Background Campylobacter is a genus of bacteria that has been isolated from the gastrointestinal tract of humans and animals, and the environments they inhabit around the world. Campylobacter adapt to new environments by changes in their... more
Background Campylobacter is a genus of bacteria that has been isolated from the gastrointestinal tract of humans and animals, and the environments they inhabit around the world. Campylobacter adapt to new environments by changes in their gene content and expression, but little is known about how they adapt to long-term human colonization. In this study, the genomes of 31 isolates from a New Zealand patient and 22 isolates from a United Kingdom patient belonging to Campylobacter jejuni sequence type 45 (ST45) were compared with 209 ST45 genomes from other sources to identify the mechanisms by which Campylobacter adapts to long-term human colonization. In addition, the New Zealand patient had their microbiota investigated using 16S rRNA metabarcoding, and their level of inflammation and immunosuppression analyzed using biochemical tests, to determine how Campylobacter adapts to a changing gastrointestinal tract. Results There was some evidence that long-term colonization led to genome...
Research Interests:
Simple Summary Ten horses were kept on pasture for one year, with hay provided from June to October. Each month we measured how much pasture was present and collected pasture and hay samples to assess their nutrient content, and faecal... more
Simple Summary Ten horses were kept on pasture for one year, with hay provided from June to October. Each month we measured how much pasture was present and collected pasture and hay samples to assess their nutrient content, and faecal samples from all horses to investigate the diversity of the bacterial species present using next-generation sequencing technology. The population of faecal bacteria was more diverse during the months when the horses were kept exclusively on pasture compared to the months when pasture was supplemented with hay. The diet offered, and the season and the month we sampled the paddock all had a major influence on the diversity of the species of bacteria in the faeces. While there were some differences between the horses, generally the bacterial populations could be grouped together in samples obtained during May, June, and July (late-autumn to winter period), and January, February, and March (a period of drought). More specifically we were able to show an a...
Research Interests:
Research Interests:
Research Interests:
Enterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases (ACBLs) are important pathogens and can cause community-acquired illnesses, such as urinary tract infections (UTIs). Fecal carriage of... more
Enterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases (ACBLs) are important pathogens and can cause community-acquired illnesses, such as urinary tract infections (UTIs). Fecal carriage of these resistant bacteria by companion animals may pose a risk for transmission to humans. Our work evaluated the sharing of ESBL- and ACBL-producing E. coli isolates between humans and companion animals. We found that in some households, dogs carried the same strain of ESBL-producing E. coli as the household member with a UTI. This suggests that transmission events between humans and animals (or vice versa) are likely occurring within the home environment and, therefore, the community as a whole. This is significant from a health perspective, when considering measures to minimize community transmission, and highlights that in order to manage community spread, we need to consider interventions at the household level.
Research Interests:
Campylobacter enteritis in humans is primarily associated with C. jejuni/coli infection. Other species cause campylobacteriosis relatively infrequently; while this could be attributed to bias in diagnostic methods, the pathogenicity of... more
Campylobacter enteritis in humans is primarily associated with C. jejuni/coli infection. Other species cause campylobacteriosis relatively infrequently; while this could be attributed to bias in diagnostic methods, the pathogenicity of non-jejuni/coli Campylobacter spp. such as C. upsaliensis and C. helveticus (isolated from dogs and cats) is uncertain. Galleria mellonella larvae are suitable models of the mammalian innate immune system and have been applied to C. jejuni studies. This study compared the pathogenicity of C. jejuni, C. upsaliensis, and C. helveticus isolates. Larvae inoculated with either C. upsaliensis or C. helveticus showed significantly higher survival than those inoculated with C. jejuni. All three Campylobacter species induced indistinguishable histopathological changes in the larvae. C. jejuni could be isolated from inoculated larvae up to eight days post-inoculation whereas C. upsaliensis and C. helveticus could only be isolated in the first two days. There wa...
Research Interests:
The draft genome sequences for eight isolates of Campylobacter helveticus isolated from companion animals are described and compared with that of the type strain. On average, the genomes are 1,825,025 bp long and have a GC content of... more
The draft genome sequences for eight isolates of Campylobacter helveticus isolated from companion animals are described and compared with that of the type strain. On average, the genomes are 1,825,025 bp long and have a GC content of 34.4% and 1,885 coding DNA sequences (CDSs). CRISPRs were detected in only one isolate and phages in none.
