Acute encephalitis syndrome (AES) is associated with high morbidity and mortality, and affects both children and adults. The main etiologic agent is Japanese encephalitis virus (JEV); however, there are also reports of Dengue virus (DENV) encephalitis. The objectives of this study were to determine the proportion of patients with encephalitis due to JEV during the 2014 outbreak in Son La Province in Vietnam and to explore the association of DENV in non-JEV viral encephalitis cases. Of 90 patients, 6 (6.7%) were positive for anti-JEV immunoglobulin M (IgM), 5 (5.6%) were positive for anti-DENV IgM, 30 (33.3%) were positive for both anti-JEV and anti-DENV IgM, and 56 (62.2%) were positive for flavivirus immunoglobulin G (IgG). In 5 patients with AES, who had positive anti-DENV IgM results in at least one of the paired serum samples, DENV was confirmed by neutralization testing. The incidence of JEV infection was high. There is still a need to maintain and strengthen the national JEV immunization program. This noticeable occurrence of DENV infection was not reported in Son La Province in 2013–2014. Our data suggested that in addition to JEV, DENV was also a causative agent of AES in 2014 in Son La Province, and this finding also confirmed the local occurrence of DENV infection.

Japanese encephalitis virus (JEV) is a flavivirus, responsible for over 30,000 annual cases of encephalitis worldwide, with a mortality rate of approximately 30%. Therefore, it is important to examine the distribution of mosquitos carrying JEV in the fields, even though recently, the number of Japanese encephalitis cases has been approximately 5 per year in Japan. We report the seasonal dynamics of mosquitoes between 2010 and 2014 in Ishikawa Prefecture, Japan. We collected 39,308 female adult mosquitoes, 98.2% of which were classified as Culex tritaeniorhynchus Giles. We identified JEV genomic RNA belonging to genotype 1 from the homogenate of Cx. tritaeniorhynchus, collected during our study using reverse transcription-PCR and nucleotide sequencing techniques. Our results indicate that mosquito vectors for JEV are distributed not only in areas in Ishikawa, but also throughout Japan, and the results suggest that we must be careful regarding JEV outbreaks in Japan in the future.

A 9-valent human papillomavirus (HPV 6/11/16/18/31/33/45/52/58) virus-like particle vaccine (9vHPV) has been proven highly efficacious in preventing anogenital diseases related to HPV, in a pivotal phase III study for women aged 16-26 years. Here, we report the results of an open-label phase III study conducted to bridge the gap between the findings in women aged 16-26 years and Japanese girls aged 9-15 years. All subjects (n = 100) received a 3-dose regimen of 9vHPV vaccine on day 1 and at months 2 and 6. Anti-HPV serological assays were performed on day 1 and at months 7, 12, 24, and 30. At month 7 (4 weeks after the third dose), 100% of the subjects exhibited seroconversion for each type of HPV. Increases in geometric mean of the titers for anti-HPV 6/11/16/18/31/33/45/52/58 in the subjects were similar to those in Japanese women aged 16-26 years in a previous phase III study. Persistence of the anti-HPV response was observed for 2 years after administration of the third dose. In addition, administration of the 9vHPV vaccine was generally well-tolerated in Japanese girls.

Acute encephalitis syndrome (AES) is a major health problem in developing countries including India. Neuronal injury in encephalitis is attributed to direct toxicity from pathogens and proinflammatory cytokines. In this study, we assessed cytokine levels in serum and cerebrospinal fluid (CSF), and their correlation with clinical symptoms. In our study, patients with AES for a duration of less than 2 weeks underwent brain imaging followed by CSF analysis for routine parameters and viral studies. We assessed interleukin (IL)-6, IL-10, and regulated on activation, normal T cell expressed and secreted (RANTES) levels in the serum samples of all patients and in 50 CSF samples and compared them with serum cytokine levels of 64 age- and sex-matched controls. Of the 87 AES patients, 13 had Japanese encephalitis (JE). Serum IL-6, IL-10, and RANTES levels were significantly elevated in patients with AES compared with that in controls. Serum IL-10 levels were significantly reduced while RANTES levels were significantly elevated in patients who died. CSF IL-6 and IL-10 levels were significantly elevated in the non-JE group compared with that in JE patients. RANTES levels in the CSF were high in patients who had no seizures. IL-10 exerts its anti-inflammatory effect by modulating the innate and adaptive immune response, thus limiting the production of pro-inflammatory cytokines. Higher IL-10 levels were found to be protective in patients with acute encephalitis.

