scholarly journals Plasma Drug Activity in Patients on Treatment for Multidrug-Resistant Tuberculosis

2013 ◽  
Vol 58 (2) ◽  
pp. 782-788 ◽  
Author(s):  
Stellah G. Mpagama ◽  
Norah Ndusilo ◽  
Suzanne Stroup ◽  
Happiness Kumburu ◽  
Charles A. Peloquin ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Multidrug Resistant ◽  
Plasma Drug ◽  
Content Type ◽  
Drug Activity ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Drug Concentrations ◽  
Mdr Tb ◽  
Time To Detection

ABSTRACTLittle is known about plasma drug concentrations relative to quantitative susceptibility in patients with multidrug-resistant tuberculosis (MDR-TB). We previously described a TB drug activity (TDA) assay that determines the ratio of the time to detection of plasma-coculturedMycobacterium tuberculosisversus control growth in a Bactec MGIT system. Here, we assess the activity of individual drugs in a typical MDR-TB regimen using the TDA assay. We also examined the relationship of the TDA to the drug concentration at 2 h (C2) and the MICs among adults on a MDR-TB regimen in Tanzania. These parameters were also compared to the treatment outcome of sputum culture conversion. Individually, moxifloxacin yielded superior TDA results versus ofloxacin, and only moxifloxacin and amikacin yielded TDAs equivalent to a −2-log killing. In the 25 patients enrolled on a regimen of kanamycin, levofloxacin, ethionamide, pyrazinamide, and cycloserine, theC2values were found to be below the expected range for levofloxacin in 13 (52%) and kanamycin in 10 (40%). Three subjects with the lowest TDA result (<1.5, a finding indicative of poor killing) had significantly lower kanamycinC2/MIC ratios than subjects with a TDA of ≥1.5 (9.8 ± 8.7 versus 27.0 ± 19.1;P= 0.04). The mean TDAs were 2.52 ± 0.76 in subjects converting to negative in ≤2 months and 1.88 ± 0.57 in subjects converting to negative in >2 months (P= 0.08). In Tanzania, MDR-TB drug concentrations were frequently low, and a wide concentration/MIC range was observed that affected plasma drug activityex vivo. An opportunity exists for pharmacokinetic optimization in current MDR-TB regimens, which may improve treatment response.

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 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 Improvement in Plasma Drug Activity during the Early Treatment Interval among Tanzanian Patients with Multidrug-Resistant Tuberculosis

PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0122769 ◽  
Author(s):  
Norah D. Ndusilo ◽  
Scott K. Heysell ◽  
Stellah G. Mpagama ◽  
Jean Gratz ◽  
Farida H. Segesela ◽  
...  
Keyword(s):  
Early Treatment ◽  
Multidrug Resistant ◽  
Plasma Drug ◽  
Drug Activity ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Treatment Interval

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.

scholarly journals Lab-on-Chip-Based Platform for Fast Molecular Diagnosis of Multidrug-Resistant Tuberculosis

2015 ◽  
Vol 53 (12) ◽  
pp. 3876-3880 ◽  
Author(s):  
Andrea M. Cabibbe ◽  
Paolo Miotto ◽  
Raquel Moure ◽  
Fernando Alcaide ◽  
Silke Feuerriegel ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Routine Laboratory ◽  
Isoniazid Resistance ◽  
Content Type ◽  
Lab On Chip ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb ◽  
On Chip ◽  
User Friendly

We evaluated the performance of the molecular lab-on-chip-based VerePLEX Biosystem for detection of multidrug-resistant tuberculosis (MDR-TB), obtaining a diagnostic accuracy of more than 97.8% compared to sequencing and MTBDRplusassay forMycobacterium tuberculosiscomplex and rifampin and isoniazid resistance detection on clinical isolates and smear-positive specimens. The speed, user-friendly interface, and versatility make it suitable for routine laboratory use.

scholarly journals Sequence Analysis of Fluoroquinolone Resistance-Associated GenesgyrAandgyrBin Clinical Mycobacterium tuberculosis Isolates from Patients Suspected of Having Multidrug-Resistant Tuberculosis in New Delhi, India

2016 ◽  
Vol 54 (9) ◽  
pp. 2298-2305 ◽  
Author(s):  
Ritu Singhal ◽  
Paul R. Reynolds ◽  
Jamie L. Marola ◽  
L. Elaine Epperson ◽  
Jyoti Arora ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Indian Subcontinent ◽  
Amino Acid Position ◽  
Multidrug Resistant ◽  
High Rate ◽  
Fluoroquinolone Resistance ◽  
Content Type ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

