Japanese journal of infectious diseases最新文献

Tick-borne viruses are primarily transmitted to vertebrates by infected ticks during blood feeding and cause various diseases in humans and animals. Haemaphysalis longicornis is one of the main tick species responsible for human tick bites and is thought to be the primary vector of severe fever with thrombocytopenia syndrome, an important tick-borne viral disease in Japan. Although H. longicornis ticks pose a potential risk to humans in Japan, studies on tick-borne viral prevalence of this tick species in Japan are limited. In this study, we conducted RNA virome analysis of H. longicornis ticks collected in Toyooka City, Hyogo Prefecture, Japan. Two known viruses, Dabieshan tick virus and Hubei sobemo-like virus 15, and putative novel quaranjavirus-like sequences were detected. Additionally, assessments of endogenous viral elements (EVEs) related to the virus and virus-like sequences suggested putative novel quaranjavirus-like sequences existed in both RNA and DNA forms. However, we could not determine whether this quaranjavirus-like sequence was of viral origin and could not conclude whether the DNA forms of the quaranjavirus-like sequence existed as EVEs in ticks. This study provides new insights into the prevalence of tick-associated viruses in ixodid ticks and serves as a reference for future approaches to prevent tick-borne disease.

Non-typhoidal Salmonellae are significant foodborne pathogens with ≥2,600 serovars and a diverse range of hosts, which significantly increases the chances of infection in humans. Salmonella enterica subsp. enterica serovar Oslo (S. Oslo) is a rare serovar associated with foodborne illnesses. Here, we aim to report the draft, whole-genome sequences of S. Oslo ST2344 and ST1370 with reduced ciprofloxacin susceptibility, isolated from clinical samples. Thirty S. Oslo isolates were identified following the standard microbiological techniques. Twenty-six of the thirty (86.66%) S. Oslo isolates were pan-susceptible to the antimicrobials examined, while four isolates showed decreased ciprofloxacin susceptibility (minimum inhibitory concentration: 0.12-0.50 µg/mL). Pulsed-field gel electrophoresis analysis showed strains were heterogeneous with the two sequence types of ST1370 and ST2344, which were observed in multilocus sequence typing . The average genome size of the four S. Oslo isolates ranged from 4,760,441 to 5,002,787 bp, with an average G+C content of 52%. Different virulence genes encompassing Salmonella Pathogenicity Island 1 to 5 linked to disease pathogenesis were found by genome analysis. The draft genome of S. Oslo clinical isolates provides insight into the molecular characteristics of the S. Oslo currently prevalent in India, and the phylogenetic analysis sheds light on their evolutionary pattern.

Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with a high mortality rate. Identifying the predisposing factors for NF is critical for enabling diagnosis and medical treatment. This study aimed to identify the factors associated with NF in a hospital located in rural Thailand. In total, 167 NF and 147 cellulitis cases were compared between 2019 and 2021. Among the NF cases, 13.17% required amputation and 7.69% were fatal. The study identified male sex, farming occupation, Streptococcus pyogenes infection, and comorbidities, including diabetes mellitus (DM), chronic kidney disease, and hypertension, as significant predisposing factors for NF. DM was statistically significantly associated with an increased risk of amputation. For pathogen-specific NF, advanced age (≥60 years) was the only statistically significant predisposing factor for S. pyogenes-associated NF. Conversely, NF caused by Staphylococcus aureus is significantly associated with farming occupation, DM, and hypertension. For NF caused by Enterobacterales, male sex, farming occupation, DM, and chronic kidney disease were statistically significant predisposing factors. These may not be risk factors that can be generalized, but may be the only risk factors for NF in Thailand. However, these findings may inform the development of guidelines for nursing care and pathogen-specific prevention of NF.

