Epidemiology of Pseudomonas aeruginosa in a Burns Hospital: Evaluation of Serological, Bacteriophage, and Pyocin Typing Methods

In a retrospective study 36 cultures of Pseudomonas aeruginosa , isolated from patients with fatal Pseudomonas burn wound sepsis and from burned patients with nonfatal P. aeruginosa infections, were used to evaluate the consistency and reliability of serological, phage, and pyocin typing as epidemiological tools. Frequency distributions of positive reactions were analyzed by a computer in a 3-way chi-square test, and a high degree of consistency was demonstrated for each method. From these data, 75% of the cultures were differentiated by serological, 90% by phage, and 100% by pyocin typing. There was no significant difference among organisms isolated from fatal cases of burn wound sepsis and organisms from patients with nonfatal infections (χ 2 = 0.3418; P = 0.9870). The combined typing system was a sensitive and reliable epidemiological tool for intraspecific differentiation of P. aeruginosa .