MULTIDRUG RESISTANT TUBERCULOSIS - BIOMECHANISM, EPIDEMIOLOGY AND MANAGEMENT STRATEGIES.
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ABSTRACT:
SUBMITTER: Tewari SC
PROVIDER: S-EPMC5531036 | biostudies-other | 1997 Jul
REPOSITORIES: biostudies-other
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Project description:The transcontinental spread of multidrug-resistant (MDR) tuberculosis is poorly characterized in molecular epidemiologic studies. We used genomic sequencing to understand the establishment and dispersion of MDR Mycobacterium tuberculosis within a group of immigrants to the United States. We used a genomic epidemiology approach to study a genotypically matched (by spoligotype, IS6110 restriction fragment length polymorphism, and mycobacterial interspersed repetitive units-variable number of tandem repeat signature) lineage 2/Beijing MDR strain implicated in an outbreak of tuberculosis among refugees in Thailand and consecutive cases within California. All 46 MDR M. tuberculosis genomes from both Thailand and California were highly related, with a median difference of 10 single-nucleotide polymorphisms (SNPs). The Wat Tham Krabok (WTK) strain is a new sequence type distinguished from all known Beijing strains by 55 SNPs and a genomic deletion (Rv1267c) associated with increased fitness. Sequence data revealed a highly prevalent MDR strain that included several closely related but distinct allelic variants within Thailand, rather than the occurrence of a single outbreak. In California, sequencing data supported multiple independent introductions of WTK with subsequent transmission and reactivation within the state, as well as a potential super spreader with a prolonged infectious period. Twenty-seven drug resistance-conferring mutations and 4 putative compensatory mutations were found within WTK strains. Genomic sequencing has substantial epidemiologic value in both low- and high-burden settings in understanding transmission chains of highly prevalent MDR strains.
| S-EPMC4490235 | biostudies-literature
Project description:Background:Multidrug-resistant tuberculosis (MDR-TB) is an important global public health threat, but accurate estimates of MDR-TB burden among children are lacking. Methods:We analyzed demographic, clinical, and laboratory data for newly diagnosed pediatric (age <15 years) TB cases reported to the US National TB Surveillance System during 1993-2014. MDR-TB was defined as culture-confirmed TB disease with resistance to at least isoniazid and rifampicin. To ascertain potential underestimation of pediatric MDR-TB, we surveyed high-burden states for clinically diagnosed cases treated for MDR-TB. Results:Of 20789 pediatric TB cases, 5162 (24.8%) had bacteriologically confirmed TB. Among 4826 (93.5%) with drug susceptibility testing, 82 (1.7%) had MDR-TB. Most pediatric MDR-TB cases were female (n = 51 [62%]), median age was 5 years (interquartile range, 1-12 years), one-third were Hispanic (n = 28 [34%]), and two-thirds (n = 55 [67%]) were born in the United States. Most cases had additional resistance to ?1 other first-line drug (n = 66 [81%]) and one-third had resistance to ?1 second-line drug (24/73 tested). Of 77 who started treatment prior to 2013, 66 (86%) completed treatment and 4 (5%) died. Among the 4 high-TB-burden states/jurisdictions surveyed, there was 42%-55% underestimation of pediatric MDR-TB cases when using only culture-confirmed case definitions. Conclusions:Only one-quarter of pediatric TB cases had culture-confirmed TB, likely resulting in underestimation of true pediatric MDR-TB burden in the United States using strictly bacteriologic criteria. Better estimates of pediatric MDR-TB burden in the United States are needed and should include clinical diagnoses based on epidemiologic criteria.
| S-EPMC5801661 | biostudies-literature
Project description:Background Multidrug-resistant tuberculosis (MDR-TB) has become a major public health problem in China, with mounting evidence suggesting that recent transmission accounts for the majority of MDR-TB. Here we aimed to reveal the transmission pattern of an MDR-TB outbreak in the Jing'an District of Shanghai between 2010 and 2015. Methods We used whole-genome sequencing (WGS) to conduct genomic clustering analysis along with field epidemiological investigation to determine the transmission pattern and drug resistance profile of a cluster with ten MDR-TB patients in combining field epidemiological investigation. Results The ten MDR-TB patients with genotypically clustered Beijing lineage strains lived in a densely populated, old alley with direct or indirect contact history. The analysis of genomic data showed that the genetic distances of the ten strains (excluding drug-resistant mutations) were 0–20 single nucleotide polymorphisms (SNPs), with an average distance of 9 SNPs, suggesting that the ten MDR-TB patients were infected and developed the onset of illness by the recent transmission of M. tuberculosis. The genetic analysis confirmed definite epidemiological links between the clustered cases. Conclusions The integration of the genotyping tool in routine tuberculosis surveillance can play a substantial role in the detection of MDR-TB transmission events. The leverage of genomic analysis in combination with the epidemiological investigation could further elucidate transmission patterns. Whole-genome sequencing could be integrated into intensive case-finding strategies to identify missed cases of MDR-TB and strengthen efforts to interrupt transmission. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-021-06725-0.
