P-FIMBRIATION AND HEMOLYSIN PRODUCTION ARE THE MOST IMPORTANT VIRULENCE FACTORS IN DIABETIC-PATIENTS WITH ESCHERICHIA-COLI BACTEREMIA - A MULTIVARIATE STATISTICAL-ANALYSIS OF 7 BACTERIAL VIRULENCE FACTORS

Diabetic patients, as compared to non-diabetic subjects, run an increa sed risk of acquiring Gram-negative bacteraemia, We therefore studied the prevalence and coexpression of seven bacterial virulence, markers of 69 Escherichia coil strains isolated from 64 bacteraemic patients w ith diabetes mellitus and 67 E. coli strains from faeces of healthy co ntrols: The strains were analyzed for haemolysin (HLY) production, aer obactin-mediated iron uptake (AMI), cytotoxic necrotizing factor (CNF) production, expression of cell surface hydrophobicity, P-fimbriae, ma nnose-resistant haemagglutination (MRHA) and mannose-sensitive haemagg lutination (MSHA). All bacterial properties were significantly more co mmon among the bacteraemic strains (P<0.02 vs. controls). Correlations between HLY and CNF ( (P<0.0004) and between P-fimbriae and MRHA (P<0 .0001), MSHA (P<0.0002) or AMI (P<0.05), as well as between MRHA and M SHA (P<0.0005) were observed. In patients with proteinuria, as sign of diabetic complications in the urinary tract, HLY-negative strains, P- fimbriae-negative strains, and strains which were both HLY-/CNF-negati ve, were more common (P=0.04, P<0.01 and P=0.048, respectively). Using a multivariate statistical analysis, production of HLY and the expres sion of P-fimbriae were the two virulence factors with the highest dis crimination between bacteraemic and control strains. In conclusion, al l virulence factors studied were more prevalent in bacteraemic than in control strains, although HLY and P-fimbriae were shown to be of grea test and independent importance. Low virulent strains (P-fimbriae-, HL Y- and CNF-negative) were more prevalent in diabetic patients with sig ns of renal complications.