Affiliation:
1. Aix Marseille University, Institut Recherche pour le Développement (IRD), Microbes, Evolution, Phylogénie et Inféction (MEPHI), Institut Hospitalier Universitaire Méditerranée Infection, Marseille, France
2. Institut Hospitalier Universitaire Méditerranée Infection, Marseille, France
Abstract
Abstract
Background
The spectrum of infections caused by methanogens remains to be described. We searched for methanogens in the blood of febrile patients using specific tools.
Methods
Blood culture samples routinely collected in patients with fever were prospectively screened by specific PCR assays for methanogens. Positive samples were observed by autofluorescence and electron microscopy, analyzed by metagenomics and cultured using previously developed methods. Blood culture bottles experimentally inoculated were used as controls. The presence of methanogens in vascular and cardiac tissues was assessed by indirect immunofluorescence, fluorescent in situ hybridization and PCR-based investigations.
Results
PCR detection attempted in 7,716 blood samples, was negative in all 1,312 aerobic bottles and 810 bacterial culture-negative anaerobic bottles. PCRs were positive in 27/5,594 (0.5%) bacterial culture-positive anaerobic bottles collected from 26 patients. Sequencing confirmed Methanobrevibacter smithii associated with staphylococci in 14 patients, Enterobacteriaceae in nine patients and streptococci in three patients. Metagenomics confirmed M. smithii in five samples, and M. smithii was isolated in broth from two samples; the genomes of these two isolates were sequenced. Blood cultures experimentally inoculated with Enterobacteriaceae, Staphylococcus epidermidis or Staphylococcus hominis yielded hydrogen, but no methane, authentifying observational data. Three patients diagnosed with infectious mitral endocarditis, were indisputably diagnosed by microscopy, PCR-based detections and culture: we showed M. smithii microscopically and by a specific PCR followed by sequencing method in two of three cardiovascular tissues.
Conclusions
Using appropriate laboratory methods, M. smithii is demonstrated as causing archaemia and endocarditis in febrile patients who are coinfected by bacteria.
Funder
National Agency for Research
Région Sud
Plateformes de Recherche et d’Innovation Mutualisées Méditerranée Infection
European funding Fonds Européen de Développement Régional
Publisher
Oxford University Press (OUP)
Subject
Infectious Diseases,Microbiology (medical)
Cited by
23 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献