Decreased Expression of CD314 by NK Cells Correlates with Their Ability to Respond by Producing IFN-γ after BCG Moscow Vaccination and Is Associated with Distinct Early Immune Responses.

The immune response to vaccines is complex and results in various outcomes. BCG vaccination induces innate and specific responses that can lead to protection against tuberculosis, and cross-protection against other infections. NK cells have been associated with BCG-induced protection. Therefore, we hypothesize that differences in NK cell status before BCG vaccination may have a role in the ability of BCG to activate the immune response. Participants of a clinical trial were evaluated after BCG vaccination. The participants were assigned to different groups according to variation in IFN-γ expression by NK cells between days 1 and 15 after BCG vaccination. Individuals that presented a higher increase in IFN-γ expression by NK cells presented reduced CD314 expression at day 1, and after vaccination an increase in inflammatory NK cells and CD4 T-cell expression of IL-17. A negative correlation between expression of CD314 at day 1 and that of IFN-γ by NK cells after BCG vaccination was observed. Participants with lower of IFN-γ expression by NK cells after BCG vaccination presented an increase in the cytotoxic NK subpopulation and CD4 T-cell expression of IL-17 and IFN-γ. In conclusion, the expression of CD314 by NK cells before BCG vaccination influences their IFN-γ responses, generation of NK subpopulations, and the specific T immune response at 15 days after vaccination.

Repurposing miconazole and tamoxifen for the treatment of Mycobacterium abscessus complex infections through in silico chemogenomics approach.

Drug repositioning is an alternative to overcome the complexity of the drug discovery and approval procedures for the treatment of Mycobacterium abscessus Complex (MABSC) infections that are increasing globally due to the emergency of antimicrobial resistance mechanisms. Here, an in silico chemogenomics approach was performed to compare the sequences from 4942 M. abscessus subsp. abscessus (M. abscessus) proteins with 5258 or 3473 therapeutic targets registered in the DrugBank or Therapeutic Target Database, respectively. This comparison identified 446 drugs or drug candidates whose targets were homologous to M. abscessus proteins. These identified drugs were considered potential inhibitors of MABSC (anti-MABSC activity). Further screening and inspection resulted in the selection of ezetimibe, furosemide, itraconazole, miconazole (MCZ), tamoxifen (TAM), and thiabendazole (THI) for experimental validation. Among them, MCZ and TAM showed minimum inhibitory concentrations (MIC) of 32 and 24 µg mL-1 against M. abscessus, respectively. For M. bolletii and M. massiliense strains, MCZ and TAM showed MICs of 16 and 24 µg mL-1, in this order. Subsequently, the antibacterial activity of MCZ was confirmed in vivo, indicating its potential to reduce the bacterial load in the lungs of infected mice. These results show that MCZ and TAM can serve as molecular scaffolds for the prospective hit-2-lead optimization of new analogs with greater potency, selectivity, and permeability.

Ferritin from Mycobacterium abscessus is involved in resistance to antibiotics and oxidative stress.

