Streptococcus pneumoniae potently induces cell death in mesothelial cells

• DOI: 10.1371/journal.pone.0201530
• Publication Date: 2018-07-30T17:33:53Z
• Authors: Rabab Rashwan; Julius F. Varano ...; Sally M. Lansley; Hui Min Cheah; Natalia Popowicz; James C. Paton; Grant W. Waterer; Tiffany Townsend; Ian Kay; Jeremy S. Brown; Y. C. Gary Lee
• Keywords: Pneumolysin

Pleural infection/empyema is common and its incidence continues to rise. Streptococcus pneumoniae the commonest bacterial cause of empyema in children among adults. The mesothelium represents first line defense against invading microorganisms, but mesothelial cell responses pathogens, including S. pneumoniae, have seldom been studied. We assessed viability vitro following exposure pathogens. Clinical isolates from 25 patients with invasive pneumococcal disease three reference strains were tested. All potently induced death cultured cells (MeT-5A) a dose- time-dependent manner (>90% at 107 CFU/mL after 24 hours). No significant killing was observed when co-cultured Staphylococcus aureus, sanguinis milleri group bacteria. via secretory product(s) as cytotoxicity could be: i) reproduced using conditioned media derived ii) transwell studies bacteria separated. excess seen heat-killed used. Pneumolysin, cytolytic toxin, time- dose-dependent manner. lacking pneumolysin gene (D39 ΔPLY strain) failed kill compared wild type (D39) controls, confirming necessity D39-induced death. However, mutation other (TIGR4, ST3 ST23F) only partly abolished their cytotoxic effects, suggesting different may induce mechanisms.