Resistance To First-Line Antituberculosis Drugs And Prevalence Of pncA Mutations In Clinical Isolates Of Mycobacterium tuberculosis From Zunyi, Guizhou Province Of China

Isolated soft tissue tuberculosis: a case report and literature review

Soft tissue tuberculosis is a rare extrapulmonary form of tuberculosis with limited experience in diagnosis and treatment. Soft tissue tuberculosis is an extrapulmonary infection with atypical clinical symptoms that can be easily misdiagnosed. In this article, we report a case of a female patient with isolated soft tissue tuberculosis who presented with a progressively enlarging subcutaneous mass as the primary symptom, and was suspected of having a subcutaneous lipoma after ultrasonography. A review of the literature revealed that soft tissue tuberculosis is insidious and mainly occurs in muscles and subcutaneous tissues. It was indicated by histopathology and qPCR testing for Mycobacterium tuberculosis complex. There is no standard treatment protocol for soft tissue tuberculosis, and a comprehensive regimen of surgical debridement of the lesion combined with chemotherapy can be used following the guidelines for treating extrapulmonary tuberculosis. Early diagnosis and standardized anti-tuberculosis treatment can significantly improve the prognosis of patients.

Characterization of Genetic Mutations in Multi-Drug-Resistant Isolates of Mycobacterium tuberculosis Bacilli Conferring Resistance to a Second-Line Anti-tuberculosis Drug

INTRODUCTION

Multi-drug-resistant tuberculosis (MDR-TB) has become a major public health concern globally. Mutations in first- and second-line drug targets such as katG, inhA, rpoB, rrs, eis, gyrA, and gyrB have been associated with drug resistance. Monitoring predominant mutations in the MDR-TB patient population is essential to monitor and devise future therapeutic regimes. The present study is aimed to characterize genetic mutations in MDR isolates of Mycobacterium tuberculosis (MTB) bacilli conferring resistance to a second-line anti-tuberculosis drug in the Eastern Indian population.

METHODS

This cross-sectional study was conducted in the Department of Microbiology, Indira Gandhi Institute of Medical Sciences, Patna, Bihar, and in the Tuberculosis Demonstration & Training Centre, Agamkuan, Patna. A total of 3270 patients suspected to have MDR-TB were recruited in the study. Two sputum samples, one on the spot, and the other in the morning were collected from each patient and the diagnosis of rifampicin-sensitive (RS)/rifampicin-resistant (RR/MDR) TB was done by Gene-Xpert test. One hundred fifty RS-TB samples and 150 RR/MDR-TB samples were considered for line probe assay (LPA). RS samples were subjected to first-line LPA using Genotype^® MTBDR Plus ver 2.0 and RR/MDR samples were considered for second-line LPA using Genotype^® MTBDRsl ver 2.0. All sputum samples were subjected to sputum smear microscopy using the Ziehl-Neelsen staining method. Statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 26.0 (IBM Corp. Armonk, NY) and R (version 4.1; R Core Team 2021).

RESULTS

In the present study, out of 3270 patients, we detected RR/MDR-TB in 235 patients (7.19%), RS-TB in 812 patients (24.83%), the rest of the patients negative for MTB (2223, 67.98%). Out of 150 RR/MDR-TB sputum samples tested, resistance to fluoroquinolone (FQ) was observed in 41 samples. The selected patients had predominantly FQ resistance due to the gyrA gene mutations (97.56%, n=40) compared to the gyrB gene mutations (2.44%, n=1). We observed >60% of the mutations in the gyrA gene in codon 94 (MUT3C (D94G), MUT3A (D94A), and MUT3D (D94H). In addition, we found the mutations MUT1 (A90V) and MUT2 (S91P) in the codons 90 and 91 of the gyrA gene in the considered MTB patient population.

CONCLUSION

The identified genes can be further validated to be considered as therapeutic targets, but more therapeutics and advanced strategies should be applied in the management of MTB.

Integrating tuberculosis and noncommunicable diseases care in low- and middle-income countries (LMICs): A systematic review

BACKGROUND

Low- and middle-income countries (LMICs) are facing a combined affliction from both tuberculosis (TB) and noncommunicable diseases (NCDs), which threatens population health and further strains the already stressed health systems. Integrating services for TB and NCDs is advantageous in tackling this joint burden of diseases effectively. Therefore, this systematic review explores the mechanisms for service integration for TB and NCDs and elucidates the facilitators and barriers for implementing integrated service models in LMIC settings.

METHODS AND FINDINGS

A systematic search was conducted in the Cochrane Library, MEDLINE, Embase, PubMed, Bibliography of Asian Studies, and the Global Index Medicus from database inception to November 4, 2021. For our search strategy, the terms "tuberculosis" AND "NCDs" (and their synonyms) AND ("delivery of healthcare, integrated" OR a range of other terms representing integration) were used. Articles were included if they were descriptions or evaluations of a management or organisational change strategy made within LMICs, which aim to increase integration between TB and NCD management at the service delivery level. We performed a comparative analysis of key themes from these studies and organised the themes based on integration of service delivery options for TB and NCD services. Subsequently, these themes were used to reconfigure and update an existing framework for integration of TB and HIV services by Legido-Quigley and colleagues, which categorises the levels of integration according to types of services and location where services were offered. Additionally, we developed themes on the facilitators and barriers facing integrated service delivery models and mapped them to the World Health Organization's (WHO) health systems framework, which comprises the building blocks of service delivery, human resources, medical products, sustainable financing and social protection, information, and leadership and governance. A total of 22 articles published between 2011 and 2021 were used, out of which 13 were cross-sectional studies, 3 cohort studies, 1 case-control study, 1 prospective interventional study, and 4 were mixed methods studies. The studies were conducted in 15 LMICs in Asia, Africa, and the Americas. Our synthesised framework explicates the different levels of service integration of TB and NCD services. We categorised them into 3 levels with entry into the health system based on either TB or NCDs, with level 1 integration offering only testing services for either TB or NCDs, level 2 integration offering testing and referral services to linked care, and level 3 integration providing testing and treatment services at one location. Some facilitators of integrated service include improved accessibility to integrated services, motivated and engaged providers, and low to no cost for additional services for patients. A few barriers identified were poor public awareness of the diseases leading to poor uptake of services, lack of programmatic budget and resources, and additional stress on providers due to increased workload. The limitations include the dearth of data that explores the experiences of patients and providers and evaluates programme effectiveness.

