Virulence determinants in Pseudomonas aeruginosa strains from urinary tract infections.
A total of 121 uropathogenic Pseudomonas aeruginosa strains were examined for production of several virulence-related factors. These strains were distributed in five predominant O-serotypes, i.e. O 4, O 12, O 11, O 6 and O 5, which accounted respectively for 23.9, 23.1, 12.3, 8.2 and 5.7% of isolates. Pyochelin and pyoverdin siderophores were produced by most of the isolates, defective variants occurring at very low frequency (2.4% for pyochelin and 7.4% for pyoverdin). Adherence to uroepithelial cells and production of cytotoxins was demonstrated in 52.8 and 67.7% of the strains, respectively, with higher frequencies for epidemiologically related strains belonging to serotypes O 4 and O 12. Titration of total proteases, elastase and phospholipase C revealed a high degree of heterogeneity among isolates. However, examination of individual O-serotypes by exoenzyme production showed that elevated levels of total proteases and elastase were characteristics of serotypes of minor numerical importance, i.e. O 1, O 10, O 11 and O 17, whilst low levels of elastase were produced by strains belonging to the predominant serotypes, namely O 4 and O 12. Moreover, epidemiologically related strains belonging to serotypes O 4 and O 12 appeared more homogeneous than the whole serogroup, when compared with other groups on the basis of exoenzyme levels.
Visca
P
P
Institute of Microbiology, Faculty of Medicine, University of Rome La Sapienza, Italy.
Chiarini
F
F
Mansi
A
A
Vetriani
C
C
Serino
L
L
Orsi
N
N
D001422:Bacterial Adhesion / Q000502:physiology; D003603:Cytotoxins / Q000096:biosynthesis; D006801:Humans; D007502:Iron Chelating Agents / Q000378:metabolism; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000378:metabolism / Q000472:pathogenicity*; D013045:Species Specificity; D014552:Urinary Tract Infections / Q000382:microbiology*; D014774:Virulence / Q000502:physiology
D003603:Cytotoxins; D007502:Iron Chelating Agents