[Population genetics of enterohemorrhagic Escherichia coli using whole-genome sequencing analyses].

Enterohemorrhagic Escherichia coli (EHEC) is an important pathogen since more than 3,000 cases have been reported annually in Japan. With the advent of next-generation sequencing, it has become feasible to analyze numerous strains using whole-genome sequence (WGS) analysis, making its application to surveillance a realistic possibility. In this paper, we introduce the following research outcomes achieved by our group utilizing WGS analysis of EHEC: 1) development of a WGS analysis pipeline to enhance the accuracy of the surveillance, 2) investigation of the dynamics of mobile elements such as plasmids and phages, and 3) analysis of the phylogeny and pathogenicity of newly identified highly pathogenic EHEC strains.

Combined usage of serodiagnosis and O antigen typing to isolate Shiga toxin-producing O76:H7 from a hemolytic uremic syndrome case and genomic insights from the isolate.

Hemolytic uremic syndrome (HUS) is a life-threatening disease caused by Shiga toxin-producing (STEC) infection. The treatment approaches for STEC-mediated typical HUS and atypical HUS differ, underscoring the importance of rapid and accurate diagnosis. However, specific detection methods for STECs other than major serogroups, such as O157, O26, and O111, are limited.

Atypical diarrhoeagenic in milk related to a large foodborne outbreak.

A foodborne outbreak related to milk cartons served in school lunches occurred in June 2021, which involved more than 1,800 cases from 25 schools. The major symptoms were abdominal pain, diarrhoea, vomiting, and fever. Although major foodborne toxins and pathogens were not detected, a specific strain, serotype OUT (OgGp9):H18, was predominantly isolated from milk samples related to the outbreak and most patients tested.

Mutations identified in engineered with a reduced genome.

Characterizing genes that regulate cell growth and survival in model organisms is important for understanding higher organisms. Construction of strains harboring large deletions in the genome can provide insights into the genetic basis of cell growth compared with only studying wild-type strains. We have constructed a series of genome-reduced strains with deletions spanning approximately 38.

Real-time PCR assays to detect 10 Shiga toxin subtype (Stx1a, Stx1c, Stx1d, Stx2a, Stx2b, Stx2c, Stx2d, Stx2e, Stx2f, and Stx2g) genes.

To develop subtyping methods for Shiga toxin (Stx)1a, Stx1c, Stx1d, Stx2a, Stx2b, Stx2c, Stx2d, Stx2e, Stx2f, and Stx2g genes for epidemiological analyses of Shiga toxin-producing Escherichia coli (STEC), we developed 10 simplex real-time polymerase chain reaction (PCR) assays with reference to 284 valid stx sequences and evaluated their specificity and quantitative accuracy using STEC and non-STEC isolates and recombinant plasmids, respectively. Three stx and 5 stx subtype genes, except for stx and stx, were detected with high specificity using STEC isolates. However, some stx sequences potentially being close to both Stx2a and Stx2d cluster in neighbor-joining cluster analysis were positive for stx and stx by real-time PCR.

High-throughput nanopore sequencing of tandem repeat genes and reveals clade-specific patterns and recapitulates global whole genome phylogeny.

Sequencing of most genomes excludes repeat regions in and the gene, encoding the acidic repeat protein (). As a first step to understanding the evolution and function of these genes and the proteins they encode, we developed a protocol to nanopore sequence and genes from 212 clinical samples collected from ten countries on six continents. Both and repeat structures recapitulate the whole genome phylogeny, with subclade-specific patterns emerging.

Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar.

In spite of its immutable susceptibility to penicillin, Treponema pallidum (T. pallidum) subsp. pallidum continues to cause millions of cases of syphilis each year worldwide, resulting in significant morbidity and mortality and underscoring the urgency of developing an effective vaccine to curtail the spread of the infection.

RNA-binding protein Hfq downregulates locus of enterocyte effacement-encoded regulators independent of small regulatory RNA in enterohemorrhagic Escherichia coli.

Enterohemorrhagic Escherichia coli (EHEC) causes severe human diseases worldwide. The type 3 secretion system and effector proteins are essential for EHEC infection, and are encoded by the locus of enterocyte effacement (LEE). RNA-binding protein Hfq is essential for small regulatory RNA (sRNA)-mediated regulation at a posttranscriptional level and full virulence of many pathogenic bacteria.

Whole-Genome Sequencing of Shiga Toxin-Producing Escherichia coli OX18 from a Fatal Hemolytic Uremic Syndrome Case.

We report a fatal case of hemolytic uremic syndrome with urinary tract infection in Japan caused by Shiga toxin-producing Escherichia coli. We genotypically identified the isolate as OX18:H2. Whole-genome sequencing revealed 3 potentially pathogenic lineages (OX18:H2, H19, and H34) that have been continuously isolated in Japan.

Phylogenetic and genetic characterization of Treponema pallidum strains from syphilis patients in Japan by whole-genome sequence analysis from global perspectives.

