Malignant syphilis requiring differentiation from Kaposi's sarcoma.

Malignant syphilis (MS) is a rare variant of secondary syphilis. Also known as rupioid syphilis, MS is characterized by the presence of multiple papules, papulopustules, black lamellate crust that may resemble an oyster shell, or nodules with ulceration lacking central clearing. MS is often associated with immunodeficiency and frequently co-occurs with HIV infection. We here report a case of MS in a patient with HIV infection. HIV infection can cause atypical clinical symptoms of syphilis. In this case, unlike previous cases, cutaneous lesions of MS were limited to the face, making the diagnosis challenging based on clinical findings alone. However, his laboratory findings, appearance of the Jarisch-Herxheimer reaction, and a dramatic response to antibiotic therapy are characteristic of MS, making the diagnosis even more certain. Our case suggests the importance of physicians considering the possibility of MS when observing black-crusted lesions.

A case of hemophagocytic lymphohistiocytosis in a hemodialysis patient with coronavirus disease 2019.

During the treatment of a patient on hemodialysis with severe coronavirus disease 2019 (COVID-19), the patient was weaned from extracorporeal membrane oxygenation, which was used to treat severe COVID-19 pneumonia. However, the patient's condition worsened after the peak infection phase of COVID-19 because of acute respiratory distress syndrome with suspected hemophagocytic lymphohistiocytosis (HLH). After a bone marrow biopsy confirmed the diagnosis, methylprednisolone pulse therapy, followed by combination therapy (including oral prednisolone and cyclosporine) was immediately administered, and the patient survived. Because HLH can occur a month or more after the onset of COVID-19, even if the viral load is reduced to the point of being undetectable by reverse transcriptase-polymerase chain reaction, it can be considered to correspond to the "post-acute COVID-19 syndrome," which has recently been proposed. Early intervention is necessary, because HLH can be fatal. Therefore, it is important to know that HLH can occur at any stage of COVID-19 and to pay attention to the patient's progress over time, including checking the HScore.

Evaluation of anti-severe acute respiratory syndrome coronavirus 2 antibody levels in coronavirus disease breakthrough infection during immunosuppressive therapy in a patient with connective tissue disease-related interstitial lung disease.

Herein, we report the case of a 67-year-old man with severe coronavirus disease (COVID-19) pneumonia and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine breakthrough infection during immunosuppressive therapy for connective tissue disease-related interstitial lung disease (CTD-ILD). The patient received glucocorticoids combined with tacrolimus as maintenance therapy. His serum anti-SARS-CoV-2-immunoglobulin G (IgG) antibody levels were extremely low at the onset of COVID-19 pneumonia, even after the second dose of SARS-CoV-2 mRNA vaccine (BNT162b2). After treatment for COVID-19 pneumonia, the levels of anti-SARS-CoV-2-IgG antibodies increased. These results indicated a lack of the ability to produce neutralising antibodies from immune cells despite the booster vaccination. Therefore, we suggest that advanced-age patients with CTD-ILD receiving immunosuppressive therapy with polypharmacy require consistent personal protection, vaccination of close caregivers, increased awareness, and booster vaccination. Moreover, we recommend that tacrolimus should be withdrawn for a while after vaccination under controlled conditions.

Signaling via dopamine and adenosine receptors modulate viral peptide-specific and T-cell IL-8 response in COVID-19.

B-cell but not T-cell responses have been extensively studied using peripheral blood mononuclear cells (PBMCs) obtained from patients with coronavirus disease 2019 (COVID-19). Our recent study showed that not only T-helper (Th) 17 but also Th1 cells directly produce interleukin (IL)-8, a major source of neutrophilic inflammation, which is also known to induce disseminated intravascular coagulation (DIC) in COVID-19 patients. Neutrophilic inflammation caused by IL-17A or IL-8 can be fatal; thus, therapeutic intervention is highly expected. The present study aimed to investigate the T-cell responses in the Japanese patients. We synthesized spike protein-derived 15-mer peptides that are expected to bind to HLA class II allelic products frequently observed in the Japanese population, and checked the T-cell responses in Japanese patients with COVID-19. We have found that (i) patients show marked IL-8 but not IL-17A responses; (ii) these responses are restricted by HLA-DR; and (iii) IL-8 responses are abrogated by a dopamine D2 like receptor (D2R) agonist, ropinirole, and an adenosine A2a receptor (A2aR) antagonist, istradefylline. Compounds used for the treatment of Parkinson's disease may ease DIC in COVID-19. (183 words).

Evaluation of a chemiluminescent enzyme immunoassay-based high-throughput SARS-CoV-2 antigen assay for the diagnosis of COVID-19: The VITROS® SARS-CoV-2 Antigen Test.

