Characterization and antiviral susceptibility of SARS-CoV-2 Omicron BA.2.

The recent emergence of SARS-CoV-2 Omicron (B.1.1.529 lineage) variants possessing numerous mutations has raised concerns of decreased effectiveness of current vaccines, therapeutic monoclonal antibodies and antiviral drugs for COVID-19 against these variants1,2. The original Omicron lineage, BA.1, prevailed in many countries, but more recently, BA.2 has become dominant in at least 68 countries3. Here we evaluated the replicative ability and pathogenicity of authentic infectious BA.2 isolates in immunocompetent and human ACE2-expressing mice and hamsters. In contrast to recent data with chimeric, recombinant SARS-CoV-2 strains expressing the spike proteins of BA.1 and BA.2 on an ancestral WK-521 backbone4, we observed similar infectivity and pathogenicity in mice and hamsters for BA.2 and BA.1, and less pathogenicity compared with early SARS-CoV-2 strains. We also observed a marked and significant reduction in the neutralizing activity of plasma from individuals who had recovered from COVID-19 and vaccine recipients against BA.2 compared to ancestral and Delta variant strains. In addition, we found that some therapeutic monoclonal antibodies (REGN10987 plus REGN10933, COV2-2196 plus COV2-2130, and S309) and antiviral drugs (molnupiravir, nirmatrelvir and S-217622) can restrict viral infection in the respiratory organs of BA.2-infected hamsters. These findings suggest that the replication and pathogenicity of BA.2 is similar to that of BA.1 in rodents and that several therapeutic monoclonal antibodies and antiviral compounds are effective against Omicron BA.2 variants.

Comprehensive metabolic modulations of sphingolipids are promising severity indicators in COVID-19.

The COVID-19 pandemic, caused by SARS-CoV-2, has had a significant worldwide impact, affecting millions of people. COVID-19 is characterized by a heterogenous clinical phenotype, potentially involving hyperinflammation and prolonged tissue damage, although the exact underlying mechanisms are yet to be fully understood. Sphingolipid metabolites, which govern cell survival and proliferation, have emerged as key players in inflammatory signaling and cytokine responses. Given the complex metabolic pathway of sphingolipids, this study aimed to understand their potential role in the pathogenesis of COVID-19. We conducted a comprehensive examination of sphingolipid modulations across groups classified based on disease severity, incorporating a time-course in serum and urine samples. Several sphingolipids, including sphingosine, lactosylceramide, and hexosylceramide, emerged as promising indicators of COVID-19 severity, as validated by correlation analyses conducted on both serum and urine samples. Other sphingolipids, such as sphingosine 1-phosphate, ceramides, and deoxy-dihydroceramides, decreased in both COVID-19 patients and individuals with non-COVID infectious diseases. This suggests that these sphingolipids are not specifically associated with COVID-19 but rather with pathological conditions caused by infectious diseases. Our analysis of urine samples revealed elevated levels of various sphingolipids, with changes dependent on disease severity, potentially highlighting the acute kidney injury associated with COVID-19. This study illuminates the intricate relationship between disturbed sphingolipid metabolism, COVID-19 severity, and clinical factors. These findings provide valuable insights into the broader landscape of inflammatory diseases.

Characterization of mutations in hepatitis B virus DNA isolated from Japanese HBsAg-positive blood donors in 2021 and 2022.

Missense mutations in certain small envelope proteins diminish the efficacy of antibodies. Consequently, tracking the incidence and types of vaccine-escape mutations (VEMs) was crucial both before and after the introduction of universal hepatitis B vaccination in Japan in 2016. In this study, we isolated hepatitis B virus (HBV) DNA from 58 of 169 hepatitis B surface antigen (HBsAg)-positive blood samples from Japanese blood donors and determined the nucleotide sequence encoding the small envelope protein. DNA from six (10%) of the samples had VEMs, but no missense mutations, such as G145R, were detected. Complete HBV genome sequences were obtained from 29 of the 58 samples; the viral genotype was A1 in one (3%), A2 in three (10%), B1 in nine (31%), B2 in five (17%), B4 in one (3%), and C2 in 10 (34%) samples. Tenofovir-resistance mutations were detected in two (7%) samples. In addition, several core promoter mutations, such as 1762A>T and 1764G>A, and a precore nonsense mutation, 1986G>A, which are risk factors for HBV-related chronic liver disease, were detected. These findings provide a baseline for future research and highlight the importance of ongoing monitoring of VEMs and drug resistance mutations in HBV DNA from HBsAg-positive blood donors without HBV antibodies.

