Serum sensitivity of Pseudomonas aeruginosa isolated from sputum as a virulence factor in the lower respiratory tract
Sonoda, F.; Oishi, K.; Tanaka, H.; Hideaki, M.; Kobayashi, S.; Nagatake, T.; Matsumoto, K.
Nihon Kyobu Shikkan Gakkai Zasshi 29(6): 703-709
1991
ISSN/ISBN: 0301-1542 PMID: 1910122 Document Number: 369512
To elucidate the clinical significance of serum-sensitivity of respiratory pathogenic Pseudomonas aeruginosa (P. aeruginosa) strains, we examined serum-sensitivity of P. aeruginosa isolated from 16 patients with lower respiratory tract infections and clinical backgrounds of these patients. We also evaluated the virulence of four serum-resistant and four serum-sensitive P. aeruginosa strains in murine pneumonia model induced by intratracheal challenge, and the silver-stained profiles of purified lipopolysaccharide (LPS) from these strains. Serum-sensitive strains were isolated only from patients with chronic bronchitis, bronchiectasis, and diffuse panbronchiolitis colonized with P. aeruginosa, and rarely caused pneumonias, while serum-resistant strains caused pneumonias in some cases. Intratracheal challenge of mice with 5 .times. 107 cfu per mouse of a serum resistant strain caused fatal hemorrhagic pneumonia with bacteremia. In contrast, the same dose of a serum-sensitive strain provided non-fatal pneumonia without bacteremia. LD50 of serum-sensitive strains in a murine model of P. aeruginosa pneumonia were at least 2 .apprx. 10 times higher than those of serum-resistant strain. The LPS profiles of two serum-resistant strains and one serum-sensitive strain showed ladderlike patterns. The similar analysis demonstrated that one serum-sensitive strain was lack of ladderlike patterns. These data support that serum-sensitive P. aeruginosa strains are less virulent than serum-resistant P. aeruginosa strains in the lower respiratory tract, and serum sensitivity of P. aeruginosa strains is determined by the structure of the O-side chain of LPS; either lack of the O-side chain or the presence of sparse O-side chain.