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Journal of Aquatic Animal Health Jun 2021Chinook Salmon Oncorhynchus tshawytscha is a keystone fish species in the Pacific Northwest. In 2019, unusual mortalities occurred in two different populations of...
Chinook Salmon Oncorhynchus tshawytscha is a keystone fish species in the Pacific Northwest. In 2019, unusual mortalities occurred in two different populations of cultured fingerlings from the same facility in California, USA. The systems consist of outdoor, enclosed, flow-through freshwater tanks that are maintained at 18 ± 1°C. Clinical signs and gross findings were only observed in one population and included abnormal swimming, inappetence, lethargy, skin discoloration, and the presence of multifocal nodular and ulcerative skin lesions. Microscopic lesions were infrequent and consisted of severe, locally extensive granulomatous dermatitis and myositis and mild, multifocal, granulomatous branchitis, myocarditis, and hepatitis. Intracellular acid-fast organisms were observed within areas of granulomatous myositis. Posterior kidney swabs were collected and inoculated in nutrient-rich and selective agar media and incubated at 25°C for 2 weeks. Visibly pure bacterial colonies were observed 7-10 d postinoculation. Partial sequences of 16S rRNA initially identified the recovered bacteria as members of the genus Mycobacterium. However, marked variability was observed among Mycobacterium spp. isolates by using repetitive extragenic palindromic polymerase chain reaction fingerprinting. Amplification and sequencing of the ribosomal RNA internal transcribed spacer, 65-kDa heat shock protein, and RNA polymerase β-subunit gene of the cultured isolates identified M. salmoniphilum and M. chelonae, discrete members of the M. chelonae-abscessus complex, isolated from diseased Chinook Salmon fingerlings.
Topics: Animals; Fish Diseases; Mycobacteriaceae; Mycobacterium; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Salmon
PubMed: 33780059
DOI: 10.1002/aah.10124 -
G3 (Bethesda, Md.) Aug 2022Mycobacterium abscessus is an emerging pathogen of concern in cystic fibrosis and immunocompromised patients and is considered one of the most drug-resistant...
Mycobacterium abscessus is an emerging pathogen of concern in cystic fibrosis and immunocompromised patients and is considered one of the most drug-resistant mycobacteria. The majority of clinical Mycobacterium abscessus isolates carry 1 or more prophages that are hypothesized to contribute to virulence and bacterial fitness. The prophage McProf was identified in the genome of the Bergey strain of Mycobacterium chelonae and is distinct from previously described prophages of Mycobacterium abscessus. The McProf genome increases intrinsic antibiotic resistance of Mycobacterium chelonae and drives expression of the intrinsic antibiotic resistance gene, whiB7, when superinfected by a second phage. The prevalence of McProf-like genomes was determined in sequenced mycobacterial genomes. Related prophage genomes were identified in the genomes of 25 clinical isolates of Mycobacterium abscessus and assigned to the novel cluster, MabR. They share less than 10% gene content with previously described prophages; however, they share features typical of prophages, including polymorphic toxin-immunity systems.
Topics: Anti-Bacterial Agents; Humans; Mycobacterium; Mycobacterium abscessus; Mycobacterium chelonae; Prophages
PubMed: 35894699
DOI: 10.1093/g3journal/jkac188 -
Frontiers in Cellular and Infection... 2023We aimed to evaluate the activity of PBTZ169 and pretomanid against non-tuberculous mycobacteriosis (NTM) and .
OBJECTIVES
We aimed to evaluate the activity of PBTZ169 and pretomanid against non-tuberculous mycobacteriosis (NTM) and .
METHODS
The minimum inhibitory concentrations (MICs) of 11 antibiotics, against slow-growing mycobacteria (SGMs) and rapid-growing mycobacteria (RGMs) were tested using the microplate alamarBlue assay. The activities of bedaquiline, clofazimine, moxifloxacin, rifabutin, PBTZ169 and pretomanid against four common NTMs were assessed in murine models.
RESULTS
PBTZ169 and pretomanid had MICs of >32 μg/mL against most NTM reference and clinical strains. However, PBTZ169 was bactericidal against (3.33 and 1.49 log10 CFU reductions in the lungs and spleen, respectively) and (2.29 and 2.24 CFU reductions in the lungs and spleen, respectively) in mice, and bacteriostatic against Mycobacterium avium and . Pretomanid dramatically decreased the CFU counts of (3.12 and 2.30 log10 CFU reductions in the lungs and spleen, respectively), whereas it showed moderate inhibition of and . Bedaquiline, clofazimine, and moxifloxacin showed good activities against four NTMs and . Rifabutin did not inhibit and in mice.
CONCLUSION
PBTZ169 appears to be a candidate for treating four common NTM infections. Pretomanid was more active against , and than against .
