A novel diagnostic method for malaria using loop-mediated isothermal amplification (LAMP) and MinION™ nanopore sequencer.

BACKGROUND: A simple and accurate molecular diagnostic method for malaria is urgently needed due to the limitations of conventional microscopic examination. In this study, we demonstrate a new diagnostic procedure for human malaria using loop mediated isothermal amplification (LAMP) and the MinION™ nanopore sequencer. METHODS: We generated specific LAMP primers targeting the 18S-rRNA gene of all five human Plasmodium species including two P. ovale subspecies (P. falciparum, P. vivax, P. ovale wallikeri, P. ovale curtisi, P. knowlesi and P. malariae) and examined human blood samples collected from 63 malaria patients in Indonesia. Additionally, we performed amplicon sequencing of our LAMP products using MinION™ nanopore sequencer to identify each Plasmodium species. RESULTS: Our LAMP method allowed amplification of all targeted 18S-rRNA genes of the reference plasmids with detection limits of 10-100 copies per reaction. Among the 63 clinical samples, 54 and 55 samples were positive by nested PCR and our LAMP method, respectively. Identification of the Plasmodium species by LAMP amplicon sequencing analysis using the MinION™ was consistent with the reference plasmid sequences and the results of nested PCR. CONCLUSIONS: Our diagnostic method combined with LAMP and MinION™ could become a simple and accurate tool for the identification of human Plasmodium species, even in resource-limited situations.

Clinical response to liposomal doxorubicin and rituximab in HHV-8-associated multicentric Castleman's disease in an HIV-positive patient.

We report a patient with HIV-associated multicentric Castleman's disease who had recurrent human herpesvirus-8 viremia associated with intermittent febrile exanthema and lymphadenopathy. Although the patient relapsed after single-agent treatment with liposomal doxorubicin, weekly infusions of rituximab led to complete remission even though the reactivation of the Kaposi's sarcoma was unfortunately observed. Rituximab could not only eliminate the accumulation of HHV-8 load but also play a part in the modulation of dysregulated CD20-positive B cells in HIV-associated multicentric Castleman's disease.

Diagnosis of imported Ugandan typhoid fever based on local outbreak information: A case report.

Re-emerging multidrug-resistant typhoid fever is becoming a worldwide threat, especially in East Africa. At the beginning of 2015, an outbreak of typhoid fever started in the capital city of Uganda, and 1940 suspected cases were reported by 5 March 2015. In this report, we describe a case of typhoid fever caused by a MDR strain with HIV infection and hemoglobin S-syndrome thalassemia in an Ugandan from Kampala City. It is essential to consider MDR strains of Salmonella enterica serovar Typhi infections, including fluoroquinolone-resistant strains, in patients from Africa and Southeast Asia.

Mother-to-child transmission of congenital Chagas disease, Japan.

We report a patient with congenital Chagas disease in Japan. This report reemphasizes the role of neglected and emerging tropical diseases in the era of globalization. It also indicates the need for increased vigilance for detecting Chagas disease in non-disease-endemic countries.

[A case of eosinophilic granulomatosis with polyangiitis with extra-vascular granuloma and eosinophilic vasculitis diagnosed by transbronchial lung biopsy].

A 62-year-old man was suffering from bronchial asthma and referred to our institution with dry cough and dyspnea on exertion in November, 2010. He was diagnosed with eosinophilic granulomatosis with polyangiitis (EPGA, formerly Churg-Strauss syndrome) by chest radiographic findings, blood eosinophilia, mononeuritis multiplex and cardiomyopathy. Steroid therapy was started and he was rapidly improved. Steroid therapy had been tapered off by May, 2012. After 2 months, however, progressive dyspnea, neural symptoms, deafness, re-elevation of blood eosinophils and bilateral multifocal infiltrations appeared. He was re-admitted to our institution. Transbronchial lung biopsy (TBLB) specimens revealed extra-vascular granuloma, eosinophilic vasculitis and eosinophilic pneumonia and we diagnosed him with the reccurence of EGPA. He was improved by steroid pulse therapy, then tapered. This case was the antineutrophil cytoplasmic autoantibodies negative EGPA. The case of EGPA with granuloma and vasculitis diagnosed by TBLB was rare.

