International Journal of Mycobacteriology最新文献

Background: Multidrug-resistant tuberculosis (MDR-TB) is a serious threat to global tuberculosis (TB) control efforts. This study aims to investigate the trend of MDR-TB prevalence in Iran over 20 years.

Methods: A systematic literature search was conducted in various databases, including PubMed, Embase, and Web of Science, from 1981 to 2023. Studies reporting the prevalence of MDR-TB in Iran were included in the meta-analysis. Statistical analysis was performed using Comprehensive Meta-Analysis software.

Results: A total of 58 studies from different provinces of Iran were included in the meta-analysis. The majority of studies were from Tehran (n = 33), Kermanshah (n = 5), Mashhad (n = 4), and Tabriz (n = 4) provinces. Overall, 1885 cases of MDR-TB were reported in Iran during the study period. The highest number of MDR-TB cases was reported in 2000 (582 cases) and the lowest in 2001 (1 case). An increasing trend in MDR-TB prevalence was observed, particularly between 2018 and 2019. The pooled prevalence of MDR-TB in Iran was 12.31% (95% CI: 11.83-12.80) using the fixed-effects model and 20.21% (95% CI: 15.70-26.01) using the random-effects model. No evidence of publication bias was found.

Conclusion: The results of this comprehensive meta-analysis highlight the increasing trend of MDR-TB in Iran over the past two decades. This underscores the urgent need for strengthening TB control strategies, including improved surveillance, case detection, treatment, and management of MDR-TB in the country. Developing diagnostic and treatment approaches for MDR-TB should be prioritized by Iranian medical universities and public health authorities.

Background: Phenotypic drug susceptibility testing (DST) is considered the gold standard for detecting linezolid (LZD) resistance in Mycobacterium tuberculosis (MTB), but it is time-consuming. Nanopore sequencing offers a potentially faster alternative approach. This study evaluated the agreement between phenotypically detected LZD resistance and mutations in the rrl and rplC genes of MTB isolates using nanopore sequencing.

Methods: Consecutive drug-resistant MTB isolates from pulmonary samples collected in 2021 underwent liquid culture (LC) DST for LZD. All resistant isolates and an equal number of susceptible isolates were subjected to targeted sequencing of the rrl and rplC genes using nanopore technology.

Results: Sequencing identified a C154R mutation in the rplC gene in only one LZD-resistant isolate. No mutations were detected in the rrl gene. The agreement between sequencing and LC-DST for detecting LZD resistance was poor (Cohen's kappa: 0.03571, 95% confidence interval [CI]: -0.034-0.105). Additionally, no significant association was found between LZD resistance and clinical or microbiological outcomes at 6-month follow-up.

Conclusion: This study revealed a considerable discrepancy between phenotypic and genotypic detection of LZD resistance in MTB. Further research is needed to better understand the genetic mechanisms underlying LZD resistance and to develop reliable molecular diagnostics for rapid resistance detection.

Background: Tuberculous meningitis (TBM) is a challenging condition to diagnose, and current laboratory methods have limitations, especially in developing countries. This study evaluated the diagnostic utility of the Lancet consensus scoring (LCS) system in suspected TBM cases at a tertiary care center in India.

Methods: The clinical manifestations of 75 patients with suspected TBM were prospectively evaluated using the LCS system, which categorizes cases as "definite" (laboratory confirmed), "probable" (>10 points without imaging or > 12 points with imaging), and "possible" (6-9 points without imaging or 6-11 points with imaging). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the LCS system were compared to GeneXpert and mycobacterial growth indicator tube (MGIT) liquid culture, which are considered the gold standard tests.

Results: Out of 75 recruited cases, 11 were confirmed as definite TBM cases. The LCS system correctly identified 8 of these as "probable" and 3 as "possible" cases. Compared to GeneXpert, the LCS system had a specificity of 100%, sensitivity of 54.55%, NPV of 92.7%, and PPV of 100%. Compared to MGIT liquid culture, the LCS system had a specificity of 100%, sensitivity of 81.82%, NPV of 96.97%, and PPV of 100%. The diagnostic accuracy was higher for MGIT liquid culture (97.33%) than GeneXpert (93.33%).