Differential peripheral memory T cell subsets sensitively indicate the severity of nonalcoholic fatty liver disease.

AIM: Differential patterns of peripheral memory T cell subsets in nonalcoholic fatty liver disease (NAFLD) were assessed using flow cytometry (FCM) to elucidate their association with NAFLD severity and provide a new noninvasive method to sensitively detect the disease severity in addition to existing biomarkers. METHODS: We assessed the differential frequencies of peripheral memory T cell subsets in 103 patients with NAFLD according to the degree of liver fibrosis (FIB) using FCM analysis. We focused on the following populations: CCR7+ CD45RA+ naïve T, CCR7+ CD45RA- central memory T cells (TCM), CCR7- CD45RA- effector memory T, and CCR7- CD45RA+ terminally differentiated effector memory T (TEMRA) cells in CD4+ and CD8+ T, Th1, Th2, and Th17 cells, respectively. To evaluate the pathological progression of the disease, these frequencies were also examined according to the degree of the NAFLD activity score (NAS). RESULTS: Several significant correlations were observed between laboratory parameters and peripheral memory T lymphocyte frequencies according to the degree of liver FIB and NAS in NAFLD. In univariate and multivariate analyses, the frequency of CD8+ TEMRA cells predicted severe FIB, and the predictive power was validated in an independent cohort. Furthermore, the frequencies of several memory T cell subsets sensitively indicated the pathological progression of NAFLD (Th17 TCM: steatosis, CD4+ TCM: lobular inflammation, and CD8+ TEMRA and effector memory T cells: hepatocellular ballooning). CONCLUSIONS: Our results suggest that the analysis of peripheral memory T lymphocyte frequencies can noninvasively predict severe FIB and sensitively indicate the pathological progression of NAFLD.

Attenuation of hepatitis A antibody after immunization with hepatitis A vaccine (Aimmugen) in people living with HIV.

AIM: Hepatitis A (HA) is a vaccine-preventable disease. In regions with good sanitation, men who have sex with men (MSM) are the key affected populations. During the 2018-2019 HA outbreak among MSM in Japan, we actively vaccinated MSM living with HIV (MSM-LWHIV) with Aimmugen. As previously reported, their antibody seroconversion rate due to vaccination was lower than that of healthy individuals. However, the durability of Aimmugen in people living with HIV has not yet been reported. We evaluated attenuation after the one-series vaccination (comprising three inoculations) and the factors associated with attenuation. METHODS: We retrospectively examined anti-HA immunoglobulin G (anti-HA-IgG) titers and other clinical data from our hospital's medical records. Patients with no history of vaccination or HA infection (i.e., negative HA-IgG titers) who received one series of Aimmugen, achieved seropositivity, and anti-HA-IgG antibodies were tested ≥2 years after three doses were included. Fisher's exact test and the Mann-Whitney U-test were performed. p < 0.05 was considered statistically significant. RESULTS: Fifty-one MSM-LWHIV were included. All were seropositive after the third dose with a median HA-IgG titer of 10.1 (interquartile range, 7.2-12.2) (sample/cut-off values [s/co]). In 45 (40-49) months, seropositivity decreased to 90% (46/51) and was attenuated to a median of 4.4 (2.3-6.5) s/co. Lower baseline B cell counts (p = 0.049), lower anti-HA-IgG levels after the second dose (p = 0.002), and lower anti-HA-IgG levels after the third dose (p = 0.003) were associated with seronegativity. CONCLUSIONS: Anti-HA-IgG titers of vaccinated MSM-LWHIV may be attenuated; thus, additional immunizations should be considered.

