In March 2008, an outbreak of gastroenteritis occurred in a hotel in Nagano Prefecture, central Japan. There were 29 patients from four groups out of 57 guests in seven groups. The main clinical symptoms were diarrhea (75.9%), nausea (72.4%), fever (65.5%), and abdominal pain (62.1%). Fecal samples of 14 patients were examined, and human astrovirus (HAstV) genes were detected in 12 (85.7%) of them. Fecal samples of five persons who were engaged in preparing meals were examined as well : four of them were HAstV-positive, including one person who was symptomatic. The virus was identified by serotyping as HAstV serotype 8 (HAstV-8).
We presumed that the main causative virus in this case was HAstV, because HAstV was detected predominantly from the fecal samples of the patients.
The main serotypes of HAstV isolated in Japan until now are type 1, type 3, and type 4. This is the first report of a case of mass infection caused by HAstV-8 in Japan.

We analyzed 20 chest computed tomographic (CT) images from 13 patients with coronavirus disease 2019 (COVID-19)-related pneumonia who were admitted to the Osaka City General Hospital. All patients had subpleural lesions and ground-glass opacities (GGOs), while none had pleural effusion, pericardial effusion, mediastinal/hilar lymphadenopathy, or cavitary lesions. In addition, the 3 cases that required supplemental oxygen showed volume loss in both lower lobes, thickening of the bronchovascular bundles. When the chest CT findings were classified according to the symptoms, GGOs appeared earlier after onset (＜10 days). In contrast, crazy-paving pattern, consolidation, and subpleural lines or bands appeared later after the onset (＞ 10 days). Important differential diagnoses included viral pneumonia caused by influenza and organizing pneumonia. Therefore, it is important to deduce the phase after the onset of COVID-19 symptoms by detailed interviews and be aware of how the chest CT presentations change with the clinical course in patients with COVID-19-related pneumonia. Such knowledge will be helpful to predict the risk of COVID-19, as well as to promptly diagnose and treat COVID-19-related pneumonia and prevent further transmission.

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in major social and medical problems. As in other countries, Japan has seen community transfer and clusters in cities, long-term care facilities, and hospitals. SARS-CoV-2 infection can be transmitted both from and to healthcare workers and patients. Severe infection events greatly impact the functioning of the medical care system, and under extreme conditions, can lead to collapse of the system. The staff members at medical institutions who are assigned for the treatment of infectious diseases are at an especially high risk of contact with Coronavirus disease 2019 (COVID-19) patients, and it is quite important to evaluate the effectiveness of infection control measures taken at hospitals to prevent nosocomial infection by SARS-CoV-2. Towards this end, we tested serum samples collected from 375 consenting staff members of Fukuoka City Hospital, a medical institution designated as a treatment center for infectious diseases, for SARS-CoV-2 antibodies by three methods. The staff members were grouped by the risk according to their frequency of contact with COVID-19 patients, and by occupation. The effectiveness of the infection control measures adopted by us was evaluated by comparing the antibody-positive rates of the groups. Our analyses revealed that there was only one antibody-positive staff member who had no contact with COVID-19 patients. Our results suggest that the infection control measures adopted at our hospital have been effective. Our results suggest that nosocomial infection with SARS-CoV-2 infection is preventable with by the precautions that we have adopted at our hospital, even in areas of intensive medical intervention, and that the reuse of personal protective equipment (PPE) that had to be implemented during the study period did not have any adverse impact on the spread of the infection. Further improvements of the precautions are needed for continued prevention of infection, depending on the availability of PPE and the accurate route of transmission.

Purpose : In Japan, levofloxacin (LVFX) was first launched in the market 1993, and the drug was approved as an anti-tuberculosis drug in 2016. It is prescribed as part of second-line treatment for patients who are at a high risk of developing drug resistance and adverse effects to first-line anti-tuberculosis drugs. Meanwhile, LVFX is a frequently used drug for the treatment of community-acquired pneumonia and urinary tract infection in Japan. However, development of resistant Escherichia coli and Streptococcus pneumoniae to LVFX has become a major issue ; in fact, the estimated average resistance rates at our hospital between April 2014 and March 2018 are 37.6% and 5.0%, respectively. However, only a few studies on the development of resistance of LVFX have been conducted. We investigated the usage of LVFX for lung tuberculosis at our hospital and susceptibility of the causative mycobacterial strains to LVFX.
Methods ＆Materials : We retrospectively identified 83 consecutive patients with lung tuberculosis who were admitted to our hospital between April 2014 and March 2018 (age, 74±21 years ; sex, male/female 43/40 ; first treatment, 74 cases). We analyzed the outcomes of examination of resistance of the causative strains to isoniazid (INH), rifampin (RFP), streptomycin (SM), and LVFX recorded in the medical charts.
Results : LVFX was administered as a component of the initial treatment regimen in 33 cases (83%) (74 ±21 years of age) and as a component of retreatment regimens in 7 cases (17%) (73±22 years of age). The reason for retreatment in the latter 7 cases were adverse reactions to the first-line treatment in 13 cases (37%) and development of resistance to the first-line anti-tuberculosis drugs in 2 cases (6%). The drug resistance rate was 5% for INH, 3% for RFP, 0% for SM, and 0% for LVFX. One of the two patients had multidrug resistance. No adverse effects were reported, and the bacteriological negative conversion rate was 100%. Only one patient had been treated with LVFX alone for 7 days prior to admission, but there was no evidence of development of resistance.
Conclusion : LVFX was concluded as being an effective component of the tuberculosis treatment regimen in cases where standard regimens could not be administered, as it exerted no adverse effects and also had no adverse effect on the bacteriological negative conversion rates. While the usage rate of LVFX for lung tuberculosis at our hospital is more than 30%, we have never encountered any cases of tuberculosis with resistance as of 2018. Our study showed that LVFX is an essential drug for the treatment of tuberculosis if resistance/adverse effects limit the use of first-line drugs.

