Mycobacteria Growth Indicator Tube Method Research Articles

Pyrazinamide resistance in rifampicin discordant tuberculosis.

Mycobacterium tuberculosis strains with phenotypically susceptible rpoB mutations (rifampicin discordant) have emerged following implementation of rapid molecular drug resistance testing for tuberculosis. Whilst rifampicin resistance is known to be associated with resistance to other rifamycins (rifapentine and rifabutin) as well as isoniazid and pyrazinamide, rifampicin discordant strains have shown high rates of susceptibility to isoniazid and rifabutin. However, pyrazinamide susceptibly testing results have not been reported. We evaluated pyrazinamide resistance in 80 rifampicin discordant and 25 rifampicin and isoniazid susceptible isolates from KwaZulu-Natal in South Africa using Mycobacteria Growth Indicator Tube method and sequencing of the pncA. We also compared susceptibility of pyrazinamide with that of isoniazid. Pyrazinamide resistance was found in 6/80 (7.5%) rifampicin discordant isolates. All pyrazinamide resistant isolates were also resistant to isoniazid and pyrazinamide resistance was found to be associated with isoniazid resistance. No pyrazinamide resistance was found among the isoniazid susceptible isolates. Given the low prevalence of pyrazinamide resistance in rifampicin discordant TB, this anti-TB drug still has a significant role in the treatment of these patients. Performing pyrazinamide susceptibility testing remains a challenge, our findings show that isoniazid susceptible isolates are unlikely to be resistant to pyrazinamide among the discordant TB isolates.

Role of bronchoalveolar lavage cartridge-based nuclear acid amplification test in the diagnosis of sputum smear-negative pulmonary tuberculosis

Background Approximately 40–60% of clinical and radiological suspected cases of pulmonary tuberculosis (PTB) will have sputum smear result negative for acid-fast bacilli (AFB). Establishing early diagnosis and starting treatment early can have significant effect on morbidity and mortality in these patients. Bronchoalveolar lavage (BAL) samples obtained by bronchoscopy can be tested with cartridge-based nuclear acid amplification test (CBNAAT) for rapid diagnosis of sputum smear-negative PTB cases. Objectives To assess the role of BAL CBNAAT in the early diagnosis of sputum smear-negative PTB cases. Patients and methods A total of 112 patients with clinicoradiological findings suggestive of PTB with two consecutive sputum smear-negative results for AFB were enrolled in the study. BAL samples were subjected to Ziehl–Neelsen staining, CBNAAT (Xpert MTB/Rif; Cepheid), and liquid culture by mycobacteria growth indicator tube method as standard reference. Sputum samples from the same patients were also cultured. Results BAL samples were positive for AFB on Ziehl–Neelsen staining in 64.2% of smear-negative patients. CBNAAT was positive in 75.8%, whereas mycobacteria growth indicator tube was positive in 76.7% as compared with sputum culture positivity, which was positive in 19.6% of patients. Sensitivity and specificity of CBNAAT were 96.51 and 86.3%, respectively, when compared with culture results. Overall, 76.7% of patients were diagnosed as having culture-positive PTB. Conclusion BAL CBNAAT is useful in the early diagnosis of sputum smear-negative PTB, thus reducing the morbidity and mortality among these patients.

EVALUATION OF BENZYLIDENE-ACETONE ANALOGUES OF CURCUMIN AS ANTITUBERCULOSIS

Objective: The objective of this research is to evaluate the effect of benzylideneacetone analog of curcumin against Mycobacterium tuberculosis (MTB) H37Rv.Method: The activity of benzylideneacetone analog of curcumin is evaluated using mycobacteria growth indicator tube (MGIT) method and microplate alamar blue assay (MABA) method. The compound of minimum inhibitory concentration (MIC) is defined as the minimum concentration of drugs which really inhibit the growth of MTB.Result: The MIC compound of 1,5-bis(3,4-dichlorophenyl)-1,4-pentadiene-3-one (C9) and 1,5-bis(3-chlorophenyl)-1,4-pentadiene-3-one (C10) can inhibit the bacteria of MTB at the concentration of 500 μg/ml using MGIT method. Based on MABA method, it can be obtained similar MIC value of C9 compound and C10 compound that are 187.5 μg/ml.Conclusion: C9 and C10 have antituberculosis activity. Benzylideneacetone analog of curcumin which has chlor moiety has a better activity in inhibiting MTB, but it still needs further research to make it become a potent antituberculosis drug.

ANTITUBERCULOSIS ACTIVITY OF EXTRACT AND FRACTIONS OF TINOSPORA CRISPA AGAINST MYCOBACTERIUM TUBERCULOSIS H37RV USING MYCOBACTERIA GROWTH INDICATOR TUBE AND AGAR PROPORTION METHOD

Objective: The increasing incidence of multidrug-resistant tuberculosis (TB) has created a need to discover a new anti-TB drug candidates. The aim of this study was to screen extract and fractions of Tinospora crispa for activity against Mycobacterium tuberculosis H37Rv.Methods: The dried and pulverized T. crispa stem was extracted by maceration method using ethanol (96%). The anti-TB activity was carried out using mycobacteria growth indicator tube (MGIT) system and agar proportion method with Lowenstein–Jensen (LJ) medium.Result: The result of this study showed that ethanolic extract and fractions of T. Crispa did not exhibit anti-TB activity in the range of 100–1000 μg/ml with MGIT method, while with agar proportion method, there were M. tuberculosis colonies growth on the LJ containing 1000 μg/ml extract slants.Conclusion: The tested extract and fractions of T. crispa have no anti-TB activity against M. tuberculosis until 1000 μg/ml.

Genetic diversity of Mycobacterium tuberculosis from Guadalajara, Mexico and identification of a rare multidrug resistant Beijing genotype.

Determining the genetic diversity of M. tuberculosis strains allows identification of the distinct Mycobacterium tuberculosis genotypes responsible for tuberculosis in different regions. Several studies have reported the genetic diversity of M. tuberculosis strains in Mexico, but little information is available from the state of Jalisco. Therefore, the aim of this study was to determine the genetic diversity of Mycobacterium tuberculosis clinical isolates from Western Mexico. Sixty-eight M. tuberculosis isolates were tested for susceptibility to first-line drugs using manual Mycobacteria Growth Indicator Tube method and genotyped using spoligotyping and IS6110-restriction fragment length polymorphism (RFLP) pattern analyses. Forty-seven (69.1%) isolates were grouped into 10 clusters and 21 isolates displayed single patterns by spoligotyping. Three of the 21 single patterns corresponded to orphan patterns in the SITVITWEB database, and 1 new type that contained 2 isolates was created. The most prevalent lineages were T (38.2%), Haarlem (17.7%), LAM (17.7%), X (7.4%), S (5.9%), EAI (1.5%) and Beijing (1.5%). Six (12.8%) of the clustered isolates were MDR, and type 406 of the Beijing family was among the MDR isolates. Seventeen (26.2%) isolates were grouped into 8 clusters and 48 isolates displayed single patterns by IS6110-RFLP. Combination of IS6110-RFLP and spoligotyping reduced the clustering rate to 20.0%. The results show that T, Haarlem, and LAM are predominant lineages among clinical isolates of M. tuberculosis in Guadalajara, Mexico. Clustering rates indicated low transmission of MDR strains. We detected a rare Beijing genotype, SIT406, which was a highly resistant strain. This is the first report of this Beijing genotype in Latin America.