Clinical Characteristics of Corynebacterium ulcerans Infection, Japan.

Corynebacterium ulcerans is a closely related bacterium to the diphtheria bacterium C. diphtheriae, and some C. ulcerans strains produce toxins that are similar to diphtheria toxin. C. ulcerans is widely distributed in the environment and is considered one of the most harmful pathogens to livestock and wildlife. Infection with C. ulcerans can cause respiratory or nonrespiratory symptoms in patients. Recently, the microorganism has been increasingly recognized as an emerging zoonotic agent of diphtheria-like illness in Japan. To clarify the overall clinical characteristics, treatment-related factors, and outcomes of C. ulcerans infection, we analyzed 34 cases of C. ulcerans that occurred in Japan during 2001-2020. During 2010-2020, the incidence rate of C. ulcerans infection increased markedly, and the overall mortality rate was 5.9%. It is recommended that adults be vaccinated with diphtheria toxoid vaccine to prevent the spread of this infection.

Rapid Multiplex RT-PCR for Influenza A and B by Genesoc®, a Microfluidic PCR System.

Background: Rapid antigen tests are widely used to diagnose influenza. However, despite their simplicity and short turnover time, the sensitivity of these tests is relatively low, and molecular tests with greater sensitivity are being sought. In this study, we developed and clinically evaluated a protocol for the rapid multiplex testing of influenza A and B, using a rapid real-time PCR system, GeneSoC®, that is based on microfluidic thermal cycling technology. Methods: The specificity of the developed assay was validated using cultured viral strains of influenza A/B, human metapneumovirus, and respiratory syncytial virus. Analytical sensitivity was evaluated using serially diluted RNA synthesized via in vitro transcription and nasopharyngeal swab samples collected from consecutive patients seeking medical attention for a combination of upper respiratory and general symptoms. Cross-validation of GeneSoC® based on comparisons with conventional real-time RT-PCR and rapid antigen tests was performed by parallel testing of influenza-positive clinical specimens. Results: The GeneSoC® assay detected the target sequences of influenza A and B at minimum concentrations of 38 and 65 copies/µL in reaction, respectively. For the analysis of clinical specimens, the positive, negative, and overall agreement between GeneSoC® RT-PCR and a conventional real-time RT-PCR was in all cases 100%, whereas for the comparison between GeneSoC® RT-PCR and the rapid antigen test, the agreements for positive, negative, and overall findings were 100%, 90.9%, and 95.7%, respectively. The mean time for completing GeneSoC® RT-PCR was 16 min 29 s (95% confidence interval, 16 min 18 s to 16 min 39 s). Conclusion: The microfluidic real-time PCR system, GeneSoC®, has an analytical performance comparable to that of conventional real-time RT-PCR with rapid turnover time, and represents a promising alternative to rapid antigen tests for diagnosing influenza A and B.

Effect of Cetuximab and EGFR Small Interfering RNA Combination Treatment in NSCLC Cell Lines with Wild Type EGFR and Use of KRAS as a Possible Biomarker for Treatment Responsiveness.

BACKGROUND: The epidermal growth factor receptor (EGFR) is a therapeutic target for patients with non-small cell lung cancer (NSCLC). Cetuximab is an anti-EGFR monoclonal antibody that inhibits EGFR signaling and proliferation of colorectal cancer and head and neck cancers. Since only few NSCLC patients benefit from cetuximab therapy, we evaluated a novel combination treatment using cetuximab and EGFR small interfering RNA (siRNA) to strongly suppress EGFR signaling and searched for a biomarker in NSCLC cell lines harboring wild-type EGFR. METHODS: Alterations in EGFR and its downstream genes in five NSCLC cell lines (A549, Lu99, 86-2, Sq19 and Ma10) were assessed through sequencing. The protein expression levels of these molecules were assessed through western blotting. The effect of combination treatment was determined through cell proliferation assay, caspase-3/7 assay, invasion assay, and migration assay. RESULTS: All cell lines were harboring wild-type EGFR, whereas KRAS, PTEN, TP53 and TP53 were mutated in A549 and Lu99; Lu99 and Sq19; Lu99, 86-2, Sq19 and Ma10; and A549, 86-2, and Sq19 cell lines, respectively. PTEN was not expressed in Sq19, and LKB1 was not expressed in both A549 and Sq19. TP53 was not expressed in both A549 and Lu99. The combination of cetuximab and EGFR siRNA significantly suppressed cell proliferation in 86-2, Sq19 and Ma10, which express wild-type KRAS. It induced apoptosis in A549, 86-2 and Ma10 cells, which express wild type PTEN. The combination treatment had no effect either on cell invasion nor migration in all cell lines. CONCLUSION: EGFR targeted therapy using the combination of cetuximab and EGFR siRNA is effective in NSCLC cell lines harboring wild-type EGFR. Wild-type KRAS may act as a potential biomarker for response to combination treatment by the induction of apoptosis in cells with wild-type PTEN.