The purpose of this study was to investigate extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates from pediatric (aged 0 to 3 years) diarrhea patients in Surabaya, Indonesia, where this kind of survey is rare; our study included assessment of their antibiotic susceptibilities, as well as ESBL typing, multilocus sequence typing (MLST), and diarrheagenic E. coli (DEC)-typing. ESBL-producing E. coli were detected in 18.8% of all the samples. Many ESBL-producing E. coli had significantly lower susceptibility to gentamicin (p ＜ 0.0001) and the quinolones nalidixic acid (p＝0.004) and ciprofloxacin (p ＜ 0.0001) than non-producers. In ESBL-producing E. coli, 84.0% of strains expressed CTX-M-15 alone or in combination with other ESBL types. MLST revealed that 24.0% of ESBL-producers had sequence type 617, all of which expressed the CTX-M-15 gene; we also detected expression of 3 DEC-related genes: 2 enteroaggregative E. coli genes and 1 enteropathogenic E. coli gene. In conclusion, CTX-M-15-type ESBL-producing E. coli ST617 appear to have spread to Indonesia.

Encephalitis has been described worldwide as a severe complication in patients infected by dengue virus. Reactive oxygen species (ROS) production is a key mechanism involved in the neuronal damage caused by viral encephalitis. In the present study, the capability of dengue virus serotypes 2 (DENV2) and DENV4 to induce ROS production was investigated in a rat microglial cell line, HAPI cells. The cells were infected with DENV2 and DENV4 at a multiplicity of infection of 0.1 for a 2-h adsorption period. Japanese encephalitis virus (JEV) was used as the reference. DENV2- and DENV4-induced microglial activation and significantly increased ROS production corresponded to decreased cell viability. The activity of DENV4 was significantly higher than the activities of DENV2 and JEV at 48 and 72 h post infection. DENV4 partly induced ROS production via an iron-induced Fenton reaction, as demonstrated by the treatment with an iron chelator, deferiprone. Despite the induction of increased inducible nitric oxide synthase expression and nitric oxide (NO) production by JEV, DENV2, and DENV4 did not induce NO production, suggesting the activation of different pathways in response to infections by different viruses. In conclusion, DENV2 and DENV4 have the capability to induce ROS production and activate microglia, which have been reported as the key components of neuronal damage.

The first clinical case of the YG1 strain of the severe fever with thrombocytopenia syndrome virus (SFTSV) has been isolated in Japan. We found that only some of the cells underwent low pH-dependent cell fusion, although all of the cells were confirmed to have been infected with the virus. This suggested that the YG1 strain consists of a heterogeneous mixture of related viruses. Here, we established 3 subclones (termed E3, A4, and B7) from the YG1 strain, using the limiting dilution method with the pH-dependent cell fusion activity. Subclone E3 showed weak fusion activity and cytopathic effects (CPE) in Vero E6 cells. The amino acid sequence of E3 was identical to the published sequence for the YG1 strain, and it likely comprises a subpopulation of the YG1 strain. Subclone A4 displayed strong fusion activity under acidic conditions. In contrast, subclone B7 showed strong fusion activity and CPE under neutral and acidic conditions. Two amino acid differences shared between B7 and A4 were found in the envelope glycoproteins. In addition, an amino acid variant of the RNA-dependent RNA polymerase was found only in B7. These subclones will be valuable tools to elucidate cell fusion mechanisms of SFTSV and the relationship between viral proteins and their functions.

