Direct identification of bacteria by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in blood culture combined with detection of drug resistance genes may improve patient outcomes based on prompt identification of pathogenic microorganisms and prediction of drug resistance. In this study, the clinical effects of bacterial identification by MALDI-TOF-MS and detection of drug resistance genes were evaluated.

Time from starting the test to obtaining a report identifying bacteria, time until appropriate escalation, time until de-escalation, and mortality within 30 days were compared from before to after the intervention; i. e., before and after use of mass spectrometry evaluation and a drug resistance gene test.

A total of 159 specimens were examined before the intervention and 197 after the intervention. Direct identification by mass spectrometry and detection of drug resistance genes decreased the time to identify the bacteria (34.05 vs.4.58 hours, p< 0.0001), time until appropriate escalation (37.27 vs.9.47 hours, p< 0.0001), time until de-escalation (75.98 vs.57.48 hours, p=0.0029), and the 30-day mortality (10.1% vs.4.1%, p=0.026).

These results suggest that prompt identification by mass spectrometry combined with detection of drug resistance genes may improve the prognosis of patients.

We investigated the relationship between the side effects of inoculation of the BNT162b2 mRNA vaccine and the IgG antibody titers after a mass inoculation of hospital staff. The side effects were examined using a self-reported survey form to determine the side effects of a second inoculation, and the antibody titers were examined using the variations of IgG against the spike protein antibody 9 weeks after the second inoculation. The number of subjects surveyed was 228, and a relationship was found between the intensity of fever, fatigue, and headache and the IgG antibody titers. When the subjects were divided into groups under 45 years old and over 45 years old, the intensity of fatigue was associated with the increased IgG antibody titers in the under 45 years old group, and the intensity of fever was associated with the increased IgG antibody titers in the over 45 years old group. The results suggested that relationships might exist between the IgG antibody titers and the intensity of some side effects after BNT162b2 inoculation.

Purpose: Implementing antimicrobial stewardship (AS) improves the quality of medical care by optimizing antimicrobial prescription. Assuring an appropriate amount of time for performance prospective audit and feedback can be challenging.

Methods: We retrospectively analyzed 1,094 AS interventions, provided either three times a week (period A), every weekday by a part-time pharmacist (period B), or every weekday by a full-time pharmacist (period C). We compared physicians' acceptance rates, antibiotic use rate, duration of hospitalization, identification rate of multi-drug-resistant microorganisms, and incidence of Clostridioides difficile infection among the different intervention periods.

Results: The median monthly number of AS interventions in periods A, B and C were 18, 27 and 47, respectively. The number of AS interventions showed a positive correlation with the physicians' acceptance rate (R=0.685, p< 0.001) and a negative correlation with broad-spectrum antibiotic and carbapenem usage (R=-0.386, p=0.020 and R=-0.614, p< 0.001). The interrupted time series analysis revealed that as compared to period A, physicians' acceptance rates rose by 26.1% (95% CI 18.4, 33.7) in period B and by 9.7% (95% CI 2.0, 17.3) in period C. Broad-spectrum antibiotic and carbapenem use in period B decreased by −16.85 (95% CI −27.49, −6.21) and −15.84 (95% CI −19.48, −12.21), respectively, as compared with that in period A.

Conclusions: Adequately frequent AS interventions decrease the need for antimicrobial usage. Assuring an adequate amount of work time for the AS staff improved the physicians' acceptance rate and prescription rate of antibiotics.

The third and fourth epidemic waves of coronavirus disease 2019 (COVID-19) in Sapporo city were analyzed using a mathematical model. The model is an SEI_UI_CRD_URD_C model, which is extended from an SEIR model. In the SEI_UI_CRD_URD_C model, I (infectious compartment) is divided into I_U (unconfirmed infectious compartment) and I_C (confirmed infectious compartment); R (recovered compartment) is divided into RD_U (unconfirmed recovered or died compartment) and RD_C (confirmed recovered or died compartment). The mathematical model provides an analysis that the ratio of the number of I_C to that of total infectious cases (I_U+I_C) depended on the day, i. e., the ratio was about 43-68% in the third wave, and about 55-84% in the fourth wave and that about 32% and 33% of infectious cases were confirmed in the third and fourth waves, respectively, by calculating each ratio of the cumulative number of RD_C to that of RD_U plus RD_C in each wave.

Mathematical analysis is more and more important in the future, because the pandemic of COVID- 19 is considered to continue for the time being.

