We investigated a case of hepatitis E acquired after persons ate wild boar meat. Genotype 3 hepatitis E virus (HEV) RNA was detected in both patient serum and wild boar meat. These findings provided direct evidence of zoonotic foodborne transmission of HEV from a wild boar to a human.
Discriminating Escherichia albertii from other Enterobacteriaceae is difficult. Systematic analyses showed that E. albertii represents a substantial portion of strains currently identified as eae-positive Escherichia coli and includes Shiga toxin 2f–producing strains. Because E. albertii possesses the eae gene, many strains might have been misidentified as enterohemorrhagic or enteropathogenic E. coli.
Phages and plasmids play important roles in bacterial evolution and diversification. Although many draft genomes have been generated, phage and plasmid genomes are usually fragmented, limiting our understanding of their dynamics. Here, we performed a systematic analysis of 239 draft genomes and 7 complete genomes of Shiga toxin (Stx)-producing Escherichia coli O145:H28, the major virulence factors of which are encoded by prophages (PPs) or plasmids. The results indicated that PPs are more stably maintained than plasmids. A set of ancestrally acquired PPs was well conserved, while various PPs, including Stx phages, were acquired by multiple sublineages. In contrast, gains and losses of a wide range of plasmids have frequently occurred across the O145:H28 lineage, and only the virulence plasmid was well conserved. The different dynamics of PPs and plasmids have differentially impacted the pangenome of O145:H28, with high proportions of PP- and plasmid-associated genes in the variably present and rare gene fractions, respectively. The dynamics of PPs and plasmids have also strongly impacted virulence gene repertoires, such as the highly variable distribution of stx genes and the high conservation of a set of type III secretion effectors, which probably represents the core effectors of O145:H28 and the genes on the virulence plasmid in the entire O145:H28 population. These results provide detailed insights into the dynamics of PPs and plasmids, and show the application of genomic analyses using a large set of draft genomes and appropriately selected complete genomes.
EHEC O157:H7 clade 6 strains harboring stx2a and/or stx2c and clade 8 strains harboring stx2a or stx2a/stx2c were frequently associated with childhood HUS cases in Japan. Rapid and specific detection of such lineages are required for infection control measures.
SUMMARY:The previously identified Shiga toxin (Stx) 2f-producing Escherichia coli O115:HNM strain F08/101-31, isolated from a symptomatic human, was confirmed to be E. albertii in the present study by whole genome DNA-DNA hybridizations, by sequencing (cpn60, dnaJ, and 16S rRNA genes), and by multi-locus sequence typing. The F08/101-31 strain was originally identified as E. coli rather than the relatively new bacterial species E. albertii, which was first described in 2003, because it did not display any of the biochemical characteristics of E. albertii. This new classification will impact public health management strategies in Japan because the present study showed that some E. albertii strains, which are often misidentified as E. coli, produce Stx and likely cause diarrhea in humans. Therefore, further guidelines for the management and identification of Stx-producing E. albertii are required in Japan.The discovery of Shiga toxin (Stx)-producing Escherichia albertii strains was significant from a public health perspective in Japan (1). E. albertii was first described by Huys et al. in 2003 (2). This newly described enteropathogen is often misidentified as E. coli (3) or other members of the family Enterobacteriaceae because of its poorly defined biochemical characteristics and general obscurity. In addition, E. albertii closely resembles E. coli in its phenotypic characteristics. Retention of the major virulence factor intimin in E. albertii is well established (4,5), whereas little is known about the incidence of Stx-producing E. albertii (1). Stxs are the most significant virulence factors of Stx-producing E. coli (STEC) in human infections. However, STEC strains that produce intimin, a host-cell adhesin, often cause more critical symptoms in patients than STEC strains that do not produce intimin (6). Therefore, the misidentification of Stx-producing E. albertii strains that also produce intimin as E. coli may complicate public health monitoring strategies in many countries.The F08/101-31 strain, which was previously reported as Stx2f-producing E. coli O115:HNM harboring eae (7), was recently inferred to be an Stx2f-producing E. albertii strain on the basis of species-specific polymerase chain reaction (PCR) analysis (4,8). Therefore, in the present study, we attempted to definitively determine whether the strain is an E. albertii isolate by whole-genome DNA-DNA hybridization and DNA sequencing techniques. The purpose of this study was to describe the characteristics of the E. albertii strain for the benefit of public health.For genetic analysis, species-specific PCR analysis, whole-genome DNA-DNA hybridization, sequence analysis (16S rRNA genes, cpn60 (groEL), and dnaJ), and multi-locus sequence typing (MLST) were performed. The F08/101-31 strain was examined by species-specific PCR, as described previously, for the presence of E. albertii-specific sequences within lysP and mdh (4) and for E. coli, Shigella, and E. albertii/S. boydii lineage-detecting alleles of clpX (4,8). Whole-genome DNA-DNA hybridization...
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