Structure and genetics of the O-antigen of Cronobacter turicensis G3882 from a new serotype, C. turicensis O2, and identification of a serotype-specific gene

Authors

  • Yamin Sun,

    1. The Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, China
    2. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
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  • Nikolay P. Arbatsky,

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
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  • Min Wang,

    1. The Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, China
    2. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
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  • Alexander S. Shashkov,

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
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  • Bin Liu,

    1. The Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, China
    2. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
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  • Lei Wang,

    Corresponding author
    1. TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
    • The Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, China
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  • Yuriy A. Knirel

    1. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
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Correspondence: Lei Wang, TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, #23 HongDa Street, Tianjin 300457, China. Tel.: +186 22 66229591; fax: +186 22 66229596; e-mail: wanglei@nankai.edu.cn

Abstract

Lipopolysaccharides on the cell surface of Gram-negative bacteria are an important factor in pathogenicity, and the O-specific polysaccharide chain (O-polysaccharide, O-antigen) defines the immunospecificity of different bacterial strains. Cronobacter turicensis is an emerging foodborne pathogen which causes severe invasive infections in neonates. In this study, a new O serotype, C. turicensis O2, was established, the structure and genetics of the O-antigen were investigated, and a serotype-specific gene was identified. Sugar and methylation analyses, and nuclear magnetic resonance spectroscopy indicated that the O-polysaccharide contains d-galactose (d-Gal), N-acetyl-d-glucosamine (d-GlcNAc), l-rhamnose (l-Rha) and 5,7-diacetamido-3,5,7,9-tetradeoxy-d-glycero-d-galacto-non-2-ulosonic acid (di-N-acetyllegionaminic acid, Leg5Ac7Ac). The structure of the tetrasaccharide repeat of the O-polysaccharide was established as:

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The O-antigen gene cluster of C. turicensis O2 was sequenced and compared with related gene clusters from available databases. Putative genes for the synthesis of l-Rha and Leg5Ac7Ac, and genes encoding sugar transferases and O-antigen processing genes (wzx and wzy) were found. The tentatively assigned functions of the O-antigen genes were in agreement with the structure of the O-polysaccharide. In addition, primers based on the wzy gene were shown to be specific for C. turicensis O2 in a screen against 145 strains.

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