A case of hypervirulent K1-ST23 Klebsiella pneumoniae endocarditis and papillary muscle rupture secondary to multiple site abscesses.

Hypervirulent Klebsiella pneumoniae (hvKP) causes multisite infections and abscesses. However, endocarditis is a rare presentation of hvKP infection. Herein, we report a case of K. pneumoniae native valve infective endocarditis secondary to community-acquired liver and prostate abscesses. The patient developed papillary muscle rupture, leading to mitral regurgitation, and underwent emergent mitral valve replacement. The diagnosis of endocarditis was confirmed microbiologically and histologically. The causative strain belonged to the hypermucoid K1 capsular genotype and possessed the rmpA gene. The genome sequence was deposited in GenBank under the accession number JAQZBZ000000000.

Teicoplanin and vancomycin as treatment for glycopeptide-susceptible Enterococcus faecium bacteraemia: a propensity score-adjusted non-inferior comparative study.

OBJECTIVES: Limited evidence is available regarding alternative therapeutic agents to vancomycin in treating glycopeptide-susceptible Enterococcus faecium (GSEF) bacteraemia. This study assessed the effectiveness and safety of teicoplanin compared with vancomycin for treating GSEF bacteraemia. PATIENTS AND METHODS: This was a retrospective, non-inferiority cohort study. Patients aged ≥18 years who developed GSEF bacteraemia and received either teicoplanin or vancomycin were included. The primary effectiveness outcome was the clinical success at the end of treatment, with a generalized linear model using the propensity score for selecting the agent as a covariate. We used an absolute difference of 20% in clinical success as the non-inferiority margin. Using multivariable logistic regression, the primary safety outcome was the incidence of acute kidney injury (AKI). RESULTS: In total, 164 patients (74 and 90 in the teicoplanin and vancomycin groups, respectively) were included. Overall, 64.9% (48/74) and 48.9% (44/90) of patients in the teicoplanin and vancomycin groups, respectively, achieved the primary effectiveness outcome. A generalized linear analysis showed an adjusted effectiveness difference of 9.9% (95% CI, -0.9% to 20.0%; P = 0.07), indicating non-inferiority of teicoplanin versus vancomycin. The incidence of AKI was 8.1% (6/74) and 24.4% (22/90) in the teicoplanin and vancomycin groups, respectively, with an adjusted OR of 0.242 (95% CI, 0.068 to 0.864; P = 0.029), indicating significantly lower AKI risk in the teicoplanin than in the vancomycin group. CONCLUSIONS: Teicoplanin is a safe and useful alternative therapeutic agent for treating GSEF bacteraemia.

Incidence of sexually transmitted hepatitis C virus infection among men who have sex with men in Japan from 2009 to 2023.

Although the prevalence of hepatitis C virus (HCV) infection has decreased significantly with the advent of direct-acting antiviral agents, HCV is known to spread as a sexually transmitted disease among men who have sex with men (MSM), and this study aims to provide a perspective on the future prevalence of HCV in Japan. We examined incidence in two groups of MSM with HIV attending our institution in this retrospective cohort study, from 2009 to 2019 and from 2020 to May 2023 and investigated their background factors. Twenty-two cases were newly confirmed to be HCV infection in 2009-2019 and a total of 9 cases in 2020-2023, with an incidence rate of 5.04 per 1000 person-years in 2009-2019 and 5.55 per 1000 person-years in 2020-2023. All of them were diagnosed at routine outpatient visits for HIV, and few cases were considered to have symptoms of suspected hepatitis that led to a visit to the hospital and a diagnosis of HCV. Although HCV is still prevalent among MSM in Japan, it is possible that it would not have been diagnosed without testing at regular visits as in the case of people with HIV, and that the true prevalence rate among MSM, including non-HIV-infected persons, may be much higher.

Research article antibody induction and immune response in nasal cavity by third dose of SARS-CoV-2 mRNA vaccination.