A high-throughput, fully automated antigen detection test for SARS-CoV-2 is a viable alternative to reverse-transcription polymerase chain reaction (RT-qPCR) for mass screening during outbreaks. In this study, we compared RT-qPCR for viral load and the VITROS® SARS-CoV-2 Antigen Test with reference to the results of the LUMIPULSE® SARS-CoV-2 Ag Test. Of 128 nasopharyngeal swab specimens taken from patients suspected of being infected with SARS-CoV-2, 49 were positive and 79 were negative according to RT-qPCR. Consistent dose-dependent detection with VITROS® assay was successfully achieved when using nasopharyngeal swab specimens with Ct values of 32.0 or lesser, whereas the CLEIA-based LUMIPULSE® assay was able to detect lower viral loads compared with the VITROS® assay. Our results show that the performance of the VITROS® assay was satisfactory for the diagnosis of contagious COVID-19 patients in the clinical setting. Highlights The performance of the VITROS® SARS-CoV-2 Antigen Test was sufficient for the diagnosis of contagious COVID-19. This test showed high sensitivity and specificity in the detection of SARS-CoV-2 in samples with a Ct value of 32 or less.

Thoracic aortic mycotic aneurysm due to Staphylococcus argenteus: A case report.

Staphylococcus argenteus was subdivided as a novel species from Staphylococcus aureus in 2014. We herein report a case of mycotic aneurysm caused by S. argenteus. A 59-year-old woman with diabetes and schizophrenia visited at the emergency room because of falling. Chest computed tomography revealed a left humerus fracture and a thoracic aortic aneurysm. With her elevated WBC count and CRP level, she was suspected to have a mycotic aneurysm. After being transferred to our hospital, vascular graft replacement surgery was performed. Isolates of blood cultures and surgical specimens were identified as S. argenteus by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MAS MALDI Biotyper Ver. 8.0). Although S. argenteus lacks staphyloxanthin, a carotenoid pigment, it is coagulase positive. In addition to traditional and automated biochemical identification systems, even MALDI-TOF MAS may misidentify the organism as S. aureus depending on its version. S. argenteus should be considered when coagulase-negative Staphylococcus like colonies are obtained from samples of S. aureus infection. To our knowledge, this is the first case of aortic mycotic aneurysm caused by S. argenteus in Japan. Although S. argenteus is considered less virulent than Staphylococcus aureus, we should closely monitor the prevalence and the clinical impact of this pathogen on community-acquired infections and health care-associated infections.

Bloodstream infection by multidrug-resistant Streptococcus oralis in a leukemic patient with febrile neutropenia after hematopoietic stem cell transplantation.

We reported the case of a patient with leukemia who developed febrile neutropenia after hematopoietic stem cell transplantation. Blood culture results revealed the presence of Streptococcus oralis, while antimicrobial susceptibility testing showed the resistance to penicillin and cephem. Furthermore, isolates were not susceptible to either meropenem or daptomycin but not to vancomycin. S oralis is known to belong to Streptococcus mitis group and be a causative agent of bacteremia in the neutropenic patients, but multidrug resistance of S oralis is rare. Our findings suggest that we might pay attention to the emergence of the microorganisms acquiring multidrug resistance in neutropenic patients.

Endogenous endophthalmitis secondary to septic arthritis caused by group A Streptococcus infection: A case report and literature review.

Streptococcus pyogenes is a rare pathogen that causes endogenous endophthalmitis (EE). A healthy 58-year-old woman was diagnosed with EE secondary to septic arthritis caused by S. pyogenes. She underwent enucleation after hospitalization for 14 days with appropriate antibiotic cover. A literature search for outcomes of this condition revealed reports on only 10 eyes among 8 cases identified: 8 eyes (80%) developed poor visual outcome and 5 eyes (50%) underwent enucleation. There were no cases with immunocompromise. Our case report and literature review suggest the importance of awareness of the occurrence of S. pyogenes infection in immunocompetent hosts, and thus early diagnosis and aggressive treatment may be required to improve visual outcome.

Clinical characteristics in blood stream infections caused by Klebsiella pneumoniae, Klebsiella variicola, and Klebsiella quasipneumoniae: a comparative study, Japan, 2014-2017.

BACKGROUND: Klebsiella variicola and K. quasipneumoniae are new species distinguishable from K. pneumoniae but they are often misidentified as K. pneumoniae in clinical settings. Several reports have demonstrated the possibility that the virulence factors and clinical features differ among these three phylogroups. In this study, we aimed to clarify whether there were differences in clinical and bacterial features between the three phylogroups isolated from patients with bloodstream infections (BSIs) in Japan. METHODS: Isolates from all patients with BSIs caused by K. pneumoniae admitted to two hospitals between 2014 and 2017 (n = 119) were included in the study. Bacterial species were identified via sequence analysis, and their virulence factors and serotypes were analyzed via multiplex PCR results. Clinical data were retrieved from medical records. RESULTS: Of the 119 isolates, 21 (17.7%) were identified as K. variicola and 11 (9.2%) as K. quasipneumoniae; K1 serotype was found in 16 (13.4%), and K2 serotype in 13 (10.9%). Significant differences in the prevalence of rmpA, iutA, ybtS, entB and kfu (p < 0.001), and allS genes (p < 0.05) were found between the three phylogroups. However, there were no significant differences in clinical features, including the 30-day mortality rate, between the three organisms, although K. variicola was more frequently detected in patients over 80 years old compared with other Klebsiella species (p < 0.005), and K. quasipneumoniae more frequently occurred in patients with malignancy (p < 0.05). CONCLUSIONS: Our findings demonstrated the differences in bacterial pathogenicity and clinical features among these three phylogroups. Further epidemiological studies into BSI caused by Klebsiella species are warranted.

