Publications by authors named "Hidekazu Niwa"

is one of the major clinical anaerobic bacteria belonging to the family . Herein, we report the complete genome sequence of a clinical isolate of new species obtained from equine bronchial lavage fluid in Japan. The genome comprised a circular chromosome with a length of 2,948,037 bp.

View Article and Find Full Text PDF

Introduction: Protection of horse welfare during transport is crucial. The aim of this study was to determine the effect of head and neck restraint on behavior and airway bacteria.

Methods: In a randomized crossover study, six healthy Thoroughbreds were transported by road for 22 h in an individual bay with tight head restraint (50 cm short-rope) or loose head restraint (95 cm long-rope).

View Article and Find Full Text PDF

Strangles is a globally widespread, commonly diagnosed and important infectious disease of equids caused by Streptococcus equi subsp. equi. We performed whole genome sequencing of 19 S.

View Article and Find Full Text PDF

Fosfomycin (FOM) is an approved veterinary medicinal product for large animals in Japan, but Clinical breakpoint (CBP) for antimicrobial susceptibility test (AST) is not defined for animals. This study aimed at conducting a pharmacokinetics/pharmacodynamics (PK/PD) analysis to determine the PK/PD cutoff for the CBP in horses. Drug concentrations following single intravenous administration (IV) of 20 mg/kg body weight (BW) FOM in nine horses were measured using liquid chromatography/mass spectrometry.

View Article and Find Full Text PDF

A pharmacokinetic/pharmacodynamic (PK/PD) approach was used to determine a dosage regimen of cephalothin (CET) after intramuscular (IM) administration in horses. CET plasma concentrations were measured in eight horses after a single IM administration of 11 mg/kg bwt of CET. The data were modeled using a nonlinear mixed-effect model, and the probability of target attainment (PTA) of the PK/PD target was calculated for 5,000 horses generated by Monte Carlo simulations.

View Article and Find Full Text PDF
Article Synopsis
  • Infectious ulcerative keratitis is prevalent in racehorses, prompting a study to analyze the antimicrobial resistance of bacteria and fungi from the corneas of affected Japanese Thoroughbreds.
  • Out of 166 swabs from 107 cases, 85% showed bacterial or fungal infections, with Staphylococcus species being the most common bacteria, including methicillin-resistant strains (MRSA) and Aspergillus as the primary fungus.
  • Resistance to the antibiotic Ofloxacin was notably high, especially among Staphylococcus and Streptococcus isolates, while all Aspergillus strains were susceptible to voriconazole, indicating a need for more research on effective treatments for resistant infections.
View Article and Find Full Text PDF

is the predominant equine sp. isolated from clinically normal horses and is suspected to be associated with inflammatory airway disease in which cough is the primary sign. Quantitative evaluation of bacterial counts is useful in assessing the association between the bacteria in samples and observed clinical signs, but this evaluation has been difficult with conventional culture methods of given the need for pre-enrichment using liquid cultures.

View Article and Find Full Text PDF

Surgical site infection (SSI) is one of the major complications of equine fracture surgery. The purpose of this study was to investigate the incidence of and risk factors for SSI after internal fixation of the first phalangeal bone (P1) and the third metacarpal/metatarsal bone (MC3/MT3) fractures in Thoroughbred racehorses. Between 2011 and 2020, 451 cases underwent surgery with screws or a locking compression plate (LCP) for sagittal fractures of P1 or condylar fractures of MC3/MT3.

View Article and Find Full Text PDF

We encountered 34 Clostridioides difficile (C. difficile) infection (CDI) cases among Thoroughbred horses in Japan from 2010 to 2021. Among them, 79.

View Article and Find Full Text PDF
Article Synopsis
  • A study in Japan recommends a two-dose revaccination for horses over 2 years old who haven't been vaccinated in the past year.
  • The evaluation showed no significant difference in antibody levels between one- and two-dose regimens for most of the year, except at 8 weeks with the multivalent vaccine.
  • The findings indicate that just one dose of the vaccine is effective enough to provide tetanus protection for at least a year, regardless of whether it's monovalent or multivalent.
View Article and Find Full Text PDF

Equine proliferative enteropathy (EPE) is an equine infectious disease that can lead to severe weight loss and hyperplasia of the intestinal mucosa due to infection with Lawsonia intracellularis. In this study, we investigated the prevalence of EPE in a major Thoroughbred breeding area: Hidaka district, Hokkaido, Japan. Of the 252 symptomatic horses that we tested, 192 EPE cases (76.

View Article and Find Full Text PDF
Article Synopsis
  • * Twelve horses were given an intravenous dose of 22 mg/kg CET, and samples were collected at 1, 3, and 5 hours post-administration.
  • * CET was effective in treating septic arthritis, pleuritis, and peritonitis caused by certain bacteria but was not effective for osteomyelitis due to low levels in bone tissue.
View Article and Find Full Text PDF

Methicillin-resistant (MRSA) has often been isolated from livestock and companion animals, including horses. Seven cases of MRSA infection in Thoroughbred racehorses were observed in an equine hospital in Japan in 2020. In this study, MRSA isolates from these seven horses and nine veterinarians in the equine hospital were studied to examine their genetic relatedness and evaluate the possibility of MRSA transmission.

