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BMC Microbiology Jan 2022M. intracellulare is a frequent causative pathogen of nontuberculous mycobacteria infection that causes infections in the respiratory tract, whose incidence is...
BACKGROUND
M. intracellulare is a frequent causative pathogen of nontuberculous mycobacteria infection that causes infections in the respiratory tract, whose incidence is increasing in many countries. This study aimed at determining the VNTR-based genetic diversity of a collection of 39 M. intracellulare human strains isolated from respiratory specimens over the last 5 years.
RESULTS
The VNTR analysis showed that M. intracellulare strains displayed a high genetic diversity, indicating that the M. intracellulare genotypes are quite heterogeneous in our geographical area. Moreover, a comparison with VNTR profiles of strains from other countries confirmed that genotypes of clinical strains of M. intracellulare are not related to geographical origin.
CONCLUSIONS
VNTR typing has proved to be a highly discriminatory method for better understanding the molecular epidemiology of M. intracellulare.
Topics: Genetic Variation; Genotype; Humans; Italy; Minisatellite Repeats; Molecular Epidemiology; Molecular Typing; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Respiratory System
PubMed: 34979921
DOI: 10.1186/s12866-021-02426-5 -
Microbiology Spectrum Oct 2021The Mycobacterium avium complex (MAC) is one of the most prevalent causes of nontuberculous mycobacteria pulmonary infection in the United States, and yet it remains...
The Mycobacterium avium complex (MAC) is one of the most prevalent causes of nontuberculous mycobacteria pulmonary infection in the United States, and yet it remains understudied. Current MAC treatment requires more than a year of intermittent to daily combination antibiotic therapy, depending on disease severity. In order to shorten and simplify curative regimens, it is important to identify the innate bacterial factors contributing to reduced antibiotic susceptibility, namely, antibiotic tolerance genes. In this study, we performed a genome-wide transposon screen to elucidate M. avium genes that play a role in the bacterium's tolerance to first- and second-line antibiotics. We identified a total of 193 unique M. avium mutants with significantly altered susceptibility to at least one of the four clinically used antibiotics we tested, including two mutants (in DFS55_00905 and DFS55_12730) with panhypersusceptibility. The products of the antibiotic tolerance genes we have identified may represent novel targets for future drug development studies aimed at shortening the duration of therapy for MAC infections. The prolonged treatment required to eradicate Mycobacterium avium complex (MAC) infection is likely due to the presence of subpopulations of antibiotic-tolerant bacteria with reduced susceptibility to currently available drugs. However, little is known about the genes and pathways responsible for antibiotic tolerance in MAC. In this study, we performed a forward genetic screen to identify M. avium antibiotic tolerance genes, whose products may represent attractive targets for the development of novel adjunctive drugs capable of shortening the curative treatment for MAC infections.
Topics: Anti-Bacterial Agents; Clarithromycin; DNA Transposable Elements; Drug Therapy, Combination; Drug Tolerance; Ethambutol; Humans; Moxifloxacin; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Rifabutin
PubMed: 34523947
DOI: 10.1128/Spectrum.00246-21 -
Research in Microbiology 1994
Review
Topics: Antigens, Bacterial; Bacterial Proteins; Glycolipids; Glycopeptides; Humans; In Vitro Techniques; Morphogenesis; Mycobacterium avium Complex; Virulence
PubMed: 7809478
DOI: 10.1016/0923-2508(94)90024-8 -
Microbiology Spectrum Feb 2022Although serum anti-glycopeptidolipid (GPL)-core IgA antibody is a highly specific test for infection with Mycobacterium avium complex (MAC), Mycobacterium abscessus,...
Although serum anti-glycopeptidolipid (GPL)-core IgA antibody is a highly specific test for infection with Mycobacterium avium complex (MAC), Mycobacterium abscessus, and its subspecies , subsp. , and subsp. (MAB), its use for the definitive diagnosis of MAC pulmonary disease (PD) and MAB-PD are unknown. To clarify the diagnostic accuracy of the anti-GPL-core IgA antibody test among patients with radiologically suspected MAC-PD or MAB-PD who already have a single positive sputum culture test. The first isolations of MAC and MAB from patients with radiologically suspected MAC-PD or MAB-PD at the Osaka Toneyama Medical Center between January 2006 and December 2020 were collected. Patients were enrolled when their serum anti-GPL-core IgA antibody was measured during the 3 months before and after the first isolation. We retrospectively compared the results of anti-GPL-core IgA antibody testing with the final diagnoses based on the current guidelines. We included 976 patients for analysis. The serum anti-GPL-core IgA antibody was positive in 699 patients (71.6%). The positive predictive value of anti-GPL-core IgA antibody for the diagnosis of MAC-PD or MAB-PD was 97.4%. The median time required for the second positive culture after the first isolation was 51 days (interquartile range 12 to 196 days). The positive serum anti-GPL-core IgA antibody test allowed an early and definitive diagnosis of MAC-PD or MAB-PD in those who already had a single positive sputum culture test. To satisfy the microbiologic criteria of the current diagnostic guideline for nontuberculous mycobacterial pulmonary disease (PD), at least two positive sputum cultures of the same species of mycobacteria from sputum are required to avoid the casual isolation of mycobacteria. This study showed that the positivity of a serum anti-glycopeptidolipid (GPL)-core IgA antibody test has an excellent diagnostic ability among patients with radiologically suspected Mycobacterium avium complex (MAC)-PD or Mycobacterium abscessus (MAB)-PD who already had a single positive sputum culture test. The usage of single culture isolation plus anti-GPL-core IgA antibody as another diagnostic criterion has a time, cost, and effort-saving effect. Furthermore, it will facilitate the diagnosis of MAC-PD or MAB-PD in the early stage of disease because serum anti-GPL-core IgA antibody becomes high in these patients. Therefore, we proposed adding single culture isolation plus anti-GPL-core IgA antibody as "combined microbiological and serological criteria" to the diagnostic guidelines for MAC-PD and MAB-PD.
