The ability to produce elastase was examined in 1 168 strains of 11 representative genera of Gram-negative non-fermenting bacteria isolated from weakened patients in the course of eight years. Detection of the elastase activity was performed parallelly using the conventional method and its pulverisation variant. The difference between the results accomplished by the classical method and its pulverisation variant (53.9% versus 60.5% detected elastase-positive strains) was highly significant (p < 0.05). Among the examined strains 500 (42.8%) displayed elastase activity. The highest proportion of the elastase positive strains was found in Pseudomonas aeruginosa (84.5%), P. fluorescens (60.5%), P. stutzeri (56.4%), Burkholderia cepacia (43.8%) and Shewanella putrefaciens (39.7%). Elastase activity detected in Burkholderia cepacia, Pseudomonas alcaligenes, P. mendocina, P. putida, P. stutzeri and in Shewanella putrefaciens is apparently described for the first time.

        Key words: elastase activity – Gram-negative non-fermenting bacteria – detection.