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Frontiers in Medicine 2023Targeted next-generation sequencing (tNGS) has emerged as a rapid diagnostic technology for identifying a wide spectrum of pathogens responsible for pulmonary infections.
BACKGROUND
Targeted next-generation sequencing (tNGS) has emerged as a rapid diagnostic technology for identifying a wide spectrum of pathogens responsible for pulmonary infections.
METHODS
Sputum samples were collected from patients unable or unwilling to undergo bronchoalveolar lavage. These samples underwent tNGS analysis to diagnose pulmonary infections. Retrospective analysis was performed on clinical data, and the clinical efficacy of tNGS was compared to conventional microbiological tests (CMTs).
RESULTS
This study included 209 pediatric and adult patients with confirmed pulmonary infections. tNGS detected 45 potential pathogens, whereas CMTs identified 23 pathogens. The overall microbial detection rate significantly differed between tNGS and CMTs (96.7% vs. 36.8%, < 0.001). Among the 76 patients with concordant positive results from tNGS and CMTs, 86.8% (66/76) exhibited full or partial agreement. For highly pathogenic and rare/noncolonized microorganisms, tNGS, combined with comprehensive clinical review, directly guided pathogenic diagnosis and antibiotic treatment in 21 patients. This included infections caused by complex, certain atypical pathogens, Aspergillus, and nontuberculous Mycobacteria. Among the enrolled population, 38.8% (81/209) of patients adjusted their treatment based on tNGS results. Furthermore, tNGS findings unveiled age-specific heterogeneity in pathogen distribution between children and adults.
CONCLUSION
CMTs often fall short in meeting the diagnostic needs of pulmonary infections. This study highlights how tNGS of sputum samples from patients who cannot or will not undergo bronchoalveolar lavage yield valuable insights into potential pathogens, thereby enhancing the diagnosis of pulmonary infections in specific cases.
PubMed: 38179267
DOI: 10.3389/fmed.2023.1321515 -
The Journal of Antimicrobial... Apr 2024Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is increasing worldwide, with Mycobacterium avium complex (MAC) and Mycobacterium abscessus as the predominant...
BACKGROUND
Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is increasing worldwide, with Mycobacterium avium complex (MAC) and Mycobacterium abscessus as the predominant pathogens. Current treatments are poorly tolerated and modestly effective, highlighting the need for new treatments. SPR719, the active moiety of the benzimidazole prodrug SPR720, inhibits the ATPase subunits of DNA gyrase B, a target not exploited by current antibiotics, and therefore, no cross-resistance is expected with standard-of-care (SOC) agents.
OBJECTIVES
To evaluate the in vitro activity of SPR719 against MAC and M. abscessus clinical isolates, including those resistant to SOC agents, and in vivo efficacy of SPR720 in murine non-tuberculous mycobacteria (NTM) pulmonary infection models.
METHODS
NTM isolates were tested for susceptibility to SPR719. Chronic C3HeB/FeJ and severe combined immunodeficient murine models of pulmonary infection were used to assess efficacy of SPR720 against MAC and M. abscessus, respectively.
RESULTS
SPR719 was active against MAC (MIC90, 2 mg/L) and M. abscessus (MIC90, 4 mg/L) clinical isolates. Efficacy of SPR720 was demonstrated against MAC pulmonary infection, both as a monotherapy and in combination with SOC agents. SPR720 monotherapy exhibited dose-dependent reduction in bacterial burden, with the largest reduction observed when combined with clarithromycin and ethambutol. Efficacy of SPR720 was also demonstrated against M. abscessus pulmonary infection where monotherapy exhibited a dose-dependent reduction in bacterial burden with further reductions detected when combined with SOC agents.
CONCLUSIONS
In vitro activity of SPR720 against common NTM pathogens and efficacy in murine infections warrant the continued clinical evaluation of SPR720 as a new oral option for the treatment of NTM-PD.
Topics: Humans; Animals; Mice; Nontuberculous Mycobacteria; Mycobacterium Infections, Nontuberculous; Disease Models, Animal; Mycobacterium avium Complex; Anti-Bacterial Agents; Lung Diseases; Pneumonia
PubMed: 38394463
DOI: 10.1093/jac/dkae046 -
Journal of Global Antimicrobial... Mar 2024Genetic changes in Mycobacterium abscessus during antibiotic treatment are not fully understood. This study aimed to investigate the genetic changes in M. abscessus in...
OBJECTIVES
Genetic changes in Mycobacterium abscessus during antibiotic treatment are not fully understood. This study aimed to investigate the genetic changes in M. abscessus in patients receiving antibiotic treatment, and their clinical implications.
METHODS
Pretreatment and 12-month post-treatment M. abscessus isolates were obtained from patients with M. abscessus pulmonary disease. Isolates from each time point were separated into six groups based on their distinctive morphological characteristics. Twenty-four isolates, comprising 12 from patient A exhibiting progressive disease and 12 from patient B demonstrating stable disease, underwent sequencing. Subsequently, minimal inhibitory concentrations (MICs) for the administered antibiotics were measured.
RESULTS
Persistent infection with a single strain was observed in patients A and B. During 12 months of treatment, MICs for administered drugs did not generally change over time in either patient and single nucleotide variations (SNV) associated with antimicrobial resistance (rrl, rrs, erm(41), gyrA, gyrB, whiB7 and hflX) were not mutated. Although not significant, 47 and 52 non-synonymous SNVs occurred in M. abscessus from patients A and B, respectively, and the accumulation of these SNVs differed in patients A and B, except for five SNVs. The most variable positions were within a probable NADH-dependent glutamate synthase gene and a putative YrbE family protein gene in patients A and B, respectively.
CONCLUSIONS
Persistent infections by a single strain of M. abscessus were observed in two patients with different clinical courses. Genetic changes in M. abscessus during antibiotic treatment were relatively stable in these patients.
CLINICAL TRIALS IDENTIFIER
NCT01616745 (ClinicalTrials.gov ID).
Topics: Humans; Anti-Bacterial Agents; Lung Diseases; Microbial Sensitivity Tests; Mycobacterium abscessus
PubMed: 38128724
DOI: 10.1016/j.jgar.2023.12.004 -
Biometals : An International Journal on... Aug 2023Skin and soft tissue infection (SSTI) caused by atypical mycobacteria such as Mycobacterium abscessus and Mycobacterium avium intracellulare complex (MAIC) have...
Skin and soft tissue infection (SSTI) caused by atypical mycobacteria such as Mycobacterium abscessus and Mycobacterium avium intracellulare complex (MAIC) have increased in recent years. Current therapeutic options are limited, and hence new and better therapies are urgently required. Colloidal Silver (CS) has been identified for its widespread antibacterial properties and silver-impregnated dressings have been used for SSTIs caused by various pathogens. The efficacy of Green Synthesized Colloidal Silver (GSCS) was investigated for bacterial growth inhibition (BGI) using a microdilution method and minimum biofilm eradication concentration (MBEC) using resazurin assay and confocal scanning laser microscopy (CSLM) of M. abscessus (n = 5) and MAIC (n = 5). The antibacterial effect of GSCS against M. abscessus infected macrophages was also evaluated. The in vitro cytotoxicity of GSCS on a human keratinocyte cell line (HaCaT) and neonatal foreskin fibroblasts was analyzed by the crystal violet proliferation assay. Average BGI and MBEC of GSCS varied between 0.7 and 22 ppm for M. abscessus and MAIC. The concentration of 3 ppm reduced M. abscessus-infection in macrophages significantly. GSCS was not cytotoxic to HaCaT and neonatal foreskin fibroblast cells at concentrations < 3 ppm up to 2 h exposure time. GSCS therefore, has the potential for topical application against atypical mycobacterial SSTI.