| S-EPMC8557015 | biostudies-literature
Project description:BACKGROUND:Multidrug-resistant tuberculosis (MDR-TB) is burgeoning globally, and has been a serious challenge in TB management. Clinically, the ability to identify MDR-TB is still limited, especially in smear-negative TB. The aim of this study was to develop a nomogram for predicting MDR-TB. METHODS:Demographics and clinical characteristics of both MDR-TB and drug-susceptible TB patients were utilized to develop a nomogram for predicting MDR-TB. The LASSO regression method was applied to filter variables and select predictors, and multivariate logistic regression was used to construct a nomogram. The discriminatory ability of the model was determined by calculating the area under the curve (AUC). Moreover, calibration analysis and decision curve analysis (DCA) of the model were performed. This study involved a second analysis of a completed prospective cohort study conducted in a country with a high TB burden. RESULTS:Five variables of TB patients were selected through the LASSO regression method, and a nomogram was built based on these variables. The predictive model yielded an AUC of 0.759 (95% CI, 0.719-0.799), and in the internal validation, the AUC was 0.757 (95% CI, 0.715-0.793). The predictive model was well-calibrated, and DCA showed that if the threshold probability of MDR-TB was between 70 and 90%, using the proposed nomogram to predict MDR-TB would obtain a net benefit. CONCLUSIONS:In this study, a nomogram was constructed that incorporated five demographic and clinical characteristics of TB patients. The nomogram may be of great value for the prediction of MDR-TB in patients with sputum-free or smear-negative TB.
| S-EPMC7276074 | biostudies-literature
Project description:In a nationwide survey in 2011, multidrug-resistant tuberculosis (MDR TB) was found in 5.2% and 40.8% of patients with new and previously treated TB, respectively. These levels of drug resistance are among the highest ever documented in Africa and the Middle East. This finding presents a serious challenge for TB control in Somalia.
| S-EPMC3647667 | biostudies-literature
Project description:BACKGROUND:The treatment outcomes of multidrug-resistant tuberculosis (MDR-TB) patients in the 1990s in Taiwan was not satisfactory. To strengthen programmatic management of drug-resistant tuberculosis (PMDT), Taiwan MDR-TB Consortium (TMTC) was established in 2007. We assess the performance and epidemiologic impact of TMTC. METHODOLOGY/PRINCIPLE FINDINGS:We analyzed the trends of proportion of TB cases with drug susceptibility testing, enrollment of MDR-TB patients into TMTC and outcomes of treatment of all MDR-TB patients in Taiwan from 2007-2016. We computed the trends of both incidence and prevalence of MDR-TB from 2007-2016. We assessed the trends of MDR-TB among both new and recurrent TB cases. The proportion of TB cases with drug susceptibility testing results increased from 24.2% in 2007 to 97.9% in 2016. Of the 1,452 MDR-TB patients who were eligible for TMTC care, 1,197 (82.4%) were enrolled in TMTC, in whom 82.9% had treatment success. MDR-TB incidence was 9.0 cases per million in 2007, which declined to 4.6 cases per million in 2016 (p<0.0001). MDR-TB prevalence decreased from 19.4 cases per million in 2007 to 8.4 cases per million in 2016 (p<0.0001). The proportion of MDR-TB among new TB cases decreased from 1.4% in 2010 to 1.0% in 2016 (p = 0.039); and that among recurrent TB cases from 9.0% in 2010 to 1.8% in 2016 (p<0.0001). CONCLUSIONS:We concluded that effective PMDT have had a significant impact on the epidemic of drug-resistant TB in Taiwan.