The Coronavirus disease 2019 (COVID-19) pandemic has disproportionately affected vulnerable populations in long-term care hospitals (LTCHs). This study examined the interplay between patient and hospital factors in relation to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 mortality in Korean LTCHs. This retrospective cohort study included 262,221 patients (aged ≥60) who were hospitalized for ≥30 days in 2021. Multilevel logistic regression models were used to assess the association of hospital and patient factors with SARS-CoV-2 infection and COVID-19 mortality. At the hospital level, more doctors were associated with a decreased risk of SARS-CoV-2 infection (odds ratio [OR] = 0.84, 95% confidence interval [CI]: 0.73-0.98) and COVID-19 mortality (OR = 0.85, 95% CI: 0.78-0.93), whereas nurses/aides were associated with an increased risk of SARS-CoV-2 infection (OR = 1.02, 95% CI: 1.00-1.03) and COVID-19 mortality (OR = 1.01, 95% CI: 1.00-1.02). Among patient-level factors, female sex (infection OR = 0.89, 95% CI: 0.83-0.96; mortality OR = 0.65, 95% CI: 0.55-0.77) was associated with decreased risks of both infection and mortality. These findings highlight the importance of staffing and infection control measures to mitigate COVID-19 risk in LTCH settings.

The human bocavirus (HBoV) in children have been identified with an acute lower respiratory tract disease (LRTD). Its prevalence, clinical characteristics, and function as an RTD causal agent are unclear. This study sought to evaluate the laboratory and clinical data of HBoV patients, pinpoint the clinical characteristics linked to HBoV, and examine the distinctions between detecting HBoV alone and in combination with other agents. We used molecular testing to confirm the presence of HBoV DNA and 20 other respiratory pathogens in 1739 nasopharyngeal samples from hospitalized children at the Pediatric Infectious Diseases Service. 73 children, whose median age was 15 months, had HBoV. Concomitant infection of Bocavirus with another virus was observed in 41 (56.1%) of the patients. Coinfections were observed most frequently with rhinovirus (n=17) and RSV (n=10). There was no difference between the isolated bocavirus and coinfection groups in terms of age, clinical presentations, chest X-ray findings, or laboratory results. A role of HBoV in RTD is supported by the fact that the majority of patients were admitted to the hospital with a diagnosis of pneumonia or bronchopneumonia. HBoV mainly affects the respiratory tract, but it can also cause different clinical manifestations.

This study investigated the etiology of hand, foot and mouth disease (HFMD) in Yunnan Province, China, in 2023 by sequencing the complete VP1 region of enteroviruses. A total of 185 enteroviruses were identified from 429 stool samples collected from nine prefectures/cities in Yunnan Province in 2023. These findings revealed that CVA16 was the most prevalent serotype, followed by CVA4, CVA6, CVA10 and EV-A71. Phylogenetic analysis revealed that among the 76 CVA16 strains, 73 strains were subgenotype B1a, and 3 strains were B1b. Among the 32 CVA4 strains, 31 strains were subgenotype C2, and only 1 strain was C5. All 25 CVA6 strains belong to subgenotype D3a, all 22 CVA10 strains are genotype C, and all 11 EV-A71 strains are of the C4a subgenotype. HFMD genotypes and sub-genotypes are crucial for public surveillance and outbreak response, and can inform vaccine development.

Group A Streptococcus (GAS) is a major pathogen of respiratory infections in children. This study investigated recent trends in antimicrobial susceptibility among GAS isolates in our hospital and compared them with past data. Between 2021 and 2023, 195 GAS isolates were obtained from 195 pediatric patients. Minimum inhibitory concentrations (MICs) of 22 antimicrobial agents were determined using the broth microdilution method. Susceptibility was categorized as susceptible (S), intermediate (I), or resistant (R) according to the Clinical and Laboratory Standards Institute criteria and compared with six previous surveys (1996-2018; total 1,871 isolates). The number of isolates was low in 2021-2022 but increased sharply in 2023 (n=157). Most isolates were from throat swabs, and the median age was 5 years (range: 1-15 years). Resistance (I + R) rates were as follows: azithromycin (20%), erythromycin (19%), clarithromycin (19%), tetracycline (8%), and clindamycin (4%). Erythromycin resistance increased from 9% in 1996 to 58% in 2013 but declined to 19% in this study. No β-lactam resistance was previously observed; however, two isolates (1%) showed elevated MICs to cefalexin, suggesting reduced susceptibility. These findings underscore the importance of continued monitoring of GAS isolation trends and antimicrobial resistance, including emerging β-lactam reduced susceptibility.

