Infection With Pseudomonas Cepacia In Chronic Granulomatous Disease: Role Of Nonoxidative Killing By Neutrophils In Host Defense

Abstract

Pseudomonas aeruginosa and Pseudomonas cepacia are catalase-producing bacteria, but only P. cepacia causes infections in patients with chronic granulomatous disease (CGO). The in vitro killing of P. aeruginosa and P. cepacia by polymorphonuclear leukocytes (PMNL) from patients with CGO and from healthy adults was assessed. Of 6 patients with CGO who developed severe infections with P. cepacia, 4 died. PMNL from the 2 survivors and 6 other patients with CGO killed P. aeruginosa strains efficiently and P. cepacia strains poorly. PMNL from 2 patients with autosomal recessive CGO and from 2 carriers for X-linked CGO killed P. cepacia intermediately between normal controls and patients with X-linked CGO. When superoxide anion and hydrogen peroxide were scavenged with superoxide dismutase and catalase, normal PMNL killed P. aeruginosa but not P. cepacia. Thus, P. cepacia, but not P. aeruginosa, is a pathogen in patients with CGO, because it resists neutrophil-mediated nonoxidative bactericidal effects.