Drug resistance profile of Mycobacterium tuberculosis and predictors associated with the development of drug resistance

Burden and Patterns of Multidrug-Resistant Tuberculosis in Pediatric and Adolescent Patients at a Tertiary Care Hospital in Pakistan

Background Multidrug-resistant tuberculosis (MDR-TB) presents a significant global health challenge, particularly in developing countries. This study focuses on the burden and pattern of pediatric and adolescent MDR-TB in a tertiary care hospital setting. Aims/objectives The main objective is to evaluate MDR-TB's prevalence and resistance patterns among pediatric and adolescent patients, highlighting critical demographic factors and resistance trends. Materials and methods The study utilized a prospective analytical design in two tertiary care facilities, focusing on children aged four months to 18 years diagnosed with extra-pulmonary tuberculosis. Data on demographic profiles, clinical outcomes, and drug resistance patterns were collected and analyzed using the Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 27.0, Armonk, NY). Results Out of 99 enrolled participants, 63 (63.64%) met the inclusion criteria. The mean age was 70.22±48.90 months. A significant proportion, 60 (95.2%) of the cases, originated from Punjab. Notably, 10 (15.9%) of the cultures demonstrated MDR, with specific resistance observed to isoniazid (INH) in 10 (15.9%) cases, rifampicin (RIF) in 11 (17.5%) cases, and pyrazinamide (PZA) in seven (11.1%) cases. The study also recorded a high prevalence of tuberculous meningitis, affecting 52 (82.5%) participants, and malnutrition, affecting 49 (77.8%). Conclusions MDR-TB in 10 (15.9%) of the study children and adolescents presenting in Pakistan's specialized health centres is a notable burden. This points to a need for better diagnostic methods and treatment plans for pediatric patients. Implementing advanced diagnostics and personalized therapies is crucial for managing MDR-TB in susceptible demographics. Our findings emphasize the importance of updating treatment protocols to tackle the impacts of MDR-TB and its evolving resistance.

Risk factors for multidrug resistance in tuberculosis patients with diabetes mellitus

Objective

To study the risk factors and prediction models of multidrug resistance in patients with tuberculosis and diabetes and those with a history of tuberculosis treatment.

Methods

A total of 256 tuberculosis patients with diabetes who were registered in Luoyang city, Henan Province, from January 2018 to December 2021. Logistic regression analysis was performed to analyse the risk factors for multidrug resistance. ROC curves were used to analyse the predictive model for multidrug resistance.

Results

Age < 65 years old, HbA1c, and a history of tuberculosis treatment were independent risk factors for multidrug resistance in patients with tuberculosis and diabetes (P < 0.05). The area under the ROC curve of predictive model for MDR was 0.878 (95% CI (0.824, 0.932)). Age < 65 years old and HbA1c were independent risk factors for MDR in patients with TB and diabetes with a history of TB treatment. The area under the ROC curve of predictive model for MDR was 0.920 [95% CI (0.831, 0.999)].

Conclusion

The predictive model had certain prediction value for the risk of multidrug resistance in patients with tuberculosis and diabetes.

Drug Resistance Patterns and Trends in Patients with Suspected Drug-Resistant Tuberculosis in Dalian, China: A Retrospective Study

Purpose

The emergence of drug-resistant tuberculosis (DR-TB) represents a threat to the control of tuberculosis. This study aimed to estimate the patterns and trends of DR-TB in patients with suspected DR-TB. In addition, risk factors for multidrug-resistant tuberculosis (MDR-TB) were identified among suspected DR-TB patients in Dalian, China.

Patients and Methods

A total of 5661 patients with suspected DR-TB from Jan 1, 2013 to Dec 31, 2020 were included in the final analysis. The resistance pattern of all resistant strains was determined by drug susceptibility testing (DST) using the conventional Lowenstein-Jensen Proportion Method (LJ). DR-TB trends were estimated from 2013 to 2020. During the research period, the chi-square test was employed to analyze the significance of linear drug-resistance trends across time. Bivariate and multivariate logistic regression were performed to assess factors associated with MDR-TB.