BACKGROUND: The mucosa serves as the first defence against pathogens and facilitates the surveillance and elimination of symbiotic bacteria by mucosal immunity. Recently, the mRNA vaccine against SARS-CoV-2 has been demonstrated to induce secretory antibodies in the oral and nasal cavities in addition to a systemic immune response. However, the mechanism of induced immune stimulation effect on mucosal immunity and commensal bacteria profile remains unclear. METHODS: Here, we longitudinally analysed the changing nasal microbiota and both systemic and nasal immune response upon SARS-CoV-2 mRNA vaccination, and evaluated how mRNA vaccination influenced nasal microbiota in 18 healthy participants who had received the third BNT162b. RESULTS: The nasal S-RBD IgG level correlated significantly with plasma IgG levels until 1 month and the levels were sustained for 3 months post-vaccination. In contrast, nasal S-RBD IgA induction peaked at 1 month, albeit slightly, and correlated only with plasma IgA, but the induction level decreased markedly at 3 months post-vaccination. 16 S rRNA sequencing of the nasal microbiota post-vaccination revealed not an overall change, but a decrease in certain opportunistic bacteria, mainly Fusobacterium. The decrease in these bacteria was more pronounced in those who exhibited nasal S-RBD IgA induction, and those with higher S-RBD IgA induction had lower relative amounts of potentially pathogenic bacteria such as Pseudomonas pre-vaccination. In addition, plasma and mucosal S-RBD IgG levels correlated with decreased commensal pathogens such as Finegoldia. CONCLUSIONS: These findings suggest that the third dose of SARS-CoV-2 mRNA vaccination induced S-RBD antibodies in the nasal mucosa and may have stimulated mucosal immunity against opportunistic bacterial pathogens. This effect, albeit probably secondary, may be considered one of the benefits of mRNA vaccination. Furthermore, our data suggest that a cooperative function of mucosal and systemic immunity in the reduction of bacteria and provides a better understanding of the symbiotic relationship between the host and bacteria in the nasal mucosa.

Treatment and outcome of hepatorenal syndrome in Japan: a retrospective cohort study using a national inpatient database.

BACKGROUND: Hepatorenal syndrome (HRS) is a life-threatening complication of end-stage liver disease. This study aimed to clarify the status of HRS in Japan by analyzing the Japanese Diagnosis Procedure Combination database. METHODS: Patients hospitalized for cirrhosis and HRS from July 2010 to March 2019 were sampled. They were divided into two groups according to their prognosis upon discharge: the transplant-free survival group and the death or liver transplantation group. The two groups' baseline patient characteristics and treatments were compared. RESULTS: The mean age of the 1,412 participants was 67.3 years (standard deviation: 12.3 years), and 65.4% were male. The Child-Pugh grades was B and C in 18.8% and 81.2%, respectively. Hepatocellular carcinoma was present in 27.1% of the patients, and the proportion of spontaneous bacterial peritonitis was 2.3%. Albumin, noradrenaline, and dopamine were administered to 57.9%, 8.0%, and 14.9% of the patients, respectively; 7.0% of the patients underwent renal replacement therapy; and 5.0% were admitted to the intensive care unit. Intravenous antibiotics were administered to 30.8% of the patients. A total of 925 patients (65.5%) died or underwent liver transplantation. In addition to a higher proportion of patients with poor baseline liver function, the death or liver transplantation group included more males, patients with hepatocellular carcinoma, and those with spontaneous bacterial peritonitis. CONCLUSIONS: HRS in Japan has a high mortality rate. Albumin was administered to over 50% of participants. Although noradrenaline is recommended in Japanese clinical guidelines, dopamine was more frequently used as a vasoconstrictor in clinical practice.

Injection drug use and sexually transmitted infections among men who have sex with men: A retrospective cohort study at an HIV/AIDS referral hospital in Tokyo, 2013-2022.