| S-EPMC6445419 | biostudies-literature
Project description:BackgroundDespite the existence of effective drug treatments, tuberculosis (TB) causes 2 million deaths annually worldwide. Effective treatment is complicated by multidrug-resistant TB (MDR TB) strains that respond only to second-line drugs. We projected the health benefits and cost-effectiveness of using drug susceptibility testing and second-line drugs in a lower-middle-income setting with high levels of MDR TB.Methods and findingsWe developed a dynamic state-transition model of TB. In a base case analysis, the model was calibrated to approximate the TB epidemic in Peru, a setting with a smear-positive TB incidence of 120 per 100,000 and 4.5% MDR TB among prevalent cases. Secondary analyses considered other settings. The following strategies were evaluated: first-line drugs administered under directly observed therapy (DOTS), locally standardized second-line drugs for previously treated cases (STR1), locally standardized second-line drugs for previously treated cases with test-confirmed MDR TB (STR2), comprehensive drug susceptibility testing and individualized treatment for previously treated cases (ITR1), and comprehensive drug susceptibility testing and individualized treatment for all cases (ITR2). Outcomes were costs per TB death averted and costs per quality-adjusted life year (QALY) gained. We found that strategies incorporating the use of second-line drug regimens following first-line treatment failure were highly cost-effective compared to strategies using first-line drugs only. In our base case, standardized second-line treatment for confirmed MDR TB cases (STR2) had an incremental cost-effectiveness ratio of 720 dollars per QALY (8,700 dollars per averted death) compared to DOTS. Individualized second-line drug treatment for MDR TB following first-line failure (ITR1) provided more benefit at an incremental cost of 990 dollars per QALY (12,000 dollars per averted death) compared to STR2. A more aggressive version of the individualized treatment strategy (ITR2), in which both new and previously treated cases are tested for MDR TB, had an incremental cost-effectiveness ratio of 11,000 dollars per QALY (160,000 dollars per averted death) compared to ITR1. The STR2 and ITR1 strategies remained cost-effective under a wide range of alternative assumptions about treatment costs, effectiveness, MDR TB prevalence, and transmission.ConclusionsTreatment of MDR TB using second-line drugs is highly cost-effective in Peru. In other settings, the attractiveness of strategies using second-line drugs will depend on TB incidence, MDR burden, and the available budget, but simulation results suggest that individualized regimens would be cost-effective in a wide range of situations.
| S-EPMC1483913 | biostudies-literature
Project description:Drug-resistant Mycobacterium tuberculosis is challenging elimination of tuberculosis (TB). We evaluated risk factors for TB and levels of second-line drug resistance in M. tuberculosis in patients in Europe with multidrug-resistant (MDR) TB. A total of 380 patients with MDR TB and 376 patients with non-MDR TB were enrolled at 23 centers in 16 countries in Europe during 2010-2011. A total of 52.4% of MDR TB patients had never been treated for TB, which suggests primary transmission of MDR M. tuberculosis. At initiation of treatment for MDR TB, 59.7% of M. tuberculosis strains tested were resistant to pyrazinamide, 51.1% were resistant to ≥1 second-line drug, 26.6% were resistant to second-line injectable drugs, 17.6% were resistant to fluoroquinolones, and 6.8% were extensively drug resistant. Previous treatment for TB was the strongest risk factor for MDR TB. High levels of primary transmission and advanced resistance to second-line drugs characterize MDR TB cases in Europe.
| S-EPMC4344280 | biostudies-literature
Project description:We evaluated risk factors and treatment outcomes associated with multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) in Germany in 2004-2006. In 177 (4%) of 4,557 culture-positive TB cases, Mycobacterium tuberculosis isolates were identified as MDR TB; an additional 7 (0.15%) met criteria for XDR TB. Of these 184 patients, 148 (80%) were born in countries of the former Soviet Union. In patients with XDR TB, hospitalization was longer (mean +/- SD 202 +/- 130 vs. 123 +/- 81 days; p = 0.015) and resistance to all first-line drugs was more frequent (36% vs. 86%; p = 0.013) than in patients with MDR TB. Seventy-four (40%) of these 184 patients received treatment with linezolid. Treatment success rates ranged from 59% for the entire cohort (59% for MDR TB and 57% for XDR TB) to 87% for those with a definitive outcome (n = 125; 89% for MDR TB and 80% for XDR TB). Extensive drug susceptibility testing and availability of second- and third-line drugs under inpatient management conditions permit relatively high treatment success rates in MDR- and XDR TB.
| S-EPMC2630755 | biostudies-literature
Project description:IntroductionMultidrug resistant tuberculosis (MDR-TB) presents a great challenge to public health, especially for developing countries. Some nontuberculous mycobacteria (NTM) cause the similar clinical and radiological characteristics with tuberculosis. We aimed to identify the frequency of NTM infections among subjects who were suspected to have MDR-TB due to lack of response to anti-TB treatment.MethodsThis retrospective study evaluated patients with suspected MDR-TB due to lack of sputum conversion after 2-3 month therapy with first line anti-TB treatment from 2009 through 2014. Cultures for mycobacteria were performed and identification was done to species level by phenotypic and molecular tests. The outcome of the patients with NTM disease and related risk factors for poor outcome were evaluated.ResultsOut of 117 consecutive strains isolated from suspected MDR-TB subjects, 35 (30%) strains were identified as NTM by using conventional and molecular approaches. Of these patients with positive NTM cultures, 32 (27%) patients met ATS/IDSA diagnostic criteria. Out of 32, 29 (90%) individuals with confirmed NTM diseases had underlying disorders including 8 subjects with malignancy, 5 with organ transplantations, and 4 with the human immunodeficiency virus. No known underlying disorder was found in 3 (9%) subjects. Treatment outcomes were available for 27 subjects, 17 (63%) of whom were cured and 10 (37%) had poor outcome including 6 (60%) who failed and 4 (40%) who died during treatment.ConclusionThe high costs to the patient and society should lead health care providers to consider NTM in all patients suspected of having TB.
| S-EPMC4414892 | biostudies-literature