Topics: Animals; Mice; Mycobacterium abscessus; Mycobacterium avium; Mycobacterium fortuitum; Mycobacterium chelonae; Clofazimine; Moxifloxacin; Mice, Inbred BALB C; Anti-Bacterial Agents; Nontuberculous Mycobacteria; Mycobacterium Infections; Rifabutin; Mycobacterium Infections, Nontuberculous; Microbial Sensitivity Tests
PubMed: 37077530
DOI: 10.3389/fcimb.2023.1115530 -
Internal Medicine (Tokyo, Japan) Jul 2022
Topics: Clarithromycin; Discitis; Humans; Mycobacterium Infections, Nontuberculous; Mycobacterium chelonae
PubMed: 34924460
DOI: 10.2169/internalmedicine.8539-21 -
Pathogens (Basel, Switzerland) Apr 2022Desiccation-tolerance of cells of four strains of and individual strains of , , , and were measured by two methods. The survival of water-acclimated cells both in...
Desiccation-tolerance of cells of four strains of and individual strains of , , , and were measured by two methods. The survival of water-acclimated cells both in filter paper and on the surface of stainless-steel coupons were measured. In filter paper at 40% relative humidity at 25 °C, survival of patient isolates of and cells was 28% and 34% after 21 days of incubation, whereas it was 100% for the Sorin 3T isolate of . On stainless-steel biofilms after 42 days of incubation at 40% relative humidity at 25 °C, survival of water-acclimated cells of was above 100%, while cells did not survive beyond 21 days, and survival of water-acclimated cells of and was 18% and 14%, respectively. On stainless-steel coupons, survival of patient and Sorin 3T isolates of was quite similar, specifically between 14% and 28% survival, after 42 days of incubation at 40% relative humidity at 25 °C. The experiments would support the hypothesis that some nontuberculous mycobacterial species are relatively desiccation-tolerant, whereas others are not. Further, long-term survival of the two strains is consistent with the presence of that species in Sorin 3T heater-coolers shipped throughout the world.
PubMed: 35456138
DOI: 10.3390/pathogens11040463 -
Journal of Clinical Microbiology Oct 2023Macrolides, such as clarithromycin, are crucial in the treatment of nontuberculous mycobacteria (NTM). NTM are notoriously innately drug resistant, which has made the...
Macrolides, such as clarithromycin, are crucial in the treatment of nontuberculous mycobacteria (NTM). NTM are notoriously innately drug resistant, which has made the dependence on macrolides for their treatment even more important. Not surprisingly, resistance to macrolides has been documented in some NTM, including and , which are the two NTM species most often identified in clinical isolates. Resistance is mediated by point mutations in the 23S ribosomal RNA or by methylation of the rRNA by a methylase (encoded by an gene). Chromosomally encoded genes have been identified in many of the macrolide-resistant isolates, but not in . Now, Brown-Elliott et al. (J Clin Microbiol 61:e00428-23, 2023, https://doi.org/10.1128/JCM.00428-23) describe the identification of a new variant, (55) which was found either on the chromosome or on a plasmid in highly macrolide-resistant clinical isolates of . The chromosomal (55) gene appears to be associated with mobile elements; one gene is within a putative transposon and the second is in a large (37 kb) insertion/deletion. The plasmid carrying (55) also encodes type IV and type VII secretion systems, which are often linked on large mycobacterial plasmids and are hypothesized to mediate plasmid transfer. While the conjugative transfer of the (55)-containing plasmid between NTM has yet to be demonstrated, the inferences are clear, as evidenced by the dissemination of plasmid-mediated drug resistance in other medically important bacteria. Here, we discuss the findings of Brown-Elliott et al. and the potential ramifications on treatment of NTM infections.
Topics: Humans; Anti-Bacterial Agents; Mycobacterium chelonae; Macrolides; Drug Resistance, Bacterial; Clarithromycin; Mycobacterium; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Chromosomes
PubMed: 37724858
DOI: 10.1128/jcm.00628-23 -
The Journal of Dermatology Nov 2022Nontuberculous mycobacteria cause a wide range of infections, including cutaneous infections, in both immunocompromised and immunocompetent patients. Although pulmonary... (Review)
Review
Nontuberculous mycobacteria cause a wide range of infections, including cutaneous infections, in both immunocompromised and immunocompetent patients. Although pulmonary nontuberculous mycobacterial infections have increased significantly in Japan in recent years, there is less evidence on clinical and microbiological characteristics of cutaneous nontuberculous mycobacterial infections in Japan. We reviewed 86 Japanese cases reported between July 2016 and November 2021 and analyzed them in conjunction with the eight patients from our institution who were diagnosed with cutaneous nontuberculous mycobacterial infections by culture between 2015 and 2021. In the aggregate series, the average patient age was 60 years, and the ratio of immunocompromised hosts was 53%, both of which were higher than those in previous reports from other countries. No female predominance was observed, unlike in pulmonary nontuberculous mycobacteria infections. Rapidly growing mycobacteria accounted for 58% of the cases (n = 54), whereas slowly growing mycobacteria for 43% (n = 40). Mycobacterium marinum (also known as Mycobacteroides marinum) (n = 20, 21%) was the most common cause, followed by Mycobacterium chelonae (n = 18, 19%), Mycobacterium abscessus (also known as Mycobacteroides abscessus) (n = 15, 16%), and Mycobacterium ulcerans (n = 11, 12%). While clinical appearance was variable, M ulcerans infections usually presented with ulcers, while nodules were common among infections caused by M chelonae and M marinum. Disseminated infections involving multiple organs were observed in 23 patients (24%). Thirty-two cases (30%) were preceded by exposure, including raising or handling fish, trauma, and invasive medical procedures. Most patients were treated with more than two antibiotics and responded to therapy.
