Abstract
Twentynine strains of Pseudomonas aeruginosa were isolated from 2518 specimens from patients with oral infections and the following clinical diagnoses: periodontitis apicalis, necrosis pulpae, pulpitis and alveolitis maxillaris and mandibularis. All strains produced at least one haemolytic toxin and most of the following extracellular enzymes: lecithinase, protease, elastase, lipase and an esterase. The importance of these proteins for the development of tissue necrosis during infection is discussed. The antibiogram showed that most strains were sensitive to treatment with gentamicin, carbenicillin or streptomycin, but were resistant to several other antibiotics. The strains belonged to 9 different phage types and 15 strains were of the same serotype (Habs's group 1) which is remarkable, since Habs's group 6 is most frequently found among isolated strains from infections outside the oral cavity.