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The FilmArray® Gastrointestinal (GI) Panel is a modern, sensitive, and comprehensive stool testing technique for identifying common gastrointestinal pathogens, including viruses, bacteria, and parasites. Its increasing demand is due to ease of operation and automation. Pathogens, particularly viruses, undergo constant genetic evolution. For instance, human astrovirus (HAstV), which causes gastroenteritis in children, the elderly, and immune-compromised individuals, can be identified by the GI Panel. HAstV has evolved into several clades, including the classic (HAstV1-8), novel Melbourne (MLB1-3), and Virginia (VA1-5) clades. This study investigated whether the GI Panel accurately detects all HAstV clades. A total of 12 stool and three sewage water (SW) samples were selected post-confirmation of distinct HAstV strains using conventional RT-PCR and sequence-based genotyping for reassessment by the GI Panel. The GI Panel accurately detected the classic HAstV in stool and SW samples. However, our results confirm the GI Panel's inability to detect the novel MLB (MLB1-3) and VA (VA2) clades in fecal samples, raising the possibility of false-negative results in HAstV testing. Although the GI Panel is useful for identifying a variety of gastrointestinal pathogens in stool and SW samples in a single test, our findings highlight the need to exercise caution when interpreting HAstV results from the GI Panel., Competing Interests: Declaration of competing interest None of the authors have any conflicts of interest to declare., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Introduction: Antimicrobial susceptibility patterns of bacterial pathogens isolated from patients with complicated urinary tract infections were analyzed using the national surveillance data, comprising 793 bacterial strains from eight clinically relevant species., Materials and Methods: Data were collected for the fourth national surveillance project from July 2020 to December 2021 by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Disease, and the Japanese Society of Clinical Microbiology. Surveillance was supervised with the cooperation of 43 medical institutions throughout Japan., Results: Fluoroquinolone required a minimum inhibitory concentration (MIC) of 2-64 mg/L to inhibit the 330 tested Escherichia coli strains. The proportion of levofloxacin-resistant E. coli strains increased from 28.6% in 2008 to 29.6% in 2011, 38.5% in 2015, and 44.5% in 2021. The proportion of levofloxacin-resistant strains of Pseudomonas aeruginosa also increased from previous survey results, showing a continuing downward trend. Conversely, the proportion of levofloxacin-resistant strains of Enterococcus faecalis decreased relative to previous reports. Neither multidrug-resistant P. aeruginosa nor carbapenem-resistant Enterobacteriaceae were detected. For methicillin-resistant Staphylococcus aureus (MRSA), the proportion of vancomycin-susceptible strains (MIC of 2 μg/mL) decreased from 14.7% to 7.7%., Discussion: Bacterial strains that produced extended-spectrum β-lactamase included E. coli (82/330 strains, 24.8%), Klebsiella pneumoniae (11/68 strains, 16.2%), and Proteus mirabilis (4/26 strains, 15.4%). As compared to previous surveillance reports, these strains showed an increase in proportion over the years., Competing Interests: Declaration of competing interest Satoshi Takahashi received speaker honoraria from Fujirebio Inc. and research funding from Shino-Test Corporation, Roche Diagnostic K. K., Fujirebio Inc., and Abbott Japan Co., Ltd. Koichiro Wada received speaker honoraria from Janssen Pharmaceutical K.K., and MSD K.K. Shingo Yamamoto received speaker honoraria from MSD K.K., Fuso Pharmaceutical Industries, Ltd., Daiichi Sankyo Co., Ltd. and scholarship donations from Takeda Pharmaceutical Co., Ltd., Nippon Shinyaku Co., Ltd., Ono Pharmaceutical Co., Ltd., Bayer Yakuhin, Ltd. and research funding from Takeda Pharmaceutical Co., Ltd. Tetsuya Matsumoto received speaker honoraria from MSD K.K., Pfizer Japan Inc., and Kyorin Pharmaceutical Co., Ltd., and research funding from Kewpie Corporation., Biofermin Pharmaceutical Co., Ltd. Kazumasa Matsumoto received research funding from Sysmex Corporation. Tohru Nakagawa received speaker honoraria from Astellas Pharma Inc., AstraZeneca K.K., Ono Pharmaceutical Co., Ltd., and Janssen Pharmaceutical K.K., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Introduction: Norovirus (NoV) is the most common agent causing outbreaks and sporadic cases of acute gastroenteritis among all ages, especially children under 5 years old. During the coronavirus disease 2019 (COVID-19) pandemic, NoV infection has decreased drastically in Japan due to school closures and no outbreak related to NoV infection had been reported., Method: In mid-September 2021, NoV outbreak occurred in kindergarten and nursery schools in Maizuru, Kyoto prefecture, Japan. Twenty-six stool samples collected from patients who were diagnosed of NoV gastroenteritis from the outbreak by an immunochromatographic (IC) kit at a pediatric outpatient clinic in Maizuru city during 3 weeks from September 13 to October 8, 2021 were examined