Mycobacterium abscessus pneumonia in a South Pacific islander

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Inverse correlation between salt tolerance and host-adaptation in mycobacteria

International audienceBACKGROUND: The genus Mycobacterium includes host-adapted organisms regarded as obligate and opportunistic pathogens and environmental organisms. Factors contributing to this wide range of adaptations are poorly known. RESULTS: We studied the salt tolerance of 46 Mycobacterium species of medical interest. Representative strains of the Mycobacterium tuberculosis complex, Mycobacterium avium complex, Mycobacterium chelonae-abscessus complex, Mycobacterium ulcerans, Mycobacterium marinum, Mycobacterium lentiflavum, Mycobacterium fortuitum and Mycobacterium conceptionense were inoculated on Middlebrook 7H10 medium supplemented with 0-10 % sodium chloride. Colonies were counted after 2-4 week incubation at the appropriate 30-37 °C temperature depending on the tested strain. Further comparative genomics was done on 15 Mycobacterium strains representing the spectrum of salt-tolerance of mycobacteria. Based on the results the different species were grouped according to their salt tolerance into a "salt-sensitive" group (growth up to ≤3 % salt) containing the M. tuberculosis complex, Mycobacterium chelonae, Mycobacterium lentiflavum, Mycobacterium ulcerans and Mycobacterium marinum; a "salt-intermediate" group (growth between 4 and 6 % salt) comprising Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium chimaera and a "salt-resistant" group (growth up to \textgreater6 %) comprising Mycobacterium homonissuis, Mycobacterium bolettii, Mycobacterium fortuitum and Mycobacterium conceptionense. Genomic analysis revealed that 290 genes were unique to species belonging to the salt-sensitive group; and that 15 % were annotated as being functionally associated with the ESX secretion systems Pro-Glu and Pro-Pro-Glu family proteins. CONCLUSIONS: In this work we found an inverse correlation between salt tolerance and host adaptation. We thus propose that salinity is one of the multiple factors determining the ecological niches of mycobacteri

Diversity of Mycobacterium tuberculosis lineages in French Polynesia

Background/Purpose: French Polynesia is an overseas territory located in the South Pacific. The incidence of tuberculosis in French Polynesia has been stable since 2000 with an average of 20 cases/y/100,000 inhabitants. Molecular epidemiology of Mycobacterium tuberculosis in French Polynesia is unknown because M. tuberculosis isolates have not been routinely genotyped. Methods: From 2009 to 2012, 34 isolates collected from 32 French Polynesian patients were identified as M. tuberculosis by probe hybridization. These isolates were genotyped using spoligotyping and 24-loci mycobacterial interspersed repetitive units (MIRUs)-variable number of tandem repeat (VNTR). Spoligotype patterns obtained using commercial kits were compared with the online international database SITVIT. MIRU-VNTR genotyping was performed using an in-house protocol based on capillary electrophoresis sizing for 24-loci MIRU-VNTR genotyping. Results: The results of the spoligotyping method revealed that 25 isolates grouped into six previously described spoligotypes [H1, H3, U likely (S), T1, Manu, and Beijing] and nine isolates grouped into six new spoligotypes. Comparison with the international database MIRU-VNTRplus distributed 30 isolates into five lineages (Haarlem, Latin American Mediterranean, S, X, and Beijing) and four as unassigned isolates. Conclusion: Genotyping identified four phylogenetic lineages belonging to the modern Euro–American subgroup, one Beijing genotype responsible for worldwide pandemics, including remote islands in the South Pacific, and one Manu genotype of the ancestral lineage of M. tuberculosis

“Mycobacterium mephinesia”, a Mycobacterium terrae complex species of clinical interest isolated in French Polynesia

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Cystic fibrosis respiratory tract salt concentration An Exploratory Cohort Study

International audienceIn cystic fibrosis patients, electrolytic and osmolality imbalance secondary to cystic fibrosis transmembrane conductance regulator mutations may impact on mucoid secretion accumulation and secondary colonization by opportunistic pathogens such as nontuberculous mycobacteria. We performed a noninvasive exploratory prospective controlled clinical study comparing sputum salinity and acid-base characteristics of cystic fibrosis and noncystic fibrosis control patients. A total of 57 patients and 62 controls were included. Sputum salt concentrations were 10.5 g/L (95% CI: 7.7-13.3) in patients and 7.4 g/L (95% CI: 5.9-8.9) in aged-matched controls, a difference that was found to be statistically significant (P<.05). No difference in pH was observed between patients and controls. These differences in respiratory secretions salt concentrations could influence host-pathogen interactions in the context of cystic fibrosis respiratory infections. We propose to include respiratory secretion salt measurement as a routine analysis on cystic fibrosis patients' sputum submitted for bacterial culture

Changes in inflammatory markers in patients treated for Buruli ulcer and their ability to predict paradoxical reactions

International audienceAbstract Mycobacterium ulcerans causes Buruli ulcer, the third most frequent mycobacterial disease after tuberculosis and leprosy. Transient clinical deteriorations, known as paradoxical reactions, occur in some patients during or after antibiotic treatment. We investigated the clinical and biological features of PRs in a prospective cohort of BU patients from Benin including forty-one patients. Neutrophil counts decreased from baseline to day 90 and IL-6, G-CSF and VEGF were the cytokines displaying a significant monthly decrease relative to baseline. Paradoxical reactions occurred in 10 (24%) patients. The baseline biological and clinical characteristics of the patients presenting PRs did not differ significantly from those of the other patients. However, the patients with PRs had significantly higher IL-6 and TNF-α concentrations on days 30, 60 and 90 after the start of antibiotic treatment. The absence of a decrease in IL-6 and TNF-α levels during treatment should alert clinicians to the possibility of PR onset

Prevalence of Mycobacterium lentiflavum in cystic fibrosis patients, France

International audienceBackground: Mycobacterium lentiflavum is rarely isolated in respiratory tract samples from cystic fibrosis patients. We herein describe an unusually high prevalence of M. lentiflavum in such patients. Methods: M. lentiflavum, isolated from the respiratory tract of cystic fibrosis patients, was identified using both rpoB partial sequencing and detected directly in the sputum by using real-time PCR targeting the smpB gene. Results: M. lentiflavum emerged as the third most prevalent nontuberculous mycobacterial species isolated in cystic fibrosis patients in Marseille, France. Six such patients were all male, and two of them may have fulfilled the American Thoracic Society clinical and microbiological criteria for M. lentiflavum potential lung infection. Conclusions: M. lentiflavum was the third most common mycobacteria isolated in cystic fibrosis patients, particularly in six male patients. M. lentiflavum outbreaks are emerging particularly in cystic fibrosis patients

Additional file 1: Table S1. of Prevalence of Mycobacterium lentiflavum in cystic fibrosis patients, France

Mycobacterium species tested for the specificity/sensitivity assay of real-time PCR for M. lentiflavum species. (PDF 43 kb

Additional file 2: Figure S1. of Prevalence of Mycobacterium lentiflavum in cystic fibrosis patients, France

Clinical and microbiological data concerning two cystic fibrosis patients who yielded more than one M. lentiflavum isolate and who may fulfill the American Thoracic Society’s clinical and microbiological criteria for NTM lung infection. BMI: Body Mass Index. (PDF 121 kb