Mycobacterium Tuberculosis Culture Research Articles

Diagnostic value of nucleic acid amplification tests for tuberculous pleural effusion.

Diagnosing tuberculous pleural effusion (TPE) is challenging for pulmonologists and laboratory scientists. The gold standards for TPE diagnosis are pleural fluid Ziehl-Neelsen staining, Mycobacterium tuberculosis (Mtb) culture and pleural biopsy. These tools have limitations, including low sensitivity, long turnaround time and invasiveness. The nucleic acid amplification test (NAAT) is a rapid and minimally invasive tool for diagnosing TPE. This review summarizes the diagnostic accuracy of available NAATs for TPE, with a focus on the evidence from systematic reviews and meta-analyses. The NAATs summarized in this review include in-house NAATs, GeneXpert-MTB/RIF, GeneXpert-MTB/RIF Ultra, simultaneous amplification and testing-tuberculosis, FluoroType MTB and loop-mediated isothermal amplification.

Percoll discontinuous density gradient centrifugation method for the fractionation of the subpopulations of Mycobacterium smegmatis and Mycobacterium tuberculosis from in vitro cultures

Bacterial populations in the in vitro laboratory cultures, environment, and patients contain metabolically different subpopulations that respond differently to stress agents, including antibiotics, and emerge as stress tolerant or resistant strains. To contain the emergence of such strains, it is important to study the features of the metabolic status and response of the subpopulations to stress agents. For this purpose, an efficient method is required for the fractionation and isolation of the subpopulations from the cultures. Here we describe in detail the manual setting up of a simple, easy-to-do, reproducibly robust Percoll discontinuous density gradient centrifugation for the fractionation of subpopulations of short-sized cells (SCs) and normal/long-sized cells (NCs) from Mycobacterium smegmatis and Mycobacterium tuberculosis cultures, which we had reported earlier. About 90-98% enrichment was obtained respectively for SCs and NCs for M. smegmatis and 69-67% enrichment was obtained respectively for the SCs and NCs for M. tuberculosis.•The Percoll discontinuous density gradient centrifugation helps the fractionation and isolation of mycobacterial subpopulations that differ in density.•The method offers a consistently reproducible high enrichment of the subpopulations of SCs and NCs from the in vitro cultures of M. smegmatis and M. tuberculosis.•Our earlier reports on the consistency in the differential response of the subpopulations, enriched using the method, to oxidative, nitrite, and antibiotic stress proves its validity.

Prussian blue (PB) modified gold nanoparticles as a SERS-based sensing platform for capturing and detection of pyrazinoic acid (POA)

Pyrazinoic acid (POA) is a metabolite of the anti-tuberculosis drug pyrazinamide (PZA), and its detection can be used to assess the resistance of Mycobacterium tuberculosis in cultures, as only sensitive strains of the bacteria can metabolize PZA into POA. Prussian blue is a well-known metal-organic framework compound widely used in various sensing platforms such as electrochemical, photochemical, and magnetic sensors. In this study, we present a novel sensing platform based on Prussian blue-modified gold nanoparticles (AuNPs) designed to enhance the affinity of POA towards the sensing surface and to capture POA molecules from aqueous solutions. This SERS-based method allows for the selective enrichment of POA, which can be detected in both pure aqueous solution and in the presence of its pro-drug PZA. The limit of detection (LOD) for POA was estimated to be 1.08 μM in pure aqueous solution and 0.18 mM in the presence of PZA. Furthermore, the precision of the SERS method was verified by the relative standard deviation (RSD) of 3.34–12.02% for three parallel samples using different matrices, i.e. aqueous solution, spiked river water and spiked simulated saliva. The recoveries of the samples ranged from 92.65 to 118.51%. These all demonstrate the potential application of the proposed detection scheme in medical research.