In this study, we conducted a species-level identification of group G streptococcal (GGS) isolates from companion animals in Japan and analyzed antimicrobial resistance (AMR) patterns. Strains were isolated from sterile and non-sterile specimens collected from 72 animals with clinical signs or symptoms in April-May, 2015. We identified the strain by 16S rRNA sequencing, mass spectrometry (MS), and an automated method based on their biochemical properties. Antimicrobial susceptibility was determined using the broth microdilution method and E-test. AMR determinants (erm(A), erm(B), mef(A), tet(M), tet(O), tet(K), tet(L), and tet(S)) in corresponding resistant isolates were amplified by PCR. The 16S rRNA sequencing identified the GGS species as Streptococcus canis (n = 68), Streptococcus dysgalactiae subsp. equisimilis (n = 3), and S. dysgalactiae subsp. dysgalactiae (n = 1). However, there were discrepancies between the sequencing data and both the MS and automated identification data. MS and the automated biochemical technique identified 18 and 37 of the 68 sequencing-identified S. canis strains, respectively. The AMR rates were 20.8% for tetracycline and 5.6% for clarithromycin, with minimum inhibitory concentrations (MIC)₅₀ -MIC₉₀ of 2-64 and ≤ 0.12-0.25μg/mL, respectively. AMR genotyping showed single or combined genotypes: erm(B) or tet(M)-tet(O)-tet(S). Our findings show the unique characteristics of GGS isolates from companion animals in Japan in terms of species-level identification and AMR patterns.

Adhesion of oral mitis group streptococci, such as Streptococcus gordonii, to acquired pellicle on the tooth surface is the first step in oral biofilm formation. S. gordonii strain DL1 possesses an Hsa adhesin, which recognizes the terminal sialic acid of host sialoglycoconjugates. The aim of the present study was to investigate the role of the Hsa adhesin in biofilm formation. The biofilm-forming ability of a S. gordonii hsa mutant on microtiter plates pre-coated with saliva, fetuin, or mucin was significantly lower than that of wild-type strain DL1. In contrast, no significant difference in biofilm-forming ability was observed in plates pre-coated with bovine serum albumin, which does not contain sialic acid. The biofilm-forming ability of strain DL1 in saliva-coated microtiter plates was also significantly reduced when the plate was pre-treated with neuraminidase. The sialic acid-dependent biofilm-forming ability of different wild-type S. gordonii strains varied. However, Southern and western blot analyses showed that all the tested wild-type strains possessed and expressed hsa homologs, respectively. These results indicate that the binding of Hsa adhesin to sialoglycoconjugates is associated with biofilm formation of S. gordonii DL1, and imply variation in the contribution of Hsa and its homologs to S. gordonii biofilm formation.

Staphylococcus lugdunensis (SL) is a bacterium with a highly pathogenicity than most other coagulase-negative Staphylococcus spp. (CoNS). In Japan, data on this pathogen are sparse, and the current prevalence of SL bacteremia is unknown. Therefore, we investigated the prevalence of SL in blood culture specimens in a prospective multicenter study across 5 facilities. A total of 3,284 patients had positive blood cultures, and 2,478 patients had bacteremia. Among the patients with bacteremia, 7 patients (0.28%) had SL bacteremia. A total of 281 patients had CoNS bacteremia, with SL accounting for 2.49% of these cases. Of the 7 patients with SL bacteremia, 1 patient (14.3%) had infective endocarditis, and 1 patient (14.3%) died within 30 days. In this study, SL resulted in the development of bacteremia in select patients. Clinicians in Japan should be aware of the prevalence of SL and the complications of SL bacteremia.

Monkeypox virus (MPXV) causes human monkeypox (human MPX), which is a similar disease to smallpox in humans. A previous study showed that a single vaccination of monkeys with LC16m8, a highly attenuated smallpox vaccine, protected them from MPX from 4-5 weeks post-vaccination. In this study, we evaluated the long-term efficacy of a single vaccination with LC16m8 in a nonhuman primate model of MPXV infection. The monkeys were inoculated with either LC16m8, Lister (parental strain of LC16m8), or a mock-up vaccine, and then challenged with MPXV via a subcutaneous route, at 6 and 12 months after vaccination, which we compared with either Lister or the mock-up vaccination. The LC16m8 monkeys exhibited almost no MPX-associated symptoms, whereas most of the naïve monkeys died. LC16m8 generated the protective memory immune response against MPXV, as suggested by the immediate viremia reduction and the response of the IgG antibody. The results demonstrated that the vaccination of monkeys with a single dose of LC16m8 provided durable protection against MPXV for longer than one year after immunization. The results suggest that the vaccination of humans with LC16m8 could induce long-term protection against MPXV infection.