Men who have sex with men (MSM) who use injection drugs (MSM-IDU) are at high risk of sexually transmitted infections (STIs), but the long-term incidence is unclear. We conducted a single-centre retrospective cohort study using the clinical records of non-haemophilia men with human immunodeficiency virus (HIV) who visited the Institute of Medical Science, the University of Tokyo (IMSUT) Hospital, located in Tokyo, Japan, from 2013 to 2022. We analysed 575 patients including 62 heterosexual males and 513 MSM patients, of whom 6.8% (35/513) were injection drug use (IDU). Compared to non-IDU MSM, MSM-IDU had a higher incidence of hepatitis C virus (HCV) (44.8 vs 3.5 /1,000 person-years (PY); incidence rate ratio (IRR) [95% confidence interval (95% CI)], 12.8 [5.5-29.3], p < 0.001) and syphilis (113.8 vs 53.3 /1,000 PY; IRR, 2.1 [1.4-3.1], p < 0.001). The incidence of other symptomatic STIs (amoebiasis, chlamydia, and gonorrhoea infections) was <4/1,000 PY. In multivariable Poisson regression analysis, HCV incidence was associated with MSM (IRR, 1.8 × 106 [9.9 × 105-3.4 × 106], p < 0.001), IDU (IRR, 10.1 [4.0-25.6], p < 0.001), and syphilis infection during the study period (IRR, 25.0 [1.2-518.3]/time/year, p < 0.001). Among men with HIV, the prevalence of IDU in MSM and the long-term incidence of STIs in MSM-IDU were high. IDU and sexual contact are important modes of transmission of HCV among HIV-infected MSM in Tokyo.

Triglyceride level and soft drink consumption predict nonalcoholic fatty liver disease in nonobese male adolescents.

AIM: Differential metabolic risk factors of nonalcoholic fatty liver disease (NAFLD) in nonobese male adolescents were analyzed examining relationships between NAFLD and clinical parameters of metabolic syndrome, including exercise and soft drink consumption, in male adolescents. METHODS: In total, 134 male university students (nonobese, n = 78; obese, n = 56) who underwent the first-year health checkup were divided into the NAFLD and non-NAFLD groups based on abdominal ultrasonography (AUS) findings. Relationships between NAFLD and metabolic parameters, including body mass index (BMI) and AUS score, were examined in nonobese students. RESULTS: Metabolic factors associated with hypertension, abdominal fat, liver damage, dyslipidemia, and impaired glucose tolerance were significantly less common in nonobese students than in obese students. The aforementioned factors and soft drink consumption were significantly more common in the NAFLD group than in the non-NAFLD group. The univariate and multivariate analyses of nonobese students showed that the triglyceride level (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.01-1.10, p = 0.001) was higher and soft drink consumption (OR, 36.8; 95% CI, 3.69-368, p < 0.001) was more common in the NAFLD group than the non-NAFLD group. CONCLUSIONS: Triglyceride level and soft drink consumption could aid in the detection of NAFLD in nonobese male adolescents. Our findings could provide useful information related to NAFLD and metabolic syndrome in nonobese adolescents.

HBx-induced degradation of Smc5/6 complex impairs homologous recombination-mediated repair of damaged DNA.

BACKGROUND & AIMS: HBV causes hepatocellular carcinoma (HCC). While it was recently shown that the ability of HBV X protein (HBx) to impair the Smc5/6 (structural maintenance of chromosome 5/6) complex is important for viral transcription, HBx is also a potent driver of HCC. However, the mechanism by which HBx expression induces hepatocarcinogenesis is unclear. METHODS: Degradation of the Smc5/6 complex and accumulation of DNA damage were observed in both in vivo and in vitro HBV infection models. Rescue experiments were performed using nitazoxanide (NTZ), which inhibits degradation of the Smc5/6 complex by HBx. RESULTS: HBx-triggered degradation of the Smc5/6 complex causes impaired homologous recombination (HR) repair of DNA double-strand breaks (DSBs), leading to cellular transformation. We found that DNA damage accumulated in the liver tissue of HBV-infected humanized chimeric mice, HBx-transgenic mice, and human tissues. HBx suppressed the HR repair of DSBs, including that induced by the CRISPR-Cas9 system, in an Smc5/6-dependent manner, which was rescued by restoring the Smc5/6 complex. NTZ restored HR repair in, and colony formation by, HBx-expressing cells. CONCLUSIONS: Degradation of the Smc5/6 complex by HBx increases viral transcription and promotes cellular transformation by impairing HR repair of DSBs. LAY SUMMARY: The hepatitis B virus expresses a regulatory protein called HBV X protein (or HBx). This protein degrades the Smc5/6 complex in human hepatocytes, which is essential for viral replication. We found that this process also plays a key role in the accumulation of DNA damage, which contributes to HBx-mediated tumorigenesis.