This study estimated the incidence of extraintestinal pathogenic Escherichia coli (E. coli; ExPEC) infections at Kyushu University Hospital from 2013-2018, analyzing 63,041 hospitalized and 178,690 outpatients aged ≥20 years. ExPEC infections were defined as E. coli detection in sterile specimens or urine specimens (≥103 CFU/mL) with increased SOFA scores or urological infection diagnosis codes. The incidence rate was substantially higher in hospitalized patients (1,209.3 per 100,000 person-years) compared to outpatients (94.5 per 100,000 person-years), with females showing slightly higher rates in both groups. Age was a significant risk factor, with incidence rates increasing markedly in patients ≥60 years (inpatients: 1,431.6; outpatients: 125.3 per 100,000 person-years). Importantly, the study revealed that relying solely on diagnostic names underestimated the true number of ExPEC infection cases. The precision rate, defined as the proportion of cases (n=61) with both E. coli isolated and clinically inflammatory symptoms who received an infectious disease diagnosis (n=46), was at most 75% in female outpatients. It is suggested that comprehensive microbiological data combined with clinical criteria provides more accurate surveillance. These findings establish baseline incidence rates for ExPEC infections in a Japanese hospital setting and highlight the clinical significance of these infections, particularly in elderly hospitalized patients.

The COVID-19 mortality seemed to be higher in high-income/hygienic countries; this is contrary to conventional communicable diseases which usually occur in low-income countries. Another characteristic of COVID-19 is that some proportions of the infected persons had no symptoms but transmitted the virus to others. In this paper, the author proposes a hypothesis that infected but asymptomatic persons produce two kinds of infectious respiratory particles (IRP) by speaking: large droplets and small aerosols. The large droplets are produced from the saliva by pronouncing a plosive, /p/ or /t/; and the small aerosols are produced from the laryngeal exudate by vibration of vocal cords for voicing of vowels. The heavy droplets collide with the face of other persons in conversation, resulting in droplet infection. In contrast, the lighter aerosols float in the air, accumulate inside an airtight room after a longer talking, and cause airborne infection in other persons staying in the same room. Then, the author discusses on the COVID-19 global epidemiology, which may have depended on 1) climate and housing structure, 2) cultural behaviors, and 3) languages among different countries.

Coronavirus disease 2019 (COVID-19) clusters are serious for older adults in nursing homes. Several studies have analyzed patient epidemiology and trends in blood antibody titers after COVID-19 cluster outbreaks, but few comparative analyses of pre- and post-cluster outbreaks have been reported. This study aimed to investigate epidemiological surveys and whole-genome sequences of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in clinical specimens following a COVID-19 cluster occurrence in a nursing home. Routes and modes of infection were analyzed in the study participants using 'Pomegraph', a newly developed integrated graphical tool, in combination with epidemiological and genome information. Our findings showed that although the viruses were the same XBB subvariants of SARS-CoV-2 Omicron XBB.1.5 and XBB.1.16, they were imported from three different locations, based on the genome sequences. We evaluated the amount of antibodies and neutralizing antibody titers in the participants' sera pre- and post- the cluster outbreak. Before the cluster outbreak, no significant differences were observed between infected and uninfected participants in the period after vaccination or in the amounts of antibodies and neutralizing antibody titers, which is difficult to determine in general clusters. Our results facilitated the analysis of cluster factors such as pathogens, susceptible persons, and transmission.