A 69-year-old male was admitted to Ehime University Hospital with bicytopenia. He was diagnosed with myelodysplastic syndrome (MDS) and was administered chemotherapy. He was a multimorbid patient with chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), type 2 diabetes, and Sweet's disease resulting in a skin rash. The patient was treated with oral prednisolone for Sweet's syndrome, and cefepime infusions for pneumonia that arose during the first course of chemotherapy. Both of these complications were almost recovered on physical and image findings. During the second course of chemotherapy, he developed Kytococcus schroeteri bacteremia that was successfully treated with linezolid and meropenem infusions, but he died owing to Stenotrophomonas maltophilia bacteremia that occurred 6 h after the K. schroeteri bacteremia. Postmortem microbiology (PMM) proved his reservoir of S. maltophilia bacteremia as pneumonia. There are only 20 reports of K. schroeteri bacteremia in the Medline database. According to our knowledge, this is the first case that developed K. schroeteri and S. maltophilia bacteremia sequentially. In addition, this case highlights the importance of PMM in improving treatment of infectious diseases.

The patient in this study was a healthy 9-month-old infant who was admitted to our hospital with fever. He had a 5-days's history of fever prior to admission and experienced movement restrictions of the right hip the day before he was referred to our hospital.

Blood tests revealed leukocytosis (2,4850/μL) and elevated serum C-reactive protein levels (6.43mg/dL). T2-weighted magnetic resonance images of the lower limb showed a high signal intensity in the distal aspect of the right tibia. Methicillin-sensitive Staphylococcus aureus was isolated on blood culture. After a confirmed diagnosis of a right tibial osteomyelitis, the patient was treated with intravenous cefazolin (100mg/kg/day) and oral cephalexin (100mg/kg/day) for 57 days. In our patient, the fever preceded local symptoms such as abnormal posture, impaired movements, and redness and swelling of the right ankle joint, which should be helpful for early detection of tibial osteomyelitis. Specifically, in Japan, there are few reported cases of infants with tibial osteomyelitis. However, in some of these cases, fever occurs as the presenting symptom, without local symptoms at onset. Therefore, repeated and detailed systemic examinations are essential to avoid overlooking osteomyelitis in children.

We report a case of odontogenic brain abscess caused by Fusobacterium nucleatum. An 82-year-old man presented to us with a history of convulsions. He did not have a history of fever or headache. Brain magnetic resonance imaging findings suggested a brain abscess in the left frontal lobe, and the patient was initiated on treatment with anticonvulsants and antibiotics. While the lesion was monitored to assess the effect of the antibiotics, it was found to enlarge rapidly. Therefore, we performed trephine drainage, and F. nucleatum was identified on culture of the abscess fluid. Intraoral examination revealed periodontitis in the left mandibular molars. Postoperatively, his convulsions stopped with antiepileptic treatment. The patient was diagnosed as having an odontogenic abscess, and treated with antibacterial agents and oral care. This was a case of an odontogenic abscess caused by F. nucleatum in an elderly male patient. A good outcome was obtained by performing an early surgical procedure with administration of the appropriate antibacterial agent. Although it has been suggested that brain abscesses caused by Fusobacterium species may be complicated systemic and invasive infection, appropriate treatment should be administered, including timely surgical intervention and use of the appropriate antibacterial agents, because of the high sensitivity of the infection to antibiotics.

A 61-year-old man presented with a 3-days' history of fever and headache. On admission, his body temperature was 40°C, pulse rate was 99/min, and respiratory rate was 25/min. Serum CRP was elevated, and chest X-ray showed an opacity in the left upper lung field. Under the suspected diagnosis of community-acquired pneumonia, the patient was initiated on treatment with ampicillin/sulbactam, and oxygen supplementation via a nasal cannula at 2L/min. A review of the history revealed that his current occupation was maintenance of grease traps, which are chambers for removing grease from food waste before it enters the sewer pipe. Four days before onset of his symptoms, he had worked on a very dirty restaurant grease trap while wearing a poorly equipped face mask. Legionnaires' disease was suspected, and urinary antigen testing revealed a positive result. Sputum culture and PCR were also positive for Legionella pneumophila serogroup 1, the most common causative Legionella genus of acute pneumonic illness. The antibiotic was switched to intravenous levofloxacin at 500mg/day on day 2 of admission, and the patient's symptoms improved.

Inhalation of a water aerosol containing Legionella spp. causes Legionnaires' disease, and hot spring spas, cooling towers, and domestic plumbing have been linked to outbreaks. In this case, the patient had no history of exposure to common sources of Legionella, however, his work on a grease trap was suspected as the source of infection. Since early diagnosis of Legionnaires' disease is associated with favorable patient outcomes, clinicians should obtain a precise history that includes activities in the kitchen.