Mycobacterium abscessus subsp. massiliense (Mycma) is a rapidly growing Mycobacterium belonging to the M. abscessus complex that is often associated with lung and soft tissue infection outbreaks. Mycma is resistant to many antimicrobials, including those used for treating tuberculosis. Therefore, Mycma infections are difficult to treat and may lead to high infectious complication rates. Iron is essential for bacterial growth and establishment of infection. During infection, the host reduces iron concentrations as a defense mechanism. To counteract the host-induced iron deficiency, Mycma produces siderophores to capture iron. Mycma has two ferritins (encoded by mycma_0076 and mycma_0077) modulated by different iron concentrations, which allow the survival of this pathogen during iron scarcity. In this study, we constructed knockout (Mycma 0076KO) and complemented (Mycma 0076KOc) gene strains for mycma_0076 to understand the function of 0076 ferritin. Deletion of mycma_0076 in Mycma led to the transition in colony morphology from smooth to rough, alteration of the glycopeptidolipids spectra, increased permeability of the envelope, reduction in biofilm formation, increased susceptibility to antimicrobials and hydrogen peroxide-induced oxidative stress, and decreased internalization by macrophages. This study shows that Mycma_0076 ferritin in Mycma is involved in resistance to oxidative stress and antimicrobials, and alteration of cell envelope architecture. KEY POINTS: • Deletion of the mycma_0076 gene altered colony morphology to rough; • Mycma 0076KO changed GPL profile; • Absence of Mycma_0076 ferritin results in increased susceptibility to antimicrobials and oxidative stress in Mycma. Legend: a In wild-type M. abscessus subsp. massiliense strain, iron is captured from the environment by carboxymycobactins and mycobactins (1). Iron-dependent regulator (IdeR) proteins bind to ferrous iron (Fe+2) in the bacterial cytoplasm leading to the activation of the IdeR-Fe+2 complex (2). The activated complex binds to the promoter regions of iron-dependent genes, called iron box, which in turn help in the recruitment of RNA polymerase to promote transcription of genes such as mycma_0076 and mycma_0077 ferritin genes (3). Mycma_0076 and Mycma_0077 ferritins bind to excess iron in the medium and promote Fe2+ oxidation into ferric iron (Fe3+) and store iron molecules to be released under iron scarcity conditions. (4) Genes related to biosynthesis and transport of glycopeptidolipids (GPL) are expressed normally and the cell envelope is composed of different GPL species (colored squares represented on the cell surface (GPLs). Consequently, WT Mycma present smooth colony phenotype (5). b In Mycma 0076KO strain, the lack of ferritin 0076 causes overexpression of mycma_0077 (6), but does not restore wild-type iron homeostasis and thus may result in free intracellular iron, even in the presence of miniferritins (MaDps). The excess iron potentiates oxidative stress (7) by generating hydroxyl radicals through Fenton Reaction. During this process, through an unknown mechanism, that could involve Lsr2 (8), the expression of GPL synthesis locus is regulated positively and/or negatively, resulting in alteration of GPL composition in the membrane (as represented by different colors of squares on the cell surface), resulting in a rough colony phenotype (9). The changes of GPL can increase cell wall permeability, contributing to antimicrobial susceptibility (10).

Combined antibodies against internalins A and B proteins have potential application in immunoassay for detection of Listeria monocytogenes.

Listeria monocytogenes is a food-borne bacterium that causes listeriosis upon the ingestion of contaminated food. Traditional methods to detect L. monocytogenes require pre-enrichment broths to increase its concentration. To improve the screening of contaminated food and prevent listeriosis outbreaks, rapid, specific and sensitive assays are needed to detect L. monocytogenes. This study developed a prototype lateral flow immunochromatographic assay (LFIA) employing antibodies against L. monocytogenes Internalin A (InlA) and Internalin B (InlB) proteins, that are involved in non-phagocytic cell invasion. The following antibodies were used to capture L. monocytogenes antigenic targets: mouse anti-Internalin A monoclonal antibody (MAb-2D12) conjugated to colloidal gold nanoparticles and a mouse anti-Internalin B polyclonal antibody. This test was able to detect pure L. monocytogenes from culture with a limit of detection (LOD) ranging from 5.9 × 103 to 1.5 × 104 CFU/mL. In milk artificially contaminated with L. monocytogenes, the LOD was 1 × 105 CFU/mL. This prototype test discriminated L. monocytogenes from other bacterial species (Listeria innocua, Enterobacter cloacae, Bacillus cereus). Results indicate that this LFIA developed using antibodies against L. monocytogenes InlA and InlB proteins is a sensitive and specific tool that can be potentially useful to rapidly detect L. monocytogenes in contaminated food. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05597-9.

Efficacy and Safety of BCG Revaccination With M. bovis BCG Moscow to Prevent COVID-19 Infection in Health Care Workers: A Randomized Phase II Clinical Trial.