Prevalence of HIV infection among non-elderly individuals with hepatitis C in Japan: a population-based cohort study using a health insurance claim data.

BACKGROUND: Hepatitis C virus (HCV) has been mainly transmitted through injection drug use, but recently, sexual transmission among men who have sex with men (MSM), which is also a major route of HIV transmission, is increasing. However, the prevalence of HIV and the incidence of other sexually transmitted infections (STIs) among HCV patients have been rarely reported. METHODS: Using a healthcare insurance claim data of employees and their dependents covering seven-million people in Japan, we evaluated HIV prevalence among HCV patients aged 20-59 years. Hemophilia patients were excluded. HIV and HCV were defined by registered diagnoses and receiving viral RNA testing. The time course of HCV and HIV infections was analyzed. Incidences of syphilis, amebiasis, chlamydia, gonorrhea, hepatitis A, and hepatitis B were assessed. RESULTS: From April 2012 to August 2018, 6,422 HCV patients were identified. HIV prevalence was 0.48% (31/6422, 95% CI [confidence interval]: 0.33-0.68%). HIV was diagnosed after HCV in 3.2% (1/31), before HCV in 58.1% (18/31), and concurrently in 38.7% (12/31). Compared with HCV patients without HIV infection, HCV/HIV co-infected patients were younger (median age, 37 vs 51 years, p < 0.001), more likely to be male (30/31 [96.8%] vs 3059/6391 [47.9%], p < 0.001), more likely to have other STIs (38.7% [12/31] vs 0.9% [56/6391], p < 0.001), and live in Tokyo, the most populous capital city in Japan (67.7% [21/31] vs 11.6% [742/6391], p < 0.001). In Tokyo, the HIV prevalence among 20-30 s male with HCV was 18.6% (13/70; 95% CI, 10.3-29.7%). CONCLUSIONS: HIV prevalence among young male HCV patients was very high in Tokyo. HCV/HIV co-infected patients were more likely to acquire HIV before HCV, which is a known feature of MSM. They also had a higher incidence of STIs. These findings suggest that HCV might be prevalent as an STI among MSM particularly in Tokyo.

Predictors associated with a better response to the Japanese aluminum-free hepatitis A vaccine, Aimmugen® , for people living with HIV.

AIM: After the hepatitis A virus (HAV) outbreak among men who have sex with men (MSM) around 2018, the importance of HAV vaccination was emphasized, especially for MSM-living with human immunodeficiency virus (MSM-LWHIV). Aimmugen® is licensed and distributed exclusively in Japan. While administration of three doses is recommended, 85% of recipients in the general population were reported to acquire seroprotection after the second dose. In this study, we evaluated the efficacy of two or three vaccine doses along with predictors associated with the response to Aimmugen® in MSM-LWHIV. METHODS: We retrospectively examined anti-HA-IgG titers of MSM-LWHIV vaccinated with Aimmugen® in our hospital. Patients' data were collected from medical records. RESULTS: Between January 2018 and October 2019, 141 subjects whose median age was 46 years old, were examined. All the subjects were on antiretroviral therapy (ART) and the median CD4 count was 615/µL. The acquisition rate of protectable anti-HA-IgG titers after the second and third dose was 71.1% and 98.6%, respectively. In 114 subjects whose anti-HA-IgG titers were tested after the second-dose, factors significantly associated with better response were prolonged ART duration and higher CD4 count. The titers of anti-HA-IgG after the third dose were higher in those who became seropositive after the second-dose than those who did not. CONCLUSIONS: Three-dose of Aimmugen® for MSM-LWHIV was effective while two-dose was less effective compared to non-HIV-infected people. People-LWHIV with shorter duration of ART and lesser CD4 cell count achieved lower titers of anti-HA-IgG and might require an additional vaccination.

