Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article Full Text Full Text (PDF, 251K) PPT slides of all figures Alert me when this article is cited Citation Map Services Email this article Similar articles in this journal Similar articles in PubMed Alert me to new content in the JEM Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Fang, C.-T. Articles by Wang, J.-T. Search for Related Content PubMed PubMed Citation Articles by Fang, C.-T. Articles by Wang, J.-T. Social Bookmarking                      What's this?

¹ Department of Internal Medicine, National Taiwan University Hospital
² Department of Microbiology, and ³ Department of Forensic Medicine, National Taiwan University College of Medicine, Taipei 100, Taiwan

Address correspondence to Jin-Town Wang, Dept. of Microbiology, National Taiwan University Hospital, 1 Jen-Ai Rd., Taipei 100, Taiwan. Phone: 886-2-23123456; Fax: 886-2-23948718; email: wangjt{at}ntu.edu.tw

Primary Klebsiella pneumoniae liver abscess complicated with metastatic meningitis or endophthalmitis is a globally emerging infectious disease. Its pathogenic mechanism remains unclear. The bacterial virulence factors were explored by comparing clinical isolates. Differences in mucoviscosity were observed between strains that caused primary liver abscess (invasive) and those that did not (noninvasive). Hypermucoviscosity correlated with a high serum resistance and was more prevalent in invasive strains (52/53 vs. 9/52; P < 0.0001). Transposon mutagenesis identified candidate virulence genes. A novel 1.2-kb locus, magA, which encoded a 43-kD outer membrane protein, was significantly more prevalent in invasive strains (52/53 vs. 14/52; P < 0.0001). The wild-type strain produced a mucoviscous exopolysaccharide web, actively proliferated in nonimmune human serum, resisted phagocytosis, and caused liver microabscess and meningitis in mice. However, magA^- mutants lost the exopolysaccharide web and became extremely serum sensitive, phagocytosis susceptible, and avirulent to mice. Virulence was restored by complementation using a magA-containing plasmid. We conclude that magA fits molecular Koch's postulates as a virulence gene. Thus, this locus can be used as a marker for the rapid diagnosis and for tracing the source of this emerging infectious disease.

Key Words: pathogenesis • serum resistance • virulence • genes • liver abscess • meningitis • endophthalmitis