GeneXpert MTB/RIF Ultra performance to detect uncommon rpoB mutations in Mycobacterium tuberculosis

ObjectiveTo investigate the performance of GeneXpert MTB/RIF Ultra to accurately detect rifampicin resistance for less common rpoB mutations that potentially confer phenotypic resistance, we tested 28 such Mycobacterium tuberculosis cultures with Xpert Ultra.ResultsThey represented 22 different (combinations of) rpoB mutations. Of 28 isolates tested, one was reported by Xpert Ultra as “No rifampicin resistance detected”, 8 yielded a “Rifampicin indeterminate” result, and 19 were identified as rifampicin resistant. Overall, our results corroborate previous observations on the “Indeterminate” results for mutations at codon 432, while we add Lys446Gln as additional “Indeterminate” result and Pro439Leu as a false rifampicin-susceptible result. Furthermore, we document other uncommon point mutations and indels across the rpoB gene that are mostly correctly identified as rifampicin resistant by Xpert ultra (V3). Taken together, “Indeterminate” results in Xpert Ultra may indicate underlying rpoB mutations within the rifampicin-resistance determining region and thus increase the post-test probability of rifampicin resistance, albeit to an unknown extent.

Time-to-detection in culture of Mycobacterium tuberculosis: performance for assessing index cases contact-positivity

ObjectivesTime-to-detection (TTD) in culture on liquid media is inversely correlated to bacillary load and should be a contributing factor for assessing tuberculosis transmission. We wanted to assess if TTD was a better alternative than smear status to estimate transmission risk. MethodsFrom October 2015 to June 2022, we retrospectively studied a cohort of index cases (IC) with pulmonary tuberculosis (tuberculosis disease [TD]) from which samples were culture-positive before treatment. We studied the correlation between TTD and contact-positivity (CP) of IC contacts: CP was defined as CP = 1 (CP group) in case of TD or latent tuberculosis infection (LTI) in at least one screened contact of an IC, and CP = 0 otherwise (contact-negativity [CN] group). Univariate and multivariable analyses (logistic regression) were done. ResultsOf the 185 IC, 122 were included, generating 846 contact cases of which 705 were assessed. A transmission event (LTI or TD) was identified in 193 contact cases (transmission rate: 27%). At day 9, 66% and 35% of the IC had their sample positive in culture for CP and CN groups, respectively. Age and TTD ≤9 days were independent criteria of CP (odds ratio 0.97, confidence interval [0.95-0.98], P = 0.002 and odds ratio 3.52, confidence interval [1.59-7.83], P = 0.001, respectively). ConclusionTTD was a more discriminating parameter than smear status to evaluate the transmission risk of an IC with pulmonary tuberculosis. Therefore, TTD should be considered in the contact-screening strategy around an IC.

Comparative Molecular Genetic Characteristics of <i>Mycobacterium tuberculosis</i> Cultures Isolated in the European Part of the Russian Federation in 1998–2003 and 2016–2021

The objective: to evaluate changes in detection frequency of Mycobacterium tuberculosis of the main phylogenetic lines with various genetic determinants of resistance to rifampicin, isoniazid and fluoroquinolones in 1998–2003 and 2016–2021.Subjects and Methods. 965 mycobacterial cultures were studied, those cultures were isolated from pulmonary tuberculosis patients in 1998–2003 and 2016–2021. The spoligotypes of isolated Mycobacterium tuberculosis cultures and presence of gene mutations associated with resistance to isoniazid, rifampicin, and fluoroquinolones were determined.Results. In 2016–2021 versus 1998–2003, the incidence of Beijing subline increased from 50,72% to 64,60%. Within Euro-American line, the detection frequency of subline LAM9 decreased (from 40,00% to 14,81%), while the detection frequency of sublineT1 increased (from 27,11% to 41,36%). Mycobacterium tuberculosis with MDR genotype rpoB531_Ser->Leu + katG315_Ser-> Thr [1] was selected. Mycobacterium tuberculosis with genotypic resistance to fluoroquinolones was detected only in cultures of 2016–2021, and Mycobacterium tuberculosis with preXDR genotype was significantly more common in Beijing subline compared to Euro-American line (21,67% vs. 3,73%, p <0,05).