A 75-year-old man with a history of alkaptonuria, who had gradually become bedridden due to repeated episodes of arthropathy, presented to his physician with a dayʼs history of fever and right knee joint pain. He was diagnosed by knee puncture as having purulent knee arthritis, and was started on intravenous cefazolin treatment ; however, there was no improvement. Four days after, the patient went into septic shock and was admitted to our hospital. Multidrug-resistant Citrobacter koseri (C. koseri) was detected by various bacterial cultures (blood, urine, and right knee joint fluid), and he was initiated on treatment with the appropriate antibacterial drugs based on the results of sensitivity results ; however, the right knee arthritis became worse. Contrast-enhanced CT revealed necrotic soft tissue infection extending from the distal right thigh to the muscle layer around the knee joint. Surgical intra-articular irrigation and incision were performed to drain the medial thigh abscess, followed by appropriate antibiotic treatment. The patientʼs general condition and surgical wound improved gradually, and he was discharged our hospital one month later. Severe C. koseri infections can occur in patients with alkaptonuria because of their increased susceptibility to infections. Early source control of the infection site is important for the treatment of necrotizing soft tissue infection.

Klebsiella pneumoniae subsp. ozaenae (K. ozaenae) has been reported to cause urinary tract infections and rhinosclerosis, but it has rarely been reported as a cause of lung abscess. Therefore, the clinical course and optimal antimicrobial treatment for lung abscess caused by K. ozaenae remain unclear. It has also been reported that infections caused by hyperviscous Klebsiella species are more likely to become invasive. We report a case of lung abscess caused by hyperviscous K. ozaenae. A 68-year-old woman presented with fever and right shoulder pain, and was referred to our hospital as a suspected case of pneumonia. Chest CT showed an abscess in the right S3, and we started the patient on intravenous ceftriaxone (CTRX) treatment. However, as the fever persisted and the patient became delirious, the antimicrobial agent was changed to meropenem (MEPM), based on the findings of sputum smear examination. K. ozaenae was isolated on sputum culture, with a positive string test. Although this bacterial strain is considered to be susceptible to CTRX and MEPM, the patientʼs fever and delirium failed to improve. The symptoms eventually improved with the addition of levofloxacin (LVFX). The patient was discharged without any sequelae on day 48 of hospitalization.

We report two cases of bacteremia caused by non-O1, non-O139 Vibrio cholerae in immunocompetent patients. The first patient presented with fever and watery diarrhea and had traveled recently to Thailand. V. cholerae O24 was detected in the blood and stool. The route of infection was thought to be ingestion of ice containing V. cholerae. The second patient presented with only fever and gave no history of overseas travel. V. cholerae O37 was detected in the blood and bile. Although many cases of V. cholerae infection are imported,V. cholerae is also present in Japanese rivers and can be transmitted domestically. In general, non-O1, non-O 139 V. cholerae causes extraintestinal infections in patients with underlying diseases, and is rarely identified as a cause of bacteremia in immunocompetent patients. Both patients were cholera toxin-negative, El Tor hemolysin-positive, and RTX toxin-positive, suggesting that the latter toxins may be involved in the bacteremia caused by non-O1, non-O139 V. cholerae infection. In both cases, V. cholerae could be identified from the characteristic morphological findings, and it is important to proceed with the identification tests without overlooking the characteristic microbiological findings, regardless of the patientʼs background.

Seven human coronaviruses (HCoVs) have been isolated and identified as of February 2020 ; among these, HCoV-229E is known as a common causative organism of seasonal cold, however, a few cases of severe pneumonia caused by this virus in immunocompromised patients have also been reported. Previous reports have suggested that the majority of pneumonia cases labelled as being of unknown origin have a viral cause, including this virus.
Herein, we report a case of pneumonia caused by Human Coronavirus 229E in a 78-year-old man with chronic obstructive pulmonary disease (COPD) who had been undergoing medical treatment for Behcetʼs disease as an outpatient. He presented to our hospital complaining of chills, excessive sputum, and cough. At the time of consultation, we suspected the possibility of viral pneumonia caused by SARS-CoV-2 (COVID-19),which had sporadically occurred in Japan by that time. Chest x-ray showed ground glass opacities in the periphery of the middle and lower right lung field and computed tomographic images showed ground-glass opacities in the right middle and lower lobes ; therefore, the patient was admitted to our hospital for treatment and observation in a depressurized room. Urinary rapid antigen tests for Streptococcus pneumoniae and Legionella pneumophila, the rapid influenza diagnostic test, sputum culture, and blood culture were all negative. Further, the PCR test for SARS-CoV-2 PCR was also negative. However, examination of a nasopharyngeal swab sample by nested multiplex PCR (nmPCR) revealed Coronavirus 229E ; we thus diagnosed the patient as having Coronavirus 229E-related pneumonia. He received supportive care with supplemental oxygen, his symptoms gradually improved, and he was discharged on Day 16. The few cases reported in the past had severe immunodeficiency due to hematological tumors, whereas a case like ours appears to be extremely rare. On the other hand, Coronavirus 229E-related pneumonia, which could have occurred in a larger population in the past may have remained unidentified due to a lack of suitable tests. Reports of cases of viral pneumonia in the future are expected to increase with the increased use of nmPCR tests.