scholarly journals Pyrazinamide Resistance Assays and Two-Month Sputum Culture Status in Patients with Multidrug-Resistant Tuberculosis

2016 ◽  
Vol 60 (11) ◽  
pp. 6766-6773 ◽  
Author(s):  
Gustavo E. Velásquez ◽  
Roger I. Calderon ◽  
Carole D. Mitnick ◽  
Mercedes C. Becerra ◽  
Chuan-Chin Huang ◽  
...  
Keyword(s):  
Gold Standard ◽  
Latent Class ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Content Type ◽  
Antituberculous Drugs ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

ABSTRACTPhenotypic drug susceptibility testing is the current “gold standard” for detectingMycobacterium tuberculosissusceptibility to antituberculous drugs. Pyrazinamide is one antituberculous drug for which the correlation betweenin vitroresistance and clinical outcomes remains unclear. Here we performed latent class analysis (LCA) to develop a consensus gold standard definition of pyrazinamide resistance using three paired standard pyrazinamide resistance assays. We then compared this consensus measure to the 2-month culture results for patients with multidrug-resistant tuberculosis (MDR-TB) who were treated for 2 months with first-line antituberculous drugs before their resistance results were known. Among 121 patients with MDR-TB, 60 (49.6%) were resistant to pyrazinamide by the Wayne method (L. G. Wayne, Am Rev Respir Dis 109:147–151, 1974), 71 (58.7%) were resistant by the Bactec MGIT 960 method, and 68 (56.2%) were resistant bypncAsequencing. LCA grouped isolates with positive results by at least two assays into a category which we considered the “consensus gold standard” for pyrazinamide resistance. The sensitivity and specificity for this consensus gold standard were 82.4% and 92.5%, respectively, for the Wayne method; 95.6% and 88.7%, respectively, for the Bactec MGIT 960 method; and 92.6% and 90.6%, respectively, forpncAsequencing. After we adjusted for other factors associated with poor outcomes, including age, sex, alcohol use, and baseline ethambutol resistance, patients whose isolates were resistant by the LCA-derived consensus gold standard were more likely to be culture positive at 2 months with an odds ratio of 1.95 (95% confidence interval, 0.74 to 5.11), but this result was not statistically significant. These findings underscore the need for improved diagnostics for routine use in programmatic settings.

Fidaxomicin has high in vitro activity against Mycobacterium tuberculosis

2021 ◽  
Author(s):  
Qing Sun ◽  
Shuqi Wang ◽  
Xinlei Liao ◽  
Guanglu Jiang ◽  
Hairong Huang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Type Species ◽  
Multidrug Resistant ◽  
Alamar Blue ◽  
In Vitro Activity ◽  
Content Type ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

This study aimed to evaluate whether the antibiotic fidaxomicin has in vitro activity against Mycobacterium tuberculosis (Mtb). 38 fully drug-sensitive Mtb strains and 34 multidrug-resistant tuberculosis (MDR-TB) strains were tested using the microplate alamar blue assay (MABA) method to determine the minimum inhibitory concentrations (MICs) for fidaxomicin and rifampicin. Fidaxomicin has high in vitro activity against Mtb and is a potential drug to treat Mtb, and MDR-TB infections in particular.

scholarly journals Sulfamethoxazole Susceptibility of Mycobacterium tuberculosis Isolates from HIV-Infected Ugandan Adults with Tuberculosis Taking Trimethoprim-Sulfamethoxazole Prophylaxis

2015 ◽  
Vol 59 (9) ◽  
pp. 5844-5846 ◽  
Author(s):  
Sam Ogwang ◽  
Caryn E. Good ◽  
Brenda Okware ◽  
Mary Nsereko ◽  
Michael R. Jacobs ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Multidrug Resistant ◽  
Sub Saharan Africa ◽  
Content Type ◽  
Pulmonary Tb ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Sub Saharan

ABSTRACTAdditional drugs are needed for the treatment of multidrug-resistant tuberculosis (TB). Sulfamethoxazole has been shown to havein vitroactivity againstMycobacterium tuberculosis; however, there is concern about resistance given the widespread use of trimethoprim-sulfamethoxazole prophylaxis among HIV-infected patients in sub-Saharan Africa. Thirty-eight of 40Mycobacterium tuberculosisisolates (95%) from pretreatment sputum samples from Ugandan adults with pulmonary TB, including HIV-infected patients taking trimethoprim-sulfamethoxazole prophylaxis, were susceptible with MICs of ≤38.4 μg/ml.

