Publications by authors named "Ryota Gomi"
Article Synopsis
- The study addresses the issue of antimicrobial resistance (AMR) as a critical public health threat and advocates for wastewater surveillance as a cost-effective method to monitor AMR in communities.
- Researchers conducted genomic surveillance on antimicrobial-resistant E. coli from fecal sludge and sewage in Uganda, identifying prevalent strains and high-risk clones associated with AMR.
- Findings revealed that genes contributing to AMR spread are primarily carried by diverse plasmids and through chromosomal integration, showcasing the effectiveness of combining sewage surveillance with whole-genome sequencing to track AMR in populations.
Escherichia coli has been used as an indicator of fecal pollution in environmental waters. However, its presence in environmental waters does not provide information on the source of water pollution. Identifying the source of water pollution is paramount to be able to effectively reduce contamination.
View Article and Find Full Text PDFOccurrence of extended-spectrum β-lactamase (ESBL)-producing (ESBLEC) in environmental waters is of great concern. However, unlike clinical ESBLEC, their genetic characteristics, in particular the genetic contexts of ESBL genes, are not well understood. In this study, we sequenced and analyzed the genomes of CTX-M-producing isolates recovered from river water to fully characterize the genetic contexts of genes.
View Article and Find Full Text PDFKlebsiella pneumoniae is a major cause of opportunistic healthcare-associated infections, which are increasingly complicated by the presence of extended-spectrum beta-lactamases (ESBLs) and carbapenem resistance. We conducted a year-long prospective surveillance study of K. pneumoniae clinical isolates in hospital patients.
View Article and Find Full Text PDFObjectives: Carbapenemase-producing Enterobacterales (CPE) pose serious threats to public health. Compared with clinical CPE, the genetic characteristics of environmental CPE are not well understood. This study aimed to characterize the genetic determinants of carbapenem resistance in CPE isolated from environmental waters in Japan.
View Article and Find Full Text PDFPlasmids play an important role in bacterial evolution and mediate horizontal transfer of genes including virulence and antimicrobial resistance genes. Although short-read sequencing technologies have enabled large-scale bacterial genomics, the resulting draft genome assemblies are often fragmented into hundreds of discrete contigs. Several tools and approaches have been developed to identify plasmid sequences in such assemblies, but require trade-off between sensitivity and specificity.
View Article and Find Full Text PDFMolecular Analysis of a -Harboring Class 3 Integron in Multidrug-Resistant Pseudomonas fulva.
Antimicrob Agents Chemother
August 2018
Article Synopsis
- A multidrug-resistant (MDR) strain was discovered from a urine sample in 2006, containing a specific gene within a chromosomal Tn-like class 3 integron.
- The study identified two mutations in quinolone-resistance-determining regions (QRDRs), contributing to the strain's resistance.
- Researchers report a new, full-length class 3 integron that, along with QRDR mutations, likely played a role in the strain's MDR characteristics.
Article Synopsis
- Wastewater, especially from municipal and hospital sources, is a significant contributor to antibiotic-resistant bacteria, specifically carbapenemase-producing bacteria (CPE), posing a risk to the environment.
- This study analyzed 40 wastewater samples from Japan and Taiwan, identifying 45 isolates of various microorganisms, with 38 of them containing carbapenemase-encoding genes.
- The research revealed the presence of unique class 1 integrons with different structures in Japanese and Taiwanese isolates, emphasizing the importance of tracking antibiotic resistance in wastewater to combat public health issues.
Article Synopsis
- Contamination of environmental waters by ESBL-producing bacteria from wastewater treatment plants and hospitals poses a significant public health risk.
- The study isolated and sequenced strains of ESBL-producing E. coli from wastewater samples in Japan, revealing the presence of clinically important clonal groups.
- Phylogenetic analysis identified various subgroups of sequence type 131 (ST131) strains, showing potential dissemination of antibiotic-resistant bacteria through wastewater systems.
Rapid Identification of Different Escherichia coli Sequence Type 131 Clades.
Antimicrob Agents Chemother
August 2017
Article Synopsis
- Sequence Type 131 (ST131) is a major global strain responsible for increasing resistance to antibiotics like fluoroquinolones and producing extended-spectrum-β-lactamases (ESBLs), particularly within its clade C and subclades C1-M27 and C2.
- A new multiplex conventional PCR assay was developed to detect all ST131 clades and their subclades, which successfully identified 80 fully sequenced global isolates and confirmed the presence of 565 ST131 isolates from two Japanese collections without any false positives.
- The results showed that clade C, especially the C1-M27 subclade, was the most common in recent ESBL-producing isolates in Japan, highlighting the assay's potential
Article Synopsis
- Contamination of the Yamato River in Japan was studied, focusing on antimicrobial-resistant bacteria, revealing that 14.3% of isolated strains were multidrug resistant (MDR).
- Whole-genome sequencing of 155 strains identified over 50 resistance genes and highlighted prevalent clonal groups, especially among extraintestinal pathogenic strains (ExPEC).
- The study underscores the risk of MDR and pathogenic bacteria in surface waters, which can impact drinking water, irrigation, and recreation.
The Escherichia coli sequence type (ST) 131 C2/H30Rx clade with the bla gene had been most responsible for the global dissemination of extended-spectrum β-lactamase (ESBL)-producing E. coli. ST131 C1/H30R with bla emerged among ESBL-producing E.
View Article and Find Full Text PDFArticle Synopsis
- Carbapenemase-producing Gram-negative bacilli are a significant global health threat due to their ability to cause severe and often fatal infections, primarily due to their resistance to antibiotics.
- A study using whole-genome sequencing found that a metallo-β-lactamase gene was shared between different bacterial species (Achromobacter xylosoxidans and Klebsiella pneumoniae) isolated from the same patient, highlighting the mobility of resistance plasmids through conjugation.
- The research revealed that although the plasmid containing the resistance gene wasn't self-transferable, it could be transferred from A. xylosoxidans to a non-resistant strain of K. pneumoniae, demonstrating the potential for antibiotic resistance to spread within patients
Article Synopsis
- - The study examined four genetic markers of E. coli found in human wastewater to assess how specifically and sensitively they identify human versus animal sources in Southeast Queensland.
- - All human wastewater samples tested positive for E. coli markers, with marker H8 showing the highest specificity at 0.94 for distinguishing human sources from animal ones.
- - After validation, H8 and H12 markers were prevalent in local wastewater (45% and 14%, respectively) and some environmental water samples (7% and 20%), indicating their potential for tracking E. coli sources in water bodies.
The occurrence of pathogenic Escherichia coli in environmental waters increases the risk of waterborne disease. In this study, 14 virulence genes in 669 E. coli isolates (549 isolates from the Yamato River in Japan, and 30 isolates from each of the following hosts: humans, cows, pigs, and chickens) were simultaneously quantified by multiplex PCR and dual index sequencing to determine the prevalence of potentially pathogenic E.
View Article and Find Full Text PDFArticle Synopsis
- High levels of fecal bacteria in aquatic environments pose risks for waterborne diseases, making it essential to identify their sources for effective pollution control.* -
- This study utilized next-generation sequencing to analyze 22 E. coli isolates from various known sources (humans, cows, pigs, and chickens) to discover host-specific genomic markers for better microbial source tracking.* -
- Results demonstrated that humans are a major contributor to water contamination in the Yamato River, highlighting the need for further research involving diverse animal hosts to enhance the reliability of the genetic tracking method.*
α-Amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) plays a key role in the regulation of NAD biosynthesis or the production of quinolinate from tryptophan (Trp). We investigated in this study the effect of phytol, a phytochemical known as a peroxisome proliferator-activated receptor α (PPARα) ligand, on NAD synthesis and ACMSD expression in rats. Male Sprague-Dawley rats were fed a diet containing 0.
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