The Bacillus Calmette-Guérin (BCG) vaccine, which is widely used to protect children against tuberculosis, can also improve immune response against viral infections. This unicentric, randomized-controlled clinical trial assessed the efficacy and safety of revaccination with BCG Moscow in reducing the positivity and symptoms of COVID-19 in health care workers (HCWs) during the COVID-19 pandemic. HCWs who had negative COVID-19 IgM and IgG and who dedicated at least eight hours per week in facilities that attended to individuals suspected of having COVID-19 were included in the study and were followed for 7, 15, 30, 60, and 180 days by telemedicine. The HCWs were randomly allocated to a revaccinated with BCG group, which received the BCG vaccine, or an unvaccinated group. Revaccination with BCG Moscow was found to be safe, and its efficacy ranged from 30.0% (95.0%CI -78.0 to 72.0%) to 31.0% (95.0%CI -74.0 to 74.0%). Mycobacterium bovis BCG Moscow did not induce NK cell activation at 15-20 days post-revaccination. As hypothesized, revaccination with BCG Moscow was associated with a lower incidence of COVID-19 positivity, though the results did not reach statistical significance. Further studies should be carried out to assess whether revaccination with BCG is able to protect HCWs against COVID-19. The protocol of this clinical trial was registered on August 5th, 2020, at REBEC (Registro Brasileiro de Ensaios Clínicos, RBR-4kjqtg - ensaiosclinicos.gov.br/rg/RBR-4kjqtg/1) and the WHO (# U1111-1256-3892). The clinical trial protocol was approved by the Comissão Nacional de ética de pesquisa- CONEP (CAAE 31783720.0.0000.5078).

Mycobacterium bovis PknG R242P Mutation Results in Structural Changes with Enhanced Virulence in the Mouse Model of Infection.

Mycobacterium bovis is the causative agent of tuberculosis in domestic and wild animal species and sometimes in humans, presenting variable degrees of pathogenicity. It is known that PknG is involved in the first steps of Mycobacterium tuberculosis macrophage infection and immune evasion. We questioned whether M. bovispknG genes were conserved among mycobacteria and if natural genetic modifications would affect its virulence. We discovered a single mutation at a catalytic domain (R242P) of one M. bovis isolate and established the relation between the presence of R242P mutation and enhanced M. bovis virulence. Here, we demonstrated that R242P mutation alters the PknG protein conformation to a more open ATP binding site cleft. It was observed that M. bovis with PknG mutation resulted in increased growth under stress conditions. In addition, infected macrophages by M. bovis (R242P) presented a higher bacterial load compared with M. bovis without the pknG mutation. Furthermore, using the mouse model of infection, animals infected with M. bovis (R242P) had a massive innate immune response migration to the lung that culminated with pneumonia, necrosis, and higher mortality. The PknG protein single point mutation in its catalytic domain did not reduce the bacterial fitness but rather increased its virulence.

Protease-Based Subunit Vaccine in Mice Boosts BCG Protection against Mycobacterium tuberculosis.

The significant number of people with latent and active tuberculosis infection requires further efforts to develop new vaccines or improve the Bacillus Calmette-Guérin (BCG), which is the only approved vaccine against this disease. In this study, we developed a recombinant fusion protein (PEPf) containing high-density immunodominant epitope sequences from Rv0125, Rv2467, and Rv2672 Mycobacterium tuberculosis (Mtb) proteases that proved immunogenic and used it to develop a recombinant BCG vaccine expressing the fusion protein. After challenging using Mtb, a specific immune response was recalled, resulting in a reduced lung bacterial load with similar protective capabilities to BCG. Thus BCG PEPf failed to increase the protection conferred by BCG. The PEPf was combined with Advax4 adjuvant and tested as a subunit vaccine using a prime-boost strategy. PEPf + Advax4 significantly improved protection after Mtb challenge, with a reduction in bacterial load in the lungs. Our results confirm that Mtb proteases can be used to develop vaccines against tuberculosis and that the use of the recombinant PEPf subunit protein following a prime-boost regimen is a promising strategy to improve BCG immunity.

Mycobacterium abscessus cell wall and plasma membrane characterization by EPR spectroscopy and effects of amphotericin B, miltefosine and nerolidol.