Topics: Aged; Aged, 80 and over; Antibodies, Bacterial; Female; Glycopeptides; Humans; Immunoglobulin A; Male; Middle Aged; Mycobacterium abscessus; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Retrospective Studies
PubMed: 34985326
DOI: 10.1128/spectrum.01406-21 -
Antimicrobial Agents and Chemotherapy Sep 2019is a slow-growing nontuberculous species belonging to the complex (MAC). It has been identified globally as the cause of a large outbreak of cardiovascular infections...
is a slow-growing nontuberculous species belonging to the complex (MAC). It has been identified globally as the cause of a large outbreak of cardiovascular infections following open heart surgery, but it can also cause respiratory infections in individuals with underlying structural pulmonary disease. Invasive infections are associated with poor clinical responses, and the optimal antibiotic treatment regimen for these infections is not known. In this study, the drug susceptibility profiles of clinical and environmental isolates for antimicrobial agents that are commonly considered for treatment of MAC infections were determined. All isolates were susceptible to clarithromycin, with a median MIC of 2 μg/ml, while 98% (85/87 isolates) were susceptible to amikacin. Twenty-five percent of isolates (22/87 isolates) had intermediate susceptibility and 52% (46/87 isolates) were resistant to moxifloxacin. Similarly, 39% of isolates (34/87 isolates) had intermediate susceptibility and 39% (34/87 isolates) were resistant to linezolid. MIC breakpoints derived from the literature were used to determine resistance to rifampin (16/87 isolates [18%]), ethambutol (10/87 isolates [11%]), rifabutin (2/87 isolates [2%]), and streptomycin (1/87 isolates [1%]). In conclusion, our results showed that clarithromycin, amikacin, rifabutin, and streptomycin had the best activity against isolates, while susceptibility rates were lower for rifampin and ethambutol. In contrast, there was a high prevalence of isolates that were not susceptible to moxifloxacin or linezolid. While factors in addition to antibiotic susceptibility may determine the outcomes of treatment of infections, our results should inform the selection of antimicrobials as part of the overall therapeutic strategy.
Topics: Amikacin; Ethambutol; Linezolid; Microbial Sensitivity Tests; Moxifloxacin; Mycobacterium; Mycobacterium avium Complex; Rifampin; Streptomycin
PubMed: 31262760
DOI: 10.1128/AAC.00755-19 -
Scientific Reports Dec 2023Mycobacterium saskatchewanense is a species of pigmented slow-growing Non-Tuberculous Mycobacteria (NTM), positive for Mycobacterium avium complex (MAC) by AccuProbe...
Mycobacterium saskatchewanense is a species of pigmented slow-growing Non-Tuberculous Mycobacteria (NTM), positive for Mycobacterium avium complex (MAC) by AccuProbe system. MAC organisms have frequently been isolated from different medical devices. This is the first study reporting isolation of M. saskatchewanense from medical devices and highlights the importance of correctly identifying the NTMs that often colonize sanitary water. GenoType Mycobacterium CM CE-IVD kit (CM) was used as the first step of NTM strain identification, and all positive cultures were found to be components of MAC. Then, GenoType NTM-DR CE-IVD kit (NTM-DR) was used to differentiate the different species. Sub-culture on solid media were used for: (i) phenotypical confirmation by colony morphology and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry; (ii) molecular confirmation by Next Generation Sequencing. All positive cultures were identified as M. intracellulare by CM and NTM-DR assays, whereas colony morphology showed bright yellow scotochromogenic growth. MALDI-TOF analyses identified the strains as M. saskatchewanense with a high score, and identification was confirmed by NGS analysis based on the hsp-65 region. This paper suggests that it is important to actively monitor NTM contamination in medical devices that use sanitary water, to prevent the possibility of patients becoming infected.
