Full-length genome sequencing of RNA viruses-How the approach can enlighten us on hepatitis C and hepatitis E viruses.

Among the five main viruses responsible for human hepatitis, hepatitis C virus (HCV) and hepatitis E virus (HEV) are different while sharing similarities. Both viruses can be transmitted by blood or derivatives whereas HEV can also follow environmental or zoonotic routes. These highly variable RNA viruses can cause chronic hepatitis potentially leading to hepatocarcinoma. HCV and HEV can develop new structures and functions under selective pressure to adapt to host immunity, human tissues, treatments or even various animal reservoirs. Elsewhere, with directly acting antiviral treatments, HCV can be eradicated whereas HEV is an emerging pathogen against which specific treatments have to be improved. As a unique molecular tool able to explore viral genomic plasticity, full-length genome (FLG) sequencing has become easier, faster and cheaper. The present review will show how FLG sequencing can explore these RNA viruses with the aim to investigate key genomics data to improve basic knowledge, patients' healthcare and preventive tools.

Performance evaluation of an automated SARS-CoV-2 Ag test for the diagnosis of COVID-19 infection on nasopharyngeal swabs.

OBJECTIVES: The detection of SARS-CoV-2 in infected people is a key tool to help in controlling COVID-19 pandemic. Like rapid antigenic tests, automated antigen tests, that present the advantage of a higher throughput flow, may be of interest. The LIAISON® SARS-CoV-2 Ag test was evaluated for the quantification of SARS-CoV-2 nucleocapsid antigen in nasopharyngeal swabs by comparison to RT-PCR. METHODS: The study involved 378 nasopharyngeal samples (UTM® and FLOQSwab™, Copan Diagnostics), including 46 swabs positive for SARS-CoV-2 by RT-PCR. These samples came from asymptomatic (n=99, 26.2%) or symptomatic people (n=279, 73.8%), at different times from symptom onset. The samples were analyzed on LIAISON® XL. RESULTS: The overall specificity was 99.4% (CI95% [98.6-100]). The negative predictive value reached 100% in asymptomatic people. Among the 46 positive samples, the overall sensitivity was 84.8% (CI95% [74.4-95.2]), reached 91.9% (CI95% [83.1-100]) in the first fourth days after symptoms onset and was 100% for Cq values ≤25. Antigen was not detected in samples with Cq values >25. Similar results were observed on nasopharyngeal swabs coming from patients infected with the 20I/501Y.V1 variant or the 20H/501Y.V2 variant. CONCLUSIONS: According to technical performances, the LIAISON® SARS-CoV-2 Ag test may be a useful tool for COVID-19 diagnosis, especially during the first four days of symptoms.

Variability in molecular characteristics of Hepatitis E virus quasispecies could modify viral surface properties and transmission.

Hepatitis E virus (HEV) usually causes self-limited liver diseases but can also result in severe cases. Genotypes 1 (G1) and 2 circulate in developing countries are human-restricted and waterborne, while zoonotic G3 and G4 circulating in industrialized countries preferentially infect human through consumption of contaminated meat. Our aims were to identify amino acid patterns in HEV variants that could be involved in pathogenicity or in transmission modes, related to their impact on antigenicity and viral surface hydrophobicity. HEV sequences from human (n = 37) and environmental origins (wild boar [n = 3], pig slaughterhouse effluent [n = 6] and urban wastewater [n = 2]) were collected for the characterization of quasispecies using ultra-deep sequencing (ORF2/ORF3 overlap). Predictive and functional assays were carried out to investigate viral particle antigenicity and hydrophobicity. Most quasispecies showed a major variant while a mixture was observed in urban wastewater and in one chronically infected patient. Amino acid signatures were identified, as a rabbit-linked HEV pattern in two infected patients, or the S68L (ORF2) / H81C (ORF3) residue mostly identified in wild boars. By comparison with environmental strains, molecular patterns less likely represented in humans were identified. Patterns impacting viral hydrophobicity and/or antigenicity were also observed, and the higher hydrophobicity of HEV naked particles compared with the enveloped forms was demonstrated. HEV variants isolated from human and environment present molecular patterns that could impact their surface properties as well as their transmission. These molecular patterns may concern only one minor variant of a quasispecies and could emerge under selective pressure.

