Shiga toxin-producing Escherichia coli (STEC) is an emerging pathogen. Recently there has been a global in the number of outbreaks caused by non-O157 STECs, typically involving six serogroups O26, O45, 0103, 0111, and 0145. STEC O145:H28 has been associated with severe human disease including hemolytic-uremic syndrome (HUS), and is demonstrated by the 2007 Belgian ice-cream-associated outbreak and 2010 US lettuce-associated outbreak, with over 10% of patients developing HUS in each. The goal of this work was to do comparative genomics of strains, clinical and environmental, to investigate genome diversity and virulence evolution of this important foodborne pathogen.
Understanding the genetic basis of infectious diseases is critical to enacting effective treatments, and several large-scale sequencing initiatives are underway to collect this information. Sequencing bacterial samples is typically performed by mapping sequence reads against genomes of known reference strains. While such resequencing informs on the spectrum of single-nucleotide differences relative to the chosen reference, it can miss numerous other forms of variation known to influence pathogenicity: structural variations (duplications, inversions), acquisition of mobile elements (phages, plasmids), homonucleotide length variation causing phase variation, and epigenetic marks (methylation, phosphorothioation) that influence gene expression to switch bacteria from non- pathogenic to pathogenic…
Understanding the genetic basis of infectious diseases is critical to enacting effective treatments, and several large-scale sequencing initiatives are underway to collect this information. Sequencing bacterial samples is typically performed by mapping sequence reads against genomes of known reference strains. While such resequencing informs on the spectrum of single nucleotide differences relative to the chosen reference, it can miss numerous other forms of variation known to influence pathogenicity: structural variations (duplications, inversions), acquisition of mobile elements (phages, plasmids), homonucleotide length variation causing phase variation, and epigenetic marks (methylation, phosphorothioation) that influence gene expression to switch bacteria from non-pathogenic to pathogenic…
Pulmonary non-tuberculous mycobacterial (PNTM) infections occur in patients with chronic lung disease, but also in a distinct group of elderly women without lung defects who share a common body morphology: tall and lean with scoliosis, pectus excavatum, and mitral valve prolapse. In order to characterize the human host susceptibility to PNTM, we performed whole exome sequencing (WES) of 44 individuals in extended families of patients with active PNTM as well as 55 additional unrelated individuals with PNTM. This unique collection of familial cohorts in PNTM represents an important opportunity for a high yield search for genes that regulate mucosal immunity.…
The newer hierarchical genome assembly process (HGAP) performs de novo assembly using data from a single PacBio long insert library. To assess the benefits of this method, DNA from several Salmonella enterica serovars was isolated from a pure culture. Genome sequencing was performed using Pacific Biosciences RS sequencing technology. The HGAP process enabled us to close sixteen Salmonella subsp. enterica genomes and their associated mobile elements: The ten serotypes include: Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) S. Bareilly, S. Heidelberg, S. Cubana, S. Javiana and S. Typhimurium, S. Newport, S. Montevideo, S. Agona, and S. Tennessee. In addition,…
Lameness is a significant problem resulting in millions of dollars in lost revenue annually. In commercial broilers, the most common cause of lameness is bacterial chondronecrosis with osteomyelitis (BCO). We are using a wire flooring model to induce lameness attributable to BCO. We used 16S ribosomal DNA sequencing to determine that Staphylococcus spp. were the main species associated with BCO. Staphylococcus agnetis, which previously had not been isolated from poultry, was the principal species isolated from the majority of the bone lesion samples. Administering S. agnetis in the drinking water to broilers reared on wire flooring increased the incidence of…
Clavibacter michiganensis subsp. michiganensis (Cmm) is a gram positive actinomycete, causing bacterial canker of tomato (Solanum lycopersicum) a disease that can cause significant losses in tomato production. In this study, we determined the complete genome sequence of 13 California Cmm strains and one saprophytic Clavibacter strain using a combination of Ilumina and PacBio sequencing. The California Cmm strains have genome size (3.2 -3.3 mb) similar to the reference strain NCPPB382 (3.3 mb) with =98% sequence identity. Cmm strains from California share =92% genes (8-10% are noble genes) with the reference Cmm strain NCPPB382. Despite this similarity, we detected significant alternatives…
