[Serum sensitivity of Pseudomonas aeruginosa isolated from sputum as a virulence factor in the lower respiratory tract].
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 x 10(7) 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 2-10 times higher than those of serum-resistant strain. The LPS profiles of two serum-resistant strains and one serum-sensitive strain showed ladder-like patterns. The similar analysis demonstrated that one serum-sensitive strain was lack of ladder-like 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.
Sonoda
F
F
Department of Internal Medicine, Nagasaki University, Japan.
Oishi
K
K
Tanaka
H
H
Hideaki
M
M
Kobayashi
S
S
Nagatake
T
T
Matsumoto
K
K
D000818:Animals; D005260:Female; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D051379:Mice; D011014:Pneumonia / Q000382:microbiology*; D011552:Pseudomonas Infections; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*; D012703:Serotyping; D013183:Sputum / Q000382:microbiology*; D014774:Virulence
D007106:Immune Sera