Toxin production and haemagglutination in strains of Escherichia coli from diarrhoea in Brescia, Italy.
Two hundred and ninety-nine different strains of Escherichia coli, isolated from 172 patients with diarrhoea and 113 healthy subjects, were examined for enterotoxin, cytotoxin and haemolysin (Hly) production and for mannose-resistant haemagglutination (MRHA) and invasive properties. Three strains proved enterotoxigenic, none enteroinvasive; cytotoxin and Hly production was shown in 25 strains from patients and in 3 from controls. Ten strains produced the cytotoxic necrotizing factor (CNF), 6 released other factors which kill cell cultures. Hly production was shown in 21 strains, 9 of which were also positive for CNF. MRHA was detected in 26% of strains from diarrhoea compared with 14% of strains from healthy people. A strong association between toxin production and MRHA was demonstrated. Serotyping results showed that the strains exhibiting virulence traits mostly belonged to serogroups commonly involved in extra-intestinal infections. The possible role of strains of E. coli showing one or more virulence factors as opportunistic pathogens in diarrhoeal diseases is discussed.
D000268:Adhesiveness; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003603:Cytotoxins / Q000096:biosynthesis; D003967:Diarrhea / Q000382:microbiology*; D004768:Enterotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000145:classification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D006388:Hemagglutinins / Q000096:biosynthesis; D006460:Hemolysin Proteins / Q000096:biosynthesis; D006801:Humans; D007223:Infant; D012475:Salmonella / Q000302:isolation & purification; D012703:Serotyping
D003603:Cytotoxins; D004768:Enterotoxins; D006388:Hemagglutinins; D006460:Hemolysin Proteins