Optimization and evaluation of the ARCHITECT Chagas assay and in-house ELISA for Chagas disease in clinical settings in Japan.

Approximately 250,000 immigrants from Latin America live in Japan and it is estimated that 1500-3000 of them are potentially infected with Trypanosoma cruzi, the cause of Chagas disease. Therefore, the establishment of a standardized diagnostic method for Chagas disease in Japan is urgently needed. In this study, we optimized and evaluated the ARCHITECT Chagas assay and in-house ELISA for Chagas disease in clinical settings. In particular, we evaluated the performance of ARCHITECT Chagas as well as ELISA with whole-cell lysates and three recombinant proteins (TcF, TcBCDE, and CP1 + CP3) using 93 Chagas disease-positive serum samples and 108 Chagas disease-positive samples. The sensitivities of ARCHITECT Chagas, whole-cell lysate, TcF, TcBCDE, and CP1 + CP3 ELISA were respectively 100%, 100%, 98.9%, 98.9%, and 89.2% and the corresponding specificities were 100%, 99.1%, 99.1%, 100%, and 99.1%. False-positive results were obtained for whole-cell lysate, TcF, and CP1 ± CP3 ELISA. This is the first evidence that OD cut-off values optimized for in-house ELISA are similar in terms of sensitivity and specificity to those of the ARCHITECT Chagas test, supporting the use of these in-house assays as diagnostic tests for Chagas disease in the clinical setting in Japan.

Lung adenocarcinoma with repetitive endotracheal/endobronchial metastasis 20 years after surgery: A case report.

The occurrence of endotracheal/endobronchial metastasis (EEM) after complete resection of a primary lung cancer is rare. Here, we report the case of an 86-year-old woman in whom EEM occurred twice over a 20-year period following complete resection of a primary adenocarcinoma localized to the left main bronchus and trachea. The presence of EEM was confirmed by establishing immunohistochemical homology of the metastases with the primary tumor. To the best of our knowledge, this is the first reported case of repetitive EEM of primary lung adenocarcinoma. Lymphatic invasion in the primary lesion suggested that a possible route for EEM was the peripheral lymphatic tract, explaining the slow recurrence rate. We conclude that observation of the trachea/bronchus over a long period post operation could be important in monitoring for EEM, particularly if lymphatic invasion is confirmed in the primary tumor.

Empyema with Multiple Bronchopleural Fistulae Improved by Bronchial Occlusion Using an Endobronchial Watanabe Spigot with the Push and Slide Method.

The push and slide method is a method of endoscopic bronchial occlusion using an endobronchial Watanabe spigot that facilitates occlusion of the target bronchus rapidly and accurately using a guidewire. We herein report the case of a man who was diagnosed with empyema forming bronchopulmonary fistulae that was successfully treated by endoscopic bronchial occlusion. Because of the multiple fistulae, balloon occlusion was not a favorable therapeutic approach. Instead, the push and slide method was used in order to detect the fistulae. Endoscopic occlusion, particularly that using the push and slide method, may be a valid treatment option for empyema with multiple bronchopulmonary fistulae.

Chagas disease: a report of 17 suspected cases in Japan, 2012-2017.

