Characterization of a shiga toxin-, intimin-, and enterotoxin hemolysin-producing Escherichia coli ONT:H25 strain commonly isolated from healthy cattle.
Among bovine fecal and recto-anal mucosal swab samples cultured in our laboratory for Escherichia coli O157:H7, we frequently isolated E. coli organisms that were phenotypically similar to the O157:H7 serotype as non-sorbitol fermenting and negative for beta-glucuronidase activity but serotyped O nontypeable:H25 (ONT:H25). This study determined the prevalence and virulence properties of the E. coli ONT:H25 isolates. Among dairy and feedlot cattle (n = 170) sampled in Washington, Idaho, and Alberta, Canada, the percentage of animals culture positive for E. coli ONT:H25 ranged from 7.5% to 22.5%, compared to the prevalence of E. coli O157:H7 that ranged from 0% to 15%. A longitudinal 8-month study of dairy heifers (n = 40) showed that 0 to 15% of the heifers were culture positive for E. coli O157:H7, while 15 to 22.5% of the animals were culture positive for E. coli ONT:H25. As determined by a multiplex PCR, the E. coli ONT:H25 isolates carried a combination of virulence genes characteristic of the enterohemorrhagic E. coli, including intimin, translocated intimin receptor, Stx2, and hemolysin (eae-beta, tir, stx(2vh-a), and hly). E. coli ONT:H25 isolates from diverse geographic locations and over time were fingerprinted by separating XbaI-restricted chromosomal DNA by pulsed-field gel electrophoresis (PFGE) separation. Two strains of E. coli ONT:H25 were highly similar by PFGE pattern. Experimental inoculation of cattle showed that E. coli ONT:H25, like E. coli O157:H7, colonized the bovine recto-anal junction mucosa for more than 4 weeks following a single rectal application of bacteria.
Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844-3052, USA.
Haiqing
H
Sheng
Margaret A
MA
Davis
Hannah J
HJ
Knecht
Dale D
DD
Hancock
Joyce
J
Van Donkersgoed
Carolyn J
CJ
Hovde
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D001003:Anal Canal / Q000382:microbiology; D000818:Animals; D002417:Cattle / Q000382:microbiology*; D015169:Colony Count, Microbial; D004768:Enterotoxins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D019453:Escherichia coli O157 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism*; D012007:Rectum / Q000382:microbiology; D022621:Shiga Toxin / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
D018829:Adhesins, Bacterial; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; D037521:Virulence Factors; C073819:eaeA protein, E coli; D022621:Shiga Toxin