The variability of hepatitis B envelope is associated with HBs antigen persistence in either chronic or acute HBV genotype A infection.

BACKGROUND: More than 240 million people are chronically infected by hepatitis B virus (HBV) worldwide. Envelope proteins play a crucial role in viral cellular entry and immune recognition. The loss of HBs antigen (HBsAg) correlated with a good clinical prognosis is rarely achieved with or without treatment (3-16%). OBJECTIVES: HBV envelope variability was investigated according to HBsAg persistence. STUDY DESIGN: The cohort consisted of 15 HBV genotype A-infected patients divided into "resolvers", with HBsAg clearance, and "non-resolvers", with HBsAg persistence and in subgroups: acute (n=5, AHBV) or chronic infection (n=4, CHBV) and HBV/HIV coinfection (n=6, CHBV/HIV). HBV S and preS sequences were studied by direct and ultra-deep sequencing. Amino acid sequences were analyzed with bioinformatics for predicted antigenicity. RESULTS: In S gene, the complexity was lower in AHBV than in chronic-infected patients (p=0.046). Major mutations, detected using direct sequencing, were more frequent in AHBV developing chronicity (p=0.01) than in AHBV resolvers. In the Major Hydrophilic Region, more frequent mutations were observed in non-resolvers versus resolvers (p=0.047) and non-resolvers tended to have more haplotypes with a reduced predicted antigenicity (p=0.07). Most of the mutations in preS/S region were found rather in epitopic than in non-epitopic areas (p=0.025). Interestingly, the mutation sY161F found in 3/8 non-resolvers was associated with a decrease in predicted antigenicity (28%; AnTheProt). CONCLUSIONS: HBsAg persistence was correlated with mutations and deletions in areas playing a key role in immune recognition. These data suggest that variability in HBV envelope could favor immune escape in various clinical settings of HBV genotype A-infected patients.

Optimising the diagnostic strategy for onychomycosis from sample collection to FUNGAL identification evaluation of a diagnostic kit for real-time PCR.

Onychomycosis is a common nail disorder mainly due to dermatophytes for which the conventional diagnosis requires direct microscopic observation and culture of a biological sample. Nevertheless, antifungal treatments are commonly prescribed without a mycological examination having been performed, partly because of the slow growth of dermatophytes. Therefore, molecular biology has been applied to this pathology, to support a quick and accurate distinction between onychomycosis and other nail damage. Commercial kits are now available from several companies for improving traditional microbiological diagnosis. In this paper, we present the first evaluation of the real-time PCR kit marketed by Bio Evolution for the diagnosis of dermatophytosis. Secondly, we compare the efficacy of the kit on optimal and non-optimal samples. This study was conducted on 180 nails samples, processed by conventional methods and retrospectively analysed using this kit. According to our results, this molecular kit has shown high specificity and sensitivity in detecting dermatophytes, regardless of sample quality. On the other hand, and as expected, optimal samples allowed the identification of a higher number of dermatophytes by conventional mycological diagnosis, compared to non-optimal samples. Finally, we have suggested several strategies for the practical use of such a kit in a medical laboratory for quick pathogen detection.

Discrimination between native and Tn6010-associated oqxAB in Klebsiella spp., Raoultella spp., and other Enterobacteriaceae by using a two-step strategy.

We developed a two-step PCR-based strategy to detect genes encoding OqxAB, allowing a specific assignment of Tn6010-associated oqxAB in Enterobacteriaceae. Chromosomal location in this setup was confirmed by hybridization with I-CeuI-restricted genomes. This approach led us to find that Klebsiella sp. and Raoultella sp. reference strains chromosomally carried oqxAB.

Interactions between snow chemistry, mercury inputs and microbial population dynamics in an Arctic snowpack.

