH), 4.7% to rifampicin (RMP), 3.1% to ethambutol, 18.0% to streptomycin, and 3.9% to at least both INH and RMP (multidrug-resistant [MDR]). Over 90% of the new cases, either pan-susceptible or mono-resistant, were successfully treated with the standard regimen, but four of nine MDR new cases could not be cured. CONCLUSION: The drug resistance level was high in this population, but treatment outcome using the standard treatment regimen was not seriously affected unless the patients were MDR.