For comprehensive metabolic reconstructions and a resulting understanding of the pathways leading to natural products, it is desirable to obtain complete information about the genetic blueprint of the organisms used. Traditional Sanger and next-generation, short-read sequencing technologies have shortcomings with respect to read lengths and DNA-sequence context bias, leading to fragmented and incomplete genome information. The development of long-read, single molecule, real-time (SMRT) DNA sequencing from Pacific Biosciences, with >10,000 bp average read lengths and a lack of sequence context bias, now allows for the generation of complete genomes in a fully automated workflow. In addition to the genome sequence,…
Fecal samples were obtained from human subjects in the first blinded, placebo-controlled trial to evaluate the efficacy and safety of fecal microbiota transplant (FMT) for treatment of recurrent C. difficile infection. Samples included pre-and post-FMT transplant, post-placebo transplant, and the donor control; samples were taken at 2 and 8 week post-FMT. Sequencing was done on the PacBio Sequel System, with the goal of obtaining high quality sequences covering whole genes or gene clusters, which will be used to better understand the relationship between the composition and functional capabilities of intestinal microbiomes and patient health. Methods: Samples were randomly sheared to…
Strain level microbiome profiling is needed for a full understanding of how microbial communities influence human health. Microbiome profiling of rRNA gene amplicons is a well-understood method that is rapid and inexpensive, but standard 16S rRNA gene methods generally cannot differentiate closely related strains. Whole genome/shotgun microbiome profiling is considered a higher-resolution alternative, but with decreased throughput and significantly increased sequencing costs and analysis burden. With both methods there are also challenges with microbial lysis, DNA preparation, and taxonomic analysis. Specialized microbiome-focused protocols were developed to achieve strain-level taxonomic differentiation using a rapid, high throughput rRNA gene assay. The protocol…
Complete, high-quality microbial genomes are very valuable across a broad array of fields, from environmental studies, to human microbiome health, food pathogen surveillance, etc. Long-read sequencing enables accurate resolution of complex microbial genomes and is becoming the new standard. Here we report our novel Microbial Assembly pipeline to facilitate rapid, large-scale analysis of microbial genomes. We sequenced a 48-plex library with one SMRT Cell 8M on the Sequel II System, demultiplexed, then analyzed the data with Microbial Assembly.
In the past decade, the human microbiome has been increasingly shown to play a major role in health. For example, imbalances in gut microbiota appear to be associated with Type II diabetes mellitus (T2DM) and cardiovascular disease. Coronary artery disease (CAD) is a major determinant of the long-term prognosis among T2DM patients, with a 2- to 4-fold increased mortality risk when present. However, the exact microbial strains or functions implicated in disease need further investigation. From a large study with 523 participants (185 healthy controls, 186 T2DM patients without CAD, and 106 T2DM patients with CAD), 3 samples from each…
Explore how high-quality genomes contribute to critical scientific endeavors.
The UK’s National Collection of Type Cultures (NCTC) is a unique collection of more than 5,000 expertly preserved and authenticated bacterial cultures, many of historical significance. Founded in 1920, NCTC is the longest established collection of its type anywhere in the world, with a history of its own that has reflected — and contributed to — the evolution of microbiology for more than 100 years.
Our understanding of microbiology has evolved enormously over the last 150 years. Few institutions have witnessed our collective progress more closely than the National Collection of Type Cultures (NCTC). In fact, the collection itself is a record of the many milestones microbiologists have crossed, building on the discoveries of those who came before. To date, 60% of NCTC’s historic collection now has a closed, finished reference genome, thanks to PacBio Single Molecule, Real- Time (SMRT) Sequencing. We are excited to be their partner in crossing this latest milestone on their quest to improve human and animal health by understanding the…