Publications by authors named "Makoto Ohnishi"

An ongoing pertussis epidemic in Okinawa has resulted in 227 reported cases since November 2024. Between December 2024 and February 2025, clinical specimens were collected from 31 cases. We isolated 18 macrolide-resistant Bordetella pertussis (MRBP) strains, all harboring the A2047G mutation in the 23S rRNA gene, confirmed by real-time PCR.

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In November 2024, two unvaccinated infants with ptxP3 allele-carrying macrolide-resistant Bordetella pertussis (MRBP) infection were admitted to a hospital in Okinawa, Japan, and required intensive care. These represent the first reported severe MRBP cases in Japan. Both tested positive via LAMP and failed initial macrolide therapy, requiring mechanical ventilation and a switch to trimethoprim-sulfamethoxazole.

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In 2013, foodborne outbreaks in Japan were linked to non-O1, non-O139 . However, laboratory tests have detected several serogroups, making it difficult to determine the causative agent. Therefore, whole-genome analyses revealed that only serogroup O144 possesses a genomic island with a type III secretion system (T3SS).

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Background: It has been suggested that the emergence of ceftriaxone-resistant strains of Neisseria gonorrhoeae involves the incorporation of the penA gene from commensal Neisseria spp that are resistant to ceftriaxone. However, the mechanism of this mosaic penA generation is unknown.

Methods: We obtained 10 strains of commensal Neisseria spp showing ceftriaxone minimum inhibitory concentration ≥0.

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  • * This study analyzed 264 Blockley isolates from different regions, identifying 10 distinct genetic clusters which led to the classification into two lineages—R and S—each with unique antimicrobial resistance profiles.
  • * Notably, lineage R, found mainly in Asia and Africa, contained strains with azithromycin resistance, while lineage S, primarily in Europe and the Americas, lacked this resistance, indicating a significant need for ongoing monitoring of these pathogens.
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  • The study explores gepotidacin, a new treatment for gonorrhea, and investigates genetic changes in the GyrA and ParC targets of gonococci using a large dataset of genomes.
  • Key findings show that alterations at GyrA position A92 are rare, while changes at ParC position D86 are more common, but neither type resulted in resistance to gepotidacin.
  • The authors emphasize the importance of monitoring potential antimicrobial resistance and using effective MIC testing methods to ensure gepotidacin remains effective against gonorrhea.
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  • Resistance to potassium tellurite (PT) is crucial for isolating Shiga toxin-producing E. coli (STEC) O157:H7, and a study identified an O157:H7 strain that resists PT despite lacking the common resistance gene cluster.
  • Whole-genome sequencing revealed a nonsynonymous mutation in a different PT resistance gene, which was found to enhance PT resistance by increasing the expression of this gene through a change in its internal promoter.
  • This research indicates that even strains without the typical resistance genes can achieve PT resistance due to single mutations, highlighting the adaptability of STEC in various environments.
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Atg8 paralogs, consisting of LC3A/B/C and GBRP/GBRPL1/GATE16, function in canonical autophagy; however, their function is controversial because of functional redundancy. In innate immunity, xenophagy and non-canonical single membranous autophagy called "conjugation of Atg8s to single membranes" (CASM) eliminate bacteria in various cells. Previously, we reported that intracellular Streptococcus pneumoniae can induce unique hierarchical autophagy comprised of CASM induction, shedding, and subsequent xenophagy.

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  • Pneumolysin (Ply) is a critical protein for the infection process of pneumococci, but its effectiveness can also harm bacterial survival by causing excessive disruptions in host cells.
  • A novel assay using NanoBiT-Nanobody was developed to measure the endosomal disruption effects of Ply, revealing that the pneumococcal sialidase NanA regulates Ply activity by modifying cell membrane sugars.
  • Also, the sialidase inhibitor oseltamivir amplifies Ply's destructive effects in vitro and increases tissue damage and bacterial clearance in vivo, suggesting new treatment approaches for severe pneumococcal infections that leverage Ply’s dual role.
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  • The study investigates the emergence and evolution of antimicrobial-resistant (AMR) strains in Japan over a span of 35 years, focusing on changes in microbial populations and the effectiveness of antimicrobial treatments.
  • Researchers analyzed 243 strains collected from 1971 to 2005, revealing a decline in strain diversity and the rise of specific resistant strains, particularly ST1901, after 2001.
  • Findings showed that many strains after 2001 were highly resistant to ciprofloxacin and displayed significant genetic changes, emphasizing a troubling trend in AMR development.
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  • The study investigates the decline of streptococcal toxic shock syndrome (STSS) cases in Japan, particularly its connection to group A Streptococcus (GAS) strains, and aims to understand the reasons behind this decrease.
  • Researchers analyzed 526 GAS isolates from STSS patients between 2019 and 2022, noting a significant decrease in the prevalence of emm1 strains after the COVID-19 pandemic began.
  • The findings suggest that changes in public health measures during the pandemic, such as mask-wearing, may have reduced infections, particularly those from strains linked to pharyngeal infections, contributing to the reduction in STSS cases.
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  • * Whole-genome sequencing showed that these bacteria carry a specific plasmid (IncFII) with the LT gene, suggesting they've spread through fecal contamination in chickens.
  • * The strains also have genes for multidrug resistance, indicating a need for ongoing monitoring to assess their pathogenic risks.
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  • Major serotypes of Shiga toxin-producing E. coli (STEC) usually have a specific genetic region called the locus of enterocyte effacement (LEE) which helps them cause infections by forming lesions on intestinal cells.* -
  • There is limited information on STEC that lack this LEE, even though they can still be very harmful.* -
  • This study reports the complete genomes of eight LEE-negative STEC isolates found in patients with hemolytic-uremic syndrome, contributing valuable data to the understanding of these bacteria.*
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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.