Herpes simplex virus type 2 (HSV-2) is associated with a variety of diseases that are health problems worldwide. Our early study showed that lambda-interferons (IFN-λs), induced by the activation of the Toll-like receptor 3 and retinoic acid-inducible protein I signaling pathways, contribute to inhibition of HSV-2 replication in human cervical epithelial cells. However, anti-HSV-2 mechanisms and specific differences in signaling transduction by different IFN-λs in human cervical epithelial cells remain unclear. In this study, we demonstrated potent inhibition of HSV-2 replication by IFN-λs without cytotoxicity. Investigation of the underlying mechanism(s) showed that IFN-λs induced expression of IFN-stimulated genes (ISGs) and enhanced the expression of several pattern recognition receptors (PRRs). Among the IFN-λs, IFN-λ3 induced higher levels of ISG and PRR expression. In addition, IFN-λs up-regulated a number of genes that encode components of the Janus kinase signal transducers and activators of transcription (JAK/STAT) signaling pathway. Inhibition of the JAK/STAT signaling pathway by a JAK inhibitor abolished IFN-λ-mediated anti-HSV-2 activity and induction of ISGs and PRRs, whereas the induction of ISGs and PRRs by IFN-λs was not compromised by HSV-2 infection. These findings provide further experimental evidence that IFN-λs have therapeutic potential for HSV-2 infections.

Botulinum toxin is the most poisonous substance known, and is believed to be a highly lethal as a biological weapon; researchers of the toxin are exposed to this hazard. Botulinum toxoid vaccines have been produced and used in Japan. However, since clinical studies involving these vaccines were conducted before establishment of the Ethical Guidelines for Clinical Research in Japan, their immunogenicity and safety were not systematically assessed. In this study, we produced a new tetravalent (type A, B, E, and F) botulinum toxoid vaccine, the first ever to be derived from M toxin, and conducted quality control tests with reference to the Minimum Requirements in Japan for adsorbed tetanus toxoid vaccine. Subsequently, a clinical study using the new vaccine in 48 healthy adult volunteers was conducted according to the guidelines in Japan. No clinically serious adverse event was noted. Neutralizing antibody titers for each type of toxin in the participants’ sera, 1 month after the 4th injection were more than 0.25 IU/mL, indicating sufficient protection. This study demonstrated that the vaccine has marked immunogenicity and is safe for use in humans.

We evaluated interleukin-10 (IL10) －592 C/A, IL4－589 C/T, interferon gamma (IFNG)＋874 A/T, cytotoxic T-lymphocyte-associated antigen 4 (CTLA4)＋49 A/G gene polymorphisms associated with efavirenz hypersensitivity reaction. A total of 63 human immunodeficiency virus-positive patients under treatment at a public hospital were included in the study, of whom 21 presented with efavirenz hypersensitivity. Patients who presented with efavirenz hypersensitivity reaction showed a higher frequency of the IL10 －592A allele than the controls (p＝0.028). The allele A was associated with increased risk of efavirenz hypersensitivity (odds ratio＝2.40). In case of IL4, a significant difference in the frequency of the IL4 －589 (C/T) polymorphism was not observed between patients and controls. A significant inverse correlation was observed when comparing the CTLA4＋49A/G and IL4 －589 C/T polymorphisms (r＝－0.650, p＝0.001); that is, the CTLA4 +49GG genotype, involved with the lowest capacity of inhibition, was inversely correlated IL4－589TT genotype, which induces high production of IL-4. With respect to the CTLA4＋49A/G and IFNG＋874T/A gene polymorphisms, significant differences in allele and genotype frequencies were not observed between the groups. Therefore, our data suggest that polymorphisms in regulatory regions of cytokine genes could modulate an individual’s susceptibility to efavirenz hypersensitivity reaction.

