Hawaiʻi, the United States’ most western geographic state in the Pacific, lies between the North and South American continents and the Indo-Pacific regions, including Japan. The tropical environmental conditions of the Hawaiian Islands provide favorable ecosystems for various infectious pathogens, their vectors, and reservoirs. This creates an environment conducive to the transmission of zoonotic diseases affecting both humans and animals. Hawaiʻi has experienced an increase in dengue, leptospirosis, and murine typhus outbreaks. Furthermore, toxoplasmosis and neuroangiostrongyliasis cases remain prevalent throughout the state, and the putative presence of autochthonous Zika cases identified in a retrospective study may be of national public health concern. Understanding the factors that affect the transmission and distribution of zoonoses is necessary to identify at-risk locations and populations. The One Health approach seeks to understand, report, and interpret these factors and requires collaboration between private and governmental institutions. One Health should focus on neglected tropical diseases (NTD) and prioritize development of interventions to control and prevent the transmission of diseases that spread between animals and humans. This review focuses on the epidemiological and clinical characteristics of under-recognized zoonotic and NTD affecting Hawaiʻi, including leptospirosis, murine typhus, neuroangiostrongyliasis, toxoplasmosis, dengue, and Zika.

Since 2019, many studies on coronavirus disease 2019, which has caused extensive damage as a pandemic, have been ongoing on a global scale. These include serological and biochemical studies using sera from patients and animal models. Testing with these sera must be performed after inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Heat treatment, UV irradiation, and/or gamma-ray irradiation have been used to inactivate viruses in the serum. Determining the inactivation conditions that ensure the inactivation of viruses and minimize the effect on test results after inactivation is important to ensure worker safety and the accuracy of test results. In this study, serum samples containing SARS-CoV-2 were subjected to heat, UV irradiation, and gamma irradiation to determine optimal inactivation conditions. The viral titers were below the detection limit after heating at 56°C for 1 h or 60°C for 15 min, UV-B irradiation with a transilluminator for 30 min, or gamma-ray irradiation with ⁶⁰ Co at 10 kGy. These results provide useful information for safe serological and biochemical experiments.

The association between proton-pump inhibitor (PPI) use and systemic infections caused by bacterial translocation is unclear. This study aimed to investigate whether patients receiving PPI therapy have a higher risk of bloodstream infections (BSI) without an identifiable source of infection. We conducted a hospital-based case-control study which enrolled all patients aged 20 years and older who were hospitalized in Ichinomiya Nishi Hospital with BSI confirmed by two sets of positive blood cultures in 2019. Patient data were collected from medical records, and the bacterial translocation-type (BT-type) BSI group was defined as patients with BSI without an identifiable source of infection, whereas those with a BSI from an identifiable source were assigned to the control group based on the diagnostic criteria for each infectious disease. Data from 309 patients, including 66 cases and 243 controls, were analyzed. Compared with PPI non-users, PPI users had a 2.4-fold higher risk of developing BT-type BSI after controlling for potential confounders (adjusted odds ratio: 2.41, 95% confidence interval: 1.29–4.51, P = 0.006). In conclusion, PPI use is associated with a higher risk of BSI without an identifiable source; therefore, PPI use might increase the risk of BSI secondary to bacterial translocation.

Stenotrophomonas maltophilia is a nonfermenting Gram-negative drug-resistant pathogen that causes healthcare-associated infections. Clinical isolates from Mexico were assessed for biofilm formation using crystal violet staining. Antimicrobial susceptibility was evaluated in planktonic and biofilm cells using the broth microdilution method. The effects of antibiotics on biofilms were visualized using fluorescence microscopy. Fifty isolates were included in this study, of which 14 (28%) were biofilm producers (9 [64%] from blood and 5 [36%] from respiratory samples). In planktonic cells 4/50 (8%) of isolates were resistant to levofloxacin (8.0%) and 22/50 (44%) were resistant to trimethoprim-sulfamethoxazole. All isolates were resistant to levofloxacin and trimethoprim-sulfamethoxazole in biofilm cells. Bacterial biofilms treated with different concentrations of both antibiotics were completely disrupted. In conclusion, S. maltophilia isolated from blood had higher biofilm production than those isolated from respiratory samples. Biofilm production was associated with increased antibiotic resistance. Antibiotic monotherapy might not be the best course of action for the treatment of S. maltophilia infections in Mexico, because it might cause biofilm production and antimicrobial resistance.

Escherichia coli is a Gram-negative bacterium that causes a variety of clinical infections in humans, including diarrhea, sepsis, and urinary tract infection. This bacterium is a common multidrug-resistant threat in community and hospital settings worldwide. This study examined the antimicrobial susceptibility and genetic relationship based on Clermont phylotyping and enterobacterial repetitive intergenic consensus (ERIC)-PCR of 84 E. coli urinary isolates from provincial and community hospitals in Thailand. All isolates were susceptible to nitrofurantoin, and almost all isolates were susceptible to carbapenem, fosfomycin, and amikacin. High resistance rates to fluoroquinolone, ampicillin, and trimethoprim/sulfamethoxazole were observed. Clermont phylogroup B2 was predominant (n = 58). Subtyping of the B2 phylogroup revealed diverse subgroups, of which subgroup V (n = 11), VII (n = 9), III (n = 6), and II (n = 6) were most prevalent. ERIC-PCR showed that the strains of the B2 subgroups III and V were spread between provincial and community hospitals and between hospital wards. This evidence suggests the need for comprehensive infection control monitoring, with strong active surveillance at all hospital levels.