A Rapid and Accurate Detection Approach for Multidrug-Resistant Tuberculosis Based on PCR-ELISA Microplate Hybridization Assay

2020 ◽  
Vol 51 (6) ◽  
pp. 606-613
Author(s):  
Ye-Cheng Zhou ◽  
Shu-Mei He ◽  
Zi-Lu Wen ◽  
Jun-Wei Zhao ◽  
Yan-Zheng Song ◽  
...  
Keyword(s):  
Clinical Care ◽  
Pcr Amplification ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Hybridization Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

Abstract Rapid and accurate diagnosis of multidrug-resistant tuberculosis (MDR-TB) is important for timely and appropriate therapy. In this study, a rapid and easy-to-perform molecular test that integrated polymerase chain reaction (PCR) amplification and a specific 96-well microplate hybridization assay, called PCR-ELISA (enzyme-linked immunosorbent assay), were developed for detection of mutations in rpoB, katG, and inhA genes responsible for rifampin (RIF) and isoniazid (INH) resistance and prediction of drug susceptibility in Mycobacterium tuberculosis clinical isolates. We evaluated the utility of this method by using 32 multidrug-resistent (MDR) isolates and 22 susceptible isolates; subsequently, we compared the results with data obtained by conventional drug susceptibility testing and DNA sequencing. The sensitivity and specificity of the PCR-ELISA test were 93.7% and 100% for detecting RIF resistance, and 87.5% and 100% for detecting INH resistance, respectively. These results were comparable to those yielded by commercially available molecular tests such as the GenoType MTBDRplus assay. Based on the aforementioned results, we conclude that the PCR-ELISA microplate hybridization assay is a rapid, inexpensive, convenient, and reliable test that will be useful for rapid diagnosis of MDR-TB, for improved clinical care.

scholarly journals Molecular Characterization of Multidrug-Resistant Mycobacterium tuberculosis Isolated in Nepal

2012 ◽  
Vol 56 (6) ◽  
pp. 2831-2836 ◽  
Author(s):  
Ajay Poudel ◽  
Chie Nakajima ◽  
Yukari Fukushima ◽  
Haruka Suzuki ◽  
Basu Dev Pandey ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Promoter Region ◽  
Multidrug Resistant ◽  
Content Type ◽  
Molecular Tests ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb ◽  
Substitution Mutations ◽  
Drug Resistant Strains

ABSTRACTDespite the fact that Nepal is one of the first countries globally to introduce multidrug-resistant tuberculosis (MDR-TB) case management, the number of MDR-TB cases is continuing to rise in Nepal. Rapid molecular tests applicable in this setting to identify resistant organisms would be an effective tool in reversing this trend. To develop such tools, information about the frequency and distribution of mutations that are associated with phenotypic drug resistance inMycobacterium tuberculosisis required. In the present study, we investigated the prevalence of mutations inrpoBandkatGgenes and theinhApromoter region in 158M. tuberculosisisolates (109 phenotypically MDR and 49 non-MDR isolates collected in Nepal) by DNA sequencing. Mutations affecting the 81-bp rifampin (RIF) resistance-determining region (RRDR) ofrpoBwere identified in 106 of 109 (97.3%) RIF-resistant isolates. Codons 531, 526, and 516 were the most commonly affected, at percentages of 58.7, 15.6, and 15.6%, respectively. Of 113 isoniazid (INH)-resistant isolates, 99 (87.6%) had mutations in thekatGgene, with Ser315Thr being the most prevalent (81.4%) substitution. Mutations in theinhApromoter region were detected in 14 (12.4%) INH-resistant isolates. The results from this study provide an overview of the current situation of RIF and INH resistance inM. tuberculosisin Nepal and can serve as a basis for developing or improving rapid molecular tests to monitor drug-resistant strains in this country.

scholarly journals Assessing spatiotemporal patterns of multidrug-resistant and drug-sensitive tuberculosis in a South American setting

2010 ◽  
Vol 139 (11) ◽  
pp. 1784-1793 ◽  
Author(s):  
H. LIN ◽  
S. SHIN ◽  
J. A. BLAYA ◽  
Z. ZHANG ◽  
P. CEGIELSKI ◽  
...  
Keyword(s):  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Urban Setting ◽  
South American ◽  
Resistant Disease ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb ◽  
Incident Cases

SUMMARYWe examined the spatiotemporal distribution of laboratory-confirmed multidrug-resistant tuberculosis (MDR TB) cases and that of other TB cases in Lima, Peru with the aim of identifying mechanisms responsible for the rise of MDR TB in an urban setting. All incident cases of TB in two districts of Lima, Peru during 2005–2007 were included. The spatiotemporal distributions of MDR cases and other TB cases were compared with Ripley's K statistic. Of 11 711 notified cases, 1187 received drug susceptibility testing and 376 were found to be MDR. Spatial aggregation of patients with confirmed MDR disease appeared similar to that of other patients in 2005 and 2006; however, in 2007, cases with confirmed MDR disease were found to be more tightly grouped. Subgroup analysis suggests the appearance of resistance may be driven by increased transmission. Interventions should aim to reduce the infectious duration for those with drug-resistant disease and improve infection control.