Evaluation of antigen-positive toxin-negative enzyme immunoassay results for the diagnosis of toxigenic Clostridium difficile infection.

Clostridium difficile (C. difficile)-associated diarrhea (CDAD) is a challenging nosocomial infectious disease. C. DIFF Quik Chek Complete assay is widely used to detect glutamate dehydrogenase (GDH) antigen and toxin A/B of C. difficile simultaneously. However, the interpretation of GDH positive/toxin negative results is problematic. We performed a retrospective study of patients with GDH positive/toxin negative results to determine the probability of detecting toxigenic C. difficile and its risk factors. Between April 2012 and March 2017, we investigated cultures of fecal specimens followed by toxin detection tests. The clinical histories of patients with and without toxigenic C. difficile were compared using univariate- and multivariate-analyses. In total, 2675 patients were examined using C. Diff Quik Chek Complete assay. Among 356 GDH positive/toxin negative patients, cultures were performed in 220 cases and toxigenic C. difficile was recovered from 139 (63.2%) specimens. Patients with toxigenic C. difficile had significantly lower body mass index than those without. Over half the GDH positive/toxin negative patients were infected with toxigenic C. difficile. Lower BMI was a CDAD risk factor in this patient population. These data can be utilized to initiate isolation and clinical interventions before confirmatory test results are available. J. Med. Invest. 65:131-135, February, 2018.

Splenic Infarction in Acute Cytomegalovirus and Human Parvovirus Concomitant Infection.

We present a case report of a 35-year-old woman who had splenic infarction. She had persistent high fever, systemic joint pain, and abnormal liver function. She was diagnosed with cytomegalovirus and human parvovirus B19 concomitant infection. Her coagulopathy test revealed no abnormal results. She was treated with intravenous ganciclovir for 13 days; consequently, her splenic infarction improved after 7 weeks. As per our knowledge, this is the first case of cytomegalovirus and parvovirus B19 coinfection complicated by splenic infarction. Cytomegalovirus and parvovirus B19 may induce a hypercoagulation state during the acute phase.

Leukocytapheresis for the treatment of acute exacerbation of idiopathic interstitial pneumonias: a pilot study.

OBJECTIVE: Idiopathic interstitial pneumonias (IIPs) are a group of heterogeneous diffuse parenchymal lung disorders of unknown etiology. An acute exacerbation (AE) is an acute respiratory deterioration that occurs in IIPs. The prognosis of AE of IIPs (AE-IIPs) is extremely severe; however, no established therapies exist. We aimed to evaluate the efficacy of leukocytapheresis (LCAP) to treat patients with AE-IIPs. PATIENTS AND METHODS: Six chronic IIPs patients who developed AE were enrolled in this study. We performed LCAP on days 2, 3, 9 and 10 in all six patients. All patients were also treated with high-dose corticosteroids and a continuous administration of low-molecular-weight heparin. We observed 30-day survival after the diagnosis of AE to evaluate the efficacy of LCAP. We also assessed oxygenation, high-resolution computed tomography (HRCT) findings, and certain chemical mediators in the peripheral blood. RESULTS: Five of six patients survived more than 30 days. One patient died of progressive respiratory failure. Oxygenation and HRCT findings tended to improve in all survivors. The serum levels of lactate dehydrogenase, high mobility group box-1, and interleukin-18 were significantly decreased statistically post-LCAP. No severe adverse events occurred. CONCLUSION: We suggest that LCAP is a safe and effective therapy for treating patients with AE-IIPs. J. Med. Invest. 64: 110-116, February, 2017.

