Bhawana Shrestha

Incidence of Hepatotoxicity Due to Antitubercular Medicines and Assessment of Risk Factors

BACKGROUND: Antitubercular drugs cause derangement of hepatic function revealed by clinical examination and abnormal liver function test results. Potential hepatotoxicity of some of the first-line antitubercular agents remains a problem, especially during the initial period of treatment. OBJECTIVE: To determine the incidence of antitubercular drug—induced hepatotoxicity in a Nepalese urban population and assess the risk factors. METHOD: Fifty patients diagnosed with active tuberculosis infection with normal pretreatment liver function were monitored clinically as well as biochemically in a prospective cohort analysis. RESULTS: Antitubercular drugs were found to be associated with derangement of hepatic function, resulting in elevation of liver enzymes to a variable extent (t = −4.550, p < 0.01 for aspartate aminotransferase [AST]; t = −5.467, p < 0.01 for alanine aminotransferase [ALT] at 95% CI). Thirty-eight percent of patients had 2 times and 30% had >3 times elevation of ALT. Similarly, 40% and 29% of patients showed 2 and >3 times elevation of the AST level, respectively. Four patients (8%) developed drug-induced hepatotoxicity. Jaundice was the presenting symptom in all patients. The time interval for onset of hepatotoxicity after initiation of therapy was 12–60 days (median 28). Antitubercular drug—induced hepatotoxicity was found more often in younger patients (6% vs 2%; p = 0.368, OR 2.75). Female gender was also a higher risk (p = 0.219, OR 4.2). Most patients who had developed hepatitis were diagnosed per sputum-smear positive reactions. Nutritional status, assessed by body mass index and serum albumin level, was the next predisposing factor. CONCLUSIONS: A finding of an 8% incidence of hepatotoxicity is considerably high. Risk factors of hepatotoxicity included female gender, disease extent, and poor nutritional status. Timely detection and temporary withdrawal of the offending agent can completely cure antitubercular drug—induced hepatotoxicity.

First Insights into the Phylogenetic Diversity of Mycobacterium tuberculosis in Nepal

Background Tuberculosis (TB) is a major public health problem in Nepal. Strain variation in Mycobacterium tuberculosis may influence the outcome of TB infection and disease. To date, the phylogenetic diversity of M. tuberculosis in Nepal is unknown. Methods and Findings We analyzed 261 M. tuberculosis isolates recovered from pulmonary TB patients recruited between August 2009 and August 2010 in Nepal. M. tuberculosis lineages were determined by single nucleotide polymorphisms (SNP) typing and spoligotyping. Drug resistance was determined by sequencing the hot spot regions of the relevant target genes. Overall, 164 (62.8%) TB patients were new, and 97 (37.2%) were previously treated. Any drug resistance was detected in 50 (19.2%) isolates, and 16 (6.1%) were multidrug-resistant. The most frequent M. tuberculosis lineage was Lineage 3 (CAS/Delhi) with 106 isolates (40.6%), followed by Lineage 2 (East-Asian lineage, includes Beijing genotype) with 84 isolates (32.2%), Lineage 4 (Euro-American lineage) with 41 (15.7%) isolates, and Lineage 1 (Indo-Oceanic lineage) with 30 isolates (11.5%). Based on spoligotyping, we found 45 different spoligotyping patterns that were previously described. The Beijing (83 isolates, 31.8%) and CAS spoligotype (52, 19.9%) were the dominant spoligotypes. A total of 36 (13.8%) isolates could not be assigned to any known spoligotyping pattern. Lineage 2 was associated with female sex (adjusted odds ratio [aOR] 2.58, 95% confidence interval [95% CI] 1.42–4.67, p = 0.002), and any drug resistance (aOR 2.79; 95% CI 1.43–5.45; p = 0.002). We found no evidence for an association of Lineage 2 with age or BCG vaccination status. Conclusions We found a large genetic diversity of M. tuberculosis in Nepal with representation of all four major lineages. Lineages 3 and 2 were dominating. Lineage 2 was associated with clinical characteristics. This study fills an important gap on the map of the M. tuberculosis genetic diversity in the Asian region.

Directly observed intermittent short-course chemotherapy in the Kathmandu valley

SETTING Within the national tuberculosis control programme in Nepal, cure rates of only 30%-40% were achieved using standard chemotherapy. High cure rates are particularly difficult to achieve in the Kathmandu valley, because of the mobility of the population and the large numbers of private practitioners. Short-course chemotherapy (SCC) was not used in tuberculosis (TB) control programmes in Nepal before 1991. Therefore we started our pilot programme with a fully supervised, intermittent SCC regimen. In addition we established a mycobacteriological laboratory for routine culture and susceptibility tests. OBJECTIVE The main objective was to demonstrate the high effectiveness of a three-times weekly SCC regimen and the feasibility of directly observed treatment (DOT). DESIGN In our new out-patient department we put all active TB patients under SCC. The duration of therapy was 9 months or longer, depending upon bacteriological and radiological needs. The results were well recorded and evaluated by central supervision. Outcome of treatment was recorded at 24-48 months. RESULTS From January 1990 to December 1993, 771 pulmonary TB patients (618 new cases and 153 old cases) commenced treatment. Of these, 645 (84%) were cured or completed treatment, 84 (11%) defaulted, 15 (2%) died, 15 (2%) were treatment failures and 12 (3.0%) relapsed. CONCLUSION Directly observed intermittent SCC is highly cost-effective. The results of our service programme showed that it is possible to introduce such a regimen in an urban area of Nepal.