BACKGROUND: There are no reports on the prevalence of Chagas disease in Japan. Furthermore, screening programs and access to diagnosis and treatment have not been established. This study aimed to clarify the prevalence of Chagas disease among suspected cases in Japan and provide the reference data required for disease control. METHODS: Seventeen patients with suspected Chagas disease in Japan between 2012 and 2017 were included in the study. Patients were diagnosed with Chagas disease based on the two different serological tests for antibodies to Trypanosoma cruzi. Real-time polymerase chain reaction assay and blood culture techniques were performed to confirm T. cruzi parasitemia. RESULTS: Of the 17 patients, 11 (64.7%) were immigrants from Latin America. Ultimately, 6 patients (35.3%) were diagnosed with Chagas disease. Of these 6 patients, median age was 53.5 years, 5 patients were immigrants from Latin American, and 1 was Japanese who had a congenital infection. T. cruzi parasitemia was confirmed in 4 patients (66.7%), and 5 (83.3%) were in the chronic phase (Chagas cardiomyopathy, 4; megacolon, 1). Two patients (33.3%) commenced benznidazole treatment. CONCLUSION: Our study showed that some patients of Chagas disease living in Japan are already in the chronic phase at diagnosis because of substantial diagnostic delays. Further epidemiological studies on the prevalence of Chagas disease and systematic screening programs for the Latin American population are needed.

Single nucleotide polymorphisms in genes encoding penicillin-binding proteins in ß-lactamase-negative ampicillin-resistant Haemophilus influenzae in Japan.

OBJECTIVE: ß-Lactamase-negative ampicillin-resistant Haemophilus influenzae is a common opportunistic pathogen of hospital- and community-acquired infections, harboring multiple single nucleotide polymorphisms in the ftsI gene, which codes for penicillin-binding protein-3. The objectives of this study were to perform comprehensive genetic analyses of whole regions of the penicillin-binding proteins in H. influenzae and to identify additional single nucleotide polymorphisms related to antibiotic resistance, especially to ampicillin and other cephalosporins. RESULTS: In this genome analysis of the ftsI gene in 27 strains of H. influenzae, 10 of 23 (43.5%) specimens of group III genotype ß-lactamase-negative ampicillin-resistant H. influenzae were paradoxically classified as ampicillin-sensitive phenotypes. Unfortunately, we could not identify any novel mutations that were significantly associated with ampicillin minimum inhibitory concentrations in other regions of the penicillin-binding proteins, and we reconfirmed that susceptibility to ß-lactam antibiotics was mainly defined by previously reported SNPs in the ftsI gene. We should also consider detailed changes in expression that lead to antibiotic resistance in the future because the acquisition of resistance to antimicrobials can be predicted by the expression levels of a small number of genes.

Efficacy of switching to dolutegravir plus rilpivirine, the small-tablet regimen, in patients with dysphagia: two case reports.

BACKGROUND: The advent of well-tolerated and effective anti-retroviral drugs against human immunodeficiency virus-1 (HIV-1) infection has been a major step forward that has achieved long-term survival in recent years. The number of HIV-1 infected patients who experience difficulty in swallowing tablets is expected to increase as the HIV-infected population advances in age or develops comorbidities or treatment sequelae affecting the central nervous system. CASE PRESENTATION: Here, we describe two HIV-1-infected patients who experienced progressive dysphagia leading to inability to swallow the antiretroviral tablets included in the standard regimen. Both patients had a plasma viral load < 40 copies/mL while receiving anti-retroviral therapy with the recommended combination antiretroviral therapy (cART) regimen, but the dysphagia necessitated a switch. By switching to much smaller sized combined regimen of dolutegravir (DTG) plus rilpivirine (RPV) tablets, both of our patients were able to successfully continue treatment and maintain adherence without the need for crushing tablets or preparing an oral suspension. Additionally, switching from the recommended cART regimen to DTG plus RPV successfully maintained viral suppression. At the last available follow-up (12 months after switching to DTG/RPV), HIV-1 viral load remained below the lower limit of quantification. CONCLUSIONS: An alternative therapeutic option that takes tablet size into consideration could not only contribute to improved patient adherence, but also a reduced care burden for HIV-infected patients with dysphagia. Thus, switching to the "small-tablet regimen" of DTG plus RPV has the potential to improve the survival and well-being of patients with dysphagia.