Effect of Clarithromycin on the Expression of UL16-Binding Protein 2 in Human Cells.

BACKGROUND: Clarithromycin is a macrolide antibiotic that possesses anti-inflammatory and immunomodulatory properties. Although recent data suggests that macrolide antibiotics enhance Pseudomonas aeruginosa clearance from the lung, involving natural killer (NK) T cells in this process by activating the NKG2D-NKG2D ligand system, the precise underlying mechanism is still unclear. In this study, we examined the effect of clarithromycin on a potent NKG2D ligand, UL16-binding protein 2 (ULBP2), in the lung and its shedding mechanism. METHODS: The gene expressions of ULBP2 and the shredder proteinases of ULBP2, a disintegrin and metalloproteinase domain 10 (ADAM10) and ADAM17, were measured using real-time PCR. The cell surface ULBP2 expression was measured by flow cytometry. The amount of solubilized ULBP2 (sULBP2) was measured using an ELISA. The activity of ADAM17 was examined by measurement of fluorescence intensity from the fluorescence resonance energy transfer peptide substrate cleaved by ADAM17. RESULTS: Clarithromycin significantly induced transcription of ULBP2 and ADAM17 in both A549 and LCSC #2 cells, which endogenously express minimal and abundant levels of ULBP2, respectively. However, there was no significant change on transcription of ADAM10. The same tendency was observed when LCSC #2 cells were treated with tumor necrosis factoralpha processing inhibitor-2 to inhibit ADAM17 activity. The amount of sULBP2 was significantly decreased in both A549 and LCSC #2 cells by treatment with clarithromycin. Finally, clarithromycin significantly inhibited the activity of ADAM17 in LCSC #2 cells. CONCLUSION: These findings suggest that clarithromycin induces ULBP2 expression and reduces the amount of sULBP2, by possibly inhibiting the activity of the potent ULBP2-shedding enzyme ADAM17. Because these changes in ULBP2 and sULBP2 levels could activate NKT cells, this finding might indicate a novel mechanism by which clarithromycin improves the clearance of P. aeruginosa in chronic respiratory diseases.

A new rapid method for detecting epidermal growth factor receptor mutations in non-small cell lung cancer.

Mutations in the epidermal growth factor receptor (EGFR) gene are associated with a favorable clinical response to the EGFR tyrosine kinase inhibitors gefitinib and erlotinib in non-small cell lung cancer (NSCLC). We present here, a new method for the rapid detection of the two most common EGFR mutations (delE746-A750 and L858R) from clinical samples. The methodology involves the combination of newly designed mutation-specific primers and a novel real-time PCR machine with an innovative thermo-control mechanism that enables ultrarapid PCR. We evaluated this method using a cell mixture composed of various ratios of lung cancer cells harboring mutated or wild-type EGFR, lung cancer tissues obtained by surgery, and a cytology sample obtained by bronchoscopy from a lung cancer patient. In the cell mixture analysis, our method detected 0.1% of cells with delE746-A750 and 1% of cells with L858R among cells with wild-type EGFR. In 143 lung cancer tissues, the result of this assay was concordant with those of direct sequencing in 138 samples. The five samples with discordant results were tested using a PCR-Invader assay and the result matched those of our method at 100%. We also successfully detected EGFR mutations in the lavage obtained from a lung cancer patient. The turnaround time for this method was <10 min, and all steps could be accomplished in <50 min after sample collection. Thus, our novel PCR method offers a rapid, simple, and less expensive test for EGFR mutations and can be applied as a point-of-care diagnostic test.

[A case of lung abscess due to Aspergillus viridinutans in a patient with aplastic anemia].

A 75-year-old woman with aplastic anemia was admitted to our university hospital because of a dry cough that had persisted for a month. Chest computed tomography showed a mass shadow with a central low attenuation area in the lower lobe of the left lung. Filamentous fungus resembling Aspergillus fumigatus was cultured from the specimens obtained by transthoracic needle aspiration biopsy and bronchoalveolar lavage. The initial diagnosis was a lung abscess due to A. fumigatus, although the patient did not respond well to antifungal agents. Subsequently, the filamentous fungus was identified as Aspergillus viridinutans by sequence analysis of the ß-tubulin gene, and the patient was successfully treated with combination therapy along with granulocyte colony-stimulating factor. The incidence of A. viridinutans infection is very rare. A. viridinutans is morphologically similar to A. fumigatus; however, the response to antifungal agents is generally worse than that observed in A. fumigatus infections. Therefore, the selection of agents and supplemental therapy is of vital importance in cases of A. viridinutans infection.