Respiratory samples from 139 hospitalized children were screened for the human bocavirus (HBoV) genome. Positive samples were sequenced for the partial VP1/VP2 gene followed by molecular and phylogenetic analyses. HBoV positivity was noted in 7.2% (10/139) of patients. All HBoV-positive children presented with fever, cough, and respiratory distress (90%, 9/10). Three children developed multisystemic viral illness, with one fatality. Eight children required intensive care management and five required mechanical ventilation. The nucleotide percent identity of the partial VP1/VP2 gene in the HBoV study strains ranged from 97.52% to 99.67%. Non-synonymous mutations in the VP1 protein were T591S (n = 8) and Y517S (n = 1) in the HBoV St1 strain and N475S (n = 8) and S591T (n = 2) in the HBoV St2 strain. One strain showed A556P, H556P, I561S, and M562R non-synonymous mutations. All the study strains belonged to the HBoV1 type. Seven HBoV strains belonged to the same lineage, and three belonged to another lineage. For evolutionary dynamics, GTR+I substitution model with uncorrelated relaxed lognormal clock and Bayesian Skyline tree prior showed 9.0 × 10^-4 (95% highest probability density interval: 3.1 × 10^-6, 2.1 × 10^-3) nucleotide substitutions per site per year. Clinical suspicion and virological screening are necessary to identify HBoV infections in children.

All clinical isolates of Streptococcus dysgalactiae subsp. equisimilis (SDSE) are considered susceptible to β-lactams, the first-line drugs used to treat SDSE infections. However, given that penicillin-non-susceptible SDSE strains have been isolated in Denmark, in this study, we aimed to identify β-lactam-non-susceptible clinical isolates of SDSE in Japan. In 2018, we collected 150 clinical isolates of S. dysgalactiae, and species identification was performed using a Rapid ID Strep API kit. The minimum inhibitory concentrations (MIC) of six β-lactams (penicillin G, oxacillin, ceftizoxime, ceftibuten, cefoxitin, and cefaclor) were determined for the 85 clinical isolates identified as SDSE using the agar dilution method standardized by the Clinical & Laboratory Standards Institute. The MIC ranges of penicillin G, oxacillin, ceftizoxime, ceftibuten, cefoxitin, and cefaclor were 0.007–0.06, 0.03–0.12, 0.015–0.06, 0.25–2, 0.12–2, and 0.06–0.5 μg/mL, respectively. None of the clinical isolates of SDSE were non-susceptible to penicillin G, indicating that all 85 clinical isolates of SDSE were susceptible to β-lactams. Our findings indicate that almost all clinical isolates of SDSE, from several prefectures of Japan, are still susceptible to β-lactams. Nevertheless, there remains a need for continuous and careful monitoring of drug susceptibility among clinical SDSE isolates in Japan.

Patients with acquired immune deficiency syndrome (AIDS) are susceptible to numerous complications, such as sepsis and acute kidney injury (AKI), leading to adverse outcomes. Continuous renal replacement therapy (CRRT) is becoming increasingly popular for treating sepsis and AKI. This study aimed to verify the effectiveness of CRRT in the treatment of patients with AIDS with sepsis and AKI to provide new directions for the treatment of severe AIDS. Data of 74 people with AIDS, sepsis, and AKI were collected. The patients were divided into CRRT and non-CRRT groups. There was no difference in the indicators between the two groups at admission. Vital signs, pH, serum potassium level, renal function, blood lactate level, acute physiology and chronic health evaluation II score, and sequential organ failure assessment score in the CRRT group demonstrated significant improvements over those in the non-CRRT group at both 24 and 72 h after admission (P < 0.05). The levels of interleukin 6 and procalcitonin declined more significantly in the CRRT group at 72 h after admission (P < 0.05). The CRRT group had a higher 28-day survival rate than the non-CRRT group (P < 0.05). CRRT improves the clinical indicators and increases the short-term survival rate of patients with AIDS, sepsis, and AKI.

We report the first case of necrotizing fasciitis caused by Pigmentibacter ruber. The isolated strain could not be identified by biochemical characterization or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry but was identified as P. ruber by 16S ribosomal RNA and whole-genome sequencing. Although much remains unknown about the pathogenicity of this bacterial species in humans, it has been shown to cause life-threatening infections such as septicemia and necrotizing fasciitis. Because the isolate was highly resistant to β-lactams, it was difficult to treat with antimicrobial therapy. Thus, further documentation of cases and analyses are required.