We investigated the interactions between snowpack chemistry, mercury (Hg) contamination and microbial community structure and function in Arctic snow. Snowpack chemistry (inorganic and organic ions) including mercury (Hg) speciation was studied in samples collected during a two-month field study in a high Arctic site, Svalbard, Norway (79 °N). Shifts in microbial community structure were determined by using a 16S rRNA gene phylogenetic microarray. We linked snowpack and meltwater chemistry to changes in microbial community structure by using co-inertia analyses (CIA) and explored changes in community function due to Hg contamination by q-PCR quantification of Hg-resistance genes in metagenomic samples. Based on the CIA, chemical and microbial data were linked (p = 0.006) with bioavailable Hg (BioHg) and methylmercury (MeHg) contributing significantly to the ordination of samples. Mercury was shown to influence community function with increases in merA gene copy numbers at low BioHg levels. Our results show that snowpacks can be considered as dynamic habitats with microbial and chemical components responding rapidly to environmental changes.

Characterization of a new blaOXA-48-carrying plasmid in Enterobacteriaceae.

In this work, we characterized a new, 160-kb, blaOXA-48-harboring IncL/M-type plasmid isolated from a Klebsiella pneumoniae strain from France. Moreover, we report the transfer of a 60-kb OXA-48-encoding plasmid from Klebsiella pneumoniae to other Enterobacteriaceae in two patients.

Human pathogens abundant in the bacterial metagenome of cigarettes.

BACKGROUND: Many studies have evaluated chemical, heavy metal, and other abiotic substances present in cigarettes and their roles in the development of lung cancer and other diseases, yet no studies have comprehensively evaluated bacterial diversity of cigarettes and the possible impacts of these microbes on respiratory illnesses in smokers and exposed nonsmokers. OBJECTIVES: The goal of this study was to explore the bacterial metagenomes of commercially available cigarettes. METHODS: A 16S rRNA-based taxonomic microarray and cloning and sequencing were used to evaluate total bacterial diversity of four brands of cigarettes. Normalized microarray data were compared using principal component analysis and hierarchical cluster analysis to evaluate potential differences in microbial diversity across cigarette brands. RESULTS: Fifteen different classes of bacteria and a broad range of potentially pathogenic organisms were detected in all cigarette samples. Most notably, we detected Acinetobacter, Bacillus, Burkholderia, Clostridium, Klebsiella, Pseudomonas aeruginosa, and Serratia in > or = 90% of all cigarette samples. Other pathogenic bacteria detected included Campylobacter, Enterococcus, Proteus, and Staphylococcus. No significant variability in bacterial diversity was observed across the four different cigarette brands. CONCLUSIONS: Previous studies have shown that smoking is associated with colonization by pathogenic bacteria and an increased risk of lung infections. However, this is the first study to show that cigarettes themselves could be the direct source of exposure to a wide array of potentially pathogenic microbes among smokers and other people exposed to secondhand smoke. The overall public health implications of these findings are unclear at this time, and future studies are necessary to determine whether bacteria in cigarettes could play important roles in the development of both infectious and chronic respiratory diseases.

Microbial sequences retrieved from environmental samples from seasonal arctic snow and meltwater from Svalbard, Norway.

16S rRNA gene (rrs) clone libraries were constructed from two snow samples (May 11, 2007 and June 7, 2007) and two meltwater samples collected during the spring of 2007 in Svalbard, Norway (79 degrees N). The libraries covered 19 different microbial classes, including Betaproteobacteria (21.3%), Sphingobacteria (16.4%), Flavobacteria (9.0%), Acidobacteria (7.7%) and Alphaproteobacteria (6.5%). Significant differences were detected between the two sets of sample libraries. First, the meltwater libraries had the highest community richness (Chao1: 103.2 and 152.2) and Shannon biodiversity indices (between 3.38 and 3.59), when compared with the snow libraries (Chao1: 14.8 and 59.7; Shannon index: 1.93 and 3.01). Second, integral-LIBSHUFF analyses determined that the bacterial communities in the snow libraries were significantly different from those of the meltwater libraries. Despite these differences, our data also support the theory that a common core group of microbial populations exist within a variety of cryohabitats. Electronic supplementary material The online version of this article (doi:10.1007/s00792-009-0299-2) contains supplementary material, which is available to authorized users.