scholarly journals Mode of Action of Clofazimine and Combination Therapy with Benzothiazinones against Mycobacterium tuberculosis

2015 ◽  
Vol 59 (8) ◽  
pp. 4457-4463 ◽  
Author(s):  
Benoit Lechartier ◽  
Stewart T. Cole
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Bacterial Load ◽  
Multidrug Resistant ◽  
Content Type ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Drug Resistant Strains ◽  
Transfer Chain

ABSTRACTClofazimine (CZM) is an antileprosy drug that was recently repurposed for treatment of multidrug-resistant tuberculosis. InMycobacterium tuberculosis, CZM appears to act as a prodrug, which is reduced by NADH dehydrogenase (NDH-2), to release reactive oxygen species upon reoxidation by O2. CZM presumably competes with menaquinone (MK-4), a key cofactor in the mycobacterial electron transfer chain, for its reduction by NDH-2. We studied the effect of MK-4 supplementation on the activity of CZM againstM. tuberculosisand found direct competition between CZM and MK-4 for the cidal effect of CZM, against nonreplicating and actively growing bacteria, as MK-4 supplementation blocked the drug's activity against nonreplicating bacteria. We demonstrated that CZM, like bedaquiline, is synergisticin vitrowith benzothiazinones such as 2-piperazino-benzothiazinone 169 (PBTZ169), and this synergy also occurs against nonreplicating bacteria. The synergy between CZM and PBTZ169 was lost in an MK-4-rich medium, indicating that MK-4 is the probable link between their activities. The efficacy of the dual combination of CZM and PBTZ169 was testedin vivo, where a great reduction in bacterial load was obtained in a murine model of chronic tuberculosis. Taken together, these data confirm the potential of CZM in association with PBTZ169 as the basis for a new regimen against drug-resistant strains ofM. tuberculosis.

scholarly journals Synthesis, Characterization and Antituberculosis Activity of Biologically Nanostructured Zinc and Titanium Metal Compounds

2020 ◽  
Vol 32 (6) ◽  
pp. 1286-1290
Author(s):  
Savita Belwal ◽  
Sujana Kariveda ◽  
Saritha Ramagiri
Keyword(s):  
Multidrug Resistant ◽  
Metal Compounds ◽  
Zinc Compounds ◽  
Macrotyloma Uniflorum ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Transmission Electron ◽  
H37rv Strain ◽  
Mdr Tb

Green chemistry was used to obtain nano-range sized titanium and zinc compounds from their macro-sizes by using an aqueous extract of horse gram (Macrotyloma uniflorum). Ultraviolet-visible (UV-vis) and Fourier-transform infrared (FTIR) spectrophotometers were employed for characterizing the nanoparticles of biosynthesized metal nanoparticles. Transmission electron microscopy (TEM) was used to analyse the reduced nanoparticles of Ti and Zn metals. Microdilution was employed to determine in vitro properties, such as effects of nanocomplex antimicrobials on Mycobacterium tuberculosis (MTB) H37RV strain. MTB strains isolated from patients with multidrug-resistant tuberculosis (MDR-TB) were resistant to first-line drugs. Novel synthesized nano-complexes exhibited potential antituberculosis activities. Titanium nanocomplexes exhibited the highest minimal inhibitory concentration (MIC) in comparison to zinc nanocomplex. In a cytotoxic study, an IC50 of 1000 μg/mL, for both Ti and Zn nanocomplexes, was reported, and thus, these complexes were non-toxic when compared to isoniazid.

scholarly journals Overcoming the health system barriers to early diagnosis and management of multidrug-resistant tuberculosis in a rural setting in North India

2020 ◽  
Vol 13 (1) ◽  
pp. e231009
Author(s):  
Mohammad Abu Bashar ◽  
Arun Aggarwal ◽  
Sudip Bhattacharya
Keyword(s):  
Disease Transmission ◽  
Local Community ◽  
Health Centre ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
North India ◽  
Rural Setting ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