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  • * In the U.S., a specific strain, called the US N. meningitidis urethritis clade (US_NmUC), is responsible for these urethral infections, and researchers have identified similar strains in Japan known as the Japan N. meningitidis urethritis clade (J_NmUC).
  • * The study highlights the need for global monitoring of these urethritis-linked meningococci to better understand their spread and characteristics, as they may have a common ancestor that is found worldwide.
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  • A study analyzed 290 meningococcal isolates from Japan between 2003 and 2020 to assess their susceptibility to eight antibiotics, including penicillin and ciprofloxacin.
  • Most isolates were found susceptible to chloramphenicol, ceftriaxone, meropenem, minocycline, and rifampicin, while two isolates were resistant to azithromycin and some were resistant or intermediate to penicillin and ciprofloxacin.
  • Genetic analysis revealed that around 40% of penicillin-resistant isolates belonged to unique Japanese strains, indicating that resistance traits appear to be spread clonally rather than through gene transfer from other bacteria.
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Introduction: Shigellosis remains a considerable public health concern in developing countries. and are prevalent worldwide and has been replacing .

Gap Statement: still causes outbreaks of shigellosis in northern Vietnam but limited information is available on its genetic characteristics.

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Periodontal disease has become a serious public health problem, not only causing tooth loss, but also inducing chronic disorders of extra-oral organs. The present study assessed an intranasal vaccine strategy to prevent periodontal disease using outer membrane vesicles (OMVs) of two major periodontopathic bacteria, Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa). We compared the morphology, composition, and immune activity between OMVs of Pg strain ATCC 33277 and Aa strain Y4.

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  • *Analysis of strains from Chiba prefecture revealed distinct tandem repeat patterns corresponding to major clades, leading to the creation of a likelihood database for improved clade subdivision.
  • *Results showed high concordance ratios (CRs) for most clades when comparing MLVA and single-nucleotide polymorphism analysis, demonstrating that MLVA can effectively classify O157 strains with less laboratory effort.
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  • The study focuses on Shiga toxin-producing E. coli (STEC), particularly on the O165:H25 strain and its relationship to closely related strains, defining them all as clonal complex 119 (CC119).
  • Researchers conducted whole-genome sequencing of 202 strains to analyze their genetic similarities and differences, focusing on the presence and behavior of specific phages and virulence genes.
  • The findings revealed that the CC119 lineage retains certain genetic traits that enhance virulence, but also shows notable variations in toxin production and lacks genes typical for tellurite resistance, indicating potential vulnerabilities in these strains.
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We report a ceftriaxone-resistant, multidrug-resistant urogenital in a female sex worker in Sweden, September 2022, who was treated with ceftriaxone 1 g, but did not return for test-of-cure. Whole genome sequencing of isolate SE690 identified MLST ST8130, NG-STAR CC1885 (new NG-STAR ST4859) and mosaic . The latter, causing ceftriaxone resistance in the internationally spreading FC428 clone, has now also spread to the more antimicrobial-susceptible genomic lineage B, showing that strains across the gonococcal phylogeny can develop ceftriaxone resistance.

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Streptococcus pneumoniae is a major, encapsulated Gram-positive pathogen that causes diseases including community-acquired pneumonia, meningitis, and sepsis. This pathogen colonizes the nasopharyngeal epithelia asymptomatically but can often migrate to sterile tissues and cause life-threatening invasive infections (invasive pneumococcal disease). Although multivalent pneumococcal polysaccharides and conjugate vaccines are available and effective, they also have major shortcomings with respect to the emergence of vaccine-resistant serotypes.

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  • A case-control study was conducted to assess COVID-19 infection risk among healthcare workers, collecting data on demographics, contact behaviors, and protective equipment usage.
  • Out of 1,899 participants, 161 (8.5%) were found to be seropositive, with physical contact and aerosol-generating procedures significantly increasing risk.
  • The use of goggles and N95 masks effectively reduced the risk of infection, and seroprevalence was notably higher in outbreak wards compared to COVID-19 dedicated wards.
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In 2022, one of its worst cholera outbreaks began in Bangladesh and the icddr,b Dhaka hospital treated more than 1300 patients and ca. 42,000 diarrheal cases from March-1 to April-10, 2022. Here, we present genomic attributes of V.

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Zoliflodacin is a promising novel antimicrobial in clinical development for treatment of gonorrhea; currently, it is in a global phase 3 randomized controlled clinical trial. High activity against global Neisseria gonorrhoeae strains has been shown. We present the complete reference genome of the zoliflodacin-resistant strain H035, which was identified in Japan in 2000.

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