CONCLUSIONS

Integration of TB and NCD services encourages the improvement of health service delivery across disease conditions and levels of care to address the combined burden of diseases in LMICs. This review not only offers recommendations for policy implementation and improvements for similar integrated programmes but also highlights the need for more high-quality TB-NCD research.

Prevalence of primary anti-tuberculosis drug resistance at the tertiary center in Saudi Arabia and associated risk factors

OBJECTIVES

To estimate the prevalence mono-resistant tuberculosis (MR-TB) and multidrug resistant TB (MDR-TB), and evaluate the risk factors associated with the drug-resistant tuberculosis (DR-TB).

METHODS

A descriptive, retrospective study was applied, utilizing the TB patients' medical records at King Fahd Armed Forces Hospital (KFAFH), Jeddah, Saudi Arabia. The records of patients notified between 2000 and 2018 were reviewed and culture positive cases for Mycobacterium tuberculosis species were included. Moreover, the risk factors included were age, gender, smoking history, renal disease, liver disease, hyperbilirubinemia, diabetes mellitus, and human immunodeficiency virus (HIV).

RESULTS

Nine hundred and one cases in entirety were involved in the research, out of which 193 had drug-resistant tuberculosis (DR-TB) (21.4%). Out of the 21.4% DR-TB, 91.7% were MR-TB and 8.3% were MDR-TB. The highest MR prevalence was for pyrazinamide at 33.4%, while the lowest resistance was for ethambutol at 7.1%. For the risk factors of drug-resistant TB, only age depicted a statistically significant (p<0.01) but weak negative (r= -0.145) correlation with anti-TB drug resistance.

CONCLUSION

Rates of DR-TB reported in the study are considered higher compared to the recently reported national and international rates. According to the results, only younger people are at risk of developing DR-TB. Moreover, genetic mutation may play a role in drug resistance among our cases specifically for pyrazinamide monoresistance.

Efflux pumps in Mycobacterium tuberculosis and their inhibition to tackle antimicrobial resistance

Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis, was the leading cause of mortality worldwide in 2019 due to a single infectious agent. The growing threat of strains of M. tuberculosis untreatable by modern antibiotic regimens only exacerbates this problem. In response to this continued public health emergency, research into methods of potentiating currently approved antimicrobial agents against resistant strains of M. tuberculosis is an urgent priority, and a key strategy in this regard is the design of mycobacterial efflux pump inhibitors (EPIs). This review summarises the current state of knowledge surrounding drug-related efflux pumps in M. tuberculosis and presents recent updates within the field of mycobacterial EPIs with a view to aiding the design of an effective adjunct therapy to overcome efflux-mediated resistance in TB.

Drug-Resistant Mycobacterium tuberculosis Isolates from New and Previously Treated TB Patients in China, 2017-2019

INTRODUCTION

Mycobacterium tuberculosis (MTB) is a causative agent of tuberculosis (TB) that causes death worldwide.

METHODS

MTB was subjected to phenotypic drug-susceptibility tests (DST), and drug-resistant genes were sequenced.

RESULTS

Previously treated patients were more likely to have positive smear results and exhibit drug resistance. New patients were more likely to be mono SM-resistant and less likely to be INH- and RIF-resistant. The most common mutations were katG (S315T), rpoB (S450L), rpsL (K43R), and embB (M306V).

CONCLUSIONS

The proportion of mono-SM-resistant TB among new patients was higher.

Pyrazinamide resistance and pncA mutations in drug resistant Mycobacterium tuberculosis clinical isolates from Myanmar

Pyrazinamide (PZA) is an important anti-tuberculosis drug, which is active against semi-dormant bacilli and used as a component of first-line drugs and drug-resistant tuberculosis regimens. Mutations in pncA and its promoter region are main cause of PZA resistance. There are limited PZA susceptibility data as there is no routine drug susceptibility testing (DST) for PZA. This study was aimed to determine the proportion of PZA resistance among rifampicin-resistant tuberculosis patients and to identify mutations which are responsible for PZA resistance in pncA and its promoter region. Liquid-based DST was performed to detect PZA susceptibility on 192 culture positive rifampicin-resistant isolates collected from National Tuberculosis Reference Laboratory. Sequencing on pncA including its promoter region was performed and analysis was done on 157 isolates. Phenotypic PZA resistance was detected in 58.9% of isolates. Sixty-five different mutations were distributed in pncA or promoter region of 82 isolates. Sensitivity and specificity of pncA sequencing in detection of PZA resistance showed 89.8% and 95.6% respectively. High proportion of PZA resistance among rifampicin-resistant cases highlighted the need for effective treatment regimen development for PZA-resistant MDR-TB. It is also suggested that routine PZA susceptibility test should be incorporated to treatment monitoring regimen and National Drug Resistance surveys.