for the presence of NoV GII by reverse transcriptase-polymerase chain reaction (RT-PCR), genome sequencing, and phylogenetic analysis., Result: All 26 samples were confirmed positive to NoV GII and their genotypes were identified as GII.4 Sydney[P31]. The amino acid substitutions in open reading frame1 (ORF1) and ORF2 genes were found when compared with previously detected sporadic NoV GII.4 Sydney[P31] strains isolated in Japan. The clinical characterization of infected children was described. Most of the children were mild cases and vomiting was the most frequent clinical symptom., Conclusion: This study reported a recent emergence of NoV GII.4 Sydney[P31] causing acute gastroenteritis outbreak in children in Japan during the COVID-19 pandemic and suggests a need for further monitoring of NoV GII.4 variants., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

To control the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the promotion of vaccination is important. However, adverse reactions following vaccination remain a concern. To investigate adverse events in the vaccinated Japanese population, we conducted a survey-based study among health care workers, including medical doctors and nurses; other medical staff; and medical university faculty, staff, and students in a single medical school and affiliated hospital in Japan. In addition, we analyzed the association of different adverse events with individual factors (e.g., age, sex) by performing network analysis. While young age and female sex are often considered risk factors for more severe adverse events, the regression models showed neither age nor sex was associated with local injection-site reactions after the second dose in this study. In contrast to local reactions, systemic adverse events were associated with young age and female sex. However, myalgia was unique in that it was not associated with younger age even though the network analysis showed that myalgia was consistently related to arthralgia and belonged to the group of systemic events after both the first and second vaccine doses. Further study is needed to ensure safe and effective vaccination to aid in controlling the COVID-19 pandemic., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Introduction: Recently, increased frequencies of carbapenemase-producing Enterobacteriaceae have been reported worldwide. Among multiple genetic subtypes, oxacillinase (OXA)-48 β-lactamase-producing strains have been associated with inbound infection because they have been detected predominantly in patients who traveled outside of Japan. However, a recent case report of OXA-48 β-lactamase-producing Enterobacteriaceae suggested the latent spread of domestic infections. Due to a lack of specific inhibitors, culture-based detection of OXA-48 β-lactamase-producing bacteria is difficult. Thus, DNA-based detection methods, including PCR, direct sequencing and loop-mediated isothermal amplification (LAMP), have been employed. Among these methods, LAMP detection is more favorable than other methods because of its technical simplicity and low cost., Methods: We designed novel LAMP primers to detect OXA-48 β-lactamase-producing bacteria and investigated their possible clinical applications with bacterial genome-spiked human materials (cerebrospinal fluid, blood, feces, urine, and sputum). We evaluated the specificity of the LAMP primers using 37 bacterial strains: 8 standard, 9 reference, and 20 clinical Gram-negative strains., Results: Our LAMP primers detected 10 copies of the OXA-48 type β-lactamase gene and exhibited no cross reactivity with other β-lactamase genes. Sensitivity was not influenced in any clinical sample, in contrast to PCR detection, which was strongly inhibited by substances in fecal samples., Conclusions: These results suggest the superior performance of LAMP compared with conventional PCR for detecting the OXA-48 type β-lactamase gene in various clinical samples., (Copyright © 2021 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Introduction: Rotavirus (RV) is the major pathogen responsible for acute gastroenteritis in infants. Since RV vaccines were introduced, a substantial decline in the incidence of severe RV infection has been reported. However, some burden still exists, even in developed countries, including Japan., Methods: We retrospectively surveyed 380 patients hospitalized for acute gastroenteritis from 2015 to 2019. In 2019, additional detailed clinical information of 21 patients with RV gastroenteritis was obtained to evaluate the efficacy of the RV vaccine. Nine fecal samples from those patients were collected to detect the RV genotypes., Results: Our data showed an increasing trend in hospitalizations for severe RV gastroenteritis in children older than 5 years. According to the Vesikari clinical severity scores in the older group (≥5 years), the gastrointestinal symptoms in vaccinated patients were less severe than those in unvaccinated patients (p = 0.014). The genotype analysis revealed that G9P[8]I1 was the major genotype in the recruited patients in 2019., Conclusions: This report warns that children older than 5 years could be affected by severe RV infection and suggests prompt intervention