Topics: Humans; Mycobacterium; Nontuberculous Mycobacteria; Mycobacterium avium Complex; Mycobacterium Infections, Nontuberculous; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Water
PubMed: 38062133
DOI: 10.1038/s41598-023-48974-w -
Cancer Control : Journal of the Moffitt... Jan 2017Right middle lobe (RML) syndrome is defined as recurrent or chronic obstruction or infection of the middle lobe of the right lung. Nonobstructive causes of middle lobe...
Right middle lobe (RML) syndrome is defined as recurrent or chronic obstruction or infection of the middle lobe of the right lung. Nonobstructive causes of middle lobe syndrome include inflammatory processes and defects in the bronchial anatomy and collateral ventilation. We report on 2 case patients with RML syndrome, one due to infection with Mycobacterium avium complex followed by M asiaticum infection and the other due to allergic bronchopulmonary aspergillosis. A history of atopy, asthma, or chronic obstructive pulmonary disease has been reported in up to one-half of those with RML. The diagnosis can be made by plain radiography, computed tomography, and bronchoscopy. Medical treatment consists of bronchodilators, mucolytics, and antimicrobials. Patients whose disease is unresponsive to treatment and those with obstructive RML syndrome can be offered surgical treatment.
Topics: Anti-Bacterial Agents; Aspergillosis, Allergic Bronchopulmonary; Bronchodilator Agents; Female; Humans; Middle Aged; Middle Lobe Syndrome; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Prognosis
PubMed: 28178715
DOI: 10.1177/107327481702400110 -
Clinical Drug Investigation Apr 2021Amikacin liposome inhalation suspension (ALIS) [Arikayce Liposomal (EU); Arikayce (USA)], a liposomal suspension of the aminoglycoside amikacin (590 mg) for... (Review)
Review
Amikacin liposome inhalation suspension (ALIS) [Arikayce Liposomal (EU); Arikayce (USA)], a liposomal suspension of the aminoglycoside amikacin (590 mg) for nebulization via the Lamira Nebulizer System, is available as add-on therapy for treatment-refractory Mycobacterium avium complex (MAC) lung disease in adults who have little or no alternative treatment options. Its addition to guideline-based therapy (GBT) significantly improved the likelihood of achieving sputum culture conversion (defined as three consecutive monthly MAC-negative sputum cultures) by month 6 relative to GBT alone in adults with treatment-refractory MAC lung disease, with the conversion response maintained over up to 12 months' therapy and at 3 months' post treatment in significantly higher proportions of ALIS plus GBT than GBT alone recipients. ALIS as an add-on therapy to GBT was associated with an increased risk of respiratory adverse reactions compared with GBT alone, but treatment-emergent adverse events associated with systemic amikacin exposure were uncommon.
Topics: Administration, Inhalation; Adult; Amikacin; Anti-Bacterial Agents; Humans; Liposomes; Lung Diseases; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Sputum
PubMed: 33723805
DOI: 10.1007/s40261-021-01010-z -
Journal of Clinical Microbiology Jan 2021Bovine tuberculosis (bTB) is an ongoing issue in several countries within the European Union. Microbiological culture is the official confirmation technique for the...
Bovine tuberculosis (bTB) is an ongoing issue in several countries within the European Union. Microbiological culture is the official confirmation technique for the presence of complex (MTBC) members in bovine tissues, but several methodological issues, such as moderate sensitivity and long incubation times, require the development of more sensitive and rapid techniques. This study evaluates the analytical and diagnostic performance, comparative to culture, of a real-time PCR targeting the MTBC-specific IS transposon using a panel of bovine tissue samples sourced from the Spanish bTB eradication campaign. Robustness and repeatability were evaluated in an interlaboratory trial between European Union National Reference Laboratories. The limit of detection with 95% confidence was established at 65 fg/reaction of purified genomic equivalents. Diagnostic sensitivity (Se) and specificity (Sp) were, respectively, 96.45% and 93.66%, and the overall agreement (κ) was 0.88. Cross-reactivity was detected against two mycobacterial isolates identified as and " subsp. ," and whole-genome sequencing (WGS) analysis of the latter isolate revealed an IS-like sequence with 83% identity. An identical IS-like element was found in other complex species in the NCBI nucleotide and WGS databases. Despite this finding, this methodology is considered a valuable alternative to culture, and the strategy of use should be defined depending on the control or eradication programs.
Topics: Animals; Cattle; Humans; Mycobacterium; Mycobacterium avium Complex; Mycobacterium tuberculosis; Real-Time Polymerase Chain Reaction; Sensitivity and Specificity
PubMed: 33239374
DOI: 10.1128/JCM.01404-20 -
Clinical Microbiology and Infection :... Nov 2018
Topics: Cardiac Surgical Procedures; Disease Outbreaks; Global Health; Humans; Infection Control; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Postoperative Complications
PubMed: 30036667
DOI: 10.1016/j.cmi.2018.06.031