Open Access Research article

Phenotypic and genotypic properties of Microbacterium yannicii, a recently described multidrug resistant bacterium isolated from a lung transplanted patient with cystic fibrosis in France

Poonam Sharma1, Seydina M Diene1, Sandrine Thibeaut1, Fadi Bittar1, Véronique Roux1, Carine Gomez2, Martine Reynaud-Gaubert12 and Jean-Marc Rolain1*

Author Affiliations

1 Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergents (URMITE), CNRS-IRD, UMR 6236, Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, 27 Bd Jean Moulin, Marseille Cedex 05, 13385, France

2 Centre de Soins de la mucoviscidose et Centre de transplantation Pulmonaire, Centre Hospitalo-Universitaire Nord, chemin des Bourrelly, Marseille, 13015, France

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BMC Microbiology 2013, 13:97  doi:10.1186/1471-2180-13-97

Published: 3 May 2013

Abstract

Background

Cystic fibrosis (CF) lung microbiota consists of diverse species which are pathogens or opportunists or have unknown pathogenicity. Here we report the full characterization of a recently described multidrug resistant bacterium, Microbacterium yannicii, isolated from a CF patient who previously underwent lung transplantation.

Results

Our strain PS01 (CSUR-P191) is an aerobic, rod shaped, non-motile, yellow pigmented, gram positive, oxidase negative and catalase positive bacterial isolate. Full length 16S rRNA gene sequence showed 98.8% similarity with Microbacterium yannicii G72T type strain, which was previously isolated from Arabidopsis thaliana. The genome size is 3.95Mb, with an average G+C content of 69.5%. In silico DNA-DNA hybridization analysis between our Microbacterium yannicii PS01isolate in comparison with Microbacterium testaceum StLB037 and Microbacterium laevaniformans OR221 genomes revealed very weak relationship with only 28% and 25% genome coverage, respectively. Our strain, as compared to the type strain, was resistant to erythromycin because of the presence of a new erm 43 gene encoding a 23S rRNA N-6-methyltransferase in its genome which was not detected in the reference strain. Interestingly, our patient received azithromycin 250 mg daily for bronchiolitis obliterans syndrome for more than one year before the isolation of this bacterium.

Conclusions

Although significance of isolating this bacterium remains uncertain in terms of clinical evolution, this bacterium could be considered as an opportunistic human pathogen as previously reported for other species in this genus, especially in immunocompromised patients.

Keywords:
Cystic fibrosis; Antibiotic resistance; Multidrug resistant bacteria; Microbacterium yannicii