A novel detection procedure for mutations in the 23S rRNA gene of Mycoplasma pneumoniae with peptide nucleic acid-mediated loop-mediated isothermal amplification assay.

Rapid and easy detection of a single nucleotide point mutation of bacterial genes, which is directly linked to drug susceptibility, is essential for the proper use of antimicrobial agents. Here, we established a detection method using a peptide nucleic acid mediated loop-mediated amplification (LAMP) assay for macrolide (ML)-susceptible Mycoplasma pneumoniae. This assay specifically detected the absence of missense mutations encoding the central loop of domain V in the gene encoding 23S rRNA, which can reduce the affinity for MLs and subsequently generate ML-resistant strains of M. pneumoniae. Reactions were performed at 62°C for 60min and targeted gene amplifications were detected by real-time turbidity with a turbidimeter and naked-eye inspection of a color change. The assay had an equivalent detection limit of 100.0fg of DNA with the turbidimeter and showed specificity against 54 types of pathogens, whereas amplification was completely blocked, even at 100.0pg of DNA per reaction, in the presence of point mutations at 2063A and 2064A. The expected LAMP products were confirmed through identical melting curves in real-time LAMP procedures. This method would be a simple and rapid protocol for single nucleotide polymorphism genotyping as point-of-care testing technology without amplification of the sequences carrying the point mutations 2063A and 2064A in ML-resistant M. pneumoniae strains.

Development of a highly resolved loop-mediated isothermal amplification method to detect the N526K ftsI mutation of ß-lactamase-negative ampicillin-resistant Haemophilus influenzae.

Rapid and easy detection of sequence polymorphisms, including nucleotide point mutations of bacterial pathogens responsible for amino acid substitutions linked to drug resistance, is essential for the proper use of antimicrobial agents. Here, a detection method using loop-mediated amplification (LAMP) combined with amplification refractory mutation system (ARMS) to accurately distinguish a different single nucleotide in the target sequence was established, named ARMS-SNP LAMP. This procedure is capable of species-specific detection of a nucleotide (1578T) in the ftsI gene on Haemophilus influenzae without amplifying the sequence carrying the point mutations (T1578G/A) in ß-lactamase-negative ampicillin resistant (BLNAR) strains. Reactions were performed at 61°C for 45min. Successful target gene amplifications were detected by measuring real-time turbidity using a turbidimeter and visual detection. The assay had a detection limit of 10.0pg of genomic DNA per reaction and showed specificity against 52 types of pathogens, whereas amplifications were completely blocked in even 100.0ng/µL of genomic DNA with point mutations at T1578G and T1578A. The expected ARMS-SNP LAMP products were confirmed through identical melting curves in real-time LAMP procedures. This novel procedure was also used to analyze 57 clinical isolates of H. influenzae. All 25 clinical isolates with the naïve sequence of 1578T gave positive results. In addition, concordant negative results were obtained for 31 of the BLNAR strains with the T1578G mutation and one strain with the T1578A mutation. The ARMS-SNP LAMP method is a simple and rapid method for SNP-genotyping of a clinical isolate as point-of-care testing (POCT) technology. It is suitable for use in both resource-limited situations and well-equipped clinical settings because of its simplicity and convenience.

Progressive HIV-associated Cholangiopathy in an HIV Patient Treated with Combination Antiretroviral Therapy.

We herein describe a case of progressive human immunodeficiency virus (HIV)-associated cholangiopathy despite normalization of laboratory parameters, which had indicated liver dysfunction, after the initiation of combined anti-retroviral therapy (cART). HIV-associated cholangiopathy remains important as a differential diagnosis of bile duct disorders, although it is considered to be a rare disease in the era of cART. Magnetic resonance cholangiopancreatography could thus be a powerful tool for the diagnosis and follow-up of this disease.