Presence of Enterohemorrhagic Escherichia coli ST678/O104:H4 in France Prior to 2011

Abstract

International audienceTwo isolates of enterohemorrhagic Escherichia coli (EHEC) O104:H4 were isolated in France in 2004 and 2009. Both were characterized and compared to the strain which caused the German outbreak in 2011 and to other O104:H4 strains. This suggests that different O104:H4 EHEC strains were present several years prior to the 2011 outbreak. From May to July 2011, a large-scale outbreak of enterohe-morrhagic Escherichia coli (EHEC) was observed in several European countries, mainly affecting northern Germany. Altogether , about 4,000 cases of EHEC infections and nearly 50 fatalities were reported (8). This outbreak also led to massive economic losses for farmers and to widespread public concern, after various vegetables and sprouts as well as a possible bio-terrorist attack were publicly discussed as possible sources of the infection. Recent epidemiological studies singled out imported fenugreek seeds, although this has not yet been substantiated by laboratory evidence (6). In order to understand the evolution and possibly the origin of the recent outbreak strain, it is of great interest to identify related or ancestral isolates. Only a few cases of infections caused by E. coli O104:H4 were described earlier than 2011. One was a case of hemolytic-uremic syndrome (HUS) from South Korea (1), but the causative strain appeared not to be closely related to the current European outbreak strain, differing in toxin carriage, resistance properties, and pulsed-field gel electrophoresis profiles (10). Another one originated from Italy in 2009 (18). A recently described and fully sequenced strain, HUSEC 41 isolate 01-0991, originated from a HUS case in Germany in 2001 (4, 11). Prior to the 2011 outbreak, E. coli O104:H4 was also detected in two isolated clinical cases in France. One patient was a 6-year-old male child from the Lyon area treated for HUS in 2009. He was hospitalized, treated with azithromycin, and cured. The other one was an adult male patient with hemor-rhagic colitis from the town of Lille, in northern France, in 2004. The clinical course and outcome are not known. Both isolates were characterized by microarray analysis using a previously described system (9), and they yielded identical hybri

Lability of the pAA Virulence Plasmid in Escherichia coli O104:H4: Implications for Virulence in Humans

“…The lability of pAA (and of its virulence loci) might reflect the rarity with which this particular pathogen has been identified in human disease before 2011 [2], [3], [8], [48], [49]. The influence of a loss of an important virulence locus on the pathogen’s virulence as demonstrated in our study for the EHEC O104:H4 2011 outbreak strain serves as a paradigm for a possible regulation of population-based virulence in other emerging pathogens.…”

Comparative Genomics of Recent Shiga Toxin-Producing Escherichia coli O104:H4: Short-Term Evolution of an Emerging Pathogen

“…This strain does not produce Shiga toxin; furthermore, 55989, like the Shiga toxin-producing 2001 German O104:H4 isolate 01-09591 (HUSEC041) (12), harbors plasmids conferring the enteroaggregative phenotype through a different set of fimbriae genes (AAF/III) (12). Additional O104:H4 isolates from 2004 and 2009 identified in France share with the 2011 outbreak strain the presence of an Stx2-encoding prophage but carry an AAF/III-containing plasmid like the one of 55989 (11, 19). While differences between the TY2482 and 55989 (17) genomes and TY2482 and 01-09591 genomes have been reported (14), comprehensive comparisons of the outbreak genome with additional O104:H4 isolates from other time points can lead to an improved understanding of the fine-scale evolution of this emerging pathogen’s genome over the very short term, as well as the ongoing gene flux mediated by mobile genetic elements (MGEs), including phages, plasmids, and transposons, all of which can carry pathogenicity factors.…”

2011 German Escherichia coli O104:H4 outbreak: whole-genome phylogeny without alignment

“…Recently, additional historical isolates of HUS-causing E. coli O104:H4 were characterized [18-20]. However, genome sequences of these isolates are not available.…”