Effect of Stenotrophomonas maltophilia on Tuberculosis.

Tuberculosis (TB) is an important infectious disease suffered by many countries, including China. In this stage, accurate diagnosis and treatment are key measures for the prevention and control of TB. Stenotrophomonas maltophilia is a global emerging Gram-negative, multidrug-resistant (MDR) organism characterized by its high contribution to the increase in crude mortality rates. By single cell preparation and strain identification, we isolated S. maltophilia from stored cultures of Mycobacterium tuberculosis (Mtb). We found that S. maltophilia could not be removed from sputum by alkali treatment or inhibited by antibiotic mixture added to MGIT 960 indicator tubes. When co-cultured with Mtb on a Löwenstein-Jensen (L-J) slant, it could inhibit the growth of Mtb and liquefy the medium. More seriously, it was resistant to 10 of the 12 anti-TB drugs, including isoniazid and rifampin, and made the mixed samples display multidrug-resistant Mtb (MDR-TB) results in the drug sensitivity test, which might change a treatment regimen and increase disease burden. Following, we conducted a small-scale surveillance which showed that the isolation rate of S. maltophilia in TB patients was 6.74%, but these patients had no special characteristics and the presence of S. maltophilia was hidden. The effect of S. maltophilus on TB and its mechanism are unclear and require more attention. IMPORTANCE China is a high-burden country for tuberculosis (TB), multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB), and HIV-associated TB. Increasing the positive rate of culture and the accuracy of antibiotic susceptibility testing (AST) are important for diagnosis, treatment, and control of TB. In our study, we found that the isolation rate of Stenotrophomonas maltophilia in TB patients was not neglectable and that this bacterium affects the isolation and AST results of TB. Due to a lack of relevant research, the impact of S. maltophilia on the course and outcome of TB is unclear. However, the characteristics of S. maltophilia that increase disease mortality require attention. Therefore, in the clinical testing of TB, in addition to mycobacteria, it is recommended to increase the detection of co-infected bacteria and improve the awareness of TB clinicians of these bacteria.

Analysis of tuberculosis epidemiological characteristics and drug resistance among the floating population in Beijing in 2019

Objective: To analyze the epidemic characteristics and drug resistance of pulmonary tuberculosis among the floating population in Beijing and to provide a scientific basis for formulating strategies for the prevention and control of tuberculosis among the floating population. Methods: Data of tuberculosis patients who were positive for Mycobacterium tuberculosis culture was collected from 16 districts and one municipal institution of tuberculosis control and prevention in Beijing in 2019. The strain samples were tested for drug sensitivity by the proportional method. According to household registration location, patients were divided into the floating population and Beijing registration. SPSS 19.0 software analyzed tuberculosis patients' epidemic characteristics and drug resistance in the floating population. Results: In 2019, there were 1 171 culture-positive tuberculosis patients in Beijing, among the floating population, 593 (50.64%) patients were identified, with a male-to-female sex ratio of 2.2∶1 (409∶184). Compared to patients under household registration as Beijing residents, a higher proportion of young adults aged 20-39 years (65.09%,386/593) were noticed, with 55.65% (330/593) reported from the urban areas and 96.80% (574/593) were reported the first time. The differences were statistically significant (all P<0.05). After completing the drug sensitivity test, 37 cases were with multiple drug-resistant tuberculosis, accounting for 6.24% (37/593). The rates of isoniazid resistance (42.11%,8/19) and multidrug resistance (21.05%,4/19) in floating population patients after retreatment were significantly higher than those in newly treated patients (11.67%, 67/574 and 5.75%, 33/574), and the differences were statistically significant (all P<0.05). Conclusions: Most patients with tuberculosis in the floating population in Beijing in 2019 were young males aged 20-39 years. The reporting areas were urban areas and the newly treated patients mainly. The patients with tuberculosis in the re-treated floating population were more likely to suffer from multidrug and drug resistance, which should be taken as the key population for prevention and control.