India contributes a quarter of the global burden of multidrug-resistant tuberculosis (MDR-TB) and has inadequate diagnostic infrastructure and institutional capacities for drug susceptibility testing. Subsequently, this leads to a large number of undetected and untreated cases of MDR-TB. In this report, we describe a case of a 55-year-old man from rural North India presenting with complaints of continued symptoms of chronic cough, fever and dyspnoea despite being recently diagnosed with recurrent tuberculosis and receiving treatment from the local community health centre. MDR-TB was suspected, but confirmatory diagnostic capabilities were not available in the local setting. The patient was finally diagnosed with MDR-TB. Treatment was coordinated by the district tuberculosis programme officer. Through this case, we describe the various barriers to detecting MDR-TB in the rural regions of India. Prompt identification of patients with presumptive MDR-TB, diagnosis of the disease and initiation of treatment are crucial to preventing disease transmission and reducing morbidity and mortality.

scholarly journals Novel Regimens Identified in Mice for Treatment of Latent Tuberculosis Infection in Contacts of Patients with Multidrug-Resistant Tuberculosis

2014 ◽  
Vol 58 (4) ◽  
pp. 2316-2321 ◽  
Author(s):  
Jean-Philippe Lanoix ◽  
Fabrice Betoudji ◽  
Eric Nuermberger
Keyword(s):  
Clinical Trials ◽  
Latent Tuberculosis ◽  
Multidrug Resistant ◽  
Content Type ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
New Chemical Entities ◽  
Mdr Tb ◽  
Latent Tb Infection ◽  
Effective Drugs

ABSTRACTPreventing the development of tuberculosis (TB) in contacts of patients with multidrug-resistant TB (MDR-TB) by the treatment of latent TB infection (LTBI) is highly desirable. However, few safe, well tolerated, and effective drugs are available to treat MDR-LTBI and the published guidance is limited. Fortunately, six new chemical entities from four classes developed to treat TB have entered clinical trials in the past decade. We tested three of these drugs alone and in combination in an experimental paucibacillary LTBI chemotherapy model using BALB/c and C3HeB/FeJ mice immunized with a recombinant strain ofMycobacterium bovisbacillus Calmette-Guérin (rBCG30) and then challenged with a low-dose aerosol ofM. tuberculosisH37Rv. The regimens tested contained bedaquiline (TMC), PA-824 (Pa), sutezolid (PNU), and/or one of two fluoroquinolones. Control mice received rifampin (RIF) or isoniazid (INH). In BALB/c mice, TMC-containing regimens and the Pa-PNU combination were the most active test regimens and were at least as effective as RIF. Pa, PNU, and levofloxacin had activity comparable to that of INH. Virtually identical results were observed in C3HeB/FeJ mice. This study confirms the potent activity of TMC observed previously in BALB/c mice and highlights Pa alone or in combination with either PNU or a fluoroquinolone as a regimen worthy of evaluation in future clinical trials of MDR-LTBI. Given their closer pathological representation of human TB lesions, C3HeB/FeJ mice may become a preferred model for the experimental chemotherapy of LTBI. Future studies should evaluate additional clinically relevant LTBI regimens in this strain including relapse as an endpoint.

scholarly journals Primary Clofazimine and Bedaquiline Resistance among Isolates from Patients with Multidrug-Resistant Tuberculosis

2017 ◽  
Vol 61 (6) ◽  
Author(s):  
Jian Xu ◽  
Bin Wang ◽  
Minghao Hu ◽  
Fengmin Huo ◽  
Shaochen Guo ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Cross Resistance ◽  
Drug Resistant ◽  
Content Type ◽  
Tb Treatment ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb ◽  
Previously Treated ◽  
Alamarblue Assay

ABSTRACT Clofazimine has been repurposed for the treatment of tuberculosis, especially for multidrug-resistant tuberculosis (MDR-TB). To test the susceptibility to clofazimine of Mycobacterium tuberculosis clinical isolates, MICs of clofazimine were determined using the microplate alamarBlue assay (MABA) method for 80 drug-resistant isolates and 10 drug-susceptible isolates for comparison. For five clofazimine-resistant strains isolated from previously treated pre-extensively drug-resistant TB (pre-XDR-TB) and XDR-TB patients without prior exposure to clofazimine or bedaquiline, clofazimine MICs were ≥1.2 μg/ml. Four isolates with cross-resistance to bedaquiline had Rv0678 mutations. The other isolate with no resistance to bedaquiline had an Rv1979c mutation. This study adds to a recent study showing that 6.3% of MDR-TB patients without prior clofazimine or bedaquiline exposure harbored isolates with Rv0678 mutations, which raises concern that preexisting resistance to these drugs may be associated with prior TB treatment. Furthermore, we propose a tentative breakpoint of 1.2 μg/ml for clofazimine resistance using the MABA method. More-widespread surveillance and individualized testing for clofazimine and bedaquiline resistance, together with assessment of their clinical usage, especially among previously treated and MDR-TB patients, are warranted.

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