OBJECTIVE: To obtain population-based data on Mycobacterium tuberculosis drug resistance in Pakistan.
METHODS: To obtain drug resistance data, we conducted a population-based study of TB cases in all provinces of Pakistan. We performed culture and drug susceptibility testing on M. tuberculosis isolates from patients with a prior history of anti-tuberculosis treatment (retreatment cases) from all over the country.
RESULTS: Of 544 isolates from previously treated cases, 289 (53.1%) were susceptible to all first-line drugs, 255 (46.9%) were resistant to at least one anti-tuberculosis drug and 132 (24.3%) were MDR-TB. Among MDR-TB isolates, 47.0% were ofloxacin (OFX) resistant. Extensively drug-resistant TB was found in two (0.4%) isolates.
CONCLUSION: Prevalence of drug resistance in retreatment isolates was high. The alarmingly high prevalence of OFX resistance among MDR-TB isolates may threaten the success of efforts to control and treat MDR-TB.
METHODS: A retrospective study was conducted to recognize the epidemiology facts of EPTB. Individual data for EPTB patients were collected from TB registers, laboratory TB registers, treatment cards and TB medical personal files into a standardized study questionnaire. Crude (COR) and adjusted odds ratios (AOR) and 95% confidence intervals (CI) were determined to assess the risk factors for EPTB and unsuccessful treatment outcomes.
RESULTS: There were 1222 EPTB patients presenting 13.1% of all TB cases during 2006-2008. Pleural effusion and lymph node TB were the most frequent types and accounted for 45.1% of all EPTB cases among study participants. Treatment success rate was 67.6%. The best treatment completion rates were found in children ≤15 years (0.478 [0.231-1.028]; p = 0.05). On multivariate analysis, age group 56-65 years (1.658 [1.157-2.376]; p = 0.006), relapse cases (7.078 [1.585-31.613]; p = 0.010), EPTB-DM (1.773 [1.165-2.698]; p = 0.008), patients with no formal (2.266 [1.254-4.095]; p = 0.001) and secondary level of education (1.889 [1.085-3.288]; p = 0.025) were recorded as statistically positive significant risk factors for unsuccessful treatment outcomes. Patients at the risk of EPTB were more likely to be females (1.524 [1.311-1.746]; p
MATERIALS AND METHODS: A total of 103 patients from the Chest Clinic of Hospital Tengku Ampuan Rahimah with sputum smears positive for acid-fast bacilli were included in this cross-sectional study. All sputa were tested using Xpert MTB/RIF to confirm the presence of M. tuberculosis complex and detect rifampicin resistance. Sputa were also sent to a respiratory medicine institute for mycobacterial culture. Positive cultures were then submitted to a reference laboratory, where isolates identified as M. tuberculosis complex underwent drug susceptibility testing (DST).
RESULTS: A total of 58 (56.3%) patients were newly diagnosed and 45 (43.7%) patients were previously treated. Xpert MTB/RIF was able to detect rifampicin resistance with a sensitivity and specificity of 87.5% and 98.9%, respectively. Assuming that a single resistant result from Xpert MTB/RIF or any DST method was sufficient to denote resistance, a total of 8/103 patients had rifampicinresistant M. tuberculosis. All eight patients were previously treated for PTB (p<0.05). The overall prevalence of rifampicin resistance among smear-positive PTB patients was 7.8%, although it was 17.8% among the previously treated ones.
CONCLUSION: The local prevalence of rifampicin-resistant M. tuberculosis was particularly high among previously treated patients. Xpert MTB/RIF can be employed in urban district health facilities not only to diagnose PTB in smear-positive patients, but also to detect rifampicin resistance with good sensitivity and specificity.