The value of metagenomic next-generation sequencing for the diagnosis of pulmonary tuberculosis using bronchoalveolar lavage fluid.

The aim of this study was to compare metagenomic next-generation sequencing (mNGS) with other methods, including Xpert MTB/RIF, Mycobacterium tuberculosis (MTB) culture, and acid-fast bacillus (AFB) staining in the diagnosis of pulmonary tuberculosis (PTB) using bronchoalveolar lavage fluid (BALF). The data of 186 patients with suspected PTB were retrospectively collected from January 2020 to May 2021 at Tongji Hospital. BALF samples were collected from all patients and analyzed using AFB staining, MTB culture, Xpert MTB/RIF, and mNGS. Of the 186 patients, 38 patients were ultimately diagnosed as PTB. Metagenomic next-generation sequencing exhibited a sensitivity of 78.95%, which was higher than AFB staining (27.59%) and MTB culture (44.12%) but similar to Xpert MTB/RIF (72.73%). Utilization of combined methods demonstrates improvement for PTB diagnosis. In support of this, the area under the receiver operating characteristic curve for the combination of mNGS and MTB culture (0.933, 95% CI: 0.871, 0.995) was larger than those of mNGS, Xpert MTB/RIF, MTB culture, and the combination of Xpert MTB/RIF and MTB culture. The sensitivity of mNGS in the diagnosis of PTB using BALF specimen is similar to Xpert MTB/RIF.Metagenomic next-generation sequencing in combination with MTB culture may further improve the diagnosis of pulmonary tuberculosis.

Xpert MTB/RIF Assay for the Diagnosis of Pulmonary Tuberculosis Based on Bronchoalveolar Lavage Fluid: A Systematic Review and Meta-analysis

Abstract Currently, tuberculosis (TB) is the second most lethal disease in the world caused by a single infectious pathogen. Rapid diagnosis of TB is of great importance for its treatment and management. Xpert MTB/RIF is a novel rapid diagnostic assay for the diagnosis of pulmonary TB (PTB). Use of the Xpert assay based on bronchoalveolar lavage fluid (BALF) samples is indicated when TB is suspected and sputum smears or cultures are negative. The aim of this meta-analysis was to systematically evaluate the diagnostic performance of the Xpert assay based on BALF samples for the diagnosis of PTB. A systematic review of previously published articles was performed, and relevant data were extracted. Meta-DiSc 1.4 and Stata 12.0 were used to analyze the data. When Mycobacterium tuberculosis cultures were used as the criterion standard, the combined sensitivity of BALF-based Xpert was 0.89 (95% CI, 0.87–0.91), the specificity was 0.87 (95% CI, 0.85-0.88), the positive likelihood ratio was 8.28 (95% CI, 5.39–12.71), the negative likelihood ratio was 0.14 (95% CI, 0.10–0.19) and the diagnostic ratio was 84.08 (95% CI, 42.00–168.31). When composite reference standard was used as the criterion standard, the above observations were 0.69 (95% CI, 0.67–0.72), 0.98 (95% CI, 0.97–0.98), 41.40 (95% CI, 14.56–117.71), 0.28 (95% CI, 0.21–0.37) and 190.47 (95% CI, 50.56–717.54), respectively. The area under the summary receiver operating characteristic curve was close to 1 for both. Overall, the Xpert MTB/RIF assay based on BALF samples showed high sensitivity and specificity for the diagnosis of PTB and seems to be a reliable rapid detection method.

