International Journal of Mycobacteriology最新文献

Tuberculosis (TB) affecting calcaneum is relatively rare in immunocompetent adults. Due to its nonspecific presentation and the absence of constitutional symptoms of TB, diagnosis is often delayed. The authors present a case of TB of calcaneum in a young male. A 20-year-old male presented with persistent pain and mild swelling of the right heel for 6 months. Upon evaluation with radiographs, a lytic lesion was noted in the posteromedial aspect of the right calcaneum. Magnetic resonance imaging was done and was reported as subacute osteomyelitis with Brodie's abscess. An open biopsy was performed and the obtained tissue was sent for histopathological examination. Histopathology showed features suggestive of Koch's etiology. All the microbiological investigations, including polymerase chain reaction for TB were negative. The patient was started on antitubercular therapy (ATT) based on weight. After 4 months of ATT, the patient developed multiple discharging sinuses over a previous open biopsy scar for which repeat debridement was done. After 12 months of ATT, the patient was asymptomatic, and radiologically, the lesion was healed. Early diagnosis and treatment with ATT will prevent massive destruction and collapse of the calcaneal body and further spread into the subtalar joint. Repeated debridements may be needed in case of nonhealing discharging sinuses to decrease the local infection load.

Background: Pili are polymeric, hydrophobic, proteinaceous structures generally composed of a major repeating subunit called pilin and, in some cases, a minor tip-associated adhesin subunit. Pili are involved in many virulence-associated functions, such as biofilm formation, adherence, and colonization of mucosal surfaces.

Methods: Mycobacterium tuberculosis (MTB) strains were isolated from clinically and laboratory-confirmed cases of tuberculosis (TB). The TB isolates were subjected to the Xpert MTB/rifampicin test and then, further susceptibility testing was performed on them against first- and second-line drugs using proportional methods. Thereafter, the selected isolates were subculture in Dubos Tween-albumin liquid culture medium, and at their exponential growth phase (OD₆₀₀ = 0.05 (5 × 10⁶ colony-forming unit/mL), cells were observed under atomic force microscopy (AFM). For each isolate, 15-20 steel sample packs were prepared and observed under AFM. Here, the data presented are the result of average observation.

Results: Under AFM, seven different types of pili were detected, out of which four types, i.e., Type III, Type IV secretion pili, and Type IV-like pili, curli-like pili (MTP) were similar to reported pili in Gram-negative and Gram-positive bacteria. Whereas the other three forms, i.e., Type V (relief funnel pili), Type VI (adhesion tapering), and Type VII (adhesion flap pili), were newly identified and named according to their appearance. Both Types of IV pili were detected in all clinical isolates irrespective of their susceptibility patterns, although significant differences were observed from the side of their protruding. Type Curli pili is similar in appearance in all clinical isolates. Types VI and VII were detected only in extensively drug-resistant and totally drug-resistant-TB isolates (100%). The Type III pili (secretion needle pili) was present in both susceptible- and drug-resistant bacilli, although in drug-resistant strains, we found a considerable difference in their length (50 μ ±10 nm in length) and sometimes, they also had tapering at end. The Type V pili was seen in susceptible isolates but it was at the resting stage (100%; lying aside of cell wall) whereas in drug-resistant isolates, they were getting apart from the cell wall of bacilli with a clear tapering or funnel shape structure.

Conclusion: The results of this study highlight the importance of new types of pili expressions in respect of susceptibility patterns in TB. The identified new types of pili would be promising approaches for the treatment and prevention of drug-resistant TB, which needs further investigation.

Background: Over the past 10 years, the clinical importance of opportunistic bacteria of the order Actinomycetales has increased significantly. While many problems for the Mycobacterium tuberculosis complex have been solved, for nontuberculous mycobacteria, some questions remain open. These pathogens have a number of structural features that allow them to persist in the external environment for a long time.

