Bacteriocin typing of Klebsiella spp. isolated from different sources

To evaluate whether clinical Klebsiella isolates differ from nonclinical strains with respect to bacteriocin susceptibility patterns, a total of 452 Klebsiella pneumoniae and K. oxytoca strains isolated from different sources were examined. Bacteriocin typing was done by a modification of the scrape-and-point method, using a set of eight producer strains. 96% of the strains were typable. Forty-one different bacteriocin susceptibility patterns were observed. While two thirds of the K. oxytoca isolates belonged to only three different bacteriocin types, the K. pneumoniae strains showed a more heterogeneous distribution of patterns. No differences in pattern distribution were observed between isolates from clinical, fecal, or environmental sources. Certain bacteriocins showed a very broad spectrum of activity; e.g. 93% of all isolates were susceptible to bacteriocin type 3. The results suggest that nonclinical Klebsiella strains do not show other bacteriocin susceptibility types than clinical isolates do.