Cutaneous Tuberculosis in Heart Transplant

Tuberculosis is a disease with a significant global burden in terms of morbidity and mortality. It usually presents as a pulmonary disease but can occasionally have extrapulmonary presentations. Immunosuppressed people are at an increased risk of tuberculosis and more frequently have atypical manifestations of the disease. Cutaneous involvement is estimated to occur in only 2% of extrapulmonary presentations. We report a case of a heart transplant recipient with disseminated tuberculosis who initially presented with cutaneous manifestations in the form of multiple abscesses that were mistaken for a community-acquired bacterial infection. The diagnosis was made after positive nucleic acid amplification testing and cultures for Mycobacterium tuberculosis from the drainage of the abscesses. After initiating antituberculous treatment, the patient had 2 instances of immune reconstitution inflammatory syndrome. A combination of diminished immunosuppression due to discontinuation of mycophenolate mofetil in the setting of acute infection, rifampin drug interactions with cyclosporine, and the beginning of treatment of tuberculosis all contributed to this paradoxical worsening. The patient responded favorably to increased glucocorticoid therapy and showed no signs of treatment failure after 6 months of antituberculous therapy.

Strain identification of Mycobacterium tuberculosis in multidrug-resistant tuberculosis (MDR-TB) patients at Undata Hospital, Palu, Central Sulawesi

MDR-TB is a tuberculosis disease resistant to the two most effective anti-TB drugs, rifampin and isoniazid. MDR-TB is a threat to TB control. This study aims to identify the Mycobacterium tuberculosis strain in MDR-TB patients at Undata Hospital in Palu, Central Sulawesi. This type of research is descriptive and observational with a cross-sectional design. The study was conducted in Palu City, Donggala Regency, and Sigi Regency from April–June 2021. The sample in this study consisted of 22 patients who had undergone MDR-TB treatment from 2019 to 2020. The results showed that 55% of the patients with MDR-TB lived in Palu City, 27% in Donggala Regency, and 18% in Sigi Regency. Out of the 22 patients, 13 were men (59%) and nine were women (41%). Based on the results of the examination of Mycobacterium tuberculosis culture, three samples from patients with MDR-TB were positive for M. tuberculosis. The results of the spoligotyping examination showed that the strain belonged to the Beijing family. Identifying the type of M. tuberculosis strain through spoligotyping examination should be carried out in TB patients who have not undergone MDR-TB treatment or those who have failed treatment and are still found to be positive for M. tuberculosis bacteria.

Clinical Application of the Mycobacterium tuberculosis-RNA Assay of Pericardial Tissue Specimens in the Diagnosis of Tuberculous Pericarditis.

To assess the accuracy of the Mycobacterium tuberculosis (MTB)-RNA assay using pericardial tissue specimens for tuberculous pericarditis (TBP) diagnosis. MTB culture and MTB-RNA assay were performed for patients with suspected TBP. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of these two assays were analyzed. This study included 79 patients. The sensitivity, specificity, PPV, NPV, and AUC were 28.1% (18/64), 100.0% (15/15), 100.0% (18/18), 24.6% (15/61), and 0.64 for the MTB culture and 37.5% (24/64), 100.0% (15/15), 100.0% (24/24), 27.3% (15/55), and 0.69 for the MTB-RNA assay, respectively. Patients with positive pericardial tissue culture were defined as having definite TBP; in other words, culture was the gold standard for this group of patients and had a sensitivity, specificity, PPV, and NPV of 100% and an AUC of 1.00. However, these values were found to be 72.2% (13/18), 100.0% (15/15), 100.0% (13/13), 75.0% (15/20), and 0.86 for the MTB-RNA assay, respectively. Among patients with probable TBP (culture-negative patients), the sensitivity, specificity, NPV, and AUC of MTB culture were 0.0% (0/46), 100.0% (15/15), 24.6% (15/61), and 0.50, respectively, but the PPV could not be determined. These values were found to be 23.9% (11/46), 100.0% (15/15), 100.0% (11/11), 30.0% (15/50), and 0.62 for the MTB-RNA assay, respectively. MTB-RNA assay using pericardial tissues had limited diagnostic efficacy for TBP. In culture-positive TBP, the diagnostic accuracy of MTB-RNA was good. In contrast, in culture-negative TBP, its diagnostic accuracy was unsatisfactory.

