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 Mukherjee, A.
Right arrow Articles by Cebula, T. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mukherjee, A.
Right arrow Articles by Cebula, T. A.

 Previous Article  |  Next Article 

Journal of Bacteriology, March 2008, p. 1710-1717, Vol. 190, No. 5
0021-9193/08/$08.00+0     doi:10.1128/JB.01737-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Altered Utilization of N-Acetyl-D-Galactosamine by Escherichia coli O157:H7 from the 2006 Spinach Outbreak{triangledown}

Amit Mukherjee, Mark K. Mammel, J. Eugene LeClerc, and Thomas A. Cebula*

Division of Molecular Biology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, Maryland 20708

Received 30 October 2007/ Accepted 12 December 2007

In silico analyses of previously sequenced strains of Escherichia coli O157:H7, EDL933 and Sakai, localized the gene cluster for the utilization of N-acetyl-D-galactosamine (Aga) and D-galactosamine (Gam). This gene cluster encodes the Aga phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) and other catabolic enzymes responsible for transport and catabolism of Aga. As the complete coding sequences for enzyme IIA (EIIA)Aga/Gam, EIIBAga, EIICAga, and EIIDAga of the Aga PTS are present, E. coli O157:H7 strains normally are able to utilize Aga as a sole carbon source. The Gam PTS complex, in contrast, lacks EIICGam, and consequently, E. coli O157:H7 strains cannot utilize Gam. Phenotypic analyses of 120 independent isolates of E. coli O157:H7 from our culture collection revealed that the overwhelming majority (118/120) displayed the expected Aga+ Gam– phenotype. Yet, when 194 individual isolates, derived from a 2006 spinach-associated E. coli O157:H7 outbreak, were analyzed, all (194/194) displayed an Aga– Gam– phenotype. Comparison of aga/gam sequences from two spinach isolates with those of EDL933 and Sakai revealed a single nucleotide change (G:C->A:T) in the agaF gene in the spinach-associated isolates. The base substitution in agaF, which encodes EIIAAga/Gam of the PTS, changes a conserved glycine residue to serine (Gly91Ser). Pyrosequencing of this region showed that all spinach-associated E. coli O157:H7 isolates harbored this same G:C->A:T substitution. Notably, when agaF+ was cloned into an expression vector and transformed into six spinach isolates, all (6/6) were able to grow on Aga, thus demonstrating that the Gly91Ser substitution underlies the Aga– phenotype in these isolates.

* Corresponding author. Mailing address: Office of Applied Research and Safety Assessment, US FDA (HFS-25), 8301 Muirkirk Road, Laurel, MD 20708. Phone: (301) 210-6158. Fax: (301) 210-6093. E-mail: Thomas.Cebula{at}fda.hhs.gov

{triangledown} Published ahead of print on 21 December 2007.

Journal of Bacteriology, March 2008, p. 1710-1717, Vol. 190, No. 5
0021-9193/08/$08.00+0     doi:10.1128/JB.01737-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Biondi, E. G., Tatti, E., Comparini, D., Giuntini, E., Mocali, S., Giovannetti, L., Bazzicalupo, M., Mengoni, A., Viti, C. (2009). Metabolic Capacity of Sinorhizobium (Ensifer) meliloti Strains as Determined by Phenotype MicroArray Analysis. Appl. Environ. Microbiol. 75: 5396-5404 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»