Spin label electron paramagnetic resonance (EPR) spectroscopy was used to characterize the components of the Mycobacterium abscessus massiliense cell envelope and their interactions with amphotericin B (AmB), miltefosine (MIL), and nerolidol (NER). Spin labels analogous to stearic acid and phosphatidylcholine (PC) were distributed on an envelope layer with fluidity comparable to other biological membranes, probably the mycobacterial cell wall, because after treatment with AmB a highly rigid spectral component was evident in the EPR spectra. Methyl stearate analogue spin labels found a much more fluid membrane and did not detect the presence of AmB, except for at very high drug concentrations. Unlike other spin-labeled PCs, the TEMPO-PC spin probe, with the nitroxide moiety attached to the choline of the PC headgroup, also did not detect the presence of AmB. On the other hand, the steroid spin labels were not distributed across the membranes of M. abscessus and, instead, were concentrated in some other location of the cell envelope. Both MIL and NER compounds at 10 µM caused increased fluidity in the cell wall and plasma membrane. Furthermore, NER was shown to have a remarkable ability to extract lipids from the mycobacterial cell wall. The EPR results suggest that the resistance of mycobacteria to the action of AmB must be related to the fact that this drug does not reach the bacterial plasma membrane.

Tuberculosis, BCG Vaccination, and COVID-19: Are They Connected?

Evidence from multiple scientific studies suggests that the Bacillus Calmette-Guérin (BCG) vaccine, widely used worldwide as a preventive measure against tuberculosis, also offers crossprotection against other pathogens. This review aimed to gather data from research that studied the mechanisms involved in the immunological protection induced by the BCG vaccine, which may be important in the control of viral infections, such as COVID-19. Through a literature review, we compiled information about the different BCG strains used worldwide, as well as the responses and protection elicited by them. We commented on the mechanisms of immune response to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and we discussed the possibility of cross-protection of different BCG strains on the control of COVID-19. Due to the immunomodulatory properties of BCG, some BCG strains were able to induce an effective cellular immune response and, through epigenetic modifications, activate cells of the innate immune system, such as monocytes, macrophages and natural killer cells, which are crucial for the control of viral infections. Although several vaccines have already been developed and used in an attempt to control the COVID-19 pandemic, some BCG vaccine strains may help stimulate the basal defences against these pathogens and can be used as additional defences in this and future pandemics.

Listeria monocytogenes: review of pathogenesis and virulence determinants-targeted immunological assays.

Listeria monocytogenes is one of the most invasive foodborne pathogens and is responsible for numerous outbreaks worldwide. Most of the methods to detect this bacterium in food require selective enrichment using traditional bacterial culture techniques that can be time-consuming and labour-intensive. Moreover, molecular methods are expensive and need specific technical knowledge. In contrast, immunological approaches are faster, simpler, and user-friendly alternatives and have been developed for the detection of L. monocytogenes in food, environmental, and clinical samples. These techniques are dependent on the constitutive expression of L. monocytogenes antigens and the specificity of the antibodies used. Here, updated knowledge on pathogenesis and the key immunogenic virulence determinants of L. monocytogenes that are used for the generation of monoclonal and polyclonal antibodies for the serological assay development are summarised. In addition, immunological approaches based on enzyme-linked immunosorbent assay, immunofluorescence, lateral flow immunochromatographic assays, and immunosensors with relevant improvements are highlighted. Though the sensitivity and specificity of the assays were improved significantly, methods still face many challenges that require further validation before use.

YOKENELLA REGENSBURGEI osteoarticular infection: a case report

okenella regensburgei belongs to the family Enterobacteriaceae and is an opportunistic agent rarely associated with infections in humans. We report a case of osteoarticular knee infection caused by Y. regensburgei in a patient under treatment for rheumatoid arthritis, using corticosteroids, with complication in primary total arthroplasty of the knee. Y. regensburgei was identified using the VITEK2 system. Antimicrobial susceptibility testing was performed using the disk-diffusion method, according to the guidelines from the Clinical and Laboratory Standards Institute. The patient presented favorable clinical evolution after the second debridement, with complete removal of the prosthesis and antibiotic therapy with sulfamethoxazole/trimethoprim. This is the first case of Y. regensburgei infection described d in Brazil.

Correction to: BCG revaccination of health workers in Brazil to improve innate immune responses against COVID-19: A structured summary of a study protocol for a randomised controlled trial.

An amendment to this paper has been published and can be accessed via the original article.

