AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lehmacher, A.
Right arrow Articles by Bockemühl, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lehmacher, A.
Right arrow Articles by Bockemühl, J.
Agricola
Right arrow Articles by Lehmacher, A.
Right arrow Articles by Bockemühl, J.

 Previous Article  |  Next Article 

Appl Environ Microbiol, July 1998, p. 2449-2453, Vol. 64, No. 7
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Detection of Hemolysin Variants of Shiga Toxin-Producing Escherichia coli by PCR and Culture on VancomycinCefixime-Cefsulodin Blood Agar

Anselm Lehmacher,* Heidi Meier, Stojanka Aleksic, and Jochen Bockemühl

Hygiene Institute Hamburg, Division of Bacteriology, National Reference Centre for Enteric Pathogens, D-20539 Hamburg, Germany

Received 9 February 1998/Accepted 7 April 1998

The presence of a hemolysin-encoding gene, elyA or hlyA, from Shiga toxin-producing Escherichia coli (STEC) was detected by PCR in each of 95 strains tested. PCR products of elyA from human STEC isolates of serovars frequently detected in Germany, such as O157:H-, O103:H2, O103:H-, O26:H11, and O26:H-, showed nucleotide sequences identical to previously reported ones for O157:H7 and O111:H- strains. Compared to them, four elyA amplicons derived from human isolates of rare STEC serovars showed identity of about 98% but lacked an AluI restriction site. However, the nucleotide sequence of an amplicon derived from a porcine O138:K81:H- STEC strain was identical to the corresponding region of hlyA, encoding alpha-hemolysin, from E. coli. This hlyA amplicon showed 68% identity with the nucleotide sequence of the corresponding elyA fragment. It differed from the elyA PCR product in restriction fragments generated by AluI, EcoRI, and MluI. Of the 95 representative STEC strains, 88 produced hemolysin on blood agar supplemented with vancomycin (30 mg/liter), cefixime (20 µg/liter), and cefsulodin (3 mg/liter) (BVCC). The lowest added numbers of two to six STEC CFU per g of stool or per ml of raw milk were detectable on BVCC plates after seeding of the preenrichment broth, modified tryptic soy broth (mTSB) supplemented with novobiocin (10 mg/liter), with 16 STEC strains. These strains represented the seven prevailing serovars diagnosed from German patients. However, with ground-beef samples, PCR was essential to identify the lowest added numbers of two to six STEC CFU among colonies of hemolyzing Enterobacteriaceae, such as Serratia spp. and alpha-hemolysin-producing E. coli. We conclude that preenrichment of stool and food samples in mTSB for 6 h followed by overnight culturing on BVCC is a simple method for the isolation and presumptive identification of STEC.

* Corresponding author. Mailing address: Hygiene Institute Hamburg, Division of Bacteriology, Marckmannstr. 129a, D-20539 Hamburg, Germany. Phone: 49-40-78964270. Fax: 49-40-78964274. E-mail: hygiene.institut{at}hamburg.de.

Appl Environ Microbiol, July 1998, p. 2449-2453, Vol. 64, No. 7
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 1998 by the American Society for Microbiology. All rights reserved.