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.

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.

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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...

Intestinal microbiota is a complex ecosystem and is mainly dominated by approximately 10 11 obligate anaerobic bacteria (such as the genus Bacteroides and Clostridium) per gram.1) It is said that culturable bacteria compose a fecal flora of only 20-30% despite the progression of the cultivation technology. 2,3) In order to understand a relationship between physical condition of host human and intestinal microbiota, many kinds of culture independent methods such as fluorescent in situ hybridization (FISH), terminal restriction fragment length polymorphism (T-RFLP), and clone library method have recently been conducted. 1,[4][5][6] Moreover, large scale and time-consuming molecular analysis like metaHIT using pyrosequencing method has been performed to comprehensively analyze intestinal microbiota.7) These reports showed that intestinal microbiota was unique to the individual, and that it was different even between family members. 3,8,9) From birth to one year old, the infant intestinal microbiota progresses to a mixture of bacteria that is very similar to the adult intestinal microbiota. This is because the infant depended on breast feeding and the children had been independent from breast feeding. 10) Diet is considered one of the main factors contributing to the diversity of human intestinal microbiota.11) Furthermore, antibiotics administration changes distinctly the diversity of the intestinal microbiota and influences on the host metabonome.12) Change of intestinal microbita by antibiotics administration causes an increase of the pathogenic bacteria (such as Bacteroides fragilis and Clostridium difficile) [13][14][15] and susceptibility to enteric pathogens.12) If intestinal microbiota is evaluated promptly, it would be useful for medical care and prevention of hospital-acquired infection. We have designed a convenient clone library method to analyze 96 clones from each sample and evaluated the dominated bacterial composition. [16][17][18] Until now, the small number of fecal samples of Japanese healthy adults was analyzed, 8,9) and Japanese fecal microbiotas have not been analyzed enough yet.In this study, using our clone library method, we analyzed microbiota of 58 fecal specimens, which were collected twice at an interval of 5 months from 29 healthy Japanese adult volunteers. Based on these data, an effect of antibiotic treatment of beta-lactam and macrolide on fecal microbiota was evaluated. Intestinal microbiotas of human subjects and effect of antibiotic treatment on them have been reported with cultivation independent methods. However, Japanese fecal microbiotas have not been studied enough. We have constructed a clone library method to obtain results within 3 d. In this study, intestinal microbiotas of 29 healthy Japanese adults, whose fecal samples were collected twice at 5 month intervals from each subject, were analyzed with our clone library method, and using those data as a benchmark effect of antibiotic treatment on intestinal microbiotas was evaluated. The fifty-eight fecal microbiotas were as...