The selC-associated SHI-2 pathogenicity island of Shigella flexneri

Authors

  • Jeremy E. Moss,

    1. Skirball Institute, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA.,
    2. Department of Microbiology, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA.,
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  • Timothy J. Cardozo,

    1. Skirball Institute, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA.,
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  • Arturo Zychlinsky,

    1. Skirball Institute, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA.,
    2. Department of Microbiology, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA.,
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  • Eduardo A. Groisman

    1. Howard Hughes Medical Institute, Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA.
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Arturo Zychlinsky. E-mail zychlins@saturn.med.nyu.edu; Tel. (1) 212 263 7058; Fax (+1) 212 263 5711.

Abstract

Pathogenicity islands are chromosomal gene clusters, often located adjacent to tRNA genes, that encode virulence factors present in pathogenic organisms but absent or sporadically found in related non-pathogenic species. The selC tRNA locus is the site of integration of different pathogenicity islands in uropathogenic Escherichia coli, enterohaemorrhagic E. coli and Salmonella enterica. We show here that the selC locus of Shigella flexneri, the aetiological agent of bacterial dysentery, also contains a pathogenicity island. This pathogenicity island, designated SHI-2 (Shigellaisland 2), occupies 23.8 kb downstream of selC and contains genes encoding the aerobactin iron acquisition siderophore system, colicin V immunity and several novel proteins. Remnants of multiple mobile genetic elements are present in SHI-2. SHI-2-hybridizing sequences were detected in all S. flexneri strains tested and parts of the island were also found in other Shigella species. SHI-2 may allow Shigella survival in stressful environments, such as those encountered during infection.

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