Japan has had a substantial increase in syphilis cases since 2013. However, research on the genomic features of the Treponema pallidum subspecies pallidum (TPA) strains from these cases has been limited. Here, we elucidated the genetic variations and relationships between TPA strains in Japan (detected between 2014 and 2018) and other countries by whole-genome sequencing and phylogenetic analyses, including syphilis epidemiological surveillance data and information on patient sexual orientation.

Characterization of 2 Neisseria gonorrhoeae Strains With High-Level Azithromycin Resistance Isolated in 2015 and 2018 in Japan.

We identified and characterized the first 2 Neisseria gonorrhoeae strains with high-level azithromycin resistance isolated in Japan. These were in the clade of ceftriaxone- and azithromycin-resistant strains isolated in Australia and the United Kingdom. The multilocus sequence typing, N.

Additional Og-Typing PCR Techniques Targeting Escherichia coli-Novel and -Unique O-Antigen Biosynthesis Gene Clusters.

The O-serogrouping of pathogenic is a standard method for subtyping strains for epidemiological studies and controls. O-serogroup diversification shows a strong association with the genetic diversity in some O-antigen biosynthesis gene clusters. Through genomic studies, in addition to the types of O-antigen biosynthesis gene clusters (Og-types) from conventional O-serogroup strains, a number of novel Og-types have been found in isolates.

Global distribution of epidemic-related Shiga toxin 2 encoding phages among enteroaggregative Escherichia coli.

Since the Shiga toxin-producing enteroaggregative Escherichia coli (Stx-EAEC) O104:H4 strain caused a massive outbreak across Europe in 2011, the importance of Stx-EAEC has attracted attention from a public health perspective. Two Stx-EAEC O86 isolates were obtained from patients with severe symptoms in Japan in 1999 and 2015. To characterize the phylogeny and pathogenic potential of these Stx-EAEC O86 isolates, whole-genome sequence analyses were performed by short-and long-read sequencing.

Multiple-Locus Variable-Number Tandem Repeat Analysis Scheme for Non-O157 Shiga Toxin-Producing Escherichia coli: Focus on Serogroups O103, O121, O145, O165, and O91.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) infections are a growing concern for public health. The number of sporadic cases and outbreaks of non-O157 STEC infections have increased in recent years. Molecular subtyping is an essential tool that allows high-resolution and rapid differentiation of isolates, identification of case clusters, and detection of outbreak clusters.

Differential dynamics and impacts of prophages and plasmids on the pangenome and virulence factor repertoires of Shiga toxin-producing O145:H28.

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 O145:H28, the major virulence factors of which are encoded by prophages (PPs) or plasmids.

Complete Genome Sequence of an Enterohemorrhagic Escherichia coli O111:H8 Strain Recovered from a Large Outbreak in Japan Associated with Consumption of Raw Beef.

We present the complete genome sequence of an enterohemorrhagic O111:H8 strain. This strain was isolated from a hemolytic-uremic syndrome patient and was responsible for a large outbreak associated with the consumption of raw beef in 2011.

Effective Surveillance Using Multilocus Variable-Number Tandem-Repeat Analysis and Whole-Genome Sequencing for Enterohemorrhagic Escherichia coli O157.

Due to the potential of enterohemorrhagic (EHEC) serogroup O157 to cause large food borne outbreaks, national and international surveillance is necessary. For developing an effective method of molecular surveillance, a conventional method, multilocus variable-number tandem-repeat analysis (MLVA), and whole-genome sequencing (WGS) analysis were compared. WGS of 369 isolates of EHEC O157 belonging to 7 major MLVA types and their relatives were subjected to comprehensive typing, core genome single nucleotide polymorphism (cgSNP), and core genome multilocus sequence typing (cgMLST) analyses.

Enterohaemorrhagic Escherichia coli O121:H19 acquired an extended-spectrum β-lactamase gene during the development of an outbreak in two nurseries.

Enterohaemorrhagic Escherichia coli (EHEC) is an important human pathogen worldwide. Although serotype O157 is currently the most dominant and important EHEC strain, serotypes O26, O111, O91, O103 and O121 are also recognized as serious pathogens that affect public health. EHEC outbreaks often occur in nurseries and elderly care facilities.

Clonal expansion and spread of the ceftriaxone-resistant Neisseria gonorrhoeae strain FC428, identified in Japan in 2015, and closely related isolates.

Objectives: Ceftriaxone resistance in Neisseria gonorrhoeae is a major public health concern globally because a high-dose (1 g) injection of ceftriaxone is the only remaining option for empirical monotherapy of gonorrhoea. The ceftriaxone-resistant gonococcal strain FC428, cultured in Osaka in 2015, is suspected to have spread nationally and internationally. We describe the complete finished genomes of FC428 and two closely related isolates from Osaka in 2015, and examine the genomic epidemiology of these isolates plus three ceftriaxone-resistant gonococcal isolates from Osaka and Hyogo in 2016-17 and four ceftriaxone-resistant gonococcal isolates cultured in 2017 in Australia, Canada and Denmark.