There is an ongoing worldwide coronavirus disease 2019 (Covid-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At present, confirmatory diagnosis is by reverse transcription polymerase chain reaction (RT-PCR), typically taking several hours and requiring a molecular laboratory to perform. There is an urgent need for rapid, simplified, and cost-effective detection methods. We have developed and analytically validated a protocol for direct rapid extraction-free PCR (DIRECT-PCR) detection of SARS-CoV-2 without the need for nucleic acid purification. As few as six RNA copies per reaction of viral nucleocapsid (N) gene from respiratory samples such as sputum and nasal exudate can be detected directly using our one-step inhibitor-resistant assay. The performance of this assay was validated on a commercially available portable PCR thermocycler. Viral lysis, reverse transcription, amplification, and detection are achieved in a single-tube homogeneous reaction within 36 min. This minimizes hands-on time, reduces turnaround-time for sample-to-result, and obviates the need for RNA purification reagents. It could enable wider use of Covid-19 testing for diagnosis, screening, and research in countries and regions where laboratory capabilities are limiting.
There is an ongoing worldwide coronavirus disease 2019 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At present, confirmatory diagnosis is by reverse transcription polymerase chain reaction (RT-PCR), typically taking several hours and requiring a molecular laboratory to perform. There is an urgent need for rapid, simplified and cost-effective detection methods. We have developed and analytically validated a protocol for direct rapid extraction-free PCR (DIRECT-PCR) detection of SARS-CoV-2 without the need for nucleic acid purification. As few as 6 RNA copies per reaction of viral nucleocapsid (N) gene from respiratory samples such as sputum and nasal exudate can be detected directly using our one-step inhibitor-resistant assay. The performance of this assay was validated on a commercially available portable PCR thermocycler. Viral lysis, reverse transcription, amplification and detection are achieved in a single-tube homogeneous reaction within 36 minutes. This minimized hands-on time, reduces turnaround-time for sample-to-result and obviates the need for RNA purification reagents. It could enable wider use of Covid-19 testing for diagnosis, screening and research in countries and regions where laboratory capabilities are limiting.
Whole-genome sequencing of prokaryotes is now readily available and affordable on next-generation sequencing platforms. However, the process of de novo assembly can be complicated and tedious for those without a background in computational biology, bioinformatics, or UNIX. Licenses for commercial bioinformatics software may be costly and limited in flexibility. GALAXY is a powerful graphical open-source code-free bioinformatics platform that is freely available on multiple public and private servers. Here, we describe a bacterial de novo assembly workflow using GALAXY. It performs de novo genome assembly using short reads, long reads, or a hybrid method using both short and long reads. Genome annotation, prediction of antimicrobial resistance genes, and multi-locus sequence typing are subsequently performed to characterize the draft genome. Performing genome assembly and annotation on this pipeline allows documentation, parameterization, and sharing, facilitating replication, reuse, and reproducibility of both data and methods.
Here, we report the genome sequence of
Enterobacter hormaechei
subsp.
steigerwaltii
strain BEI01, originally deposited as a member of the
Enterobacter cloacae
complex. The genome is 4,900,246 bp in size with a GC content of 55.44%; it contains multidrug antimicrobial resistance genes and several metal resistance gene operons.
Environmental studies often require culture and characterization to understand the prevalence, distribution, persistence and functions of target microorganisms in ecological habitats. Isolating pure microbiological monocultures allows the phenotypic characterization of microorganisms to study their functional properties. For efficient isolation of low-prevalence organisms, enrichment followed by PCR screening is performed to identify positive samples for subsequent culture. Molecular characterization, strain-typing, and genotyping of isolated microorganisms is best comprehensively performed using whole-genome sequencing. This article outlines end-to-end protocols for screening, isolation, and sequencing of microbes from environmental samples. We provide systematic methods for environmental study design, enrichment, screening, and isolation of target microorganisms. Species identification is performed using qPCR or MALDI-TOF MS. Genomic DNA is extracted for whole-genome sequencing using the Oxford Nanopore platform.
Here, we report the genome of ESBL-producing
Klebsiella pneumoniae
strain C43, which was isolated from an environmental water sample. The genome is 5,614,412 bp in size with GC content of 56.86% with multidrug antimicrobial resistance genes and several metal resistance gene operons.
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