Extensive application of routine insecticide i.e., dichlorodiphenyltrichloroethane (DDT) to control Phlebotomus argentipes (Diptera: Psychodidae), the proven vector of visceral leishmaniasis in India, had evoked the problem of resistance/tolerance against DDT, eventually nullifying the DDT dependent strategies to control this vector. Because tolerating an hour-long exposure to DDT is not challenging enough for the resistant P. argentipes, estimating susceptibility by exposing sand flies to insecticide for just an hour becomes a trivial and futile task.

Therefore, this bioassay study was carried out to investigate the maximum limit of exposure time to which DDT resistant P. argentipes can endure the effect of DDT for their survival. The mortality rate of laboratory-reared DDT resistant strain P. argentipes exposed to DDT was studied at discriminating time intervals of 60 min and it was concluded that highly resistant sand flies could withstand up to 420 min of exposure to this insecticide. Additionally, the lethal time for female P. argentipes was observed to be higher than for males suggesting that they are highly resistant to DDT’s toxicity. Our results support the monitoring of tolerance limit with respect to time and hence points towards an urgent need to change the World Health Organization’s protocol for susceptibility identification in resistant P. argentipes.

This cross-sectional descriptive study aimed to investigate the incidence of rotavirus and enteric bacterial infections among children up to 5 years old with diarrhea living in suburban and rural areas of Kenya. Between August 2011 and December 2013, a total of 1,060 diarrheal fecal specimens were obtained from 722 children at Kiambu County Hospital (KCH), located in a suburban area, and from 338 children from Mbita District Hospital (MDH), located in a rural part of western Kenya. Of the 1,060 isolates, group A rotavirus was detected in 29.6% (214/722) and 11.2% (38/338) fecal specimens from KCH and MDH, respectively. Diarrheagenic Escherichia coli (DEC) was found to be the most frequently isolated bacterial pathogens in both study areas (32.8% at KCH and 44.1% at MDH). Two different mixed infection patterns (virus/bacteria and bacteria/bacteria) were observed among patients. A significantly higher infection rate of rotavirus (17.6%, p = 0.001) and DEC (10.5%, p = 0.007) were observed during the dry season. Our study found that in both suburban and rural settings in Kenya, rotavirus and DEC are the principal cause of pediatric diarrhea and exhibit higher incidence during the dry season.

In Japan, monovalent and pentavalent rotavirus (RV) vaccines were approved in 2011 and 2012, respectively. To monitor changes in the RV genotypes before and after vaccine introduction, we performed a prospective observational study among children (＜ 5 years) with gastroenteritis who tested RV-positive on antigen rapid tests. Stool samples were collected from 3 different sites in Japan: Tsu City, Mie Prefecture; Kurashiki City, Okayama Prefecture; and Isumi City, Chiba Prefecture. RV genotypes were determined using reverse transcription-polymerase chain reaction. In Tsu City, G3P[8] was dominant (61.0–77.1%) before vaccine introduction, but decreased after introduction. Meanwhile, in an inverse proportion to the decrease in G3P[8], G1P[8] increased until the 2013/14 season, when a sudden predominance of G2P[4] (100%) occurred. A similar trend was observed in Kurashiki City in terms of the extent of reduction in G3P[8] and the emergence of G2P[4]. In Isumi City, G1P[8] was dominant (70.3%) before vaccine introduction, and G9P[8] became predominant (83.3%) in the 2013/14 season. To determine whether the genotype changes are attributable to vaccines or natural epidemiological changes, ongoing continuous monitoring of the RV genotypes is required.

Intrauterine infections are associated with life-threatening neonatal conditions such as sepsis, intracranial hemorrhage, and chronic lung disease. Herein we present a case of generalized congenital folliculitis caused by Pseudomonas aeruginosa in a preterm neonate of 27 weeks gestational age successfully treated with antibiotics. Folliculitis is an important manifestation of intrauterine P. aeruginosa infection, and prompt, effective treatment is crucial to ensuring a good prognosis.