Conclusion: The LCS system is a practical and easily applicable tool that can aid the diagnosis of suspected TBM cases, particularly in resource-limited settings. Despite some limitations, the LCS system demonstrated good diagnostic performance, suggesting its potential utility in improving TBM diagnosis and management.

Background: Tuberculosis (TB) is a leading cause of death in patients with human immunodeficiency virus (HIV)/AIDS. About 60% of HIV-positive individuals with latent TB infection (LTBI) develop active TB. Isoniazid preventive therapy (IPT) is recommended by the World Health Organization to prevent the progression of active TB in people living with HIV/AIDS (PLWHA). However, IPT implementation has been limited in some countries like Indonesia. The objective of this study was to assess the effect of IPT administration on the incidence of active TB in HIV patients with latent TB.

Methods: This was a quasi-experimental prospective cohort study conducted in an academic hospital in Indonesia. Interferon-gamma release assay-positive HIV-TB patients were randomly divided into an IPT group (received 6 months of IPT) and a non-IPT group. The incidence of active pulmonary TB was compared between the two groups after 6 months of follow-up.

Results: Of the 23 eligible patients, 22 were enrolled (10 in the IPT group, 12 in the non-IPT group). The incidence of active pulmonary TB was 0% in both groups. Factors associated with the absence of TB in both groups were the use of antiretroviral therapy for >4 years and a CD4+ T lymphocyte count >200 cells/μL. IPT was found to be safe with minimal adverse effects.

Conclusions: In this setting, the use of long-term antiretroviral therapy and higher CD4+ counts, rather than just IPT, were the key factors associated with preventing active TB in latent HIV-TB patients. These findings suggest that comprehensive HIV management may be more important than IPT alone for TB control in PLWHA. Further research is needed to optimize TB prevention strategies in this high-risk population.

Background: Tuberculosis (TB) is caused due to the infection of Mycobacterium tuberculosis (MTB) and it can infect the various parts of the human body. The disease is highly prevalent and is the second most common cause of death worldwide after COVID-19. Apart from sputum specimen, it is exceedingly difficult to diagnose due to its paucibacillary nature. The current study was intended to evaluate the accuracy of Smart Sure™ MTB and multidrug-resistant-TB (MDR-TB) kits (Genetix Biotech Asia Pvt. Ltd., India) with Xpert ultra and Mycobacterium growth indicator tube (MGIT) culture on nonsputum specimens from TB suspects.

Methods: A total of 205 nonsputum specimens were received between October 2023 and May 2024 at Intermediate Reference Laboratory, Department of Medicine, All India Institute of Medical Sciences, New Delhi, India. Xpert ultra and Smart Sure™ MTB and MDR-TB tests were done directly on samples. However, processed specimens were used for MGIT culture and drug-susceptibility testing (DST). Invalid and MGIT contaminated specimens were excluded from the final calculation.

Results: Overall, sensitivity and specificity of Smart Sure™ MTB screening kit was 71.59% and 98.28%, respectively, with Xpert ultra and 68.35% and 90.83%, respectively, with MGIT culture. While comparing with both Xpert ultra and MGIT-DST to detect rifampicin (RIF) resistant, Smart Sure™ MDR-TB kits showed sensitivity of 75.0% and 100% of specificity. However, for isoniazid (INH) resistance, Smart Sure™ MDR-TB kits showed 100% of sensitivity and specificity with MGIT-DST.

Conclusion: For the detection of MTB and its drug-resistance patterns (RIF and INH) in the specimens other than sputum, Smart Sure™ MTB and MDR-TB kits could play a vital role in TB endemic countries. While comparing the set-ups and skilled staffs, it required almost same as compared with previously approved WHO diagnostics used in resource-limited countries.