Topics: Infant, Newborn; Humans; Nontuberculous Mycobacteria; Silver; Anti-Bacterial Agents; Biofilms; Macrophages
PubMed: 36729280
DOI: 10.1007/s10534-023-00494-w -
Microbiology Spectrum Aug 2023Mycobacterium abscessus, an intracellular nontuberculous mycobacterium, is considered the most pathogenic species among the group of rapidly growing mycobacteria. The...
Mycobacterium abscessus, an intracellular nontuberculous mycobacterium, is considered the most pathogenic species among the group of rapidly growing mycobacteria. The resistance of M. abscessus to the host innate response contributes to its pathogenicity in addition to several virulence factors. We have recently shown in that antimicrobial peptides (AMPs), whose production is induced by M. abscessus, are unable to control mycobacterial infection. This could be due to their inability to kill mycobacteria and/or the hidden location of the pathogen in phagocytic cells. Here, we demonstrate that the rapid internalization of M. abscessus by macrophages allows it to escape the AMP-mediated humoral response. By depleting phagocytes in AMP-deficient flies, we found that several AMPs were required for the control of extracellular M. abscessus. This was confirmed in the Tep4 opsonin-deficient flies, which we show can better control M. abscessus growth and have increased survival through overproduction of some AMPs, including Defensin. Furthermore, Defensin alone was sufficient to kill extracellular M. abscessus both and and control its infection. Collectively, our data support that Tep4-mediated opsonization of M. abscessus allows its escape and resistance toward the Defensin bactericidal action in . Mycobacterium abscessus, an opportunistic pathogen in cystic fibrosis patients, is the most pathogenic species among the fast-growing mycobacteria. How M. abscessus resists the host innate response before establishing an infection remains unclear. Using , we have recently demonstrated that M. abscessus resists the host innate response by surviving the cytotoxic lysis of the infected phagocytes and the induced antimicrobial peptides (AMPs), including Defensin. In this work, we demonstrate that M. abscessus resists the latter response by being rapidly internalized by phagocytes. Indeed, by combining and approaches, we show that Defensin is able to control extracellular M. abscessus infection through a direct bactericidal action. In conclusion, we report that M. abscessus escapes the host AMP-mediated humoral response by taking advantage of its internalization by the phagocytes.
Topics: Animals; Mycobacterium abscessus; Drosophila; Opsonization; Mycobacterium; Antimicrobial Peptides; Defensins; Mycobacterium Infections, Nontuberculous; Anti-Bacterial Agents
PubMed: 37260399
DOI: 10.1128/spectrum.00777-23 -
Annals of the American Thoracic Society Aug 2023
Topics: Adult; Humans; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Wisconsin; Anti-Bacterial Agents
PubMed: 37526483
DOI: 10.1513/AnnalsATS.202305-420ED -
ELife Sep 2023Lateral partitioning of proteins and lipids shapes membrane function. In model membranes, partitioning can be influenced both by bilayer-intrinsic factors like molecular...
Lateral partitioning of proteins and lipids shapes membrane function. In model membranes, partitioning can be influenced both by bilayer-intrinsic factors like molecular composition and by bilayer-extrinsic factors such as interactions with other membranes and solid supports. While cellular membranes can departition in response to bilayer-intrinsic or -extrinsic disruptions, the mechanisms by which they partition de novo are largely unknown. The plasma membrane of spatially and biochemically departitions in response to the fluidizing agent benzyl alcohol, then repartitions upon fluidizer washout. By screening for mutants that are sensitive to benzyl alcohol, we show that the bifunctional cell wall synthase PonA2 promotes membrane partitioning and cell growth during recovery from benzyl alcohol exposure. PonA2's role in membrane repartitioning and regrowth depends solely on its conserved transglycosylase domain. Active cell wall polymerization promotes de novo membrane partitioning and the completed cell wall polymer helps to maintain membrane partitioning. Our work highlights the complexity of membrane-cell wall interactions and establishes a facile model system for departitioning and repartitioning cellular membranes.