Diagnostic Accuracy of GeneXpert MTB/RIF Assay in Comparison to Conventional Drug Susceptibility Testing Method for the Diagnosis of Multidrug-Resistant Tuberculosis

Xpert MTB/RIF assay is regarded as a great achievement of modern medicine for the rapid diagnosis of multidrug-resistant tuberculosis (MDR-TB). The main purpose of this study was to determine the performance of Xpert MTB/RIF assay compared to conventional drug susceptibility testing (DST) method for the diagnosis of MDR-TB. A comparative cross sectional study was carried out at German-Nepal Tuberculosis Project, Kathmandu, Nepal, from April 2014 to September 2014. A total of 88 culture positive clinical samples (83 pulmonary and 5 extra-pulmonary) received during the study period were analyzed for detection of multidrug-resistant tuberculosis by both GeneXpert MTB/RIF assay and conventional DST method. McNemar chi square test was used to compare the performance of Xpert with that of DST method. A p-value of less than 0.05 was considered as statistically significant. Of total 88 culture positive samples, one was reported as invalid while 2 were found to contain nontuberculous Mycobacteria (NTM). Among remaining 85 Mycobacterium tuberculosis culture positive samples, 69 were found to be MDR-TB positive by both methods. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of GeneXpert MTB/RIF assay were found to be 98.6%, 100%, 100% and 93.8% respectively. Statistically, there was no significant difference between the diagnostic performance of Xpert and conventional DST method for detection of MDR-TB. GeneXpert MTB/RIF assay was found to be highly sensitive, specific and comparable to gold standard conventional DST method for the diagnosis of MDR-TB.

Use of Genotype MTBDRplus Assay for Diagnosis of Multidrug-Resistant Tuberculosis in Nepal

The main aims of this study were to study the patterns of mutations in rpoB, katG, and inhA genes in Mycobacterium tuberculosis strains isolated from patients from Nepal and to evaluate the performance of genotype MTBDRplus assay, taking conventional drug susceptibility testing as gold standard for diagnosis of MDR-TB. A total of 69 Mycobacterium tuberculosis strains isolated from 73 smear positive sputum samples from patients suspected of suffering from multidrug-resistant tuberculosis were used in our study. The drug susceptibility pattern of Mycobacterium tuberculosis isolated from these sputum specimens was determined by using genotype MTBDRplus assay taking conventional drug susceptibility testing as reference. The sensitivity and specificity of the genotype MTBDRplus assay for the detection of MDR-TB were found to be 88.7% and 100%, respectively. 88.7% of the rifampicin resistant isolates had mutations in rpoB gene. Similarly, 79.7% and 9.4% of isoniazid resistant isolates had mutations in katG and inhA genes, respectively. Genotype MTBDRplus assay was found to be very rapid and highly sensitive and specific method for diagnosis of MDR-TB and will be very helpful for early diagnosis of MDR-TB in high tuberculosis burden countries.

Rapid Detection of Rifampicin and Isoniazid Resistant Mycobacterium tuberculosis Using Genotype MTBDRplus Assay in Nepal

Rapid line probe assay (LPA) can be a practical and rapid alternative to the slow conventional phenotypic drug susceptibility testing (DST) for detection of drug resistant tuberculosis (TB). The purpose of this study is to determine the diagnostic accuracy of Genotype MTBDRplus, LPA for TB, and compare its performance with conventional DST. A total of 54 culture samples were analyzed for DST using both conventional proportion method and MTBDRplus, where conventional DST identified 43 isolates (79.6%) as drug resistant. Among these 43 drug resistant isolates, 30 isolates (69.7%) were found to be multidrug resistant (MDR). Of all observed mutations using MTBDRplus, codon 531 of rpoB gene and codon 315 of katG gene were found to have highest mutational frequency for RIF resistance (64.7%) and INH resistance (96.8%), respectively. In the present study, MTBDRplus assay was shown to have excellent specificity (100%) for both RIF and INH resistance while sensitivity of the assay was little lower with value of 89.4% for RIF resistance and 91.4% for INH resistance. Therefore, the assay can be a rapid, reliable, and promising molecular test for early detection of MDR-TB in Nepal.

Light emitting diode fluorescence microscopy versus Ziehl-Neelsen smear microscopy for the diagnosis of pulmonary tuberculosis.

Tuberculosis is a serious public health issue mainly in under developing countries like Nepal.1 Early diagnosis of the disease is a very important step for the effective control of the tuberculosis but the lack of rapid diagnostic methods with high sensitivity in developing countries is a serious obstacle for the global control of the disease. Due to its low cost, Ziehl–Neelsen (ZN) smear microscopy is widely used for diagnosis of tuberculosis in the resource limited countries.2 But in the poorer countries where the load of tuberculosis patients is very high, the laboratory with limited resources may not bear the workload created by the time required for examination of the ZN smears.1 The recently developed light emitting diode fluorescence microscopy (LED-FM) has been reported to be a rapid and cheap method for the diagnosis of tuberculosis with high sensitivity.2 However, in world literature there are only limited data regarding the use of the LED-FM for routine diagnostic purpose.3 So we evaluated the performance of