Spread of a Distinct Stx2-Encoding Phage Prototype among Escherichia coli O104:H4 Strains from Outbreaks in Germany, Norway, and Georgia

Abstract

Shiga toxin 2 (Stx2)-producing Escherichia coli (STEC) O104:H4 caused one of the world's largest outbreaks of hemorrhagic colitis and hemolytic uremic syndrome in Germany in 2011. These strains have evolved from enteroaggregative E. coli (EAEC) by the acquisition of the Stx2 genes and have been designated enteroaggregative hemorrhagic E. coli . Nucleotide sequencing has shown that the Stx2 gene is carried by prophages integrated into the chromosome of STEC O104:H4. We studied the properties of Stx2-encoding bacteriophages which are responsible for the emergence of this new type of E. coli pathogen. For this, we analyzed Stx bacteriophages from STEC O104:H4 strains from Germany (in 2001 and 2011), Norway (2006), and the Republic of Georgia (2009). Viable Stx2-encoding bacteriophages could be isolated from all STEC strains except for the Norwegian strain. The Stx2 phages formed lysogens on E. coli K-12 by integration into the wrbA locus, resulting in Stx2 production. The nucleotide sequence of the Stx2 phage P13374 of a German STEC O104:H4 outbreak was determined. From the bioinformatic analyses of the prophage sequence of 60,894 bp, 79 open reading frames were inferred. Interestingly, the Stx2 phages from the German 2001 and 2011 outbreak strains were found to be identical and closely related to the Stx2 phages from the Georgian 2009 isolates. Major proteins of the virion particles were analyzed by mass spectrometry. Stx2 production in STEC O104:H4 strains was inducible by mitomycin C and was compared to Stx2 production of E. coli K-12 lysogens.

Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

“…We found that the sequence of phage Phi-191 was about 90% homologous to that of TL-2011c (data not shown), similarly to how reported for the phage P13374, present in the EAHEC O104:H4 that caused the German outbreak in 2011 (Beutin et al, 2012). Additionally, in the Phi-C125-06 an IS 1203 was detected in the gene encoding the B subunit of the Stx.…”

“…This is hold true for EAggEC, which beside the German outbreak have been described as being associated with HUS at least in other two outbreaks occurred in the 90s in France (Morabito et al, 1998) and in 2013 in Italy (unpublished) as well as in some unrelated cases recorded in Europe and Asia in the period 2000–2012 (Iyoda et al, 2000; Scavia et al, 2011; Beutin et al, 2012; Dallman et al, 2012). …”

Immunization with a Chimera Consisting of the B Subunit of Shiga Toxin Type 2 and Brucella Lumazine Synthase Confers Total Protection against Shiga Toxins in Mice

“…Abs able to block binding to the specific receptor (Gb3Cer) in mammalian cells should prevent the first step of the toxicity cascade (45). In addition, an Stx-based vaccine against HUS would not only protect against known EHEC strains, typically O157 and non-O157 serotypes, it would also be useful against new or rare pathogenic strains of Stx-producing E. coli, such as the recent large outbreak of HUS caused by the O104:H4 strain (46,47).…”

Virulence Gene Profiles and Clonal Relationships of Escherichia coli O26:H11 Isolates from Feedlot Cattle as Determined by Whole-Genome Sequencing

“…The strain was isolated prior to the E. coli O104:H4 strain that caused a large outbreak in Germany in 2011 (33). The O104:H4 strain was characterized as a new pathotype or atypical E. coli, being phylogenetically close to enteroaggregative E. coli (EAEC) and carrying virulence genes often observed in those strains, but carrying a stx 2a phage, as well (34,35). These O104:H4 strains caused a large number of disease cases, with 22.3% of the patients developing HUS (36).…”