The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

SPAdes, a new genome assembly algorithm and its applications to single-cell sequencing ( 7th Annual SFAF Meeting, 2012)

BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.

“Bioinformatics” 특집을 내면서

Gene families are growing rapidly, but standard methods for inferring phylogenies do not scale to alignments with over 10,000 sequences. We present FastTree, a method for constructing large phylogenies and for estimating their reliability. Instead of storing a distance matrix, FastTree stores sequence profiles of internal nodes in the tree. FastTree uses these profiles to implement neighbor-joining and uses heuristics to quickly identify candidate joins. FastTree then uses nearest-neighbor interchanges to reduce the length of the tree. For an alignment with N sequences, L sites, and a different characters, a distance matrix requires O(N^2) space and O(N^2 L) time, but FastTree requires just O( NLa + N sqrt(N) ) memory and O( N sqrt(N) log(N) L a ) time. To estimate the tree's reliability, FastTree uses local bootstrapping, which gives another 100-fold speedup over a distance matrix. For example, FastTree computed a tree and support values for 158,022 distinct 16S ribosomal RNAs in 17 hours and 2.4 gigabytes of memory. Just computing pairwise Jukes-Cantor distances and storing them, without inferring a tree or bootstrapping, would require 17 hours and 50 gigabytes of memory. In simulations, FastTree was slightly more accurate than neighbor joining, BIONJ, or FastME; on genuine alignments, FastTree's topologies had higher likelihoods. FastTree is available at http://microbesonline.org/fasttree.

/pdf/fast-tree-computing-large-minimum-evolution-trees-with-4grq0gwfpy.pdf

Fast Tree: Computing Large Minimum-Evolution Trees with Profiles instead of a Distance Matrix

International study of the prevalence and outcomes of infection in intensive care units

Review of antibiotic resistance in China and its environment

BACKGROUND: Coronavirus disease 2019 (COVID-19) is an emerging serious global health problem. Gastrointestinal symptoms are common in COVID-19 patients, and SARS-CoV-2 RNA has been detected in stool specimens. However, the relationship between the gut microbiome and disease remains to be established. METHODS: We conducted a cross-sectional study of 30 COVID-19 patients, 24 influenza A (H1N1) patients, and 30 matched healthy controls (HC) to identify differences in the gut microbiota by 16S ribosomal RNA (rRNA) gene V3-V4 region sequencing. RESULTS: Compared with HC, COVID-19 patients had significantly reduced bacterial diversity, a significantly higher relative abundance of opportunistic pathogens, such as Streptococcus, Rothia, Veillonella and Actinomyces, and a lower relative abundance of beneficial symbionts. Five biomarkers showed high accuracy for distinguishing COVID-19 patients from HC with an area under the curve (AUC) up to 0.89. Patients with H1N1 displayed lower diversity and different overall microbial composition compared with COVID-19 patients. Seven biomarkers were selected to distinguish the two cohorts with an AUC of 0.94. CONCLUSION: The gut microbial signature of patients with COVID-19 was different from that of H1N1 patients and HC. Our study suggests the potential value of the gut microbiota as a diagnostic biomarker and therapeutic target for COVID-19, but further validation is needed.

/pdf/alterations-of-the-gut-microbiota-in-patients-with-1ws20a2miq.pdf

Alterations of the Gut Microbiota in Patients With Coronavirus Disease 2019 or H1N1 Influenza

In order to investigate the epidemiology, molecular characteristics, and distribution of extended-spectrum β-lactamase (ESBL)- and AmpC-producing Escherichia coli from community-onset infections in Chinese county hospitals. 
E. coli isolates were collected from patients with community-onset infections in 30 county hospitals. ESBL activity was confirmed by double-disc diffusion. Genetic confirmation and molecular typing of ESBL- and AmpC-producing isolates was determined by PCR and DNA sequencing. ESBL-positive isolates were further characterised by multi-locus sequence typing. Of 550 E. coli isolates, 256 (46.5%) carried ESBL genes and all were of the CTX-M type. The prevalence of ESBL-producing strains varied from 30.2% to 57.0% across different regions of China. Overall, 12 bla
CTX-M subtypes were detected; the most abundant were bla
CTX-M-14 (163/256 isolates, 64.5%), bla
CTX-M-55(47/256, 18.4%), and bla
CTX-M-15 (31/256, 12.1%). CMY-2-like AmpC β-lactamases were detected in 11 strains, three of which co-existed with bla
CTX-M. A total of 64 sequence types (STs) were detected in 256 ESBL-producing strains, including nine that were new. ST131 was the most abundant type (27 isolates, 12.7%), followed by ST69 (14 isolates, 6.6%), ST405 (14 isolates, 6.6%), and ST38 (12 isolates, 5.6%). This study revealed that the widespread prevalence of ESBLs among outpatient infections has reached a high level in county hospitals. The CTX-M genotype was most dominant, comprising a variety of subtypes. This is the first time the incidence of CTX-M-55 has exceeded that of CTX-M-15 in China. No predominant ST was detected, suggesting that ESBL-producing E. coli strains originate in different clones.

/pdf/nationwide-high-prevalence-of-ctx-m-and-an-increase-of-ctx-m-3en7937pqg.pdf

Nationwide high prevalence of CTX-M and an increase of CTX-M-55 in Escherichia coli isolated from patients with community-onset infections in Chinese county hospitals.

xonghong xiao and colleagues analyze the challenge of antimicrobial resistance in china. a government strategy to promote rational use of antimicrobials in health care reduced antibiotic sales and percentage of prescriptions for antimicrobials for both hospitalized patients and outpatients, and offers insights to shape future initiatives. please see later in the article for the editors' summary

/pdf/changes-in-chinese-policies-to-promote-the-rational-use-of-52qa4k6w2r.pdf

changes in chinese policies to promote the rational use of antibiotics

Coexistence of MCR-1 and NDM-1 in Clinical Escherichia coli Isolates.

Between March and June, 2013, forty H7N9 patients were hospitalized in our hospital. Next-generation sequencing technologies have been used to sequence the fecal DNA samples of the patient, the within sample diversity analysis, enterotyping, functional gene and metagenomic species analysis have been carried on both the patients and healthy controls. The influence of associated treatment in H7N9 infected patients is dramatic and was firstly revealed in species level due to deep sequencing technology. We found that most of the MetaGenomic Species (MGS) enriched in the control samples were Roseburia inulinivorans DSM 16841, butyrate producing bacterium SS3/4 and most of MGS enriched in the H7N9 patients were Clostridium sp. 7 2 43FAA and Enterococcus faecium. It was concluded that H7N9 viral infection and antibiotic administration have a significant effect on the microbiota community with decreased diversity and overgrowth of the bacteria such as Escherichia coli and Enterococcus faecium. Enterotype analysis showed that the communities were unstable. Treatment including antivirals, probiotics and antibiotics helps to improve the microbiota diversity and the abundance of beneficial bacteria in the gut.

/pdf/influence-of-h7n9-virus-infection-and-associated-treatment-3tvk1x68p5.pdf

Beiwen Zheng

Papers

Alterations of the Gut Microbiota in Patients With Coronavirus Disease 2019 or H1N1 Influenza

Nationwide high prevalence of CTX-M and an increase of CTX-M-55 in Escherichia coli isolated from patients with community-onset infections in Chinese county hospitals.

changes in chinese policies to promote the rational use of antibiotics

Coexistence of MCR-1 and NDM-1 in Clinical Escherichia coli Isolates.

Influence of H7N9 virus infection and associated treatment on human gut microbiota