Topics: Cell Membrane; Benzyl Alcohol; Cell Wall; Mycobacterium smegmatis
PubMed: 37665120
DOI: 10.7554/eLife.81924 -
BMC Infectious Diseases Oct 2023Mycobacterium abscessus subsp. massiliense (MMA) comprises a group of non-tuberculous, rapidly growing mycobacteria. Although MMA can cause pulmonary diseases, surgical...
BACKGROUND
Mycobacterium abscessus subsp. massiliense (MMA) comprises a group of non-tuberculous, rapidly growing mycobacteria. Although MMA can cause pulmonary diseases, surgical site infections, and disseminated diseases, aortic endograft infection has not been reported. Here, we describe the first case of aortic endograft infection caused by MMA.
CASE PRESENTATION
Two months after stent-graft insertion for an abdominal aortic aneurysm, an 85-year-old man was admitted with fever and abdominal pain and was diagnosed with aortic endograft infection. Despite 14 days of meropenem and vancomycin intravenous administration, periaortic fluid pooling increased as compared to that before antibiotic administration. The abscess was drained, and fluorescent acid-fast staining of the abscess fluid revealed bacilli. We conducted genetic tests on the genes hsp65, rpoB, and sodA, performed Whole Genome Sequencing (WGS), and identified the organism as MMA. Intravenous imipenem-cilastatin (IPM/CS), amikacin (AMK), and oral clarithromycin (CAM) were administered. After 2 months, oral CAM and sitafloxacin were administered because the abscess had decreased in size. However, after 6 weeks, the abscess increased in size again. Antimicrobial susceptibility testing of the drainage fluid from the abscess resulted in the isolation of an MMA strain that had acquired resistance to CAM. Intravenous IPM/CS, AMK, and oral linezolid were added to the treatment regimen along with oral CAM and STFX. However, he was not fully cured and died 6 months later. Neither the full-length erythromycin ribosome methyltransferase (erm)(41) gene nor the rrl or rpIV gene mutations were found by Sanger sequencing in the pre- and post-treatment strains. Whole-genome sequence analysis of the post-treatment strain revealed mutations in genes with no previous reports of association with macrolide resistance.
CONCLUSIONS
Aortic endograft infection caused by MMA strain is extremely rare; nonetheless, MMA should be suspected as the causative microorganism when broad-spectrum antimicrobials are ineffective.
Topics: Male; Humans; Aged, 80 and over; Clarithromycin; Anti-Bacterial Agents; Mycobacterium abscessus; Abscess; Macrolides; Drug Resistance, Bacterial; Amikacin; Mycobacterium Infections, Nontuberculous; Cilastatin, Imipenem Drug Combination; Stents; Microbial Sensitivity Tests
PubMed: 37848843
DOI: 10.1186/s12879-023-08702-1 -
The Lancet. Global Health Apr 2024
Topics: Humans; Nontuberculous Mycobacteria; Aminoglycosides; Anti-Bacterial Agents; Deafness
PubMed: 38485424
DOI: 10.1016/S2214-109X(24)00082-2 -
Antimicrobial Agents and Chemotherapy Sep 2023Necrotic lesions and cavities filled with caseum are a hallmark of mycobacterial pulmonary disease. Bronchocavitary disease is associated with poor treatment outcomes....
Necrotic lesions and cavities filled with caseum are a hallmark of mycobacterial pulmonary disease. Bronchocavitary disease is associated with poor treatment outcomes. In caseum surrogate, entered an extended stationary phase showing tolerance to killing by most current antibiotics, suggesting that caseum persisters contribute to the poor performance of available treatments. Novel ADP-ribosylation-resistant rifabutin analogs exhibited bactericidal activity against these persisters at concentrations achievable by rifamycins in caseum.
Topics: Humans; Rifabutin; Mycobacterium Infections, Nontuberculous; Mycobacterium abscessus; Anti-Bacterial Agents; Rifamycins; Microbial Sensitivity Tests
PubMed: 37493373
DOI: 10.1128/aac.00381-23