Diagnostic Dilemma of Chest Wall Tuberculosis Masquerading Breast Lump and Sarcoma

Chest wall tuberculosis (TB) is rare and can often masquerade as a tumour. Diagnostic confirmation is made by bacteriological findings of acid-fast bacilli and culture of Mycobacterium tuberculosis or histopathological findings. This is a 37-year-old immunocompetent lady who presented with a 3-month history of gradually increasing right breast lump with suspicious characteristics during clinical examinations. Ultrasound of the breast showed normal breast tissue with a well-defined hypoechoic lesion within the anterior inferior pectoralis muscle. CT scan of the thorax revealed a right anterior chest wall lesion with multiple lung nodules and consolidations. Thus, there was a high suspicion of chest wall tumour and an initial diagnosis of soft tissue sarcoma was made. Biopsy of the lesion showed necrotising granulomatous inflammation but no acid-fast bacilli. A revised diagnosis of chest wall tuberculosis was made. She attended follow-up complaining of shortness of breath and pleuritic chest pain with signs of right pleural effusion. Her symptoms improved after the initiation of anti-TB treatment. This case demonstrated the challenge in making an early diagnosis of chest wall TB and commencement of anti-TB treatment.

Air-fluid level in the mediastinum.

A 19-year-old man presented to the emergency department with weakness, loss of appetite, and a weight loss of at least 13 kg in 5 months. He also complained of exertional dyspnea, dry cough, day and night sweats, and abdominal plus lower back pain. The physical examination revealed a temperature of 39.3°C but nothing else abnormal. The chest x-ray (Figure 1) revealed a mass that appeared to be located in the posterior mediastinum. A computed tomography (CT) scan (Figure 2) was performed in the emergency department to assess the extent of the disease, which showed pulmonary tuberculosis and spinal osteomyelitis associated with a perispinal collection from T1 to T12 and from L5 to S2, suggesting Pott's disease.1 The diagnosis of disseminated tuberculosis was confirmed by the presence of Mycobacterium tuberculosis in culture.2 A quadri-therapy for tuberculosis was initiated with isoniazid, rifampicin, pyrazinamide, and ethambutol, then downgraded to a tri-therapy because of the absence of resistance at the antibiogram.3 Magnetic resonance imaging (Figure 3) performed later during the hospitalization revealed a staged spondylodiscitis associated with collections from the beginning of the extension to the central nervous system. Echocardiography confirmed the presence of associated chronic pericarditis. Finally, the indication for radio-controlled drainage of the posterior mediastinal collection was decided owing to the important risk of fistulization.4 Tuberculosis is caused by slow growing aerobic bacilli, Mycobacterium tuberculosis complex. This disease, affecting mainly the lungs, also takes osteoarticular forms, the most frequent of which is spondylodiscitis. Spinal involvement is always secondary to hematogenous dissemination of bacilli from the primary site.5 Pott's disease results from an infection of the vertebrae (spondylitis) and intervertebral discs (discitis) with M. tuberculosis. The intervertebral disc is a relatively avascular structure and is spared until late stage of the disease. Bone destruction in spinal tuberculosis can be fragmentary, osteolytic, subperiosteal, or localized destruction with sclerosed margins. Cold abscesses are pus collections that lack surrounding inflammatory response and are seen in nearly 70% of patients with spinal tuberculosis. This is a severe form of the disease, located near nerve structures, which may be significantly and permanently affected, and may be life threatening.