Results

From 2013 to 2020, the resistance rates of rifampicin (RFP) and isoniazid (INH) decreased significantly, whereas the resistance rates of ethambutol (EMB) and streptomycin (SM) increased in patients with suspected DR-TB. From 2013 to 2020, the prevalence of DR-TB decreased in all patients from 34.71% to 28.01% with an average annual decrease of 3.02%. Among new cases, from 2013 to 2020, the prevalence of DR-TB (from 26.67% to 24.75%), RFP-resistant TB (RR-TB) (from 15.09% to 3.00%) and MDR-TB (from 6.08% to 2.62%) showed a significant downward trend. Among patients with a previous treatment history, DR-TB (from 54.70% to 37.50%), RR-TB (from 44.16% to 11.49%) and MDR-TB (from 26.90% to 10.34%) showed a significant downward trend from 2013 to 2020. Males (AOR 1.28, 95% CI 1.035–1.585), patients 45 to 64 years of age (AOR 1.75, 95% CI 1.342–2.284), patients 65 years and older (AOR 1.65, 95% CI 1.293–2.104), rural residents (AOR 1.24, 95% CI 1.014–1.519) and a previous treatment history (AOR 3.94, 95% CI 3.275–4.741) were risk factors for MDR-TB.

Conclusion

The prevalence of DR-TB, RR-TB and MDR-TB was significantly reduced from 2013 to 2020. Considerable progress has been made in the prevention and treatment of DR-TB during this period. However, the increasing rate of drug resistance in EMB and SM should be taken seriously. Suspected DR-TB patients who are male, older than 45 years of age, live in rural areas, and have a history of TB treatment should be given priority by health care providers.

Determinants of drug resistant & drug sensitive tuberculosis patients from North India-a case control study

BACKGROUND AND OBJECTIVE

The burden of drug resistant tuberculosis (DRTB) has posed a huge challenge to for the governments, throughout the world. India has 27% of the global DRTB burden with incidence of 130,000 cases. India has kept an ambitious target of elimination of tuberculosis by 2025 which requires understanding and mitigating various determinants of DRTB.

METHODS

The retrospective case control study was undertaken from May to September 2019 among drugresistant (cases) and drug sensitive (controls) tuberculosis patients from two districts of Himachal Pradesh, India. A total of 211 participants were recruited in the study, which includes all 102 cases and randomly selected, age and sex matched 109 controls. A semi structured questionnaire, adapted from a study by Lobo et al, was used for assessing the determinants of DRTB and DSTB. The data collection was undertaken from district and block level health care facilities followed by home visits to patients. Multivariate logistic regression was used to determine risk factors associated with DRTB.

RESULTS

Diagnostic delay (aOR-7.72, p value 0.000), history of treatment default (aOR-2.97, self history of tuberculosis (aOR 1.42, p value 0.01), migration (aOR-4.84, p value 0.000), smoking (aOR-2.70, p value 0.014), and belonging to rural area (aOR-2.62, p value- 0.013) were found as independent risk factors for the occurrence of DRTB.

CONCLUSION

The risk factors identified in the study should be prioritized by the policy makers, implementators and educators for framing appropriate policies in TB control programme in India. The diagnostic delay as a risk factor merits active case finding of TB patients and educating health care staff and community.

Risk factors for drug-resistant tuberculosis, the association between comorbidity status and drug-resistant patterns: a retrospective study of previously treated pulmonary tuberculosis in Shandong, China, during 2004-2019

OBJECTIVE

This study was designed to identify the risk factors for drug-resistant tuberculosis (DR-TB) and the association between comorbidity and drug resistance among retreated pulmonary tuberculosis (PTB).

DESIGN

A retrospective study was conducted among all the 36 monitoring sites in Shandong, China, over a 16-year period. Baseline characteristics were collected from the TB Surveillance System. Categorical variables were compared by Fisher's exact or Pearson's χ² test. The risk factors for drug resistance were identified using univariable analysis and multivariable logistic models. The influence of comorbidity on different types of drug resistance was evaluated by performing multivariable logistic models with the covariates adjusted by age, sex, body mass index, drinking/smoking history and cavity.