Positive Predictive Value of True Bacteremia according to the Number of Positive Culture Sets in Adult Patients.

BACKGROUND: Performing multiple blood culture sets simultaneously is a standard blood culture methodology, although it is often difficult to distinguish true bacteremia from contamination when only one of several blood culture sets is positive. This study clarified the relationship between the number of positive blood culture sets and clinical significance in patients with positive blood culture. METHODS: Patients aged 18 years and over with at least 1 positive blood culture were enrolled. Positive blood culture episodes were categorized from clinical records as true bacteremia, contamination, or unknown clinical significance. The associations among episodes of true bacteremia, isolated bacteria, the number of positive blood culture sets from among the performed sets, and the clinical background of patients were analyzed. RESULTS: Among a total of 407 episodes, 262, 67 and 78 were true bacteremia, contamination and unknown clinical significance, respectively. The positive predictive values (PPVs) of 1 out of 1, 1 out of 2 and 2 out of 2 positive sets in cases of Staphylococcus aureus, were 81.3%, 50% and 100% respectively; those in cases of coagulase-negative Staphylococci were 20.5%, 10.8% and 63.5%, respectively. Almost all cases of Escherichia coli, Pseudomonas aeruginosa, Klebsiella species and Candida species were true bacteremia. The probability of true bacteremia was strongly associated with recent surgery in multivariate analysis (P < 0.05). CONCLUSION: The probability of true bacteremia based on the number of positive culture sets from among the performed sets varies by microorganism. Therefore, PPVs calculated using this method may help physicians distinguish true bacteremia from contamination.

Phase separation dynamics of aqueous solutions of thermoresponsive polymers studied by a laser T-jump technique.

Poly(N-isopropylacrylamide) and poly(vinyl methyl ether) are well-known thermoresponsive polymers. The aqueous solutions of these polymers exhibit a phase transition followed by phase separation with LCST approximately 305-310 K. In the present study, the dynamic behavior of the phase separation was analyzed by a laser T-jump method. Two different T-jump methodologies were employed: the first was a dye-photosensitized T-jump technique (indirect heating) using 532 nm laser pulses, while the other was a direct heating T-jump technique using 1.2 mum laser pulses. Both methods gave similar results. The time constants (tau) of the phase separation were systematically determined for 1-10 wt % aqueous solutions of the polymers, and a hydrodynamic radius (R) dependence for tau was clearly observed. The values of tau increased linearly with increasing square of R. The present behavior is interpretable in the framework of Tanaka's model for the volume phase transition of a gel, since each of the polymer chains are entangled in the present sample solutions, which can be regarded as approximating to a gel in solution.

Molecular probe for a fluorous medium: long-lived phosphorescence of alpha-diketones in perfluoromethylcyclohexane at room temperature.

We found that alpha-diketones (2,3-butanedione (BD) and 1-phenyl-1,2-propanedione (PPD)) were very suitable luminescence probes for studying the properties of a perfluorinated solvent (i.e., fluorous solvent; perfluoromethylcyclohexane (PFMC)), since these compounds were soluble in PFMC and showed long-lived phosphorescence even at room temperature. The phosphorescence lifetime (tau(p)) of BD in PFMC (650 micros) was much longer than that in cyclohexane (CH, 270 micros). The longer tau(p) value of BD in PFMC was ascribed to the variation of the intersystem crossing rate constant (k(isc)) from the excited triplet state (T1) to the ground state (S0) with the solvent. Some possible reasons for the change in k(isc) were discussed in terms of solute-solvent interactions. Furthermore, by utilizing phosphorescence quenching of BD by pyrene, we, determined a rate constant of the diffusion-controlled reaction in PFMC. Characteristic behaviors of mixing/separation processes between PFMC and a common organic solvent observed by Schlieren photographs were also reported.