Correlation between serogroup, in vitro biofilm formation and elaboration of virulence factors by uropathogenic Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the leading causes of catheter-associated urinary tract infections (UTIs), associated with high mortality and morbidity. In this study, 50 P. aeruginosa isolates from urine of patients with UTIs were serotyped according to the international antigenic typing system. The majority of the isolates (34%) belonged to serogroup O11, whereas 22%, 10%, 8%, 8%, 6%, 6%, 4% and 2% strains belonged to serogroups OII, O6, O1, O8, O7/8, O3, O4 and O15, respectively. Uroisolates belonging to serogroup O11 were strong biofilm producers, whereas serogroup O6 were weak biofilm producers. O11 serogroup uroisolates also showed increased adhesion to uroepithelium and elaborated higher levels of all the virulence factors. A strong correlation between serotype, in vitro biofilm formation and elaboration of virulence factors was observed. The data suggest that differences in virulence potential according to serotype should be taken into account to design effective preventive strategies against P. aeruginosa-induced UTIs.