DETECTION OF PAP, SFA AND AFA ADHESIN-ENCODING OPERONS IN UROPATHOGENIC ESCHERICHIA-COLI STRAINS - RELATIONSHIP WITH EXPRESSION OF ADHESINSAND PRODUCTION OF TOXINS

A total of 243 Escherichia coli strains isolated from patients with ur inary tract infections (UTI) were investigated for the presence of pap , sfa and afa adhesin-encoding operons by using the polymerase chain r eaction. It was found that 54%, 53% and 2% of the strains exhibited th e pap, sfa and afa genotypes, respectively. Pap(+) and/or sfa(+) strai ns were more frequent in cases of acute pyelonephritis (94%) than in c ases of cystitis (67%) (P < 0.001) and asymptomatic bacteriuria (57%) (P < 0.001). The pap and/or sfa operons were found in 90% of strains e xpressing mannose-resistant haemagglutination (MRHA) versus 37% of MRH A-negative strains (P < 0.001). The presence of pap and sfa operons wa s especially significant in strains belonging to MRHA types III (100%) (without P adhesins) and IVa (97%) (expressing the specific Gal-Gal b inding typical of P adhesins). Both pap and sfa operons were closely a ssociated with toxigenic E. coli producing alpha-haemolysin (Hly(+)) a nd/or the cytotoxic necrotizing factor type 1. There was an apparent c orrelation between the pap and sfa operons and the O serogroups of the strains. Thus, 93% of strains belonging to O1, O2, O4, O8, O7, O14, O 15, O18, O22, O75 and O83 possessed pap and/or sfa operons, versus onl y 32% of strains belonging to other serogroups (P < 0.001). The result s obtained in this study confirm the usefulness of our MRHA typing sys tem for presumptive identification of pathogenic E. coli exhibiting di fferent virulence factors. Thus, 85% of strains that possessed both pa p and sfa adhesin-encoding operons showed MRHA types III or IVa previo usly associated with virulence of E. coli Strains that cause UTI and b acteraemia.