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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROLLING EGG CONTAMINATION WITH SALMONELLA ENTERICA BY UNDERSTANDING ITS EVOLUTION AND PATHOBIOLOGY

Location: Egg Safety and Quality

Title: Nucleotide sequence of a predicted diguanylate cyclase unique to egg contaminating Salmonella enteritidis that does not form biofilm.

Authors
item Guard, Jean
item Morales, Cesar

Submitted to: Scientific and Technical Review
Publication Type: Popular Publication
Publication Acceptance Date: March 20, 2008
Publication Date: June 5, 2008
Citation: Bouldin, J.G., Morales, C. 2008. Nucleotide sequence of a predicted diguanylate cyclase unique to egg contaminating Salmonella enteritidis that does not form biofilm.. National Center for Biotechnology Information (NCBI). Available:http://www.ncbi.nlm.nih/entrez/viewer.fcgi?db=nuccore&id=170516891

Interpretive Summary: No summary required

Technical Abstract: This is a nucleotide sequence submitted as bankit1052494 and given the GenBank accession number EU375808A post-review. It will be released to the public in June 2008 in coordination with an ASM abstract presentation. A paper will also be submitted that refers to this accession number. A diguanylate cyclase of egg-contaminating Salmonella enterica serovar Enteritidis (S. enteritidis) that no longer formed biofilm was found by mutational mapping and confirmatory sequencing to have a 215bp deletion that encompassed 135bp of upstream sequence and the initial 80bp of coding sequence in the minus strand. The wildtype gene was similar to STM4551 of Salmonella typhimurium LT2 and was conserved throughout the Salmonellae. The deletion changed the predicted ORF, but it still appeared to be an intact gene because no ribosomal binding sites were disrupted. The wildtype ORF for the original diguanylate cyclase labeled as SEN4316 in the reference genome at the Sanger Institute (dgc1) of 1065bp was shortened to an ORF of 996 for dgc2 and 987 for dgc3 in S. enteritidis strain 21046 that retained egg contamination but lost biofilm. The near identical twin of strain 21046 that formed biofilm but could not contaminate eggs, namely S. enteritidis strain 21027, had the wildtype dgc1 sequence. Thus, the presence of this mutation is linked to loss of biofilm, but not to the loss of the ability to contaminate eggs. This mutation is an epidemiological marker of an unusual subpopulation of S. enteritidis that retains the ability to contaminate eggs but may be limited in its ability to initiate oral colonization and to survive in the environment.

Last Modified: 4/16/2014