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18 papers found.
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Bandage: interactive visualization of de novo genome assemblies

Summary: Although de novo assembly graphs contain assembled contigs (nodes), the connections between those contigs (edges) are difficult for users to access. Bandage (a Bioinformatics Application for Navigating De novo Assembly Graphs Easily) is a tool for visualizing assembly graphs with connections. Users can zoom in to specific areas of the graph and interact with it by moving...

Extensive Capsule Locus Variation and Large-Scale Genomic Recombination within the Klebsiella pneumoniae Clonal Group 258

Klebsiella pneumoniae clonal group (CG) 258, comprising sequence types (STs) 258, 11, and closely related variants, is associated with dissemination of the K. pneumoniae carbapenemase (KPC). Hospital outbreaks of KPC CG258 infections have been observed globally and are very difficult to treat. As a consequence, there is renewed interest in alternative infection control measures...

SRST2: Rapid genomic surveillance for public health and hospital microbiology labs

Takehiro Tomita 1 3 Justin Zobel 4 Kathryn E Holt 0 0 Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , Parkville, Victoria

Short read sequence typing (SRST): multi-locus sequence types from short reads

BackgroundMulti-locus sequence typing (MLST) has become the gold standard for population analyses of bacterial pathogens. This method focuses on the sequences of a small number of loci (usually seven) to divide the population and is simple, robust and facilitates comparison of results between laboratories and over time. Over the last decade, researchers and population health...

Evidence of microevolution of Salmonella Typhimurium during a series of egg-associated outbreaks linked to a single chicken farm

Background The bacterium Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most frequent causes of foodborne outbreaks of gastroenteritis. Between 2005–2008 a series of S. Typhimurium outbreaks occurred in Tasmania, Australia, that were all traced to eggs originating from a single chicken farm. We sequenced the genomes of 12 isolates linked to these outbreaks...

Adaptive Change Inferred from Genomic Population Analysis of the ST93 Epidemic Clone of Community-Associated Methicillin-Resistant Staphylococcus aureus

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a major public health problem around the world. In Australia, ST93-IV[2B] is the dominant CA-MRSA clone and displays significantly greater virulence than other S. aureus. Here, we have examined the evolution of ST93 via genomic analysis of 12 MSSA and 44 MRSA ST93 isolates, collected from...

On the origin of Mycobacterium ulcerans, the causative agent of Buruli ulcer

BackgroundMycobacterium ulcerans is an unusual bacterial pathogen with elusive origins. While closely related to the aquatic dwelling M. marinum, M. ulcerans has evolved the ability to produce the immunosuppressive polyketide toxin mycolactone and cause the neglected tropical disease Buruli ulcer. Other mycolactone-producing mycobacteria (MPM) have been identified in fish and...

High-Resolution Genotyping of the Endemic Salmonella Typhi Population during a Vi (Typhoid) Vaccination Trial in Kolkata

Background Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), is a major health problem especially in developing countries. Vaccines against typhoid are commonly used by travelers but less so by residents of endemic areas. Methodology We used single nucleotide polymorphism (SNP) typing to investigate the population structure of 372 S. Typhi isolated during a...

An Outpatient, Ambulant-Design, Controlled Human Infection Model Using Escalating Doses of Salmonella Typhi Challenge Delivered in Sodium Bicarbonate Solution

Background. Typhoid fever is a major global health problem, the control of which is hindered by lack of a suitable animal model in which to study Salmonella Typhi infection. Until 1974, a human challenge model advanced understanding of typhoid and was used in vaccine development. We set out to establish a new human challenge model and ascertain the S. Typhi (Quailes strain...

Detecting SNPs and estimating allele frequencies in clonal bacterial populations by sequencing pooled DNA

Summary: Here, we present a method for estimating the frequencies of SNP alleles present within pooled samples of DNA using high-throughput short-read sequencing. The method was tested on real data from six strains of the highly monomorphic pathogen Salmonella Paratyphi A, sequenced individually and in a pool. A variety of read mapping and quality-weighting procedures were tested...

A Salmonella Typhimurium-Typhi Genomic Chimera: A Model to Study Vi Polysaccharide Capsule Function In Vivo

The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi+), harbouring the Salmonella pathogenicity island (SPI)-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi...

Characterization of the yehUT Two-Component Regulatory System of Salmonella enterica Serovar Typhi and Typhimurium

Mark J. Arends Kathryn E. Holt Leanne Kane Lynda F. Mottram Louise Ellison Ruben Bautista Chris J. McGee Sally J. Kay Thomas M. Wileman Linda J. Kenney Calman A. MacLennan Robert A. Kingsley Gordon

A Bioinformatic Strategy for the Detection, Classification and Analysis of Bacterial Autotransporters

Autotransporters are secreted proteins that are assembled into the outer membrane of bacterial cells. The passenger domains of autotransporters are crucial for bacterial pathogenesis, with some remaining attached to the bacterial surface while others are released by proteolysis. An enigma remains as to whether autotransporters should be considered a class of secretion system, or...

Emergence of a Globally Dominant IncHI1 Plasmid Type Associated with Multiple Drug Resistant Typhoid

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), remains a serious global health concern. Since their emergence in the mid-1970s multi-drug resistant (MDR) S. Typhi now dominate drug sensitive equivalents in many regions. MDR in S. Typhi is almost exclusively conferred by self-transmissible IncHI1 plasmids carrying a suite of antimicrobial resistance genes...

High-throughput bacterial SNP typing identifies distinct clusters of Salmonella Typhi causing typhoid in Nepalese children

Background Salmonella Typhi (S. Typhi) causes typhoid fever, which remains an important public health issue in many developing countries. Kathmandu, the capital of Nepal, is an area of high incidence and the pediatric population appears to be at high risk of exposure and infection. Methods We recently defined the population structure of S. Typhi, using new sequencing technologies...

Pseudogene accumulation in the evolutionary histories of Salmonella enterica serovars Paratyphi A and Typhi

Background Of the > 2000 serovars of Salmonella enterica subspecies I, most cause self-limiting gastrointestinal disease in a wide range of mammalian hosts. However, S. enterica serovars Typhi and Paratyphi A are restricted to the human host and cause the similar systemic diseases typhoid and paratyphoid fever. Genome sequence similarity between Paratyphi A and Typhi has been...

Temporal Fluctuation of Multidrug Resistant Salmonella Typhi Haplotypes in the Mekong River Delta Region of Vietnam

Background Typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi), which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We...

The Burden and Characteristics of Enteric Fever at a Healthcare Facility in a Densely Populated Area of Kathmandu

Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi A (S. Typhi and S. Paratyphi A) remains a major public health problem in many settings. The disease is limited to locations with poor sanitation which facilitates the transmission of the infecting organisms. Efficacious and inexpensive vaccines are available for S. Typhi, yet are not commonly deployed to...