Clinically mild encephalitis/encephalopathy with reversible splenial lesions (MERS) is a mild form of encephalitis/encephalopathy that appears in association with various conditions, including infection. COVID-19 is also known to cause MERS. MERS more commonly occurs in children, and adult cases are relatively rare. Typical head MRI findings include a round lesion in the mid-layer of the corpus callosum with a high signal intensity on diffusion-weighted images. Most improve within a week. Although the exact mechanism by which the cerebral corpus callosum is affected is still unknown, several hypotheses have been proposed, including the involvement of electrolyte abnormalities (e.g., hyponatremia) and inflammatory cytokines (e.g., IL-6). In this report, we describe the first case of COVID-associated MERS with a typical imaging course and hyponatremia, with a review of the relevant literature. When psychiatric symptoms and the disturbance of consciousness appear in COVID patients, MERS should be considered in addition to delirium due to fever and hypoxia.

We report a case of Talaromyces marneffei fungemia in a patient with HIV infection with a history of travelling to southern China. At first, Pneumocystis pneumonia was considered in this case because chest CT images showed typical ground-glass opacity and elevated beta-D-glucan levels. However, PCR testing of sputum for Pneumocystis jirovecii was negative and a filamentous fungus was isolated from blood cultures. The cultured fungus was subsequently identified as T. marneffei, and the patient was considered to have pneumonia caused by this or-ganism. However, skin disease and lymphadenopathy, which are common in T. marneffei infections, were not observed during the disease course. This patient was successfully treated with voriconazole and consequently the chest CT shadow disappeared. In the present case, T. marneffei infection required differentiation from pneumonia with Pneumocystis jirovecii infection.

Extracellular adenosine, produced from ATP secreted by neuronal or immune cells, may play a role in endogenous regulation of inflammatory responses. However, the underlying molecular mechanisms are largely unknown. Here, we show that adenosine primes hypersecretion of interleukin (IL)-17A by CD4 ⁺ T cells via T cell receptor activation. This hypersecretion was also induced by an adenosine A2a receptor (A2aR) agonist, PSB0777. In addition, an A2aR antagonist (Istradefylline), and inhibitors of adenyl cyclase, protein kinase A, and cAMP response element binding protein (which are signaling molecules downstream of the Gs protein coupled with the A2aR), suppressed IL-17A production, suggesting that activation of A2aR induces IL-17A production by CD4 ⁺ T cells. Furthermore, immune subset studies revealed that adenosine induced hypersecretion of IL-17A by T-helper (Th)17 cells. These results indicate that adenosine is an endogenous modulator of neutrophilic inflammation. Administration of an A2aR antagonist to mice with experimental autoimmune encephalomyelitis led to marked amelioration of symptoms, suggesting that suppression of adenosine-mediated IL-17A production is an effective treatment for Th17-related autoimmune diseases.

Vancomycin-resistant enterococci (VRE) are a significant cause of healthcare-associated infections. In Japan, the estimated isolation rate of VRE is approximately 0.2%; however, sporadic outbreaks continue to occur in healthcare facilities. Despite sporadic cases of VRE at our hospital since the 2007 outbreak, it is unclear whether the same strains from 2007 were still prevalent. Therefore, we performed whole-genome sequencing of stored VRE strains at our hospital and assessed their potential utility as an alternative to pulsed-field gel electrophoresis (PFGE) for infection control. In contrast to previous studies, our analysis focused on examining strain characteristics over time. The results of taxonomic characterization using average nucleotide identity (ANI) values and multilocus sequence typing (MLST) showed good agreement with the PFGE analysis, indicating that ANI values and MLST were viable potential alternatives to PFGE. Notably, many of the strains isolated in 2010 belonged to ST1421. The first reported VRE outbreak in Japan, caused by pstS -null VRE ST1421, occurred in Aomori in 2018. However, the present study demonstrated, for the first time, that the ST1421 strain existed in Japan as early as 2010. In the time series analysis, the observed PFGE pattern did not correlate with the time of strain isolation, particularly for isolates collected after 2012. We also observed cases where isolates sharing the same Tn1546 variant were found on distinct clonal backgrounds. While ANI and MLST may serve as suitable alternatives to PFGE for short-term outbreak evaluations, a plasmid analysis may prove useful for long-term assessments. IMPORTANCE: Our study emphasizes the efficacy of whole-genome sequencing (WGS) in addressing outbreaks of vancomycin-resistant enterococci. WGS enables the identification and tracking of resistant bacterial strains, early detection and management of novel infectious disease outbreaks, and the appropriate selection and use of antibiotics. Furthermore, our approach deepens our understanding of how resistant bacteria transfer genes and adapt to their environments or hosts. For modern medicine, these insights have significant implications for controlling infections and effectively managing antibiotic use in the current era, where antibiotic resistance is progressing.

A 36-year-old female healthcare worker with no past medical history, accidentally injected her flexed right middle finger with live attenuated Mycobacterium bovis bacillus Calmette-Guérin (BCG). Swelling and erythema around the injured area appeared two days after the needlestick injury. She was referred to the hospital and presented approximately nine days after self-inoculation. Surgical debridement was immediately performed. After 38 days, colonies were observed on cultures of the removed tissue on Ogawa's medium. This isolate was identified as M. bovis BCG by polymerase chain reaction (PCR) based on RD1 gene deletion. She had a history of BCG vaccination and her skin lesion appeared immediately after the accidental injection of M. bovis BCG. Therefore, in the differential diagnosis, the possibility that the lesion was an allergic reaction to BCG was considered. The subsequent culture results came back positive for M. bovis BCG and acute tenosynovitis caused by M. bovis BCG was diagnosed. The skin lesion was treated with anti-mycobacterial drugs and resolved. The allergic reactions to BCG should be considered in the differential diagnosis of skin lesions following BCG vaccination. It is important to promptly submit a specimen for culture as delayed initiation of appropriate treatment can lead to a poor prognosis. In patients with accidental injection of M. bovis BCG, it is important to consider timely surgical excision and appropriate antimycobacterial therapy.