Campylobacter ureolyticus has been considered as a potentially pathogenic bacterium. In this study, a total of 586 stool samples were collected from 0-12-year-old children with diarrhea between November 2013 and April 2015 and examined with microbiological tests in the hospital for the diagnosis of common enteric pathogens including C. jejuni and C. coli. Then in our laboratory, these samples were analyzed by 16S rRNA sequence-based Campylobacter genus-specific PCR (C16S PCR); 283 (48.3%) samples showed positive results with this PCR assay. Furthermore, C. ureolyticus was screened in these 283 samples by PCR assay, which can detect this species specifically. Surprisingly, C. ureolyticus was detected in 147 of the 283 C16S PCR-positive diarrheal stool samples (51.9%), which is much higher than the prevalence of C. jejuni and C. coli (15.5%), and 96 samples out of 147 were negative for any of the other enteric pathogens tested in the hospital; namely, C. ureolyticus was detected as a single pathogen in 96 samples. This finding suggests that C. ureolyticus may be a pathogen associated with diarrhea in children in Japan. To the best of our knowledge, this is the first report in which C. ureolyticus was detected among Japanese children with diarrhea.

Staphylococcus haemolyticus is a coagulase-negative staphylococcus that is frequently isolated from blood cultures. Here, we report a case of methicillin-susceptible S. haemolyticus that is resistant to teicoplanin (TEC) and heteroresistant to vancomycin (VAN). The isolate was susceptible to cefoxitin and resistant to TEC by Etest. Population analysis profile-area under the curve analysis confirmed the presence of a VAN heteroresistant subpopulation. Next-generation sequencing analysis of the genome revealed the presence of blaZ and msr(A), which encode cross-resistance to macrolide, lincosamide, and streptogramin B, and the quinolone resistance-conferring gene norA. In addition, several amino acid substitutions were observed in the TEC resistance operon tcaRAB, including I3N, I390N, and L450I in tcaA and L44V, G52V, and S87P in tcaR, as well as in the transpeptidase encoding gene walK (D336Y, R375L, and V404A) and L315 and P316 in graS. We hypothesized that this combination of mutations could confer TEC resistance and reduced VAN susceptibility.

We collected 200 Pseudomonas aeruginosa isolates from dogs and cats in primary veterinary hospitals in Japan to investigate their antimicrobial resistance. Resistance rates against ciprofloxacin, cefotaxime, gentamicin, amikacin, and fosfomycin were 9%, 12.5%, 4.5%, 2.5%, and 35.5%, respectively. One strain displayed resistance (0.5%) to ceftazidime. We did not detect any imipenem-resistant or multidrug-resistant P. aeruginosa strains as defined by the Japanese Ministry of Health, Labour, and Welfare Law Concerning the Prevention of Infections and Medical Care for Patients with Infections. In addition, we did not find any P. aeruginosa isolates that produced metallo-β-lactamase, the aminoglycoside 6′-N-acetyltransferase AAC(6′)-Iae, or the aminoglycoside acetyltransferase AAC(6′)-Ib.

The source and routes of diarrheagenic Escherichia coli (DEC) remain poorly understood. To investigate the involvement of domestic animals in the dissemination of DEC, the prevalence of DEC in foods and fecal specimens from cattle, pigs, chickens, healthy carriers, and patients in Osaka and Hyogo, Japan was investigated using a multiplex real-time Polymerase Chain Reaction assay. The most abundant virulence genes were astA and eae, which had a prevalence 46.8% and 27.4%, respectively. Additionally, stx1 (26.6%) and stx2 (45.9%) were prevalent in cattle feces, while est (8.5%) and elt (7.6%) were prevalent in pig feces. afaB was the second-most prevalent gene in patients and healthy carriers, and it had detection rates of 5.1% and 8.1%, respectively. In contrast, afaB was not detected in animal feces or foods, except for three porcine fecal samples. The aggR gene was more prevalent in humans than in foods or animal feces. Both Shiga toxin-producing E. coli and atypical enteropathogenic E. coli carried by cattle may be sources for diarrheal diseases in humans. Pigs may be a source for human enterotoxigenic E. coli infections, whereas humans are expected to be the reservoir for diffusely adhering E. coli, enteroaggregative E. coli, and enteroinvasive E. coli.