Rifampicin resistance in Mycobacterium tuberculosis in Iran: a two-centre study

New insight in molecular detection of Mycobacterium tuberculosis

Mycobacterium tuberculosis, the causative agent of tuberculosis, is a pathogenic bacterium that has claimed millions of lives since the Middle Ages. According to the World Health Organization's report, tuberculosis ranks among the ten deadliest diseases worldwide. The presence of an extensive array of genes and diverse proteins within the cellular structure of this bacterium has provided us with a potent tool for diagnosis. While the culture method remains the gold standard for tuberculosis diagnosis, it is possible that molecular diagnostic methods, emphasis on the identification of mutation genes (e.g., rpoB and gyrA) and single nucleotide polymorphisms, could offer a safe and reliable alternative. Over the past few decades, as our understanding of molecular genetics has expanded, methods have been developed based on gene expansion and detection. These methods typically commence with DNA amplification through nucleic acid targeted techniques such as polymerase chain reaction. Various molecular compounds and diverse approaches have been employed in molecular assays. In this review, we endeavor to provide an overview of molecular assays for the diagnosis of tuberculosis with their properties (utilization, challenges, and functions). The ultimate goal is to explore the potential of replacing traditional bacterial methods with these advanced molecular diagnostic techniques.

Multidrug-resistant tuberculosis in Iran: a multicenter study

The worldwide incidence of multi-drug-resistant tuberculosis (MDR-TB) is rapidly increasing, and it has emerged as a pressing public health issue in Iran. Nevertheless, there is a scarcity of up-to-date research on the prevalence of MDR-TB in individuals with pulmonary TB in the country. In this cross-sectional study, we gathered a total of 1216 respiratory samples, each corresponding to a unique patient, from five distinct regional TB laboratories in Iran. We identified clinical isolates as Mycobacterium tuberculosis using the IS6110-based PCR assay and Xpert MTB/RIF. Drug susceptibility testing (DST) was conducted using the conventional proportion method. Out of the collected specimens, 448 tested positive for M. tuberculosis. Among these isolates, 445 (99.4%) exhibited susceptibility to the tested drugs, while 3 (0.6%) were found to be MDR. The findings from this recent study indicate that the prevalence of MDR in Iran stands at 0.6%. The absence of recently approved treatment protocols in various regions of Iran, along with inadequately equipped laboratories lacking DST capabilities, could contribute significantly to the rise in TB/MDR-TB prevalence in Iran. Therefore, the implementation of enhanced treatment management strategies and the adoption of innovative technologies are essential steps towards improving the current situation.

Previous pulmonary tuberculosis enhances the risk of lung cancer: systematic reviews and meta-analysis

PURPOSE

The possible association between history of pulmonary tuberculosis (TB) and lung cancer (LC) has attracted researchers' attention for several decades. This systematic review and meta-analysis aim to assess the association between previous pulmonary TB infection and LC risk.

METHODS

A Systematic and comprehensive search was performed in the following databases: PubMed, Embase, clinical key, Web of Science and Google Scholar, in articles and abstracts published from 1987 to 2021. Thirty-two articles (involving 50,290 cases and 846,666 controls) met the inconclusive criteria. The Comprehensive Meta-Analysis version 2.2 software was used for this meta-analysis.

RESULTS

The result of this meta-analysis demonstrates that pre-existing active pulmonary TB increases the risk of LC (RR = 2.170, 95% confidence interval [CI] 1.833-2.569, p < .001, I² = 91.234%). The results showed that the risk of the history of active pulmonary TB infection in adenocarcinoma was 2.605 (95% CI 1.706-3.979, p < .001, I² = 55.583%), in small-cell carcinoma was 2.118 (95% CI 1.544-2.905, p < .001, I² = 0.0%), in squamous-cell carcinoma, was 3.570 (95% CI 2.661 - 4.791, p < .001, I² = 42.695%) and 2.746 (95% CI 2.300-3.279, p < .001, I² = 41.686%) for other histological types of LCs. According to these results, a history of active pulmonary TB increases the risk of LC.

CONCLUSIONS

This study emphasizes the importance of LC screening in pulmonary TB patients even after the infection is treated. With the increased chances of LC in a patient who had a history of active pulmonary TB, there could be a need for a further follow-up period after pulmonary TB recovery.