Synthesis, Computational Studies, and Anti-Tuberculosis Activity of Benzoxazines That Act as RAGE Inhibitors

Novel benzoxazines were synthesized by microwave irradiation and tested for their potential binding affinity towards receptors of advanced glycation end products (RAGE). We found that the compound (2-(2-bromophenyl)-6-methyl-2,4-dihydro-1H-benzo[d][1,3]oxazine) (3i) is a lead inhibitor of RAGE. Further, our in silico prediction that benzoxazines dock towards the AGE binding region of RAGE suggests that these ligands could bind effectively at the hydrophobic pocket of the receptor and additionally form key interactions with Arg48 and Arg104, revealing its diversity in developing anti-RAGE drugs to treat AGE–RAGE-dominant disease conditions. Functionally, we herein report the anti-tuberculosis activity of small molecules which could be bioactive in the culture of mycobacterium tuberculosis.

Real time endobronchial ultrasound transbronchial needle aspiration for the diagnosis of tuberculous intrathoracic lymphadenopathy: Saudi Arabian Western region experience.

To assess the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for presumptive tuberculosis (TB) patients with intrathoracic enlarged lymph nodes in a country with low to moderate TB incidence. Thirty-one patients with clinical features of TB and intrathoracic lymphadenopathy, who had EBUS-TBNA sampling and final confirmation of intrathoracic TB lymphadenopathy, were retrospectively reviewed over an 8-year period. Routine clinical and laboratory evaluations including computerized tomography scans were performed before the EBUS-TBNA. Sociodemographic characteristics, clinical profile, pathological, and microbiological findings were collected. The EBUS-TBNA confirmed TB diagnosis in 26 (83.9%) subjects with a consistent pathological finding or positive culture of Mycobacterium tuberculosis. Pathological analysis had findings consistent with TB in 25 (80.6%) patients. Culture of the EBUS-TBNA sample was positive for Mycobacterium tuberculosis in 12 (38.7%) patients. Other supportive investigations like purified protein derivative (PPD) skin test was positive in 28 (90.3%) participants. Overall, the sensitivity of the EBUS-TBNA alone was 83.9%. No complications were recorded during the procedure. The EBUS-TBNA aspirate culture positivity was significantly related to having a larger size lymph node (p=0.048) only, while PPD positivity was significantly related to baseline and clinical features of the participants. The EBUS-TBNA demonstrated effective utility and safety in the evaluation and diagnosis of intrathoracic TB lymphadenopathy among individuals with compatible symptoms in a country with low-moderate TB-incidence.

Performance of Xpert MTB/RIF and sputum microscopy compared to sputum culture for diagnosis of tuberculosis in seven hospitals in Indonesia.

Tuberculosis (TB) is a major public health concern in Indonesia, where the incidence was 301 cases per 100,000 inhabitants in 2020 and the prevalence of multi-drug resistant (MDR) TB is increasing. Diagnostic testing approaches vary across Indonesia due to resource limitations. Acid-fast bacilli (AFB) smear is widely used, though Xpert MTB/RIF has been the preferred assay for detecting TB and rifampicin resistance since 2012 due to higher sensitivity and ability to rapidly identify rifampicin resistance. However, <1,000 Xpert instruments were available in Indonesia as of 2020 and the Xpert supply chain has suffered interruptions. We compared the performance of Xpert MTB/RIF and AFB smear to facilitate optimization of TB case identification. We analyzed baseline data from a cohort study of adults with pulmonary TB conducted at seven hospitals across Indonesia. We evaluated sensitivity and specificity of AFB smear and Xpert MTB/RIF using Mycobacterium tuberculosis (Mtb) culture as the gold standard, factors associated with assay results, and consistency of Xpert MTB/RIF with drug susceptibility test (DST) in detecting rifampicin resistance. Sensitivity of AFB smear was significantly lower than Xpert MTB/RIF (86.2 vs. 97.4%, p-value <0.001), but specificity was significantly better (86.7 vs. 73.3%, p-value <0.001). Performance varied by hospital. Positivity rate for AFB smear and Mtb culture was higher in subjects with pulmonary cavities and in morning sputum samples. Consistency of Xpert MTB/RIF with DST was lower in those with rifampicin- sensitive TB by DST. Additional evaluation using sputa from primary and secondary Indonesian health centers will increase the generalizability of the assessment of AFB smear and Xpert MTB/RIF performance, and better inform health policy. [https://clinicaltrials.gov/], identifier [NCT027 58236].

