Purpose: To report early confirmation of Mycobacterium tuberculosis (MTB) endophthalmitis by detection of 85B mRNA in vitreous by a reverse transcriptase polymerase chain reaction (RT-PCR) technique.Methods: Retrospective, interventional case series of 5 patients with MTB endogenous endophthalmitis. Vitreous aspirate was subjected to Ziehl-Neelsen (ZN) staining, BACTEC MicroMGIT culture, RT-PCR targeting the 85B gene, real-time PCR targeting the IS6110 region, and nested PCR targeting the MPB64 gene and IS6110 region. Correlation between detection of MTB RNA, culture positivity, and ZN staining was studied.Results: Five patients with endophthalmitis with no history of tuberculosis revealed acid-fast bacilli on ZN staining of vitreous. RT-PCR detected 85B RNA within 24 h. Culture for MTB was positive in 3/5 patients after 1 month. None of the eyes recovered any useful vision.Conclusions: RT-PCR can detect viable MTB RNA and provide evidence of active infection much earlier than culture.
We announce the draft genome sequence of a streptomycin monoresistant Mycobacterium tuberculosis strain (VRFCWCF MRTB 180) isolated from sputum of a clinically suspected tuberculosis patient.
This study reports on the structural and functional basis of pyrazinamide (PZA) resistance conferred by a novel mutation Ala102Pro in pncA gene as sequenced from a PZA resistant Mycobacterium tuberculosis strain. Molecular modeling studies of Wild Type (WT) and Mutant Type (MT) of Pyrazinamidase (PZase) showed the mutation at Ala102Pro does not impact on the conformation of the protein. However, the docking studies infer that MT has a higher inhibitory constant (Ki-990.0m) compared to WT (Ki-822.42m), which is indicative of drug resistance in MT. Furthermore, molecular interaction studies also reveal that WT forms 4 hydrogen bonds involved in PZA-WT inhibitory interactions, whereas, in case of MT, it formed 5 hydrogen bonds with PZA. However, Ala102 in WT was found to be less fluctuating and more stable in molecular dynamics simulation when compared to Pro102 in MT which was highly fluctuating and unstable. This implies that Ala102 shall be a key residue involved in PZA inhibitory interactions. Moreover, MT does not show hydrogen bonding with PZA with Pro102 and also deviating in terms of PZA binding pose in comparison with WT. Hence, the observed deviations in terms of MT-PZA interactions shall be attributed to the drug resistance conferred.
Abstract Background: Rapid detection of tuberculosis (TB) and its resistance are essential for the prompt initiation of correct drug therapy and for stopping the spread of drug-resistant TB. There is an urgent need for increased use of rapid diagnostic tests to control the threat of increased TB and multidrug-resistant TB (MDR-TB). Methods: EMPE Diagnostics has developed a multiplex molecular diagnostic platform called mfloDx ™ by combining nucleotide-specific padlock probe-dependent rolling circle amplification with sensitive lateral flow biosensors, providing visual signals, similar to a COVID-19 test. The first test kit of this platform, mfloDx ™ MDR-TB can identify Mycobacterium tuberculosis (MTB) complex and its clinically significant mutations in the rpoB and katG genes and in the inhA promotor contributing resistance to rifampicin (RIF) and isoniazid (INH), causing MDR-TB. Results: We have evaluated the performance of the mfloDx ™ MDR-TB test on 210 sputum samples (110 from suspected TB cases and 100 from TB-negative controls) received from a tertiary care center in India. The clinical sensitivity for detecting MTB compared to acid-fast microscopy and mycobacteria growth indicator tube (MGIT) cultures was 86.4% and 84.9%, respectively. All the 100 control samples were negative indicating excellent specificity. In smear-positive sputum samples, the mfloDx ™ MDR-TB test showed a sensitivity of 92.5% and 86.4% against MGIT culture and Xpert MTB/RIF, respectively. The clinical sensitivity for the detection of RIF and INH resistance in comparison with MGIT drug susceptibility testing was 100% and 84.6%, respectively, while the clinical specificity was 100%. Conclusion: From the above evaluation, we find mfloDx ™ MDR-TB to be a rapid and efficient test to detect TB and its multidrug resistance in 3 h at a low cost making it suitable for resource-limited laboratories.
We announce the draft genome sequence of a polyresistant Mycobacterium tuberculosis strain (CWCFVRF PRTB 19) isolated from the sputum of a clinically suspected tuberculosis patient, and it closely clusters to the East African Indian 5 (EAI5) lineage.
Abstract Background Driver mutations are seen in 80% of lung adenocarcinomas, and they influence prognosis and choice of therapy. Aim Aim of this study was to analyse the frequency of epidermal growth factor receptor (EGFR) mutations, ALK and ROS1 rearrangements and their association with age and gender in non‐small cell lung cancer reported from a tertiary care center in South India. Methods Tumors from patients with non‐small cell carcinoma of lung were evaluated for EGFR mutations, ALK and ROS1 rearrangements and their association with age and gender were studied. Results Two thirds of non‐small cell carcinomas had driver mutations or rearrangements. EGFR mutation was common and seen in 34.1%, whereas ALK rearrangement was seen in 11.1% and ROS1 rearrangement in 2% patients. Among EGFR mutations, most common were Exon 19 deletion and L858R seen in 21.3% and 11% of patients, respectively. Adenocarcinoma was the histologic diagnosis in 81% to 85% of patients with exon 19 deletion and L858R mutation, respectively. EGFR mutation frequency in patients less than 36 years was 13.6%, whereas in older patients, it varied from 34% to 36%. Exon 19 deletion was seen in 29.8% females and 17.2% of males. Conclusion EGFR mutations are more common than ALK and ROS1 rearrangements. They are more common in females. Patients less than 36 years have reduced frequency of EGFR mutations. Exon 19 deletion and L858R are most common and are more prevalent in lung adenocarcinomas. Rare EGFR mutations are seen in patients aged more than 50 years.
There is an urgent need for a rapid and reliable test to detect actively multiplying Mycobacterium tuberculosis directly from clinical specimens for an early initiation of the appropriate antituberculous treatment. This study was aimed at the optimization and application of nested reverse transcriptase-PCR (nRT-PCR) targeting the messenger RNA of the icl2, hspx, and rRNAP1 genes directly from sputum specimens, and their evaluation against the culture by the BACTEC MicroMGIT mycobacterial culture system. 203 Sputum samples from clinically suspected tuberculosis patients and 30 control specimens (clinically proven viral or bacterial infections other than tuberculosis) were included in this study. The mycobacterial culture was performed by the BACTEC MicroMGIT system following the manufacturer's instructions. The primers for nRT-PCRs targeting icl2, hspx, and rRNAP1 genes were indigenously designed using the Primer-BLAST software, and optimized for sensitivity and specificity. The icl2, hspx, and rRNAP1 genes were able to pick up 63.9%, 67.2%, and 58.75%, respectively, of culture-negative sputum specimens collected from clinically suspected tuberculosis patients. However, three (1.4%) were negative for nRT-PCR, but M. tuberculosis culture positive. All the 30 controls were negative for culture by the BACTEC MicroMGIT method and all three nRT-PCR. The novel nRT-PCRs targeting icl2, hspx, and rRNAP1 genes developed in this study are rapid and reliable diagnostic tools to detect viable M. tuberculosis directly from sputum specimens. However, further study by including a larger number of sputum specimens needs to be carried out to ascertain the diagnostic utility of the novel nRT-PCRs optimized in the study.
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