The use of novobiocin and cefixime-tellurite in broth, and of cefixime-tellurite, salicin, rhamnose and MUG in agar medium for the detection of Escherichia coli O157:H7 in ground beef

Gülmez M., Baz E., Güven A.

Turkish Journal of Veterinary and Animal Sciences, vol.28, no.4, pp.753-759, 2004 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 28 Issue: 4
  • Publication Date: 2004
  • Journal Name: Turkish Journal of Veterinary and Animal Sciences
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.753-759
  • Kayseri University Affiliated: No


We aimed to improve the selectivity of lauryl tryptose (LST) broth and HC (hemorrhagic colitis Escherichia coli strains) agar for the detection of E. coli O157:H7 in frozen ground beef samples. The selectivity of LST broth was superior to that of LST containing novobiocin (20 mg/l) (LST + n), but LST containing novobiocin, cefixime (0.05 mg/l) and tellurite (2.5 mg/l) (LST + nct) was found to be unsuitable as an enrichment medium. The sorbitol positive strains were significantly more resistant to novobiocin than were the sorbitol negative strains (P < 0.05). As a result, the enrichment of ground beef samples in a selective broth without antibiotics such as LST, and then spread plating a subsequent amount from this original enrichment culture and the first three 10-fold serial dilutions onto a rhamnose and sorbitol based selective medium such as cefixime-tellurite HC medium (CTR-HC) was found to be recommendable as a routine cultural method. Transferring the metallic sheen property of eosin methylene blue (EMB) agar to CTR-HC agar can represent an alternative to the available media, and this will shorten the analysis time by 1 day. Use of salicine or 4-methylumbelliferyl-b-D glucuronide appears unnecessary in routine cultural techniques.