Use of tellurite for the selection of verocytotoxigenic Escherichia coli O157.
Potassium tellurite was assessed for the selection of verocytotoxigenic (VT+) Escherichia coli O157. MICs were higher for VT+ E. coli O157 than for other strains of E. coli and for Aeromonas spp. MacConkey medium containing sorbitol, tellurite and cefixime (TC-SMAC) permitted the growth of VT+ E. coli O157 and Shigella sonnei but partially or completely inhibited the growth of 67% of other strains of E. coli and all or most strains of other sorbitol-non-fermenting species tested. Of 391 rectal swabs from cattle screened on TC-SMAC medium, 26 yielded isolates of VT+ E. coli O157 whereas sorbitol-MacConkey medium with cefixime and rhamnose yielded only nine isolates. Inclusion of potassium tellurite in sorbitol-MacConkey agar markedly increased the rate of isolation of VT+ E. coli O157 from cattle rectal swabs and may do so for other types of specimen.
Zadik
P M
PM
Public Health Laboratory, Sheffield.
Chapman
P A
PA
Siddons
C A
CA
D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis*; D002417:Cattle; D003470:Culture Media; D003603:Cytotoxins / Q000096:biosynthesis*; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D006801:Humans; D022622:Shiga Toxin 1; D013691:Tellurium / Q000494:pharmacology
D001427:Bacterial Toxins; D003470:Culture Media; D003603:Cytotoxins; D022622:Shiga Toxin 1; C026899:potassium tellurate(IV); D013691:Tellurium