Abbreviations used in this paper: HV, hypermucoviscosity; LB, Luria-Bertani; ORF, open reading frame.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Pan, Y.-J., Fang, H.-C., Yang, H.-C., Lin, T.-L., Hsieh, P.-F., Tsai, F.-C., Keynan, Y., Wang, J.-T. (2008). Capsular Polysaccharide Synthesis Regions in Klebsiella pneumoniae Serotype K57 and a New Capsular Serotype. J. Clin. Microbiol. 46: 2231-2240 [Abstract] [Full Text]  
• Sng, C C A, Jap, A, Chan, Y H, Chee, S-P (2008). Risk factors for endogenous Klebsiella endophthalmitis in patients with Klebsiella bacteraemia: a case-control study. Br. J. Ophthalmol. 92: 673-677 [Abstract] [Full Text]  
• Twenhafel, N. A., Whitehouse, C. A., Stevens, E. L., Hottel, H. E., Foster, C. D., Gamble, S., Abbott, S., Janda, J. M., Kreiselmeier, N., Steele, K. E. (2008). Multisystemic Abscesses in African Green Monkeys (Chlorocebus aethiops) with Invasive Klebsiella pneumoniae--Identification of the Hypermucoviscosity Phenotype. Vet Pathol 45: 226-231 [Abstract] [Full Text]  
• Lin, T.-L., Lee, C.-Z., Hsieh, P.-F., Tsai, S.-F., Wang, J.-T. (2008). Characterization of Integrative and Conjugative Element ICEKp1-Associated Genomic Heterogeneity in a Klebsiella pneumoniae Strain Isolated from a Primary Liver Abscess. J. Bacteriol. 190: 515-526 [Abstract] [Full Text]  
• Wu, J. H., Wu, A. M., Tsai, C. G., Chang, X.-Y., Tsai, S.-F., Wu, T.-S. (2008). Contribution of Fucose-Containing Capsules in Klebsiella pneumoniae to Bacterial Virulence in Mice. Exp. Biol. Med. 233: 64-70 [Abstract] [Full Text]  
• Kuo, C.-F., Wang, Y.-H., Lei, H.-Y., Wang, C.-H., Tsao, N. (2007). Concanavalin A Protects Mice from a Lethal Inoculation of Intragastric Klebsiella pneumoniae and Reduces the Induced Liver Damage. Antimicrob. Agents Chemother. 51: 3122-3130 [Abstract] [Full Text]  
• Turton, J. F., Englender, H., Gabriel, S. N., Turton, S. E., Kaufmann, M. E., Pitt, T. L. (2007). Genetically similar isolates of Klebsiella pneumoniae serotype K1 causing liver abscesses in three continents. J Med Microbiol 56: 593-597 [Abstract] [Full Text]  
• Hui, J. Y. H., Yang, M. K. W., Cho, D. H. Y., Li, A., Loke, T. K. L., Chan, J. C. S., Woo, P. C. Y. (2007). Pyogenic Liver Abscesses Caused by Klebsiella pneumoniae: US Appearance and Aspiration Findings. Radiology 242: 769-776 [Abstract] [Full Text]  
• Yeh, K.-M., Kurup, A., Siu, L. K., Koh, Y. L., Fung, C.-P., Lin, J.-C., Chen, T.-L., Chang, F.-Y., Koh, T.-H. (2007). Capsular Serotype K1 or K2, Rather than magA and rmpA, Is a Major Virulence Determinant for Klebsiella pneumoniae Liver Abscess in Singapore and Taiwan. J. Clin. Microbiol. 45: 466-471 [Abstract] [Full Text]  
• Lin, J.-C., Siu, L. K., Fung, C.-P., Yeh, K.-M., Chang, F.-Y. (2007). Nosocomial Liver Abscess Caused by Extended-Spectrum Beta-Lactamase-Producing Klebsiella pneumoniae. J. Clin. Microbiol. 45: 266-269 [Abstract] [Full Text]  
• Lin, C.-T., Huang, T.-Y., Liang, W.-C., Peng, H.-L. (2006). Homologous Response Regulators KvgA, KvhA and KvhR Regulate the Synthesis of Capsular Polysaccharide in Klebsiella pneumoniae CG43 in a Coordinated Manner. J Biochem 140: 429-438 [Abstract] [Full Text]  
• Lin, J.-C., Siu, L. K., Fung, C.-P., Tsou, H.-H., Wang, J.-J., Chen, C.-T., Wang, S.-C., Chang, F.-Y. (2006). Impaired Phagocytosis of Capsular Serotypes K1 or K2 Klebsiella pneumoniae in Type 2 Diabetes Mellitus Patients with Poor Glycemic Control. J. Clin. Endocrinol. Metab. 91: 3084-3087 [Abstract] [Full Text]  
• Yeh, K.-M., Chang, F.-Y., Fung, C.-P., Lin, J.-C., Siu, L. K. (2006). magA is not a specific virulence gene for Klebsiella pneumoniae strains causing liver abscess but is part of the capsular polysaccharide gene cluster of K. pneumoniae serotype K1. J Med Microbiol 55: 803-804 [Full Text]  
• Jenney, A. W., Clements, A., Farn, J. L., Wijburg, O. L., McGlinchey, A., Spelman, D. W., Pitt, T. L., Kaufmann, M. E., Liolios, L., Moloney, M. B., Wesselingh, S. L., Strugnell, R. A. (2006). Seroepidemiology of Klebsiella pneumoniae in an Australian Tertiary Hospital and Its Implications for Vaccine Development. J. Clin. Microbiol. 44: 102-107 [Abstract] [Full Text]  
• Wu, J. H., Tsai, C. G. (2005). Infectivity of Hepatic Strain Klebsiella pneumoniae in Diabetic Mice. Exp. Biol. Med. 230: 757-761 [Abstract] [Full Text]  
• Struve, C., Bojer, M., Nielsen, E. M., Hansen, D. S., Krogfelt, K. A (2005). Investigation of the putative virulence gene magA in a worldwide collection of 495 Klebsiella isolates: magA is restricted to the gene cluster of Klebsiella pneumoniae capsule serotype K1. J Med Microbiol 54: 1111-1113 [Full Text]  
• Arco, Y., Llamas, I., Martinez-Checa, F., Argandona, M., Quesada, E., Moral, A. d. (2005). epsABCJ genes are involved in the biosynthesis of the exopolysaccharide mauran produced by Halomonas maura. Microbiology 151: 2841-2851 [Abstract] [Full Text]  
• Frirdich, E., Whitfield, C. (2005). Characterization of GlaKP, a UDP-Galacturonic Acid C4-Epimerase from Klebsiella pneumoniae with Extended Substrate Specificity. J. Bacteriol. 187: 4104-4115 [Abstract] [Full Text]  
• Fang, F. C., Sandler, N., Libby, S. J. (2005). Liver Abscess Caused by magA+ Klebsiella pneumoniae in North America. J. Clin. Microbiol. 43: 991-992 [Abstract] [Full Text]  

Home | Help | Feedback | Subscriptions | Archive | Search

TABLE OF CONTENTS