Background: The objective is to assess lung compliance and identify the optimal positive end-expiratory pressure (PEEP) levels in patients with tuberculosis-associated Acute Respiratory Distress Syndrome (TB-ARDS) compared to non-TB-ARDS patients.

Methods: This observational case-control study utilized electrical impedance tomography to evaluate lung mechanics in 20 TB-ARDS and 20 non-TB-ARDS patients. Participants underwent PEEP titration from 23 to 5 cm H2O in 2 cm H2O decrements. Lung compliance and the rates of hyperdistention and collapse were assessed at each PEEP level.

Results: Delta impedance values showed higher amounts in a PEEP range of 11-17 cm H2O and in patients with TB-ARDS (P > 0.05). In addition, both hyperdistention and collapse rates were nonsignificantly higher in TB-ARDS patients (P > 0.05), and the compromised levels of hyperdistention and collapse rates were at 15-17 cm H2O, indicating the most favorable PEEP level.

Conclusions: The observed patterns of hyperdistention and collapse rates across various PEEP levels provide valuable insights into the susceptibility of TB-ARDS patients to barotrauma. Notably, the identified optimal PEEP range between 15 and 17 cm H2O may guide ventilator management strategies in mitigating both hyperdistention and collapse; nonetheless, due to the high variability of lung compliances within groups, we strongly recommend individualized consideration for tailored respiratory support and evaluation.

Bacteria other than Mycobacterium tuberculosis and Mycobacterium leprae are known as nontuberculous mycobacteria (NTM), and the frequency of clinically symptomatic forms is increasing day by day. Mycobacterium fortuitum, a rapidly reproducing NTM, causes various clinical signs such as skin soft-tissue infection, surgical site infection, and disseminated infection in immunosuppressed patients. Although progress can be made in terms of diagnosis when growth is detected in culture, it is quite difficult to distinguish between infection and contamination. There is no place for antituberculosis treatment in the treatment of M. fortuitum. Antibiotics such as quinolones, trimethoprim-sulfamethoxazole, linezolid, doxycycline, clarithromycin, azithromycin, imipenem, tigecycline, linezolid, and amikacin are recommended at least in dual combination therapy. In this case presentation, the diagnosis and treatment of a 2-year skin soft-tissue infection with M. fortuitum growth in culture will be discussed.

To systematize published laboratory methods to inactivate Mycobacterium tuberculosis (MTB) and to describe their effectiveness. We carried out a review of the scientific literature to identify the publications that reported methods for the inactivation of MTB, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. The search addressed inactivation methodologies used in Public health laboratories for the treatment of biological material and only included studies reporting the efficacy of the method. The database used were PubMed (National Library of Medicine) and LILACS (Latin American and Caribbean Literature in Health Sciences). We evaluated the quality of the studies with the JBI (Joanna Briggs Institute) Critical Instrument Appraisal Checklist. We included 14 publications meeting the established inclusion and exclusion criteria. These 14 studies actually described a total of 35 inactivation methods. Most of them combined heat treatment with some chemical or enzymatic agent, and there were very few applying a single strategy. Twenty-four (68.57%) methods demonstrated significant efficacy in inactivating MTB. The systematic review identified 35 methods of inactivation of MTB, published in 14 studies. Most of the methods combined physical treatment techniques, especially heat, with chemical and/or enzymatic treatment techniques, obtaining mostly good results in preventing the reproduction of the microorganism. PROSPERO (International Prospective Register of Ongoing Systematic Reviews) (Code CRD42024503621).

Background: Mycobacterium abscessus complex (MABSc) causes chronic infection in patients with concomitant structural changes in the respiratory tract, which is especially important for patients with cystic fibrosis. To isolate an MABSc culture from clinical material, a variety of nutrient media are used. For species determination of microorganisms isolated on these media, additional identification methods are used, for example, polymerase chain reaction, sequencing, or mass spectrometry. The latter method is relatively easy to implement but requires improvement, due to the identification inaccuracy of nontuberculosis mycobacterias in general. Consequently, a set of nutrient media may be important for subsequent identification by mass spectrometry.

