These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Dual function of pneumolysin in the early pathogenesis of murine pneumococcal pneumonia.
    Author: Rubins JB, Charboneau D, Paton JC, Mitchell TJ, Andrew PW, Janoff EN.
    Journal: J Clin Invest; 1995 Jan; 95(1):142-50. PubMed ID: 7814608.
    Abstract:
    Streptococcus pneumoniae is one of the most common etiologic agents of community-acquired pneumonia, particularly bacteremic pneumonia. Pneumolysin, a multifunctional cytotoxin, is a putative virulence factor for S. pneumoniae; however, a direct role for pneumolysin in the early pathogenesis of pneumococcal pneumonia has not been confirmed in vivo. We compared the growth of a pneumolysin-deficient (PLY[-]) type 2 S. pneumoniae strain with its isogenic wild-type strain (PLY[+]) after direct endotracheal instillation of bacteria into murine lungs. Compared with PLY(-) bacteria, infection with PLY(+) bacteria produced greater injury to the alveolar-capillary barrier, as assayed by albumin concentrations in alveolar lavage, and substantially greater numbers of PLY(+) bacteria were recovered in alveolar lavages and lung homogenates at 3 and 6 h after infection. The presence of pneumolysin also contributed to the development of bacteremia, which was detected at 3 h after intratracheal instillation of PLY(+) bacteria. The direct effects of pneumolysin on lung injury and on the ability of pneumococci to evade local lung defenses was confirmed by addition of purified recombinant pneumolysin to inocula of PLY(-) pneumococci, which promoted growth of PLY(-) bacteria in the lung to levels comparable to those seen with the PLY(+) strain. We further demonstrated the contributions of both the cytolytic and the complement-activating properties of pneumolysin on enhanced bacterial growth in murine lungs using genetically modified pneumolysin congeners and genetically complement-deficient mice. Thus, pneumolysin facilitates intraalveolar replication of pneumococci, penetration of bacteria from alveoli into the interstitium of the lung, and dissemination of pneumococci into the bloodstream during experimental pneumonia. Moreover, both the cytotoxic and the complement-activating activities of pneumolysin may contribute independently to the acute pulmonary injury and the high rates of bacteremia which characterize pneumococcal pneumonia.
    [Abstract] [Full Text] [Related] [New Search]