Anti-spike protein antibody titer at the time of breakthrough infection of SARS-CoV-2 omicron.

By December 2021, about 80% of people over the age of 12 had been vaccinated in Japan, and almost all people were vaccinated with the mRNA vaccine. We investigated here the anti-spike protein antibody titer at the time of breakthrough infection of SARS-CoV-2 omicron. A total of 32 SARS-CoV2 omicron breakthrough infection was included in the study. The median antibody titer at breakthrough infection was 776 AU/mL overall, of which the median antibody titer of BNT162b2 vaccinated was 633 AU/mL and that of mRNA-1273 vaccinated was 9416 AU/mL. This result suggests that low levels of antibody titers 6 months after vaccination do not provide sufficient antibodies to prevent the omicron variant breakthrough infection, which may occur with a higher anti-spike antibody titer after vaccination with mRNA-1273. However, antibody titers in some patients were comparable to those immediately after the second vaccination with either mRNA vaccine.

An Outbreak of USA300 Methicillin-Resistant Staphylococcus aureus Among People With HIV in Japan.

BACKGROUND: USA300 produces Panton-Valentin leucocidin (PVL) and is known as a predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) strain in the United States, but it was extremely rare in Japan. We report here an outbreak of USA300 in people with HIV (PWH) in Tokyo, Japan. METHODS: We analyzed the cases of PVL-MRSA infection between 2010 and 2020 and screened for nasal colonization of PVL-MRSA in PWH who visited an HIV/AIDS referral hospital from December 2019 to March 2020. Whole-genome sequencing-based single nucleotide polymorphism (SNP) analysis was performed on these isolates. RESULTS: During the study period, a total of 21 PVL-MRSA infections in 14 patients were identified after 2014. The carriage prevalence was 4.3% (12/277) and PVL-MRSA carriers were more likely to have sexually transmitted infections (STIs) within a year compared with patients who had neither a history of PVL-MRSA infection nor colonization (33.3% [4/12] vs 10.1% [26/258]; P = .03). SNP analysis showed that all 26 isolates were ST8-SCCmecIVa-USA300. Twenty-four isolates were closely related (≤100 SNP differences) and had the nonsynonymous SNPs associated with carbohydrate metabolism and antimicrobial tolerance. CONCLUSIONS: An outbreak of USA300 has been occurring among PWH in Tokyo and a history of STI was a risk of colonization.

The Oncogenic Role of Hepatitis C Virus.

Persistent infection with hepatitis C virus (HCV) is a major risk factor for hepatocellular carcinoma (HCC). Accumulating evidence suggests that not only inflammation and subsequent fibrosis but also HCV itself are associated with hepatocarcinogenesis. To date, studies using transgenic mouse and cell-culture models, in which HCV proteins are expressed, indicate the direct pathogenicity of HCV, including oncogenic activity. In particular, the core protein of HCV induces excessive oxidative stress by impairing the mitochondrial electron transfer system by disrupting the function of the molecular chaperone, prohibitin. HCV also modulates intracellular signaling pathways, including mitogen-activated protein kinase, promoting the proliferation of hepatocytes. In addition, HCV induces disorders in lipid and glucose metabolism, thereby accelerating the progression of liver fibrosis and the development of HCC. Due to the development of direct-acting antivirals, which was made possible by basic research, HCV can be eradicated from almost all infected patients. However, such patients can develop HCC long after eradication of HCV, suggesting the genetic and/or epigenetic changes induced by HCV may be persistent. These results enhance our understanding of the role of HCV in hepatocarcinogenesis and will facilitate the development of therapeutic and preventive strategies for HCV-induced HCC.

Change in hepatitis C virus positivity among needle-stick injury source patients: a 10-year experience in a Japanese tertiary hospital.