BCG revaccination of health workers in Brazil to improve innate immune responses against COVID-19: A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: The BCG vaccine, widely used in Brazil in new-borns, induces adjuvant protection for several diseases, including childhood virus infections. BCG activates monocytes and innate memory NK cells which are crucial for the antiviral immune response. Therefore, strategies to prevent COVID-19 in health workers (HW) should be carried out to prevent them becoming unwell so that they can continue to work during the pandemic. The hypothesis is that BCG will improve the innate immune response and prevent symptomatic infection or COVID-19 severity. The primary objective is to verify the effectiveness and safety of the BCG vaccine to prevent or reduce incidence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in the city of Goiânia (Brazil) among HW previously vaccinated with BCG and also its severity and mortality during the pandemic of the disease. Secondary objectives are to estimate the incidence of COVID-19 among these professionals and the innate immune response elicited to BCG. TRIAL DESIGN: This a phase II trial for repositioning BCG as a preventive strategy against COVID-19. The trial is an open-label, parallel-group randomised clinical trial, comparing HW vaccinated with BCG and HW not vaccinated. PARTICIPANTS: The trial will recruit 800 HW of Goiânia - Goiás, Brazil to reach a total of 400 HW included after comorbidities questioning and laboratorial evaluation. Eligibility criteria: Any HW presenting BCG vaccination scar with direct contact with suspected COVID-19 patients for at least 8 hours per week, whether in hospital beds, ICU, or in transportation or admission (nurses, doctors, physiotherapists, nutritionists, receptionists, etc.) who have negative IgM and IgG COVID-19 test. Participants with any of the following characteristics will be excluded: - Have had in the last fifteen days any signs or symptoms of virus infection, including COVID-19; - Have had fever in the last fifteen days; - Have been vaccinated fifteen days before the inclusion; - Have a history or confirmation of any immunosuppressive disease such as HIV, presented solid tumour in the last two years or autoimmune diseases; - Are under preventive medication with antibiotics, steroid anti-inflammatories, or chemotherapy; - Have less than 500 neutrophils per mL of blood; - Have previously been diagnosed with tuberculosis; - Are breastfeeding or pregnant; - Are younger than 18 years old; - Are participating as an investigator in this clinical trial. INTERVENTION AND COMPARATOR: HW will be randomized into the BCG vaccinated group or the BCG unvaccinated control group. The BCG vaccinated group will receive in the right arm, intradermally, a one off dose of 0.1 mL corresponding to approximately 2 x105 to 8 x105 CFU of live, freeze-dried, attenuated BCG Moscow 361-I, Bacillus Calmette Guerin vaccine (Serum Institute of India PVT. LTD.). The unvaccinated control group will not be vaccinated. The HW allocated in both groups will be followed up at specific times points until 180 days post inclusion. The vaccinated and control groups will be compared according to COVID-19 related outcomes. MAIN OUTCOMES: The primary outcomes are the incidence coefficient of infection by SARS-CoV-2 determined by RT-PCR of naso-oropharyngeal swab specimen or rapid lateral flow IgG and IgM test, and presence of general COVID-19 symptoms, disease severity and admission to hospital during the 180 days of follow up. The secondary outcome is the innate immune response elicited 15-20 days after vaccination. RANDOMISATION: The vaccine vial contains approximately 10 doses. In order to optimize the vaccine use, the randomisation was performed in blocks of 20 participants using the platform randomization.com [ http://www.jerrydallal.com/random/permute.htm ]. The randomization was prepared before any HW inclusion. The results were printed and inserted in sealed envelopes that were numbered with BCG-001 to BCG-400. The printed results as well the envelopes had the same numbers. At the time of the randomisation, each participant that meets the inclusion criteria will receive a consecutive participant number [BCG-001-BCG-400]. The sealed envelope with the assigned number, blinded to the researchers, will be opened in front of the participant and the arm allocation will be known. BLINDING (MASKING): There is no masking for the participants or for the healthcare providers. The study will be blinded to the laboratory researchers and to those who will be evaluating the outcomes and performing the statistical analyses. In this case, only the participant identification number will be available. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): Four hundred heath workers will be randomised in two groups. Two hundred participants will be vaccinated, and 200 participants will not be vaccinated. TRIAL STATUS: The protocol approved by the Brazilian Ethical Committee is the seventh version, number CAAE: 31783720.0.0000.5078. The trial has been recruiting since September 20th, 2020. The clinical trial protocol was registered on August 5th, 2020. It is estimated that recruitment will finish by March 2021. TRIAL REGISTRATION: The protocol number was registered on August 5th, 2020 at REBEC (Registro Brasileiro de Ensaios Clínicos). Register number: RBR-4kjqtg and WHO trial registration number UTN: U1111-1256-3892. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Non-tuberculous mycobacterial lung disease: a brief review focusing on radiological findings.