for this age group, similar to that in infants. In the new period in which the RV vaccine is included in Japanese national immunization programs beginning October 2020, continuous monitoring of patient clinical characteristics and RV epidemiology is required to determine the role of vaccines., Competing Interests: Declaration of competing interest None of the authors have any conflicts of interest to declare in this study. Outside the submitted work, Ichiro Morioka has received lecture fees from MSD Co., Ltd., Shionogi Co., Ltd., and AbbVie LLC and study grants from Atom Medical Corp., (Copyright © 2020 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Pseudomonas aeruginosa is one of the most common causes of nosocomial infections, and its multi-drug resistance has been a serious problem worldwide. The aim of this study was to evaluate whether exposure to piperacillin and reactive oxygen species (ROS) could lead to multi-drug resistance for clinical isolates of P. aeruginosa. The inhibition of this acquired resistance by the anti-ROS agent was also examined. In vitro inducement of multi-drug resistance was performed against 20 clinical isolates. These strains were incubated for 24 h and transferred 5 times after being exposed to 1 mM H 2 O 2 (ROS) in addition to a sub-MIC of piperacillin by the agar dilution method. Each MIC of piperacillin and levofloxacin was determined. As the mechanism of levofloxacin resistance, mutation of QRDR was investigated. The expression level of genes encoding efflux pumps; mexA, mexY, mexC, and D2 porin; oprD were determined by real-time PCR. Multi-resistance to both piperacillin and levofloxacin was induced with 4 of 20 strains (20%). No amino acid change was confirmed in QRDR. These strains showed overexpression of mexA, mexY, mexC, and another one showed decrease of oprD expression. Resistance development in 4 strains was inhibited by the same method including the anti-ROS agent, sodium zinc histidine dithiooctanamide (DHL-His-Zn). In conclusion, stimulation by ROS promoted acquisition of multi-drug resistance in 20% of isolates of P. aeruginosa, and DHL-His-Zn completely inhibited this acquisition of resistance. Therefore, this anti-ROS agent may be useful to assist antimicrobial chemotherapy by preventing multi-drug resistance., (Copyright © 2018 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Extended-spectrum beta-lactamase (ESBL) producing bacteria spread worldwide and became major concern for antibiotic treatment. Although surveillance reports in general hospitals and long-term care facilities are increasing, their frequencies in individuals with severe motor and intellectual disabilities (SMID) are so far unknown. In this study, we examined the frequency of ESBL in stool samples collected from 146 asymptomatic SMID subjects hospitalized in a single institution. With their clinical information, we evaluated possible risk factors for ESBL colonization. From 146 fecal samples, ESBL-producing bacteria were isolated in 45 cases (31%). Drug sensitivity testing showed that 82% of the isolates were resistant to levofloxacin but were sensitive to tazobactam/piperacillin and cefmetazole. The most frequent genotype was CTX-M-9 detected in 36/45 (80%). A high degree of disability, antibiotic use within three months before sampling and post-tracheostomy were statistically significant risk factors. Tube feeding was also strongly correlated with ESBL colonization (p < 0.001) and associated with lower micro-organismic diversities. Our findings are the first to reveal a high prevalence of ESBL in the fecal samples of SMID individuals and suggest possible relationships between high degree disability, tube feeding and latest histories of antibiotic use., (Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Since human norovirus is non-cultivable, murine norovirus and feline calicivirus have been used as surrogates. In this study, the virucidal effects of ethanol-based sanitizers with different concentrations of additives (malic acid/sodium malate, glycerin-fatty acid ester) against murine norovirus and feline calicivirus F4 were examined. The ethanol-based sanitizers at pH 7 showed sufficient virucidal effects, but glycerin-fatty acid ester included in ethanol-based sanitizers at pH 4 or 6 reduced the virucidal effects against murine norovirus. The ethanol-based sanitizers containing malic acid/sodium malate inactivated feline calicivirus F4 in shorter time, but there is no difference between ethanol-based sanitizers with and without glycerin-fatty acid ester. Traditionally, feline calicivirus has been used for long time as a surrogate virus for human norovirus. However, this study suggested that murine norovirus and feline calicivirus F4 had different sensitivity with the additive components of ethanol-based sanitizers. Therefore, using feline calicivirus alone as a surrogate for human norovirus may not be sufficient to evaluate the virucidal effect of sanitizers on food-borne infections caused by human norovirus. Sanitizers having virucidal effects against at least both murine norovirus and feline calicivirus may be more suitable to inactivate human norovirus., (Copyright © 2015. Published by Elsevier Ltd.)