Fluoroquinolones (FQs) are broad-spectrum antibiotics recommended for the treatment of multidrug-resistant tuberculosis (MDR-TB) patients. FQ resistance, caused by mutations in thegyrAandgyrBgenes ofMycobacterium tuberculosis, is increasingly reported worldwide; however, information on mutations occurring in strains from the Indian subcontinent is scarce. Hence, in this study, we aimed to characterize mutations in thegyrAandgyrBgenes of acid-fast bacillus (AFB) smear-positive sediments or ofM. tuberculosisisolates from AFB smear-negative samples from patients in India suspected of having MDR-TB. A total of 152 samples from patients suspected of having MDR-TB were included in the study. One hundred forty-six strains detected in these samples were characterized by sequencing of thegyrAandgyrBgenes. The extracted DNA was subjected to successive amplifications using a nested PCR protocol, followed by sequencing. A total of 27 mutations were observed in thegyrAgenes of 25 strains, while no mutations were observed in thegyrBgenes. The most common mutations occurred at amino acid position 94 (13/27 [48.1%]); of these, the D94G mutation was the most prevalent. ThegyrAmutations were significantly associated with patients with rifampin (RIF)-resistant TB. Heterozygosity was seen in 4/27 (14.8%) mutations, suggesting the occurrence of mixed populations with different antimicrobial susceptibilities. A high rate of FQ-resistant mutations (17.1%) was obtained among the isolates of TB patients suspected of having MDR-TB. These observations emphasize the need for accurate and rapid molecular tests for the detection of FQ-resistant mutations at the time of MDR-TB diagnosis.

scholarly journals Mycobacterium tuberculosis Mutations Associated with Reduced Susceptibility to Linezolid

2016 ◽  
Vol 60 (4) ◽  
pp. 2542-2544 ◽  
Author(s):  
Shuo Zhang ◽  
Jiazhen Chen ◽  
Peng Cui ◽  
Wanliang Shi ◽  
Xiaohong Shi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rapid Detection ◽  
Multidrug Resistant ◽  
Mechanisms Of Resistance ◽  
Content Type ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Mdr Tb

ABSTRACTLinezolid (LZD) has become increasingly important for the treatment of multidrug-resistant tuberculosis (MDR-TB), but its mechanisms of resistance are not well characterized. We isolated 32 mutants ofMycobacterium tuberculosiswith reduced susceptibility to LZD, which was accounted for byrrlandrplCmutations in almost equal proportions, causing lower and higher MICs, respectively. Our findings provide useful information for the rapid detection of LZD resistance for improved treatment of MDR-TB.

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 Pharmacokinetics of anti-tuberculosis drugs in multidrug resistant tuberculosis patients in India

2020 ◽  
Author(s):  
Kumar AK Hemanth ◽  
PL Natarajan ◽  
T Kannan ◽  
R Sridhar ◽  
S Kumar ◽  
...  
Keyword(s):  
Multivariate Logistic Regression Analysis ◽  
Multidrug Resistant ◽  
Control Programme ◽  
Combination Regimen ◽  
Indian Government ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Drug Concentrations ◽  
Optimal Drug ◽  
Mdr Tb

AbstractProgrammatic Management of multidrug resistant tuberculosis (MDR TB) services were introduced in the Indian TB control programme in 2007. A pharmacokinetic (PK) study of drugs used to treat MDR TB, namely levofloxacin (LFX), ethionamide (ETH), cycloserine (CS), pyrazinamide (PZA), moxifloxacin (MFX) and isoniazid (INH) was undertaken in adult MDR TB patients treated according to the prevailing guidelines in India. Factors influencing drug PK and end-of-intensive phase (IP) status were also determined. We recruited 350 MDR TB patients receiving anti-TB treatment (ATT) in the Indian Government programme in south India. At steady state, serial blood samples were collected, after supervised drug administration. Status at end of IP was noted from the programme records. Of the 303 patients for whom end-of-IP status was known, 214 were culture negative (responders), while 45 patients were either culture positive or required change of regimen or had died before completion of IP (non-responders). The median Cmax (2.0 vs 2.9μg/ml; p = 0.005) and AUC0-12 (12.2 vs 17.0μg/ml.h; p = 0.002) of ETH were significantly lower in non-responders than responders at IP. In multivariate logistic regression analysis, after excluding defaulters and adjusting for confounders, AUC0-12 of ETH significantly influenced end-of-IP status (aOR - 1.065; 95% CI: 1.001 - 1.134; p = 0.047). Drug doses used currently in the programme produced optimal drug concentrations in majority of patients. ETH played a major role in the MDR TB combination regimen and was a key determinant of end-of-IP status.

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