Characterization of Shiga-like toxin producing Escherichia coli (SLTEC) isolated from calves with and without diarrhoea.
To determine if shiga-like toxin producing Escherichia coli (SLTEC) are involved in neonatal calf diarrhoea, isolated E. coli strains from diarrhoeic and non-diarrhoeic calves were characterized for shiga-like toxin (SLT) by colony blot hybridization and cytotoxicity assays. None of 150 E. coli strains isolated from diarrhoeic calves in 1985-1988 was positive for SLT, while 7/232 (3.0%) isolated in 1989 were positive for SLT. In contrast, samples collected during 1989 and 1990 from diarrhoeic calves were 21.9% SLTEC positive, and samples from non-diarrhoeic calves were 12.9% SLTEC positive. SLT I positive E. coli strains were isolated more often from diseased (17.8%) than from healthy animals (5.0%), while SLT II positive E. coli were more often detected in non-diarrhoeic (8.9%) than in diarrhoeic calves (4.1%). The mean percentage of SLT I positive E. coli in the whole E. coli flora of the samples was significantly higher in diarrhoeic than in healthy animals, implying a pathogenic role of SLT I producing E. coli in neonatal calf diarrhoea. Enterohemolysin was produced by 70.8% of the SLT I producing E. coli strains examined. Determination of O- and K-antigens of SLT positive E. coli revealed a highly diverse spectrum of SLTEC O-groups in calves. While no E. coli isolate belonged to serotype O157:H7, classical human enteropathogenic E. coli O-groups (O26, O111, O128) were detected. These results support the theory that cattle serve as a reservoir for human SLTEC infection.
Institut für Hygiene und Infektionskrankheiten der Tiere, Justus-Liebig-Universität Giessen.
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Wieler
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Bauerfeind
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Baljer
D000818:Animals; D000831:Animals, Newborn; D000942:Antigens, Bacterial / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D001427:Bacterial Toxins / Q000096:biosynthesis; D001483:Base Sequence; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D002460:Cell Line; D003603:Cytotoxins / Q000096:biosynthesis*; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004926:Escherichia coli / Q000145:classification* / Q000276:immunology / Q000378:metabolism; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D006461:Hemolysis; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D019081:O Antigens; D011135:Polysaccharides, Bacterial / Q000032:analysis; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2
D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001427:Bacterial Toxins; D003603:Cytotoxins; C030659:K antigens; D019081:O Antigens; D011135:Polysaccharides, Bacterial; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2