The incidence and prevalence of lung disease caused by non-tuberculous mycobacteria (NTM-LD) has increased worldwide and its diagnosis represents a complex challenge. This article aims to review the tomographic findings of NTM-LD in order to facilitate their definitive diagnosis. The search for publications on the subject was performed in PMC and Scielo using the keywords 'non-tuberculous mycobacteria', 'lung disease and computed tomography (CT)' and 'radiological findings'. The radiological findings described by 18 articles on mycobacteriosis were reviewed. In addition, CT images of patients diagnosed with NTM-LD were considered to represent radiological findings. Eighteen publications were used whose main findings were pulmonary cavitation (88.9%), bronchiectasis (77.8%), and pulmonary nodules (55.6%). Despite the overlaps in imaging-related analysis of myocobacterioses with other pulmonary infections, such as tuberculosis, the predominant involvement of the middle lobe and lingula should raise suspicion for NTM-LD.

Live Vaccines Have Different NK Cells and Neutrophils Requirements for the Development of a Protective Immune Response Against Tuberculosis.

It has been shown that neutrophils drive NK cells to activate DCs while NK cells regulate neutrophils survival. In response to mycobacteria, NK cells proliferate and produces IFN-γ, that appears to regulate the neutrophilic inflammatory responses to both M. tuberculosis infection and BCG vaccination. Although the role of neutrophils in the immune response to tuberculosis is a matter of debate, neutrophils were shown to be crucial to induce specific response against mc2-CMX vaccine. The objective of this study was to investigate the interplay between NK cells and neutrophils in regard to the development of a protective immune response against M. tuberculosis. Depletion of NK cells during vaccination did not alter the total number of neutrophils or DCs, but reduced the number of activated DCs, thus reducing the generation of Th1 specific immune responses and the protection conferred by mc2-CMX and BCG vaccines. However, only in mc2-CMX vaccination that neutrophil depletion interfered with the NK cell numbers and protection. In conclusion, it was shown that only when both NK and neutrophils were present, specific Th1 response and protection was achieved by mc2-CMX vaccine, while neutrophils although activated upon BCG vaccination were not necessary for the induced protection.

Dps protein is related to resistance of Mycobacterium abscessus subsp. massiliense against stressful conditions.

Mycobacterium abscessus subsp. massiliense (Mycma) belongs to the Mycobacterium abscessus complex and is a rapidly growing non-tuberculous mycobacterium. The chronic pulmonary, skin, and soft tissue infections that it causes may be difficult to treat due to its intrinsic resistance to the commonly used antimicrobial drugs, making it a serious world public health problem. Iron is an essential nutrient for the growth of microorganisms; nonetheless, it can be toxic when in excess. Thus, bacteria require an iron homeostasis mechanism to succeed in different environments. DNA-binding proteins from starved cells (Dps) are miniferritins with the property to act as additional iron storage proteins but also can bind to DNA, protecting it against hydroxyl radical. Annotation of the Mycma genome revealed the gene mycma_03135 with 79% sequential identity when compared to MSMEG_3242 gene from M. smegmatis mc2 155, which codifies for a known Dps. Recombinant Dps from M. abscessus (rMaDps) was produced in Escherichia coli, purified in soluble form and shown to form high mass oligomers in solution with ferroxidase activity, DNA binding, and protection against damage. The expression of the mycma_03135 gene was induced during Mycma growth in the presence of hydrogen peroxide (H2O2). Additionally, the expression of rMaDps by E. coli conferred greater resistance to H2O2. Thus, this study is the first to identify and characterize a Dps from M. abscessus. KEY POINTS: Mycobacterium abscessus subsp. massiliense express a miniferritin protein (Dps). Mycma Dps binds to DNA and protects against oxidative stress.