In vitro efficacy of combined eradication therapy with clarithromycin and daptomycin against biofilm-formed methicillin-resistant Staphylococcus aureus on the orthopedic titanium devices was evaluated. The bactericidal effect of this antibiotic was investigated by a re-culture test, the scanning electron microscopy, and fluorescence microscopy using a double-staining dyes. Clarithromycin decreased the amount to half in 24 h. Although MRSA biofilms were not eradicated with clarithromycin or daptomycin alone, clarithromycin combined with daptomycin was useful to sterilize titanium devices within 72 h. This in vitro study showed that combined treatment with clarithromycin plus daptomycin is useful to eradicate staphylococcal biofilms formed on orthopedic devices., (Copyright © 2015 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

This study examined the virucidal effects of five types of alcohol-based sanitizers including malic acid and sodium malate, or monoethanolamin, in 58 vol % ethanol (pH 4.0, pH 7.1, pH 11.8), 65 vol % ethanol (pH 4.2), and 75 vol % ethanol (pH 4.4) against murine norovirus (MNV) and feline calicivirus (FCV). The virus titer of MNV was reduced in an ethanol dose-dependent manner under the same pH (about 4.0) condition. Virucidal effect against MNV was correlated with pH when the concentration of ethanol was constant (58 vol %). All the ethanol-based sanitizers provided sufficient virucidal effects against FCV. In conclusion, the virucidal effect of the ethanol-based sanitizer at low concentration of ethanol against norovirus (NoV) is increased when the pH is adjusted to a neutral state.

A total of 89 blood samples collected from HIV-infected infants and children from provinces of southern Vietnam who were hospitalized at Children's Hospital 1, Ho Chi Minh City, during the 1-year period from October 2004 to September 2005 were submitted to serological screening for IgG, IgA, and IgM antibodies against Chlamydophila pneumoniae (C. pneumoniae). The presence of this microorganism was also evaluated by PCR. The results showed that 64 % of the samples were positive for anti-C. pneumoniae IgG, 31.5 % were positive for IgA, and 3.4 % were positive for IgM. The highest prevalences of IgG and IgA positivity, 75 % and 66.7 %, respectively, were noted in the 1- to 2-year-old age group. However, all the samples were negative for C. pneumoniae by PCR. The study revealed a high seroprevalence of C. pneumoniae in Vietnamese infants and children with HIV/AIDS.

In 2003, 826 uropathogenic strains were obtained from the urine of our patients. We assessed their activities to antibacterial agents based on the minimal inhibitory concentration (MIC) breakpoints recommended by the National Committee for Clinical Standards (NCCLS). Methicillin-resistant strains accounted for about 70% of Staphylococcus aureus and Staphylococcus epidermidis. The most common gram-positive species was Enterococcus faecalis (15.6%). Enterococcus faecium was the most resistant of the enterococcal species, and the rate of susceptibility to beta-lactams (BLs), fluoroquinolones (FQs), and tetracyclines (TCs) was 0%, 6%, and less than 18%, respectively. Escherichia coli accounted for over 50% of the gram-negative bacilli. The proportion of FQ-resistant or intermediate strains was over 20%, and four of these strains (1.1%) were suspected of producing extended-spectrum beta-lactamase (ESBL). All the ESBL-producing strains (ESBLs) possess resistance to FQs. Over 95% of Klebsiella pneumoniae was susceptible to all agents. The distribution of antimicrobial activity against Pseudomonas aeruginosa indicated a decrease in the number of multidrug-resistant strains and an increase in strains susceptible to all agents. Some differences existed in the resistance to antibacterial agents among Proteus species. No ESBL-producing or multidrug-resistant strain was isolated from Serratia marcescens. This survey suggests that serious clinical problems will result from the increasing number of enterococcal species with multidrug resistance in gram-positive cocci, and isolates of ESBL-producing or FQs-resistant strains in gram-negative bacilli.

Since 1998 more than 50 reports have described the isolation of high-level vancomycin-resistant enterococci (VRE) in Japan. Here, we report on our clinical isolates of VRE and an epidemiological study carried out using chemical and genetic techniques. VRE isolates were screened for high resistance to vancomycin (VCM) with a cutoff value of 6 microg/ml and VCM-resistant gene was confirmed by polymerase chain reaction (PCR). The epidemiological studies used pulsed-field gel electrophoresis (PFGE) and plasmid analysis. Six strains of VRE were isolated from six different patients on two wards during a 3-months period. All of the isolates possessed vanA on their plasmid, and the isolates were divided into two similar groups. Furthermore, three different patterns were defined by PFGE. Although all of the asymptomatic carriers were hospitalized for more than 3 months, we were able to prevent an outbreak of VRE in our hospital by using our guidelines for infection control, which are stricter than those for methicillin-resistant Staphylococcus aurens. From the results of this epidemiological study, we propose that there was a possibility of contamination in this hospital, and that three of the six isolates may have acquired vanA independently. In this study, we demonstrated that infection control, according to appropriate prevention guidelines, as well as regular surveillance for VRE, are essential for designing interventions to prevent the further spread of VRE.