Topics: Animals; Japan; Skin Diseases, Bacterial; Nontuberculous Mycobacteria; Mycobacterium Infections, Nontuberculous; Mycobacterium marinum; Mycobacterium abscessus
PubMed: 35906770
DOI: 10.1111/1346-8138.16531 -
Journal of Fish Diseases Oct 2019The zebrafish (Danio rerio) is a popular vertebrate model organism used in a wide range of research fields. Mycobacteriosis, caused by Mycobacterium species, is...
The zebrafish (Danio rerio) is a popular vertebrate model organism used in a wide range of research fields. Mycobacteriosis, caused by Mycobacterium species, is particularly concerning because it is a common disease associated with chronic infections in these fish. Infections are also a source of uncontrolled experimental variance that may influence research results. Live feeds for zebrafish are common and include paramecia (Paramecium caudatum), brine shrimp (Artemia franciscana) and rotifers (Branchionus spp.). Although nutritionally beneficial, live feeds may pose a biosecurity risk. In this study, we investigate transmission of Mycobacterium chelonae and Mycobacterium marinum through these three live feeds. We show that all three live feeds ingest both M. marinum and M. chelonae and can transmit mycobacterial infections to zebrafish. This observation emphasizes the need for live feeds to be included in the consideration of potential biosecurity risks. This study is of importance to other beyond the zebrafish community, including those of additional aquatic models and those using live feeds for other types of aquaculture.
Topics: Animal Feed; Animals; Artemia; Diet; Female; Fish Diseases; Male; Mycobacterium Infections, Nontuberculous; Mycobacterium chelonae; Mycobacterium marinum; Paramecium caudatum; Prevalence; Rotifera; Zebrafish
PubMed: 31418901
DOI: 10.1111/jfd.13071 -
The Journal of Antibiotics Jan 2020Methylobacterium sp. is isolated from water distribution systems and has been linked in the biofilms of the systems with a lower presence of Mycobacterium avium. In this...
Methylobacterium sp. is isolated from water distribution systems and has been linked in the biofilms of the systems with a lower presence of Mycobacterium avium. In this study we aimed to determine the in vitro activity of Methylobacterium sp. in the development of rapidly growing mycobacteria (RGM) biofilms. Methylobacterium sp. CECT 7805 was added as a suspension of living bacteria (LB), an autoclaved suspension (AS), and an extract obtained after sonication (ES) at different times (24, 48, and 72 h), to preformed biofilms of Mycobacterium abscessus DSM 44196, Mycobacterium chelonae ATCC 19235, and Mycobacterium fortuitum ATCC 6841, using a 96 h control of each species. The biofilms were analyzed by confocal laser scanning microscopy and by the Calgary biofilm device using the plates MBEC Biofilm Inoculator. A statistically significant reduction in the thickness and covered surface was observed in all mycobacterial biofilms with all forms of Methylobacterium sp. A statistically significant increase in the autofluorescence was observed in M. abscessus biofilms but not in other biofilms. The increased percentage of dead mycobacteria was statistically significant in all cases. The reduced log CFU (colony-forming units)/peg recount was statistically significant in M. chelonae biofilms after treatment with AS and ES, but in M. fortuitum biofilms the recount decreased only with AS. M. abscessus biofilms were always significantly reduced with AS at 72 h and with ES. Methylobacterium sp. could inhibit RGM biofilm formation. Living cells of Methylobacterium sp. were not necessary to inhibit the growth of a preformed biofilm. M. chelonae biofilms were the most greatly reduced.
Topics: Anti-Bacterial Agents; Biofilms; Colony Count, Microbial; Methylobacterium; Microbial Sensitivity Tests; Microscopy, Confocal; Mycobacterium; Mycobacterium abscessus
PubMed: 31481764
DOI: 10.1038/s41429-019-0232-6 -
Journal of Clinical Microbiology Mar 2022
PubMed: 35293786
DOI: 10.1128/jcm.00980-21