O-antigen biosynthesis gene clusters of Escherichia albertii: their diversity and similarity to Escherichia coli gene clusters and the development of an O-genotyping method

Abstract

Escherichia albertii is a recently recognized human enteropathogen that is closely related to Escherichia coli . In many Gram-negative bacteria, including E. coli , O-antigen variation has long been used for the serotyping of strains. In E. albertii , while eight O-serotypes unique to this species have been identified, some strains have been shown to exhibit genetic or serological similarity to known E. coli / Shigella O-serotypes. However, the diversity of O-serotypes and O-antigen biosynthesis gene clusters (O-AGCs) of E. albertii remains to be systematically investigated. Here, we analysed the O-AGCs of 65 E. albertii strains and identified 40 E. albertii O-genotypes (EAOgs) (named EAOg1–EAOg40). Analyses of the 40 EAOgs revealed that as many as 20 EAOgs exhibited significant genetic and serological similarity to the O-AGCs of known E. coli / Shigella O-serotypes, and provided evidence for the inter-species horizontal gene transfer of O-AGCs between E. albertii and E. coli . Based on the sequence variation in the wzx gene among the 40 EAOgs, we developed a multiplex PCR-based O-genotyping system for E. albertii (EAO-genotyping PCR) and verified its usefulness by genotyping 278 E. albertii strains from various sources. Although 225 (80.9 %) of the 278 strains could be genotyped, 51 were not assigned to any of the 40 EAOgs, indicating that further analyses are required to better understand the diversity of O-AGCs in E. albertii and improve the EAO-genotyping PCR method. A phylogenetic view of E. albertii strains sequenced so far is also presented with the distribution of the 40 EAOgs, which provided multiple examples for the intra-species horizontal transfer of O-AGCs in E. albertii .

Hypoosmotic stress induces flagellar biosynthesis and swimming motility in Escherichia albertii

“…Bacterial strains used and sequenced in this study are listed in Supplementary Table 1. Twenty-nine E. albertii strains were described previously 3,22 . Bacterial culture media preparation.…”

Distribution of the O-Genotypes of <i>Escherichia albertii</i> Isolated from Humans and Environmental Water in Akita Prefecture, Japan

“…The results showed that 38 of the E. albertii strains were shared by 19 other Ogenotypes and six strains were untypable (Table 1); however, the result from EC15062 was previously described (5). Among these, 24 strains were agglutinated with certain antisera of E. coli O-antigens ( Table 1).…”

“…All E. albertii strains were subjected to PCR for EAO-genotyping (5). In EAOgenotyping, 40 primer pairs to specifically detect each O-genotype and two primer pairs for an internal control were used.…”

Genomic Properties and Temporal Analysis of the Interaction of an Invasive Escherichia albertii With Epithelial Cells

“…However, if TccP3 could act similarly to modulate the inflammatory response of the host cell, it is a question that remains to be explored in further studies. Regarding TccP3, it may be noteworthy that our preliminary analysis of the prevalence of tccP3 in 243 E. albertii genomes (Ooka et al, 2019) identified only five tccP3-positive strains (including strain 1551-2). However, as there is considerable difficulty in searching for tccP family members in draft genome sequences due to the presence of internal repeats, more detailed analyses are required to determine the precise prevalence of tccp3 genes and their intactness.…”