Transcriptional analysis of the Escherichia coli ColV-Ia plasmid pS88 during growth in human serum and urine

BMC Microbiology

Research Article

Philippe Bidet¹  Stéphane Bonacorsi¹  Chloé Lemaître¹  Edouard Bingen¹ 

[1]Univ Paris Diderot, Sorbonne Paris Cité, EA 3105, F-75205, Paris, France

[2]AP-HP, Laboratoire de Microbiologie, Hôpital Robert-Debré, F-75019, Paris, France

关键词: Escherichia coli;    Plasmid;    Transcriptome;    RNA;    Virulence;    Iron;    Siderophore;   

DOI  :  10.1186/1471-2180-12-115

 received in 2012-02-09, accepted in 2012-06-07,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe sequenced O45:K1:H7 Escherichia coli meningitis strain S88 harbors a large virulence plasmid. To identify possible genetic determinants of pS88 virulence, we examined the transcriptomes of 88 plasmidic ORFs corresponding to known and putative virulence genes, and 35 ORFs of unknown function.ResultsQuantification of plasmidic transcripts was obtained by quantitative real-time reverse transcription of extracted RNA, normalized on three housekeeping genes. The transcriptome of E. coli strain S88 grown in human serum and urine ex vivo were compared to that obtained during growth in Luria Bertani broth, with and without iron depletion. We also analyzed the transcriptome of a pS88-like plasmid recovered from a neonate with urinary tract infection. The transcriptome obtained after ex vivo growth in serum and urine was very similar to those obtained in iron-depleted LB broth. Genes encoding iron acquisition systems were strongly upregulated. ShiF and ORF 123, two ORFs encoding protein with hypothetical function and physically linked to aerobactin and salmochelin loci, respectively, were also highly expressed in iron-depleted conditions and may correspond to ancillary iron acquisition genes. Four ORFs were induced ex vivo, independently of the iron concentration. Other putative virulence genes such as iss, etsC, ompTp and hlyF were not upregulated in any of the conditions studied. Transcriptome analysis of the pS88-like plasmid recovered in vivo showed a similar pattern of induction but at much higher levels.ConclusionWe identify new pS88 genes potentially involved in the growth of E. coli meningitis strain S88 in human serum and urine.

【 授权许可】

Unknown   
© Lemaitre et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.