Exacerbation of invasive Candida albicans infection by commensal bacteria or a glycolipid through IFN-γ produced in part by iNKT cells.

BACKGROUND: The commensal yeast Candida albicans is a major cause of invasive fungal infections. Despite treatment with antifungal agents, the mortality rate attributed to these types of infection is high. Although numerous cases have been reported regarding a poor outcome for patients with bacterial and C. albicans coinfection, the mechanisms by which the coinfecting bacteria exacerbate the C. albicans infection remain elusive. METHODS AND RESULTS: We evaluated how glycolipid-mediated activation of invariant natural killer T (iNKT) cells affects the clearance of C. albicans. Surprisingly, C. albicans-infected, glycolipid-treated mice exhibited significantly lower survival rates, increased fungal burden, and higher interleukin (IL)-6 production in the kidneys compared with control mice. Glycolipid-induced exacerbation of C. albicans infection was not observed in interferon-gamma knockout (IFN-γKO) mice. In the C. albicans-infected, glycolipid-treated mice, the number of neutrophils in the blood and bone marrow dramatically decreased in an IFN-γ-dependent manner. Furthermore, mice that were coinfected with C. albicans and nonfermentative gram-negative commensal bacteria exhibited increased fungal burden and inflammatory cytokine production in the kidneys that were dependent on IFN-γ and iNKT cells. CONCLUSIONS: Our results indicate that coinfecting commensal bacteria exacerbate C. albicans infection through IFN-γ produced, in part, by iNKT cells.

The mannan of Candida albicans lacking ß-1,2-linked oligomannosides increases the production of inflammatory cytokines by dendritic cells.

Mannans are mannose polymers attached to cell wall proteins in all Candida species, including the pathogenic fungus Candida albicans. Mannans are sensed by pattern recognition receptors expressed on innate immune cells. However, the detailed structural patterns affecting immune sensing are not fully understood because mannans have a complex structure that includes α- and ß-mannosyl linkages. In this study, we focused on the ß-1,2-mannosides of N-linked mannan in C. albicans because this moiety is not present in the non-pathogenic yeast Saccharomyces cerevisiae. To investigate the impact of ß-1,2-mannosides on immune sensing, we constructed a C. albicans ∆mnn4/∆bmt1 double deletant. Thin-layer chromatography and nuclear magnetic resonance analyses revealed that the deletant lacked ß-1,2-mannosides in N-linked mannan. Mannans lacking the ß-1,2-mannosides induced the production of higher levels of inflammatory cytokines, including IL-6, IL-12p40 and TNF-α, in mice dendritic cells compared to wild-type mannan. Our data show that ß-1,2-mannosides in N-linked mannan reduce the production of inflammatory cytokines by dendritic cells.

Unique interplay between sugar and lipid in determining the antigenic potency of bacterial antigens for NKT cells.

Invariant natural killer T (iNKT) cells are an evolutionary conserved T cell population characterized by features of both the innate and adaptive immune response. Studies have shown that iNKT cells are required for protective responses to Gram-positive pathogens such as Streptococcus pneumoniae, and that these cells recognize bacterial diacylglycerol antigens presented by CD1d, a non-classical antigen-presenting molecule. The combination of a lipid backbone containing an unusual fatty acid, vaccenic acid, as well as a glucose sugar that is weaker or not stimulatory when linked to other lipids, is required for iNKT cell stimulation by these antigens. Here we have carried out structural and biophysical studies that illuminate the reasons for the stringent requirement for this unique combination. The data indicate that vaccenic acid bound to the CD1d groove orients the protruding glucose sugar for TCR recognition, and it allows for an additional hydrogen bond of the glucose with CD1d when in complex with the TCR. Furthermore, TCR binding causes an induced fit in both the sugar and CD1d, and we have identified the CD1d amino acids important for iNKT TCR recognition and the stability of the ternary complex. The studies show also how hydrogen bonds formed by the glucose sugar can account for the distinct binding kinetics of the TCR for this CD1d-glycolipid complex. Therefore, our studies illuminate the mechanism of glycolipid recognition for antigens from important pathogens.