Isolation site influences virulence phenotype of serotype 14 Streptococcus pneumoniae strains belonging to multilocus sequence type 15

Amin, Z., Harvey, R. M., Wang, H., Hughes, C. E. , Paton, A. W., Paton, J. C. and Trappetti, C. (2015) Isolation site influences virulence phenotype of serotype 14 Streptococcus pneumoniae strains belonging to multilocus sequence type 15. Infection and Immunity, 83(12), pp. 4781-4790. (doi: 10.1128/IAI.01081-15) (PMID:26416904) (PMCID:PMC4645380)

Abstract

Streptococcus pneumoniae is a diverse species causing invasive as well as localized infections that result in massive global morbidity and mortality. Strains vary markedly in pathogenic potential, but the molecular basis is obscured by the diversity and plasticity of the pneumococcal genome. We have previously reported that S. pneumoniae serotype 3 isolates belonging to the same multilocus sequence type (MLST) differed markedly in in vitro and in vivo phenotypes, in accordance with the clinical site of isolation, suggesting stable niche adaptation within a clonal lineage. In the present study, we have extended our analysis to serotype 14 clinical isolates from cases of sepsis or otitis media that belong to the same MLST (ST15). In a murine intranasal challenge model, five ST15 isolates (three from blood and two from ears) colonized the nasopharynx to similar extents. However, blood and ear isolates exhibited significant differences in bacterial loads in other host niches (lungs, ear, and brain) at both 24 and 72 h postchallenge. In spite of these differences, blood and ear isolates were present in the lungs at similar levels at 6 h postchallenge, suggesting that early immune responses may underpin the distinct virulence phenotypes. Transcriptional analysis of lung tissue from mice infected for 6 h with blood isolates versus ear isolates revealed 8 differentially expressed genes. Two of these were exclusively expressed in response to infection with the ear isolate. These results suggest a link between the differential capacities to elicit early innate immune responses and the distinct virulence phenotypes of clonally related S. pneumoniae strains.

• Item Type: Articles
• Additional Information: This work was supported by Program Grants 565526 and 1071659 from the National Health and Medical Research Council of Australia (NHMRC). A.W.P. is an Australian Research Council (ARC) DORA Fellow; J.C.P. is a NHMRC Senior Principal Research Fellow; C.T. is an ARC DECRA Fellow.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hughes, Dr Catherine
• Authors: Amin, Z., Harvey, R. M., Wang, H., Hughes, C. E., Paton, A. W., Paton, J. C., and Trappetti, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Infection and Immunity
• Publisher: American Society for Microbiology
• ISSN: 0019-9567
• ISSN (Online): 1098-5522
• Published Online: 28 September 2015
• Copyright Holders: Copyright © 2015 American Society for Microbiology
• First Published: First published in Infection and Immunity 83(12):4781-4790
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher