8 results on '"Yuki Suzuki"'
Search Results
2. Clinical characteristics and molecular epidemiology of invasive Streptococcus agalactiae infections between 2007 and 2016 in Nara, Japan.
- Author
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Nobuyasu Hirai, Kei Kasahara, Ryuichi Nakano, Yoshihiko Ogawa, Yuki Suzuki, Miho Ogawa, Naokuni Hishiya, Akiyo Nakano, Sadahiro Ichimura, Hisakazu Yano, and Masahide Yoshikawa
- Subjects
Medicine ,Science - Abstract
Invasive Streptococcus agalactiae (GBS) infections are increasingly common among neonates and the elderly. Therefore, GBS surveillance for better antibiotic treatment and prophylaxis strategies are needed. We retrospectively evaluated the clinical aspects of invasive infections and the phenotypic and genetic diversity of infectious isolates from Nara, Japan, collected between 2007 and 2016, by using information from hospital records. GBS strains collected from the blood and cerebrospinal fluid cultures were evaluated for capsular types, multi-locus sequence typing (MLST), antibiotic susceptibility, antibiotics resistance gene, and pulsed-field gel electrophoresis. Forty GBS isolates (10 from children and 30 from adults) were analyzed, and the distribution of molecular serotype and allelic profiles varied between children and adults. We found the rates of early-onset disease in neonates with birth complications to be higher than that of previous reports, indicating that there could be relevance between complications at birth and early-onset disease. Standard antibiotic prophylaxis strategies may need to be reconsidered in patients with birth complications. In adults, the mean age of the patients was 68 years (male: 63%). Primary bacteremia was the most common source of infection. In the neonates, six had early-onset diseases and four had late-onset diseases. The most frequently identified strains were molecular serotype Ia ST23 (40%) and molecular serotype Ib ST10 (20%) in children and molecular serotype Ib ST10 (17%), molecular serotype VI ST1 (13%), and molecular serotype V ST1 (13%) in adults. Levofloxacin-resistant molecular serotype Ib strains and molecular serotypes V and VI ST1 were common causes of GBS infection in adults but were rarely found in children. Furthermore, pulsed-field gel electrophoresis in our study showed that specific clone isolates, that tend to have antibiotics resistance were widespread horizontally for a decade. Continuous surveillance and molecular investigation are warranted to identify the transmission route and improve antibiotic treatment strategies.
- Published
- 2020
- Full Text
- View/download PDF
3. Comparison of the inoculum size effects of antibiotics on IMP-6 β-lactamase-producing Enterobacteriaceae co-harboring plasmid-mediated quinolone resistance genes.
- Author
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Yoshihiko Ogawa, Ryuichi Nakano, Kei Kasahara, Tomoki Mizuno, Nobuyasu Hirai, Akiyo Nakano, Yuki Suzuki, Naoki Kakuta, Takashi Masui, Hisakazu Yano, and Keiichi Mikasa
- Subjects
Medicine ,Science - Abstract
Almost all cases of carbapenemase-producing Enterobacteriaceae infections in Japan are caused by blaIMP-positive Enterobacteriaceae (especially blaIMP-6) and infections caused by other types of carbapenemase-producing Enterobacteriaceae are quite rare. We examined drug resistance genes co-harboring with blaIMP-6 and their inoculum size effects. We screened β-lactamase genes, plasmid-mediated quinolone resistance (PMQR) genes, and aminoglycoside-modifying enzyme genes by PCR and performed sequencing for 14 blaIMP-6-positive Enterobacteriaceae. Further, all PMQR-positive isolates were submitted to conjugation and inoculum effect evaluation. Our data showed that 13 of the 14 isolates harbored CTX-M-2 and one co-harbored CTX-M-2 and CTX-M-1 as extended-spectrum β-lactamases. All isolates carried one or more PMQRs; aac(6')-Ib-cr was the most prevalent (92.8%), and was followed by oqxA (64.3%), qnrS (50%), oqxAB (21.4%), and qnrB (14.3%). However, Klebsiella pneumoniae contains chromosomal OqxAB. Inoculum size effects were significant in all strains for meropenem, 13 strains for imipenem, 7 for levofloxacin, and 3 for amikacin. We observed that 11 of the experimental strains (100%), 8 strains (72.7%), and 1 strain showed inoculum size effects for meropenem, imipenem, and amikacin, respectively. However, four strains harbored qnr genes and two strains harbored qnr genes and QRDR mutations concurrently; no inoculum size effect was seen for levofloxacin. The blaIMP-6-positive Enterobacteriaceae that we studied was found to harbor at least one plasmid-mediated drug resistance gene. The inoculum size effect for carbapenems was thought to be mainly due to IMP-6-type metallo-β-lactamase; however qnrB and qnrS also had a minimal impact on the inoculum size effect for levofloxacin.
- Published
- 2019
- Full Text
- View/download PDF
4. Characterization of the Holliday junction resolving enzyme encoded by the Bacillus subtilis bacteriophage SPP1.
- Author
-
Lisa Zecchi, Ambra Lo Piano, Yuki Suzuki, Cristina Cañas, Kunio Takeyasu, and Silvia Ayora
- Subjects
Medicine ,Science - Abstract
Recombination-dependent DNA replication, which is a central component of viral replication restart, is poorly understood in Firmicutes bacteriophages. Phage SPP1 initiates unidirectional theta DNA replication from a discrete replication origin (oriL), and when replication progresses, the fork might stall by the binding of the origin binding protein G38P to the late replication origin (oriR). Replication restart is dependent on viral recombination proteins to synthesize a linear head-to-tail concatemer, which is the substrate for viral DNA packaging. To identify new functions involved in this process, uncharacterized genes from phage SPP1 were analyzed. Immediately after infection, SPP1 transcribes a number of genes involved in recombination and replication from P(E2) and P(E3) promoters. Resequencing the region corresponding to the last two hypothetical genes transcribed from the P(E2) operon (genes 44 and 45) showed that they are in fact a single gene, re-annotated here as gene 44, that encodes a single polypeptide, named gene 44 product (G44P, 27.5 kDa). G44P shares a low but significant degree of identity in its C-terminal region with virus-encoded RusA-like resolvases. The data presented here demonstrate that G44P, which is a dimer in solution, binds with high affinity but without sequence specificity to several double-stranded DNA recombination intermediates. G44P preferentially cleaves Holliday junctions, but also, with lower efficiency, replicated D-loops. It also partially complemented the loss of RecU resolvase activity in B. subtilis cells. These in vitro and in vivo data suggest a role for G44P in replication restart during the transition to concatemeric viral replication.
- Published
- 2012
- Full Text
- View/download PDF
5. Impact of the COVID-19 pandemic and multiplex polymerase chain reaction test on outpatient antibiotic prescriptions for pediatric respiratory infection
- Author
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Daisuke Kitagawa, Taito Kitano, Madoka Furumori, Soma Suzuki, Yui Shintani, Hiroki Nishikawa, Rika Suzuki, Naohiro Yamamoto, Masayuki Onaka, Atsuko Nishiyama, Takehito Kasamatsu, Naoyuki Shiraishi, Yuki Suzuki, Akiyo Nakano, Ryuichi Nakano, Hisakazu Yano, Koichi Maeda, Sayaka Yoshida, and Fumihiko Nakamura
- Subjects
Multidisciplinary - Abstract
This study aimed to evaluate the impact of the prolonged COVID-19 pandemic on outpatient antibiotic prescriptions for pediatric respiratory infections at an acute care hospital in Japan in order to direct future pediatric outpatient antibiotic stewardship.The impact of the COVID-19 pandemic and FilmArray Respiratory Panel (RP) on outpatient antibiotic prescriptions was assessed from January 2019 to December 2021 using an interrupted time series analysis of children The COVID-19 pandemic was not significantly related to the antibiotic prescription rate, suggesting that it did not impact physicians’ behavior toward antibiotic prescriptions. Replacing rapid antigen tests with the FilmArray RP introduced on December 1, 2020, did not affect the magnitude of the reduction in antibiotic prescription rate for pediatric respiratory infections.
- Published
- 2022
6. Clinical characteristics and molecular epidemiology of invasive Streptococcus agalactiae infections between 2007 and 2016 in Nara, Japan
- Author
-
Masahide Yoshikawa, Nobuyasu Hirai, Miho Ogawa, Yuki Suzuki, Sadahiro Ichimura, Kei Kasahara, Yoshihiko Ogawa, Akiyo Nakano, Naokuni Hishiya, Hisakazu Yano, and Ryuichi Nakano
- Subjects
Serotype ,Bacterial Diseases ,Male ,Antibiotics ,Bacteremia ,Artificial Gene Amplification and Extension ,Levofloxacin ,medicine.disease_cause ,Polymerase Chain Reaction ,Geographical Locations ,Medical Conditions ,Japan ,Medicine and Health Sciences ,Medicine ,Antibiotic prophylaxis ,Aged, 80 and over ,Molecular Epidemiology ,Multidisciplinary ,Antimicrobials ,Drugs ,Middle Aged ,Electrophoresis, Gel, Pulsed-Field ,Infectious Diseases ,Urinary Tract Infections ,Female ,Research Article ,Adult ,medicine.medical_specialty ,Asia ,medicine.drug_class ,Science ,Urology ,Microbial Sensitivity Tests ,Research and Analysis Methods ,Serogroup ,Microbiology ,Streptococcus agalactiae ,Antibiotic resistance ,Internal medicine ,Microbial Control ,Streptococcal Infections ,Humans ,Serotyping ,Molecular Biology Techniques ,Molecular Biology ,Aged ,Pharmacology ,Molecular epidemiology ,business.industry ,Genitourinary Infections ,Biology and Life Sciences ,Neonates ,Antibiotic Prophylaxis ,medicine.disease ,Penicillin ,Antibiotic Resistance ,People and Places ,Multilocus sequence typing ,Antimicrobial Resistance ,business ,Developmental Biology ,Multilocus Sequence Typing - Abstract
Invasive Streptococcus agalactiae (GBS) infections are increasingly common among neonates and the elderly. Therefore, GBS surveillance for better antibiotic treatment and prophylaxis strategies are needed. We retrospectively evaluated the clinical aspects of invasive infections and the phenotypic and genetic diversity of infectious isolates from Nara, Japan, collected between 2007 and 2016, by using information from hospital records. GBS strains collected from the blood and cerebrospinal fluid cultures were evaluated for capsular types, multi-locus sequence typing (MLST), antibiotic susceptibility, antibiotics resistance gene, and pulsed-field gel electrophoresis. Forty GBS isolates (10 from children and 30 from adults) were analyzed, and the distribution of molecular serotype and allelic profiles varied between children and adults. We found the rates of early-onset disease in neonates with birth complications to be higher than that of previous reports, indicating that there could be relevance between complications at birth and early-onset disease. Standard antibiotic prophylaxis strategies may need to be reconsidered in patients with birth complications. In adults, the mean age of the patients was 68 years (male: 63%). Primary bacteremia was the most common source of infection. In the neonates, six had early-onset diseases and four had late-onset diseases. The most frequently identified strains were molecular serotype Ia ST23 (40%) and molecular serotype Ib ST10 (20%) in children and molecular serotype Ib ST10 (17%), molecular serotype VI ST1 (13%), and molecular serotype V ST1 (13%) in adults. Levofloxacin-resistant molecular serotype Ib strains and molecular serotypes V and VI ST1 were common causes of GBS infection in adults but were rarely found in children. Furthermore, pulsed-field gel electrophoresis in our study showed that specific clone isolates, that tend to have antibiotics resistance were widespread horizontally for a decade. Continuous surveillance and molecular investigation are warranted to identify the transmission route and improve antibiotic treatment strategies.
- Published
- 2020
7. Comparison of the inoculum size effects of antibiotics on IMP-6 β-lactamase-producing Enterobacteriaceae co-harboring plasmid-mediated quinolone resistance genes
- Author
-
Hisakazu Yano, Keiichi Mikasa, Nobuyasu Hirai, Naoki Kakuta, Akiyo Nakano, Kei Kasahara, Yoshihiko Ogawa, Tomoki Mizuno, Takashi Masui, Yuki Suzuki, and Ryuichi Nakano
- Subjects
Bacterial Diseases ,Imipenem ,Klebsiella pneumoniae ,Artificial Gene Amplification and Extension ,Drug resistance ,Pathology and Laboratory Medicine ,Polymerase Chain Reaction ,Klebsiella Pneumoniae ,Plasmid ,Antibiotics ,Klebsiella ,Medicine and Health Sciences ,0303 health sciences ,Multidisciplinary ,biology ,Antimicrobials ,Enterobacteriaceae Infections ,Drugs ,Enterobacteriaceae ,Bacterial Pathogens ,Anti-Bacterial Agents ,Infectious Diseases ,Phenotype ,Medical Microbiology ,Amikacin ,Enterobacter Infections ,Quinolines ,Medicine ,Pathogens ,Research Article ,Plasmids ,medicine.drug ,Genotype ,Science ,Microbial Sensitivity Tests ,Research and Analysis Methods ,Microbiology ,Meropenem ,beta-Lactamases ,03 medical and health sciences ,Antibiotic resistance ,Microbial Control ,medicine ,Humans ,Molecular Biology Techniques ,Microbial Pathogens ,Molecular Biology ,030304 developmental biology ,Pharmacology ,Drug Screening ,Bacteria ,030306 microbiology ,Organisms ,Biology and Life Sciences ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,biology.organism_classification ,Drug Resistance, Neoplasm ,Antibiotic Resistance ,Antimicrobial Resistance - Abstract
Almost all cases of carbapenemase-producing Enterobacteriaceae infections in Japan are caused by blaIMP-positive Enterobacteriaceae (especially blaIMP-6) and infections caused by other types of carbapenemase-producing Enterobacteriaceae are quite rare. We examined drug resistance genes co-harboring with blaIMP-6 and their inoculum size effects. We screened β-lactamase genes, plasmid-mediated quinolone resistance (PMQR) genes, and aminoglycoside-modifying enzyme genes by PCR and performed sequencing for 14 blaIMP-6-positive Enterobacteriaceae. Further, all PMQR-positive isolates were submitted to conjugation and inoculum effect evaluation. Our data showed that 13 of the 14 isolates harbored CTX-M-2 and one co-harbored CTX-M-2 and CTX-M-1 as extended-spectrum β-lactamases. All isolates carried one or more PMQRs; aac(6')-Ib-cr was the most prevalent (92.8%), and was followed by oqxA (64.3%), qnrS (50%), oqxAB (21.4%), and qnrB (14.3%). However, Klebsiella pneumoniae contains chromosomal OqxAB. Inoculum size effects were significant in all strains for meropenem, 13 strains for imipenem, 7 for levofloxacin, and 3 for amikacin. We observed that 11 of the experimental strains (100%), 8 strains (72.7%), and 1 strain showed inoculum size effects for meropenem, imipenem, and amikacin, respectively. However, four strains harbored qnr genes and two strains harbored qnr genes and QRDR mutations concurrently; no inoculum size effect was seen for levofloxacin. The blaIMP-6-positive Enterobacteriaceae that we studied was found to harbor at least one plasmid-mediated drug resistance gene. The inoculum size effect for carbapenems was thought to be mainly due to IMP-6-type metallo-β-lactamase; however qnrB and qnrS also had a minimal impact on the inoculum size effect for levofloxacin.
- Published
- 2019
8. Characterization of the Holliday Junction Resolving Enzyme Encoded by the Bacillus subtilis Bacteriophage SPP1
- Author
-
Cristina Cañas, Lisa Zecchi, Ambra Lo Piano, Kunio Takeyasu, Silvia Ayora, and Yuki Suzuki
- Subjects
DNA Replication ,DNA, Bacterial ,DNA recombination ,Semiconservative replication ,Molecular Sequence Data ,lcsh:Medicine ,Bacillus Phages ,Genome, Viral ,Biology ,Biochemistry ,Microbiology ,Viral Proteins ,Replication factor C ,Control of chromosome duplication ,Minichromosome maintenance ,Virology ,DNA-binding proteins ,Molecular Cell Biology ,Amino Acid Sequence ,lcsh:Science ,Recombination, Genetic ,Genetics ,DNA, Cruciform ,Multidisciplinary ,Base Sequence ,lcsh:R ,Ter protein ,Holliday Junction Resolvases ,Proteins ,DNA ,Theta DNA replication ,Viral Replication ,Enzymes ,Nucleic acids ,Licensing factor ,Origin recognition complex ,lcsh:Q ,Protein Multimerization ,Sequence Alignment ,Bacillus subtilis ,Protein Binding ,Research Article - Abstract
Recombination-dependent DNA replication, which is a central component of viral replication restart, is poorly understood in Firmicutes bacteriophages. Phage SPP1 initiates unidirectional theta DNA replication from a discrete replication origin (oriL), and when replication progresses, the fork might stall by the binding of the origin binding protein G38P to the late replication origin (oriR). Replication restart is dependent on viral recombination proteins to synthesize a linear head-to-tail concatemer, which is the substrate for viral DNA packaging. To identify new functions involved in this process, uncharacterized genes from phage SPP1 were analyzed. Immediately after infection, SPP1 transcribes a number of genes involved in recombination and replication from P(E2) and P(E3) promoters. Resequencing the region corresponding to the last two hypothetical genes transcribed from the P(E2) operon (genes 44 and 45) showed that they are in fact a single gene, re-annotated here as gene 44, that encodes a single polypeptide, named gene 44 product (G44P, 27.5 kDa). G44P shares a low but significant degree of identity in its C-terminal region with virus-encoded RusA-like resolvases. The data presented here demonstrate that G44P, which is a dimer in solution, binds with high affinity but without sequence specificity to several double-stranded DNA recombination intermediates. G44P preferentially cleaves Holliday junctions, but also, with lower efficiency, replicated D-loops. It also partially complemented the loss of RecU resolvase activity in B. subtilis cells. These in vitro and in vivo data suggest a role for G44P in replication restart during the transition to concatemeric viral replication.
- Published
- 2012
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