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Comparative genomic analysis of two novel sporadic Shiga toxin-producing Escherichia coli O104:H4 strains isolated 2011 in Germany.

Tietze E, Dabrowski PW, Prager R, Radonic A, Fruth A, Auraß P, Nitsche A, Mielke M, Flieger A - PLoS ONE (2015)

Bottom Line: A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths.They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods.These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, Division of Enteropathogenic Bacteria and Legionella, National Reference Centre for Salmonella and other Bacterial Enteric Pathogens, Wernigerode Branch of Robert Koch-Institute, Berlin, Germany.

ABSTRACT
A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths. The pathogen was an uncommon, multiresistant Escherichia coli strain of serotype O104:H4 which expressed a Shiga toxin characteristic of enterohemorrhagic E. coli and in addition virulence factors common to enteroaggregative E. coli. During post-epidemic surveillance of Shiga toxin-producing E. coli (STEC) all but two of O104:H4 isolates were indistinguishable from the epidemic strain. Here we describe two novel STEC O104:H4 strains isolated in close spatiotemporal proximity to the outbreak which show a virulence gene panel, a Shiga toxin-mediated cytotoxicity towards Vero cells and aggregative adherence to Hep-2 cells comparable to the outbreak strain. They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods. Whole genome sequencing of these two strains, of ten outbreak strain isolates originating from different time points of the outbreak and of one historical sporadic EHEC O104:H4 isolate was performed. Sequence analysis revealed a clear phylogenetic distance between the two variant strains and the outbreak strain finally identifying them as epidemiologically unrelated isolates from sporadic cases. These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements. Our results do also support the view that distinct new variants of STEC O104:H4 repeatedly might originate from yet unknown reservoirs, rather than that there would be a continuous diversification of a single epidemic strain established and circulating in Germany after the large outbreak in 2011.

No MeSH data available.


Related in: MedlinePlus

The two sporadic STEC O104:H4 strains 11–06681 and 11–07153 and the outbreak strain isolate 11–02027 show comparable levels of toxicity towards Vero cells.EHEC EDL933 served as a positive control and E. coli K12 C600 as a negative control. Toxicity of strain EDL933 as a quantitative reference was set to 100%. Shown are mean values of three independent experiments, each performed in triplicates. Bars represent means and standard deviation of three experiments. No significant difference in cytotoxicity of the STEC strains was observed.
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pone.0122074.g003: The two sporadic STEC O104:H4 strains 11–06681 and 11–07153 and the outbreak strain isolate 11–02027 show comparable levels of toxicity towards Vero cells.EHEC EDL933 served as a positive control and E. coli K12 C600 as a negative control. Toxicity of strain EDL933 as a quantitative reference was set to 100%. Shown are mean values of three independent experiments, each performed in triplicates. Bars represent means and standard deviation of three experiments. No significant difference in cytotoxicity of the STEC strains was observed.

Mentions: We compared the toxicity of Stx released by the two sporadic isolates, by the outbreak strain, and by the EHEC O157:H7 strain EDL933. A quantitatively comparable level of toxicity towards Vero cells was detectable for all of the STEC strains (Fig 3). Furthermore, the sporadic strains showed the same stacked brick-like aggregative adherence pattern type as the outbreak strain which is characteristic for EAEC (Fig 4).


Comparative genomic analysis of two novel sporadic Shiga toxin-producing Escherichia coli O104:H4 strains isolated 2011 in Germany.

Tietze E, Dabrowski PW, Prager R, Radonic A, Fruth A, Auraß P, Nitsche A, Mielke M, Flieger A - PLoS ONE (2015)

The two sporadic STEC O104:H4 strains 11–06681 and 11–07153 and the outbreak strain isolate 11–02027 show comparable levels of toxicity towards Vero cells.EHEC EDL933 served as a positive control and E. coli K12 C600 as a negative control. Toxicity of strain EDL933 as a quantitative reference was set to 100%. Shown are mean values of three independent experiments, each performed in triplicates. Bars represent means and standard deviation of three experiments. No significant difference in cytotoxicity of the STEC strains was observed.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383531&req=5

pone.0122074.g003: The two sporadic STEC O104:H4 strains 11–06681 and 11–07153 and the outbreak strain isolate 11–02027 show comparable levels of toxicity towards Vero cells.EHEC EDL933 served as a positive control and E. coli K12 C600 as a negative control. Toxicity of strain EDL933 as a quantitative reference was set to 100%. Shown are mean values of three independent experiments, each performed in triplicates. Bars represent means and standard deviation of three experiments. No significant difference in cytotoxicity of the STEC strains was observed.
Mentions: We compared the toxicity of Stx released by the two sporadic isolates, by the outbreak strain, and by the EHEC O157:H7 strain EDL933. A quantitatively comparable level of toxicity towards Vero cells was detectable for all of the STEC strains (Fig 3). Furthermore, the sporadic strains showed the same stacked brick-like aggregative adherence pattern type as the outbreak strain which is characteristic for EAEC (Fig 4).

Bottom Line: A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths.They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods.These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, Division of Enteropathogenic Bacteria and Legionella, National Reference Centre for Salmonella and other Bacterial Enteric Pathogens, Wernigerode Branch of Robert Koch-Institute, Berlin, Germany.

ABSTRACT
A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths. The pathogen was an uncommon, multiresistant Escherichia coli strain of serotype O104:H4 which expressed a Shiga toxin characteristic of enterohemorrhagic E. coli and in addition virulence factors common to enteroaggregative E. coli. During post-epidemic surveillance of Shiga toxin-producing E. coli (STEC) all but two of O104:H4 isolates were indistinguishable from the epidemic strain. Here we describe two novel STEC O104:H4 strains isolated in close spatiotemporal proximity to the outbreak which show a virulence gene panel, a Shiga toxin-mediated cytotoxicity towards Vero cells and aggregative adherence to Hep-2 cells comparable to the outbreak strain. They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods. Whole genome sequencing of these two strains, of ten outbreak strain isolates originating from different time points of the outbreak and of one historical sporadic EHEC O104:H4 isolate was performed. Sequence analysis revealed a clear phylogenetic distance between the two variant strains and the outbreak strain finally identifying them as epidemiologically unrelated isolates from sporadic cases. These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements. Our results do also support the view that distinct new variants of STEC O104:H4 repeatedly might originate from yet unknown reservoirs, rather than that there would be a continuous diversification of a single epidemic strain established and circulating in Germany after the large outbreak in 2011.

No MeSH data available.


Related in: MedlinePlus