Prevalence of multi-drug resistant tuberculosis in Karachi, Pakistan: identification of at risk groups

Multidrug-resistant tuberculosis (MDR-TB) is a possible threat to global tuberculosis control. Despite a disease prevalence of 263/100 000 population Pakistan lacks information on prevalence of drug resistant TB. Our objective was to estimate prevalence of MDR and associated risk factors in Patients with pulmonary tuberculosis in Karachi. Six hundred and forty consenting adult Patients were enrolled from field clinics from July 2006 to August 2008 through passive case finding. Prevalence of MDR-TB with 95% confidence interval (CI) was calculated with Epi-Info. Logistic Regression analyses were performed for risk factors associated with MDR. Overall MDR rate was 5.0%, 95% Cl: 3.3-6.6% (untreated 2.3%, treated 17.9%). Mean age was 32.5 (+/- 15.6) years and there were 292 (45.6%) females and 348 (54.4%) males. Factors independently associated with MDR were: female gender (OR 3.12, 95% CI: 1.40-6.91), and prior history of incomplete treatment (OR 10.1, 95% CI: 4.71-21.64). Ethnic groups at higher risk for MDR included Sindhis (OR 4.5, 95% CI: 1.42-14.71) and Pashtoons (OR 3.6, 95% CI: 1.12-11.62). This study reports an overall MDR rate of 5.0% in our study population. It further highlights the need for MDR prevention through re-focusing Directly Observed Treatment, Short-course DOTS delivery with emphasis on women and certain high risk sub groups. (C) 2010 Royal Society of Tropical Medicine and Hygiene

Fluoroquinolone Resistance among Mycobacterium tuberculosis Strains from Karachi, Pakistan: Data from Community-Based Field Clinics ▿

A fluoroquinolone (FQ) resistance rate of 5.9% is reported in 205 Mycobacterium tuberculosis isolates from patients presenting to field clinics in Karachi, Pakistan (2006 to 2009). FQ resistance among multidrug-resistant (MDR) strains was 11.1% (5/45), and it was 4.9% (5/103) in M. tuberculosis strains susceptible to all first-line agents. Spoligotyping of resistant strains did not show dominance of one strain type. Our data reflect considerable FQ-resistant M. tuberculosis isolates and the need to consider inclusion of FQ within first-line sensitivity testing in such settings

Characterizing Mycobacterium tuberculosis isolates from Karachi, Pakistan: drug resistance and genotypes

Objectives: To study the prevalence, risk factors, and genotypes of drug-resistant Mycobacterium tuberculosis in Karachi. Methods: Pulmonary tuberculosis (TB) Patients were recruited in a cross-sectional study (2006-2009). Drug susceptibility testing was performed for culture-positive cases (n = 1004). Factors associated with drug resistance were evaluated using logistic regression analysis. Strains were typed using spoligotyping and mycobacterial interspersed repetitive units-variable number tandem repeat (MIRU-VNTR). The associations of genotype and drug resistance were explored using the Chi-square test. Results: Resistance rates - new and previously treated - were as follows: multidrug-resistant (MDR)-TB, 2.4% and 13.9%, respectively, rifampin (RIF) monoresistance, 0.1% and 0.6%, respectively, any isoniazid (INH) resistance, 8.9% and 28.5%, respectively, and INH monoresistance, 3.0% and 6.3%, respectively. Prior TB treatment was a risk factor for MDR-TB (adjusted odds ratio (AOR) 6.8, 95% confidence interval (CI) 3.5-13.1) and INH monoresistance (AOR 2.4, 95% CI 1.1-5.2). Additional risk factors included low socioeconomic status for INH monoresistance (AOR 3.3, 95% CI 1.7-6.5), and belonging to Balouchi (AOR 9.2, 95% CI 2.5-33.4), Sindhi (AOR 4.1, 95% CI 1.2-13.5), or Pakhtun (AOR 3.4, 95% CI 1.0-11.2) ethnicity for MDR-TB. Although Central Asian strain (55.6%) was the most prevalent genotype, MDR-TB was significantly associated with Haarlem (H) genogroup (crude OR 9.2, 95% CI 3.6-23.8). Conclusion: An MDR-TB rate of 2.4% is reported in new Patients. Low RIF monoresistance supports the use of RIF as a marker for MDR-TB in this population. The need to strengthen TB care in the identified at-risk groups is emphasized. Based on INH resistance rates, a review of national treatment/prevention regimens relying on INH is suggested