Tuberculous peritonitis in patients on peritoneal dialysis: a 35-year experience from a large medical center in Northern Taiwan

Introduction Tuberculous peritonitis (TBP) is a rare but fatal complication in patients on peritoneal dialysis (PD). In this study, we aimed to determine the demographic features, clinical features, laboratory parameters, and clinical outcomes of PD patients with TBP and to clarify possible risk factors for mortality. Materials and methods We retrospectively reviewed 2084 PD patients from January 1985 to December 2019. The diagnosis of TBP was established by positive peritoneal fluid culture for Mycobacterium tuberculosis. Results 18 patients were diagnosed with TBP. The incidence was 2.029 episodes per 1000 patient-years. The most common symptom was fever (94.4%), followed by cloudy effluent (83.3%) and abdominal pain (83.3%). The average peritoneal dialysis effluent (PDE) white blood cell (WBC) count was 172.7 cells/μL. Nine patients (50%) had WBC counts lower than 100 cells/μL and 13 patients (72.2%) had neutrophilic predominant WBC counts. Acid fast stain (AFS) was positive in 7 patients (38.9%). Only 2 patients (11.1%) continued with PD after TB infection, while 10 patients (55.6%) changed to hemodialysis. Seven patients (38.9%) died within 1 year. Significant differences were observed in sex (p = 0.040), the presence of diabetes mellitus (p = 0.024), and PD catheter removal (p < 0.001) between TBP patients with and without mortality. However, none of them was a significant factor for 1-year mortality in multivariate Cox regression model. Conclusion Physicians should pay attention to the unusual presentations of peritonitis, especially if symptoms include fever or an initial low PDE WBC count. Catheter removal is not mandatory if early diagnosis and appropriate therapy are available.

Comparison of chlorhexidine 0.7% and modified Petroff's method on sputum decontamination for culture method to detect Mycobacterium tuberculosis

Background: Tuberculosis (TB) is an infectious disease that is the leading cause of death from a single infectious agent worldwide. Culture is still the gold standard for the diagnosis of pulmonary TB. As an important specimen, sputum is often contaminated by normal flora at the time of collection, making the decontamination process an essential step of Mycobacterium tuberculosis culture. Decontamination with chlorhexidine 0.7% is expected to improve the detection of Mycobacterium tuberculosis in the culture method better than Modified Petroff's method. Methods: This research is an experimental study. Sputum was collected from pulmonary TB patients. Each sputum was decontaminated with chlorhexidine 0,7% and others with Modified Petroff's. Decontaminated sputum inoculated on Lowenstein-Jensen media. Samples were incubated, and evaluated the recovery rate of Mycobacterium tuberculosis. Data were analyzed using SPSS version 25.0 for Windows. Results: In total, we collected 16 sputum with 11 (68.75%) direct smear positive, 14 (87.5%) smear positive by chlorhexidine 0.7% method, and 13 (81.25%) by Modified Petroff's method. The number of cultures positive for Mycobacterium tuberculosis by chlorhexidine 0.7% method was 14 (87.5%), of which 11 (68.75%) have specific colony characteristics of Mycobacterium tuberculosis, 3 (18.75%) non-tuberculous mycobacteria, and 1 (6.24%) mixed. In Modified Petroff's, 6 (37.5%) were positive cultures and showed only growth of Mycobacterium tuberculosis. The contamination rate was 1 (6.25%) using chlorhexidine 0.7% and 8 (50%) using Modified Petroff’s method. Conclusion: Chlorhexidine 0.7% has a higher recovery rate in the culture of Mycobacterium tuberculosis compared with Modified Petroff's, showing recovery of non-tuberculous mycobacteria and a lower contamination rate.