View Article and Find Full Text PDF

Antimicrobial administration can lead to imbalances of gastrointestinal microbiota, called dysbiosis. Dysbiosis sometimes results in diarrhea and enteritis in horses. Fecal microbiota transplantation (FMT) is used to treat affected horses, but whether it is effective as a prophylactic approach for dysbiosis in horses receiving antimicrobials remains unknown.

View Article and Find Full Text PDF
Article Synopsis
  • * Real-time PCR was found to be the most effective with the lowest detection limit at 0.77 fg/reaction, while some conventional PCR methods had detection limits exceeding 100 fg/reaction.
  • * In tests with infected samples, real-time PCR and semi-nested PCR identified 33 out of 42 positives, showing the importance of using more sensitive molecular assays for detecting T. equigenitalis in clinical scenarios.
View Article and Find Full Text PDF

Mycoplasma species are often isolated from horses with respiratory symptoms; however, the pathogenicity of Mycoplasma is still unclear. In autumn of 2018, we encountered an increase in cases with respiratory symptoms, mainly coughing, in a group of Thoroughbred racehorses in Japan. We examined tracheal wash samples obtained from 40 of those cases.

View Article and Find Full Text PDF

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is used for identification of bacterial species isolated from horses. However, because of insufficiencies in the reference database, some bacterial species isolated from horses are difficult to identify with MALDI-TOF MS, and enriching the databases is expected to enhance the accuracy of MALDI-TOF MS identification. Here we created an in-house database including 271 bacterial isolates from horses.

View Article and Find Full Text PDF

Background: Luliconazole (LCZ) is an imidazole antifungal medication that exhibits excellent activity against dermatophytes. As a topical cream and lotion (approved for human use), LCZ has demonstrated a broad spectrum of activity against human dermatophytoses.

Objectives: This is the first study to investigate the in vitro susceptibility of clinical isolates from horse dermatophytoses to LCZ.

View Article and Find Full Text PDF

Microbial communities are commonly studied by using amplicon sequencing of part of the 16S rRNA gene. Sequencing of the full-length 16S rRNA gene can provide higher taxonomic resolution and accuracy. To obtain even higher taxonomic resolution, with as few false-positives as possible, we assessed a method using long amplicon sequencing targeting the rRNA operon combined with a CCMetagen pipeline.

View Article and Find Full Text PDF

Trichophyton equinum is a zoophilic dermatophyte that is frequently isolated from horse dermatophytosis and rare infections in humans. In the present study, molecular and physiological testing were performed on T. equinum isolates from dermatophytoses of Japanese racehorses to assess genotype and phenotype patterns of these strains.

View Article and Find Full Text PDF

is a zoophilic dermatophyte that has been rarely isolated from horses and humans in Africa and Europe. This is the first reported isolation of from a horse with dermatophytosis in Japan. The isolate from a skin lesion formed a cream-colored and waxy colony that was slightly elevated in the center.

View Article and Find Full Text PDF

In the past decade, mass spectrometry has become an important technology for protein identification. Recent developments in mass spectrometry allow a large number of identifications in samples; therefore, mass-spectrometry-based techniques have been applied to the discovery of biomarkers. Here, we conducted a proteomic study to compare the proteomes in sera between healthy Thoroughbreds and Thoroughbreds with respiratory disease associated with transport (RDT).

View Article and Find Full Text PDF

The equine disease strangles, which is characterized by the formation of abscesses in the lymph nodes of the head and neck, is one of the most frequently diagnosed infectious diseases of horses around the world. The causal agent, subspecies , establishes a persistent infection in approximately 10 % of animals that recover from the acute disease. Such 'carrier' animals appear healthy and are rarely identified during routine veterinary examinations pre-purchase or transit, but can transmit to naïve animals initiating new episodes of disease.

View Article and Find Full Text PDF

The incidence of equine proliferative enteropathy, caused by Lawsonia intracellularis, is increasing around the world. To investigate the relationships of variable-number tandem repeat (VNTR) patterns with host species and clinical status in horses, multilocus VNTR analysis (MLVA) was applied to 98 L. intracellularis samples collected from horses, seven from pigs, seven from wildlife, one vaccine strain, and 17 public strains.

View Article and Find Full Text PDF
Article Synopsis
  • First-generation cephalosporins, specifically cephalothin (CET) and cefazolin (CEZ), are commonly used in horses but have limited PK/PD studies conducted.
  • The study tested different dosages and discovered that a higher frequency of CET administration is needed to effectively treat S. aureus infections in horses, while a lower frequency is suitable for CEZ.
  • The main limitation of the study is that it had a small sample size, focusing only on healthy horses, which may affect the applicability of the findings.
View Article and Find Full Text PDF