RESULTS

A total of 10 975 patients with PTB were recorded during 2004-2019, and of these 1924 retreated PTB were finally included. Among retreated PTB, 26.2% were DR-TB and 12.5% had comorbidity. Smoking (adjusted OR (aOR): 1.69, 95% CI 1.19 to 2.39), cavity (aOR: 1.55, 95% CI 1.22 to 1.97) and comorbidity (aOR: 1.44, 95% CI 1.02 to 2.02) were risk factors for DR-TB. Of 504 DR-TB, 9.5% had diabetes mellitus, followed by hypertension (2.0%) and chronic obstructive pulmonary disease (1.8%). Patients with retreated PTB with comorbidity were more likely to be older, have more bad habits (smoking, alcohol abuse) and have clinical symptoms (expectoration, haemoptysis, weight loss). Comorbidity was significantly associated with DR-TB (aOR: 1.44, 95% CI 1.02 to 2.02), overall rifampin resistance (aOR: 2.17, 95% CI 1.41 to 3.36), overall streptomycin resistance (aOR: 1.51, 95% CI 1.00 to 2.27) and multidrug resistance (aOR: 1.96, 95% CI 1.17 to 3.27) compared with pan-susceptible patients (p<0.05).

CONCLUSION

Smoking, cavity and comorbidity lead to an increased risk of drug resistance among retreated PTB. Strategies to improve the host's health, including smoking cessation, screening and treatment of comorbidity, might contribute to the control of tuberculosis, especially DR-TB, in China.

A novel, rapid (within hours) culture-free diagnostic method for detecting live Mycobacterium tuberculosis with high sensitivity

BACKGROUND

Nucleic acid amplification tests (NAATs) are widely used to diagnose tuberculosis (TB), but cannot discriminate live bacilli from dead bacilli. Live bacilli can be isolated by culture methods, but this is time-consuming. We developed a de novo TB diagnostic method that detects only live bacilli with high sensitivity within hours.

METHODS

A prospective study was performed in Taiwan from 2017 to 2018. Sputum was collected consecutively from 1102 patients with suspected TB infection. The sputum was pretreated and heated at 46°C for 1 h to induce the secretion of MPT64 protein from live Mycobacterium tuberculosis. MPT64 was detected with our ultrasensitive enzyme-linked immunosorbent assay (ELISA) coupled with thionicotinamide-adenine dinucleotide (thio-NAD) cycling. We compared our data with those obtained using a culture test (MGIT), a smear test (Kinyoun staining), and a NAAT (Xpert).

FINDINGS

The limit of detection for MPT64 in our culture-free ultrasensitive ELISA was 2.0 × 10-19 moles/assay. When the criterion for a positive response was set as an absorbance value ≥17 mAbs, this value corresponded to ca. 330 CFU/mL in the culture method - almost the same high-detection sensitivity as the culture method. To confirm that MPT64 is secreted from only live bacilli, M. bovis BCG was killed using 8 μg/mL rifampicin and then heated. Following this procedure, our method detected no MPT64. Our rapid ultra-sensitive ELISA-based method required only 5 h to complete. Comparing the results of our method with those of culture tests for 944 specimens revealed a sensitivity of 86.9% (93/107, 95% CI: 79.0-92.7%) and a specificity of 92.0% (770/837, 95% CI: 89.9-93.7%). The performance data were not significantly different (McNemar's test, P = 0.887) from those of the Xpert tests. In addition, at a ≥1+ titer in the smear test, the positive predictive value of our culture-free ultrasensitive ELISA tests was in a good agreement with that of the culture tests. Furthermore, our culture-free ultrasensitive ELISA test had better validity for drug effectiveness examination than Xpert tests because our test detected only live bacilli.

INTERPRETATION

Our culture-free ultrasensitive ELISA method detects only live TB bacilli with high sensitivity within hours, allowing for rapid diagnosis of TB and monitoring drug efficacy.

FUNDING

Matching Planner Program from JST (VP29117939087), the A-STEP Program from JST (AS3015096U), Waseda University grants for Specific Research Projects (2017A-015 and 2019C-123), the Precise Measurement Technology Promotion Foundation to E.I.