Virulence gene profiles and intimin subtypes of Shiga toxin-producing Escherichia coli isolated from healthy and diarrhoeic calves.
The virulence properties of Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrhoeic and non-diarrhoeic calves were compared. The strains were also tested for O157:H7, O111 and O26 serotypes, using PCR and conventional serotyping methods. E coli strains isolated from 297 faecal samples, from 200 diarrhoeic and 97 non-diarrhoeic calves, were screened by multiplex PCR assay for the stx1, stx2, eae and Ehly virulence genes. STECs were recovered from 8 per cent of diarrhoeic calves and 10.3 per cent of non-diarrhoeic calves. The predominant virulence gene profile was stx1/eae/Ehly (47.3 per cent) among isolates from diarrhoeic calves and eae/Ehly (36.8 per cent) among isolates from non-diarrhoeic calves. Among three tested serogroups, the predominant serogroup was O26 (18.4 per cent), and O157:H7 was not detected. Intimin subtyping by restriction fragment length polymorphism analysis revealed only three intimin subtypes (β, γ and ). A significant difference was observed in the distribution of Int- between two groups. Int- was present in 50 per cent of the isolates from diarrhoeic calves and in 11.1 per cent of the isolates from non-diarrhoeic calves; this difference was statistically significant (P=0.01).
Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
M Askari
MA
Badouei
T Zahraei
TZ
Salehi
M Rabbani
MR
Khorasgani
H
H
Tadjbakhsh
G Nikbakht
GN
Brujeni
M G
MG
Nadalian
D000818:Animals; D000831:Animals, Newborn; D016022:Case-Control Studies; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D015169:Colony Count, Microbial / Q000662:veterinary; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D012703:Serotyping / Q000662:veterinary; D022603:Shiga Toxins / Q000235:genetics; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics*
D022603:Shiga Toxins; D037521:Virulence Factors