National anti-tuberculosis drug resistance study in Tanzania.

OBJECTIVE: To assess the prevalence of anti-tuberculosis drug resistance in a national representative sample of tuberculosis (TB) patients in Tanzania according to recommended methodology. DESIGN: Cluster survey, with 40 clusters sampled proportional to size, of notified TB patients from all diagnostic centres in the country. RESULTS: The survey enrolled 1019 new and 148 retreatment patients. The adjusted prevalence of Mycobacterium tuberculosis strains resistant to any of the four first-line drugs in new patients was 8.3%, while the prevalence of multidrug-resistant TB (MDR-TB) was 1.1%. In retreatment patients, the crude prevalence for any resistance and for MDR-TB was respectively 20.6% and 3.9%. The prevalence of drug resistance did not differ in relapse patients compared to failure patients. These estimates are among the lowest in those African countries with an estimated level of drug resistance in the last 5 years. CONCLUSION: The low levels of drug resistance in Tanzania are likely due to a well performing TB control programme and the absence of noticeable involvement of the private sector in TB treatment.

How does clinical diagnosis of mycobacterial adenitis correlate with histological findings?

OBJECTIVE: To describe and compare histopathological findings with clinical criteria in diagnosis of TB adenitis. METHODS: Lymph node biopsies were obtained from 213 patients. Specimens were processed for culture and histopathologic examination, using standard methods. One hundred blocks with good preservation of tissue morphology were selected for detailed histological examination. RESULTS: About 75% of 213 patients had granulomas. In the remaining 25%, neither histopathological nor microbiological evidence of mycobacterial disease was found. Of 100 blocks selected for detailed examination, 79 blocks had granulomatous changes. The granulomas were well organised in 24%, mixed in 33%, and poorly organised in 43%. Langhans giant cells and acid-fast bacilli were observed in 88.6% and 21.5% of the 79 blocks, respectively. Cultured specimens were positive in about 10% of 79 biopsy specimens. CONCLUSIONS: Histological evidence of mycobacterial disease was only found in three quarters of patients that were clinically diagnosed and started on empirical treatment for tuberculous adenitis. Neither histological nor mycobacteriological evidence was found in a quarter of the patients who were already on treatment for TB, basing on clinical criteria. These findings call for new research on simple diagnostic tools for patients who seek care for s ymptoms of extra-pulmonary TB.

Patient knowledge, practices and challenges to health care system in early diagnosis of mycobacterial adenitis.

OBJECTIVE: To assess diagnostic delay, knowledge and practices related to tuberculosis among patients with mycobacterial adenitis. DESIGN: A cross sectional study involving comparison analysis of high-risk groups. SETTING: Seven hospitals in rural and semi-rural districts of Arusha. SUBJECTS: Four hundred and twenty six clinically diagnosed adenitis patients. INTERVENTIONS: Biopsy specimens were processed for culture, histology, and sera for HIV testing. A questionnaire was used to assess knowledge, practice, and diagnostic time. MAIN OUTCOME MEASURES: Tribal comparisons were made using proportions and means. RESULTS: About 90% (387/423) of patients first visited medical facilities within a mean time of 10.1(SD, 15.7) weeks after becoming aware of their illness, and a diagnosis was made at a mean of 27 (SD, 25) weeks. Non-Iraqw patients, especially the Datoga, practised drinking raw milk (35.2% 43/122), eating raw animal products (18.8% 24/128) and living in houses with poor ventilation (33.6% 44/131), more than Iraqw patients. Of the investigations done, 14.5% (60/415) were culture positive, 11.3% (16/142) were HIV positive, and 73.6% (128/174) had histological features consistent with tuberculosis. The knowledge of TB spread by air droplets was poorer in Iraqw (74.1%, 203/274) than in non-lraqw (61.1%, 77/126) patients. About 35.0% (45/129) of non-lraqw and 27.3% (79/289) of Iraqw patients were not aware that TB could be transmitted from animals to humans. CONCLUSIONS: The health system diagnostic delay is about twice the patient delay. The knowledge and practices related to both human and bovine TB transmission were poor in all patients, especially in the patients from nomadic tribes.

Mycobacterial adenitis: role of Mycobacterium bovis, non-tuberculous mycobacteria, HIV infection, and risk factors in Arusha, Tanzania.

OBJECTIVE: To assess risk factors and mycobacterial agents in mycobacterial adenitis. DESIGN: Cross sectional involving comparison analysis of high-risk groups. SETTING: Seven hospitals in rural and semi-rural districts of Arusha. SUBJECTS: The study comprised of 457 patients of clinically diagnosed mycobacterial adenitis. INTERVENTIONS: Biopsy materials were cultured and identification of mycobacterial isolates, and HIV infection testing were performed using standard methods. A questionnaire was used to establish information for assessing risk factors. MAIN OUTCOME MEASURES: Proportions of mycobacterial isolates, risk factors and odds ratios. RESULTS: Of the 457 specimens, 65(14.2%) were culture positive. Isolates identified were M. bovis, 7(10.8%) M. tuberculosis, 27(41.5%) and non-tuberculous mycobacteria 31(47.7%). HIV infection and ingestion of raw milk were linked with increased risk of M. bovis infection by OR of 13.6 (95% CI, 1.7 - 109.9) and 15.28 (3.26 - 71.7), respectively. On multivariate analysis, an OR of 16.2 (1.3 - 201.3) for having M. bovis adenitis was linked to HIV infection, raw milk and houses with poor ventilation. An OR of 5.2 (1.2 - 20.6) for non-tuberculous mycobacterial adenitis was linked to history of TB in the family, HIV infection, raw milk, raw animal products and poor knowledge on transmission of tuberculosis. CONCLUSIONS: M. bovis caused one out of ten cases of culture positive mycobacterial adenitis. Non-tuberculous mycobacteria were more common than M. tuberculosis (50% and 40% of the cases, respectively). HIV infection and raw animal products are among the risk factors identified for M. bovis and non-tuberculous mycobacterial adenitis.