Non-tuberculous mycobacterial lung disease: a brief review focusing on radiological findings

Abstract The incidence and prevalence of lung disease caused by non-tuberculous mycobacteria (NTM-LD) has increased worldwide and its diagnosis represents a complex challenge. This article aims to review the tomographic findings of NTM-LD in order to facilitate their definitive diagnosis. The search for publications on the subject was performed in PMC and Scielo using the keywords 'non-tuberculous mycobacteria', 'lung disease and computed tomography (CT)' and 'radiological findings'. The radiological findings described by 18 articles on mycobacteriosis were reviewed. In addition, CT images of patients diagnosed with NTM-LD were considered to represent radiological findings. Eighteen publications were used whose main findings were pulmonary cavitation (88.9%), bronchiectasis (77.8%), and pulmonary nodules (55.6%). Despite the overlaps in imaging-related analysis of myocobacterioses with other pulmonary infections, such as tuberculosis, the predominant involvement of the middle lobe and lingula should raise suspicion for NTM-LD.

Antimicrobial and Antibiofilm Effects of Peptides from Venom of Social Wasp and Scorpion on Multidrug-Resistant Acinetobacter baumannii.

Intravascular stent infection is a rare complication with a high morbidity and high mortality; bacteria from the hospital environment form biofilms and are often multidrug-resistant (MDR). Antimicrobial peptides (AMPs) have been considered as alternatives to bacterial infection treatment. We analyzed the formation of the bacterial biofilm on the vascular stents and also tested the inhibition of this biofilm by AMPs to be used as treatment or coating. Antimicrobial activity and antibiofilm were tested with wasp (Agelaia-MPI, Polybia-MPII, Polydim-I) and scorpion (Con10 and NDBP5.8) AMPs against Acinetobacter baumannii clinical strains. A. baumannii formed a biofilm on the vascular stent. Agelaia-MPI and Polybia-MPII inhibited biofilm formation with bacterial cell wall degradation. Coating biofilms with polyethylene glycol (PEG 400) and Agelaia-MPI reduced 90% of A. baumannii adhesion on stents. The wasp AMPs Agelaia-MPI and Polybia-MPII had better action against MDR A. baumannii adherence and biofilm formation on vascular stents, preventing its formation and treating mature biofilm when compared to the other tested peptides.

The mycma_1113 Gene from Mycobacterium abscessus subsp. massiliense is Related to Siderophore Synthesis.

Iron (Fe) homeostasis control is important for both pathogen and the host. During infection, the host reduces the access of microorganisms to iron, however, studies have shown that virulent pathogens are capable to sequester Fe from host proteins, and establish the infection. M. abscessus subsp. massiliense (Mycma), that is resistant to most drugs used against tuberculosis, was responsible for outbreaks around the world showing increased virulence when compared to other rapidly growing mycobacteria. The goal of this study was to determine whether Mycma produce siderophores and if the mycma_1113 gene expression, a putative homolog of M. tuberculosis mbtB gene located in the mbt gene cluster, is related to the synthesis of these molecules. For that, the effect of different iron concentrations on the growth of Mycma, the expression of mycma_1113 gene, and the production of siderophores was evaluated in vitro and in vivo. It is shown that Mycma produce siderophores under iron deprivation conditions and mycma_1113 gene expression was influenced by iron availability. The mycma_1113 gene expression was also increased after macrophage or in vivo infection indicating that mycobactin synthesis by Mycma could participate in the Fe sequestration from the host during infection. In conclusion, we show that Mycma produces siderophores under iron deprivation conditions and that the mycma_1113 gene is involved in this process, furthermore, this gene expression is induced during infection.

Proteases associated with Mycobacterium tuberculosis infection

Tuberculosis is a contagious infectious disease caused by Mycobacterium tuberculosis, an obligate intracellular bacterium that relies on infection and host-to-host transmission to survive. In a co-evolutionary process, the pathogen developed virulence mechanisms to evade the host's immune system and endure a number of factors, such as cellular stress. One of the strategies used by pathogens to succeed in causing infection is the production of proteases, which are enzymes that cleave peptide bonds between the amino acids in a protein. Proteases are widely distributed in nature and have different roles considered important to the bacteria's biological cycle. M. tuberculosis has several protease coding genes in its genome, many of which with unknown functions, but several with recognized roles in the infection process. This review presents the literature researched from 2014 to 2018 that addressed the roles of the proteases involved in M. tuberculosis infection