Methods: The main inclusion criteria were cultural characteristics in assessing the growth of microorganisms on solid egg media. If nontuberculous mycobacteria (NTM) growth was detected, identification signs were carried out using the DNA hybridization method. Subsequently, these cultures were identified using the matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectrometry method. In case of obtaining unacceptable results of identification from primary inoculations, re-identification to obtain pure cultures was carried out after transferring the material from primary media to agar media: 5% blood agar and universal chromogenic medium. When re-identifying isolated cultures using MALDI-ToF mass spectrometry, all isolated cultures were analyzed, regardless of whether they belonged to the NTM group or not.

Results: DNA hybridization, which accounted for 59.5% of the total number of cultures included in the study, performed species identification of 188 strains. Using MALDI-ToF mass spectrometry, 345 strains were identified.

Conclusion: The use of methods based on DNA hybridization makes it possible to identify quite accurately some of the most common NTM species. MALDI-ToF mass spectrometry is an important technique to allow species identification of most Actinomycetales. However, algorithms to standardize methods for their isolation from clinical material are needed.

Background: Information on genotypic with comparison of phenotypic drug sensitivity test of anti-tuberculosis (TB) has been reported in several studies, which have variable results. The present study aimed to assess the Genotype MTBDRsl version 2.0/Line probe assay (LPA) for the detection of fluoroquinolones (FQ) and aminoglycosides (AMGs) resistance mutations among drug-resistant Mycobacterium TB (MTB) strains and also to compare the patterns of genotypic mutations of gyrA/B, rrs, and eis with mycobacteria growth indicator tube (MGIT 960).

Methods: A total of 1416 samples were subjected to Genotype MTBDRsl version 2.0 assay. One hundred and twenty sputum smear positive MTB isolates and 37 sputum smear negative MTB isolates confirmed multiple drug resistance resistant to FQ and AMG by the Genotype MTBDRsl version 2.0 were subjected to phenotypic drug susceptibility testing (DST) were analyzed.

Results: The association sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the resistance detection between MGIT (DST) and the Genotype MTBDRsl version 2.0 assay was significant (P < 0.01) of moxifloxacin (MFX) concentration. Sensitivity and specificity value for kanamycin (KAN) resistance was 76% and 89%; 47% and 94% for capreomycin (CAP); and 60% and 76% for low-level KAN, respectively.

Conclusion: Our results indicate that MFX (0.25and 1 μg/mL), KAN (2.5 μg/mL), and CAP (2.5 μg/mL) significantly (P < 0.01) and support the World Health Organization guidance to test FQ and AMG by genotypic test.

Background: Pulmonary tuberculosis (TB) remains one of the main causes of morbidity and mortality in Mali. Nontuberculous mycobacteria (NTM) infections are very common but are often cofounded with TB because of the similarity of symptoms, which makes the diagnosis difficult. Hematological abnormalities associated with TB have been described, but not with NTM. Therefore, the goal of this study was to compare the hematological parameters of patients infected with TB and NTM infections.

Methods: A cross-sectional study enrolling TB and NTM participants was conducted in 2018-2020. Five milliliters of venous blood and sputum samples were collected from each participant to determine the hematological parameters using the RUBY CELL-DYN Ruby Version 2.2 ML. A BACTEC MGIT 960 and multiplex reverse transcription-polymerase chain reaction were used to distinguish Mycobacterium tuberculosis from NTM, respectively.

Results: Of the total 90 patients enrolled, there was a decrease in hemoglobin and hematocrit levels in both the groups (P = 0.05). In addition, we found that the percentages of basophil cells (P = 0.01) and mean values of platelets (P = 0.04) were significantly higher in TB patients than those of NTMs. Moreover, the mean of absolute values of eosinophil cells of TB patients was significantly lower than those of NTMs (P = 0.03).

Conclusion: We found significant statistical differences in basophils, platelets, and eosinophils in differentiating TB and NTM in this pilot study. Future studies with patients at different clinical stages are needed to confirm the hematological profiles of TB and NTM patients.