BACKGROUND: As a blood-borne pathogen, hepatitis C virus (HCV) has long been a major threat associated with needle-stick injuries (NSIs) mainly because no vaccine is available for HCV. Following an NSI, we usually test the source patient for HCV antibody (HCV-Ab). Since HCV-Ab positivity does not necessarily indicate current infection, HCV RNA is further examined in patients positive for HCV-Ab. Direct-acting antivirals (DAAs) have enabled us to treat most HCV-infected patients; therefore, we speculate that the rate of HCV RNA positivity among HCV-Ab-positive patients decreased after the emergence of DAAs. This cross-sectional study was performed to investigate the change in the actual HCV RNA positivity rate in source patients before and after the interferon (IFN)-free DAA era. METHODS: This was a cross-sectional study of NSI source patients at a tertiary academic hospital in Japan from 2009 to 2019. IFN-free DAA regimens were first introduced in Japan in 2014. Accordingly, we compared HCV status of NSI source patients that occurred between 2009 and 2014 (the era before IFN-free DAAs) with those that occurred between 2015 and 2019 (the era of IFN-free DAAs) in a tertiary care hospital in Japan. RESULTS: In total, 1435 NSIs occurred, and 150 HCV-Ab-positive patients were analyzed. The proportion of HCV RNA-positive patients significantly changed from 2009 through 2019 (p = 0.005, Cochran-Armitage test). Between 2009 and 2014, 102 source patients were HCV-Ab-positive, 78 of whom were also positive for HCV RNA (76.5%; 95%CI, 67.4-83.6%). Between 2015 and 2019, 48 patients were HCV-Ab-positive, 23 of whom were also positive for HCV RNA (47.9%; 95%CI, 34.5-61.7%; p = 0.0007 compared with 2009-2014). In the era of IFN-free DAAs, 9 of 23 HCV RNA-negative patients (39.1%) and 2 of 22 HCV RNA-positive patients (9.1%) were treated with an IFN-free combination of DAAs (p = 0.0351). Regarding the departments where NSIs occurred, HCV RNA-negative patients were predominant in departments not related to liver diseases in the era of IFN-free DAAs (p = 0.0078, compared with 2009-2014). CONCLUSIONS: Actual HCV RNA positivity in source patients of NSIs decreased after the emergence of IFN-free DAAs. IFN-free DAAs might have contributed to this reduction, and HCV RNA-negative patients were predominant in departments not related to liver diseases in the era of IFN-free DAAs.

Association of coagulopathy with liver dysfunction in patients with COVID-19.

AIM: Liver dysfunction is sometimes observed in patients with coronavirus disease 2019 (COVID-19), but most studies are from China, and the frequency in other countries is unclear. In addition, previous studies suggested several mechanisms of liver damage, but precise or additional mechanisms are not clearly elucidated. Therefore, we examined COVID-19 patients to explore the proportion of patients with liver dysfunction and also the factors associated with liver dysfunction. METHODS: We retrospectively examined 60 COVID-19 patients hospitalized at the Hospital affiliated with The Institute of Medical Science, The University of Tokyo (Tokyo, Japan). Patients who presented ≥40 U/L alanine aminotransferase (ALT) levels at least once during their hospitalization were defined as high-ALT patients, and the others as normal-ALT patients. The worst values of physical and laboratory findings during hospitalization for each patient were extracted for the analyses. Univariable and multivariable logistic regression models with bootstrap (for 1000 times) were carried out. RESULTS: Among 60 patients, there were 31 (52%) high-ALT patients. The high-ALT patients were obese, and had significantly higher levels of D-dimer and fibrin/fibrinogen degradation products, as well as white blood cell count, and levels of C-reactive protein, ferritin, and fibrinogen. Multivariable analysis showed D-dimer and white blood cells as independent factors. CONCLUSIONS: Considering that higher D-dimer level and white blood cell count were independently associated with ALT elevation, liver dysfunction in COVID-19 patients might be induced by microvascular thrombosis in addition to systemic inflammation.