Comparison of Three In-House Real PCR Assays Targeting Kinetoplast DNA, the Small Subunit Ribosomal RNA Gene and the Glucose-6-Phosphate Isomerase Gene for the Detection of Leishmania spp. in Human Serum

To perform PCR from serum for the diagnosis of visceral leishmaniasis is convenient and much less invasive than the examination of deeper compartments such as bone marrow. We compared three Leishmania-specific real-time PCRs with three different molecular targets (kinetoplast DNA, the small subunit-ribosomal RNA-(ssrRNA-)gene, the glucose-6-phosphate isomerase-(gpi-)gene) regarding their sensitivity and specificity in human serum. Residual sera from previous diagnostic assessments at the German National Reference Center for Tropical Pathogens Bernhard Nocht Institute for Tropical Medicine Hamburg and the Swiss Tropical and Public Health Institute were used. The sensitivities of kinetoplast DNA-PCR, ssrRNA-gene PCR, and gpi-PCR were 93.3%, 73.3%, and 33.3%, respectively, with 15 initial serum samples from visceral leishmaniasis patients, as well as 9.1%, 9.1%, and 0.0%, respectively, with 11 follow-up serum samples taken at various time points following anti-leishmanial therapy. Specificity was 100.0% in all assays as recorded with 1.137 serum samples from deployed soldiers and migrants without clinical suspicion of visceral leishmaniasis. Kinetoplast-DNA PCR from serum was confirmed as a sensitive and specific approach for the diagnosis of visceral leishmaniasis. The results also indicate the suitability of serum PCR for diagnostic follow-up after therapy, in particular regarding therapeutic failure in case of persisting positive PCR results.

AXIOME3: Automation, eXtension, and Integration Of Microbial Ecology

Background Advances in high-throughput sequencing accessibility have democratized small subunit ribosomal RNA gene sequence data collection, coincident with an increasing availability of computational tools for sequence data processing, multivariate statistics, and data visualization. However, existing tools often require programming ability and frequent user intervention that may not be suitable for fast-paced and large-scale data analysis by end user microbiologists who are unfamiliar with the Linux command line environment or who prefer interactions with a GUI. Here we present AXIOME3, which is a completely redeveloped AXIOME pipeline that streamlines small subunit ribosomal RNA data analysis by managing QIIME2, R, and Python-associated analyses through an interactive web interface. Findings AXIOME3 comes with web GUI to improve usability by simplifying configuration processes and task status tracking. Internally, it uses an automated pipeline that is wrapped around QIIME2 to generate a range of outputs including amplicon sequence variant tables, taxonomic classifications, phylogenetic trees, biodiversity metrics, and ordinations. The extension module for AXIOME3 provides advanced data visualization tools such as principal coordinate analysis, bubble plots, and triplot ordinations that can be used to visualize interactions between a distance matrix, amplicon sequence variant taxonomy, and sample metadata. Conclusions Because repeat analysis of small subunit ribosomal RNA amplicon sequence data is challenging for those who have limited experience in command line environments, AXIOME3 now offers rapid and user-friendly options within an automated pipeline, with advanced data visualization tools and the ability for users to incorporate additional analyses easily through extension. AXIOME3 is completely open source (https://github.com/neufeld/AXIOME3, https://github.com/neufeld/AXIOME3-GUI), and researchers are encouraged to modify and redistribute the package.

Population Structure of Phytophthora nicotianae Reveals Host-Specific Lineages on Brinjal, Ridge Gourd, and Tomato in South India

Severe outbreaks of Phytophthora fruit rot on brinjal, ridge gourd, and tomato have been observed since 2011 in Andhra Pradesh, Karnataka, Telangana, and Tamil Nadu states of India. Therefore, 76 Phytophthora nicotianae isolates, recovered from brinjal (17), ridge gourd (40), and tomato (19) from different localities in these states during the June to December cropping season of 2012 and 2013, were characterized based on phenotypic and genotypic analyses and aggressiveness on brinjal, tomato, and ridge gourd. All brinjal and ridge gourd isolates were A2, while tomato isolates were both A1 (13) and A2 (6). All isolates were metalaxyl sensitive. In addition, isolates were genotyped for three mitochondrial (ribosomal protein L5-small subunit ribosomal RNA [rpl5-rns], small subunit ribosomal RNA-cytochrome c oxidase subunit 2 [rns-cox2], and cox2+spacer) and three nuclear loci (hypothetical protein [hyp], scp-like extracellular protein [scp], and beta-tubulin [β-tub]). All regions were polymorphic but nuclear regions were more variable than mitochondrial regions. The network analysis of genotypes using the combined dataset of three nuclear regions revealed a host-specific association. However, the network generated using mitochondrial regions limited such host-specific groupings only to brinjal isolates. P. nicotianae isolates were highly aggressive and produced significantly (P ≤ 0.01) larger lesions on their respective host of origin than on other hosts. The results indicate significant genetic variation in the population of P. nicotianae, leading to identification of host-specific lineages responsible for severe outbreaks on brinjal, ridge gourd, and tomato.

First PCR isolation of Crithidia mellificae (Euglenozoa: Trypanosomatidae) in Apis mellifera (Hymenoptera: Apidae) in Italy

<em>Crithidia mellificae</em> (Langridge &amp; McGhee, 1967) is a trypanosomatid described in <em>Apis</em> <em>mellifera</em> (Linnaeus, 1758). The pathological effects of this parasite on the host are not well known. In this short communication, we report the first isolation of this pathogen in Italy, as realized in December 2013. The detection of <em>Crithidia</em> spp. was obtained by applying two PCR protocols that target the sequence of the mitochondrial cytochrome b (<em>Cytb</em>) and the sequence of small subunit ribosomal RNA (<em>SSUrRNA</em>), respectively. The PCR products were subjected to sequencing, which confirmed that the strain belonged to <em>Crithidia mellificae</em>.