Methods: The study was conducted on 64 strains of MABSc representatives: 56 strains were obtained from patients with cystic fibrosis and 8 strains from patients with pulmonary pathology unrelated to cystic fibrosis. The obtained MABSc strains were transplanted to the universal chromogenic medium and the selective medium for the Burkholderia cepacia complex (BCC) isolation. Species identification was carried out by mass spectrometry based on matrix-activated laser time-of-flight desorption/ionization (MALDI-ToF MS). Microbial identification is based on a comparison of the obtained mass spectra with reference spectra from the database. Microorganisms were identified based on the coincidence degree (Score value). Sample preparation for microbial identification by mass spectrometry was carried out by an extended direct application method. Fragments of the rpoB and hsp65 genes with lengths of 752 bp and 441 bp, respectively, were used as molecular markers for subspecific identification of MABSc strains.

Results: A comparison of the peaks obtained after mass spectrometry of MABSc strains isolated on the studied nutrient media showed significant differences between these indicators selective medium for the BCC isolation with the supplement of iron polymaltose hydroxide (III) and universal chromogenic medium (P < 0.001) and selective medium for the BCC isolation with universal chromogenic medium (P < 0.001). Twenty-five strains of MABSc representatives were sequenced: results of subspecies determination in strains isolated on the universal chromogenic medium coincided with the results sequencing in 13 (86.6%) strains out of 15.

Conclusion: MALDI-ToF mass spectrometry allows microbial identification in a short time and with minimal cost, but it does not yet allow the proper identification of the subspecies of certain microbial groups, such as MABSc. Cultivation methods need optimization and new approaches to the extraction process of the bacterial protein fraction.

Background: Tuberculosis (TB) remains a significant global health concern, with extrapulmonary manifestations, including central nervous system involvement, posing substantial morbidity and mortality. While medical treatment with anti-TB drugs is the mainstay of therapy, certain TB-related cerebral complications, such as hydrocephalus, abscesses, and large symptomatic tuberculomas, may require surgical intervention. This study aimed to evaluate the outcomes of surgical management in patients with TB-related cerebral disorders.

Methods: A retrospective analysis was conducted on 24 patients who underwent surgical intervention for TB-related cerebral disorders, including tuberculomas, hydrocephalus, and abscesses, at a tertiary care center between 2005 and December 2020. Demographic data, clinical presentations, radiological findings, surgical techniques, and treatment outcomes were analyzed.

Results: The study cohort had a mean age of 35.8 ± 13.6 years, and the majority (62.5%) were male. Underlying immunodeficiency, primarily HIV infection, was present in 75% of the patients. The most common presenting symptoms were headache (83.3%), focal neurological deficits (75%), and altered mental status (54.2%). Radiological findings revealed 13 (54.2%) tuberculomas, 8 (33.3%) instances of hydrocephalus, and 3 (12.5%) abscesses. VP shunt inserted in 8 (33.3%) cases. Microscopic craniotomy performed in 7 (29.16%) cases. Aspiration through burr hole was done in 3 (12.5%) cases and stereotactic biopsy was performed in 6 (25%) cases. After 12 months of follow-up, favorable outcome achieved in 18 cases (75%) and the mortality occurred in 2 patients (8.3%). Surgical interventions included lesion resection (n = 10), stereotactic biopsy (n = 7), and ventriculoperitoneal (VP) shunt placement (n = 7). At 12-month follow-up, 18 (75%) patients had a favorable outcome, defined as clinical improvement or stabilization. Unfavorable outcomes were observed in 6 (25%) patients, including 2 deaths.

Conclusion: Surgical management, in conjunction with appropriate anti-TB medical therapy, may be a valuable component of the comprehensive treatment approach for select patients with TB-related cerebral disorders. The favorable outcome rate observed in this study suggests that timely and tailored surgical intervention can contribute to improved patient outcomes. However, larger, prospective, multicenter studies are needed to further elucidate the role and long-term efficacy of surgical management in this patient population.