Background: Mycobacterium tuberculosis is a bacterium that has historically had a substantial impact on human health. Despite advances in understanding and management of tuberculosis (TB), the disease remains a crucial problem that necessitates ongoing work to discover effective drugs, minimize transmission, and improve global health outcomes.

Methods: The purpose of this study is to use molecular docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) analyses to explore the molecular interactions of different proteins that are involved in mycolic acid biosynthesis (HadAB, InhA, KasA, FabD, and beta-ketoacyl-acyl carrier protein synthase III) of M. tuberculosis with Demospongiae metabolites. The docking findings were evaluated using the glide gscore, and the top 10 compounds docked against each protein receptor were chosen. Furthermore, the selected compounds underwent ADMET analysis, indicating that they have the potential for therapeutic development.

Results: Among the selected compounds, makaluvamine G showed the highest binding affinity against HadAB, psammaplysin E showed highest binding affinity against InhA, pseudotheonamide D showed the highest binding affinity against KasA protein, dinordehydrobatzelladine B showed the highest binding affinity against FabD, and nagelamide X showed the highest binding affinity against beta-ketoacyl-acyl carrier protein synthase III. Additionally, molecular mechanics generalized born surface area (MM-GBSA) binding free energy and molecular dynamics simulations were used to support the docking investigations.

Conclusion: The results of the study suggest that these compounds may eventually be used to treat TB. However, computer validations were included in this study, and more in vitro research is required to turn these prospective inhibitors into clinical drugs.

An 84-year-old man visited our hospital with a high fever. He had cut his right index finger 7 days previously. Blood culture became positive on day 3. Gram staining was negative, and acid-fast staining was positive. The organism was subsequently identified as Mycobacterium obuense using a MALDI Biotyper. M. obuense was also detected in the soil at the patient's house, suggesting that it had entered his bloodstream through the cut on his finger. He was treated with a combination of imipenem/cilastatin, amikacin, and clarithromycin for 2 weeks. His clinical condition improved, and he was discharged after 2 weeks and was prescribed clarithromycin and levofloxacin therapy. Only two cases of human infection with M. obuense have been reported previously.

Background: Fluoroquinolones (FQs) have substantial activity against the Mycobacterium tuberculosis complex (MTBc) by preventing bacterial DNA synthesis through DNA gyrase inhibition. The reference standard for FQ-resistance testing is phenotypic drug-susceptibility testing (pDST) based on growth inhibition of MTBc in drug-containing Mycobacteria Growth Indicator Tube system (MGIT) media at a critical concentration (CC) that differentiates phenotypically wild-type from nonwild-type MTBc and at a clinical breakpoint that identifies strains that will likely still respond to treatment at higher doses. Despite the recent introduction of powerful new TB drugs, highly sensitive detection of clinically defined FQ resistance remains key.

Method: In this study, we re-evaluated the current WHO-recommended CCs of Lfx (1.0 mg/ml), Mfx (0.25 mg/ml), Gfx (0.25 μg/ml), and the nowadays, obsolete CC of Ofx (2.0 mg/ml) for MGIT, using 147 MTBc isolates with known gyrA and gyrB sequences including both high-and low-level FQ resistance-conferring mutants. We tested a wide range of drug concentrations covering the current and former/obsolete WHO-recommended CCs for FQs and some intermediate concentrations to challenge the current WHO-recommended CCs.

Results: The specificity of all four CCs was 100%. The sensitivities varied: 92.4% for Ofx and Lfx, 85.7% for Mfx, and 83.2% for Gfx. Lowering the CC of Mfx to 0.125 mg/ml would allow to correctly classify all wild-type and mutant isolates while lowering the CC of Gfx to 0.125 mg/ml would still misclassify some gyrA/gyrB mutants as susceptible.

Conclusion: Based on our findings, a minimal inhibitory concentration of 0.125 mg/ml on MGIT medium is a more appropriate CC for Mfx and probably also as a surrogate for overall FQ resistance in the MTBc.