Shiga Toxin 2f-Producing <i>Escherichia albertii</i> from a Symptomatic Human

Abstract

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...

Isolation of <i>Escherichia albertii</i> from Raw Chicken Liver in Fukuoka City, Japan

“…FCI-ALB001 strain was non-motile, indole-positive, lysine-and ornithine decarboxylases-positive, lactose-negative (but ONPG test [b-galactosidase]-positive), b-D-glucuronidase (MUG test)-negative and sucrose-and D-xylosenegative. These genetic and biochemical properties corresponded to features of E. albertii (3,5,10), and those biochemical properties were consistent to the strain isolated in the Fukuoka Prefecture (10). We therefore identified FCI-ALB001 strain as E. albertii.…”

Multiplex polymerase chain reaction for identification of Escherichia coli , Escherichia albertii and Escherichia fergusonii

“…and software tools allowed us to successfully generate primers to differentiate these species. Traditional PCRs for E. albertii targeting only a few genes ( clpX , lysP and mdh ) were based on the analysis of a limited number of isolates and were unable to detect all E. albertii (Hyma, Lacher et al 2005, Murakami, Etoh et al 2014, Lindsey, Fedorka-Cray et al 2015). The sequences used to design primers for E. albertii in this study included human and previously published chicken isolates (Lindsey, Fedorka-Cray et al 2015).…”

“…E. albertii frequently carries the intimin gene causing it to be mistakenly identified as enteropathogenic E. coli (EPEC) or enterohemorrhagic E. coli (EHEC) (Ooka et al, 2012). E. albertii can carry Shiga toxin 2f gene ( stx2f ) which is associated with mild clinical symptoms (Friesema et al, 2014; Murakami et al, 2014; Ooka et al, 2012). E. fergusonii is a sporadic human pathogen responsible for urinary tract infections, wound infections, and diarrhea (Gaastra et al, 2014).…”

“…A PCR that detects the uidA gene (encoding the b–glucuronidase enzyme) is frequently used to identify E. coli (Bej et al, 1991, (Frahm and Obst, 2003), Pavlovic et al, 2010). Traditionally, E. albertii was detected with a multiplex PCR for the presence of clpX, lysP , and mdh genes but this does not detect all E. albertii (Hyma et al, 2005, Murakami et al, 2014, Lindsey et al, 2015). Recently, Ooka et al developed a nested PCR to detect E. albertii (Ooka et al, 2015); however, this assay does not detect additional Escherichia species.…”

“…Recently, Ooka et al developed a nested PCR to detect E. albertii (Ooka et al, 2015); however, this assay does not detect additional Escherichia species. There are also rpoB gene sequencing based methods or multi locus sequencing of whole genome sequence (WGS), but these methods are time consuming and take days to complete (Hyma et al, 2005, Murakami et al, 2014, Lindsey et al, 2015). The wealth of WGS data provides an opportunity to develop a much needed multiplex polymerase chain reaction (PCR) assay to quickly speciate the common Escherichia species in a single reaction.…”