Prevalence of pyocin types of P. aeruginosa in a university hospital during 1981-1986

Strains of Pseudomonas aeruginosa isolated from patients in the University of Granada (Spain) from 1981 to 1986 were pyocin-typed in order to determine which types were the most common. The proportions of typable and non typable strains were similar to those obtained by other authors. A high percentage of typable strains were unclassifiable (UC) according to Govan's method. The most frequent types of typable strains were 580 (55 of Govan), 270 (UC), 280 (UC), 570 (UC), 670 (73 of Govan), 113 (10 of Govan), 470 (86 of Govan) and 180 (58 of Govan). These types were responsible for the appearance of several nosocomial outbreaks during the years of this study. Types 580, 113 and 280 remained constant for these six years; for this reason, they can be considered endemic of our hospital.