Research Interests:
Research Interests:
The global spread of multidrug resistant enterobacteria warrants new strategies to combat these pathogens. One possible approach is reconsideration of “old” antimicrobials which remain effective after decades of use. Synthetic... more
The global spread of multidrug resistant enterobacteria warrants new strategies to combat these pathogens. One possible approach is reconsideration of “old” antimicrobials which remain effective after decades of use. Synthetic 5-nitrofurans such as furazolidone, nitrofurantoin and nitrofurazone, are such a class of antimicrobial drugs. Recent epidemiological data reported a very low prevalence of resistance to this antimicrobial class amongst clinical Escherichia coli isolates in various parts of the world, forecasting the increasing importance of its uses to battle antibiotic resistant enterobacteria. However, although they have had a long history of clinical use, a detailed understanding of the 5-nitrofurans' mechanisms of action remains limited. Nitrofurans are known as prodrugs that are activated in E. coli by reduction catalyzed by two redundant nitroreductases, NfsA and NfsB. Furazolidone, nevertheless, retains relatively significant antibacterial activity in the nitroredu...
Research Interests:
Research Interests:
Research Interests:
Klebsiella pneumoniae is a Gram-negative bacterium that can be found in the environment, as well as on mucosal surfaces of humans and animals. Here, we report the genome sequence of five K. pneumoniae isolates from substrate samples and... more
Klebsiella pneumoniae is a Gram-negative bacterium that can be found in the environment, as well as on mucosal surfaces of humans and animals. Here, we report the genome sequence of five K. pneumoniae isolates from substrate samples and bird feces collected in the Subantarctic Islands of New Zealand.
Research Interests:
Shiga toxin-producing Escherchia coli O157:H7 is a zoonotic pathogen which causes numerous food and waterborne disease outbreaks. It is globally distributed but its origin and temporal sequence of geographical spread is unknown. We... more
Shiga toxin-producing Escherchia coli O157:H7 is a zoonotic pathogen which causes numerous food and waterborne disease outbreaks. It is globally distributed but its origin and temporal sequence of geographical spread is unknown. We analysed Whole Genome Sequencing data of 757 isolates from 4 continents and performed a pan genome analysis to identify the core genome and from this extracted single nucleotide polymorphisms. Timed phylogeographic analysis was performed on a subset of the isolates to investigate it's worldwide spread. The common ancestor of this set of isolates occurred around 1890 (1845-1925) and originated from the Netherlands. Phylogeographic analysis identified 34 major transmission events. The earliest were predominantly intercontinental from Europe to Australia around 1937 (1909-1958), to USA in 1941 (1921-1962), to Canada in 1960 (1943-1979), and from Australia to New Zealand in 1966 (1943-1982). This pre-dates the first reported human case of E. coli O157:H7 ...
Research Interests:
Campylobacter hyointestinalis is a member of an emerging group of zoonotic Campylobacter spp. that are increasingly identified in both gastric and non-gastric disease in humans. Here, we discovered C. hyointestinalis in three separate... more
Campylobacter hyointestinalis is a member of an emerging group of zoonotic Campylobacter spp. that are increasingly identified in both gastric and non-gastric disease in humans. Here, we discovered C. hyointestinalis in three separate classes of New Zealand ruminant livestock; cattle, sheep and deer. To investigate the relevance of these findings we performed a systematic literature review on global C. hyointestinalis epidemiology and used comparative genomics to better understand and classify members of the species. We found that C. hyointestinalis subspecies hyointestinalis has an open pangenome, with accessory gene contents involved in many essential processes such as metabolism, virulence and defence. We observed that horizontal gene transfer is likely to have played an overwhelming role in species diversification, favouring a public-goods-like mechanism of gene 'acquisition and resampling' over a tree-of-life-like vertical inheritance model of evolution. As a result, si...
Research Interests:
Research Interests:
Research Interests:
Staphylococcus aureus skin and soft tissue infection (Sa-SSTI) places a significant burden on healthcare systems. New Zealand has a high incidence of Sa-SSTI, and here most morbidity is caused by a polyclonal methicillin-susceptible... more
Staphylococcus aureus skin and soft tissue infection (Sa-SSTI) places a significant burden on healthcare systems. New Zealand has a high incidence of Sa-SSTI, and here most morbidity is caused by a polyclonal methicillin-susceptible (MSSA) population. However, MSSA also colonise asymptomatically the cornified epithelia of approximately 20% of the population, and their divide between commensalism and pathogenicity is poorly understood. We aimed to see whether MSSA is genetically differentiated across asymptomatic colonisation and SSTI; and given the close interactions between people and pets, whether strains isolated from pets differ from human strains. We compared the genomes of contemporaneous asymptomatic colonisation and clinical MSSA isolates obtained in New Zealand from humans and pets. Core and accessory genome comparisons revealed a homogeneous bacterial population across colonisation, disease, humans, and pets. The rate of MSSA colonisation in dogs was comparatively low (5.4...
Research Interests: Genomics, Symbiosis, Zoonoses, Dogs, Humans, and 15 moreAnimals, Pets, Infection, Staphylococcus aureus, New Zealand, Skin, Incidence, Clinical Sciences, Anti-Bacterial Agents, Methicillin Resistance, Microbial Sensitivity Tests, Virulence Factors, Methicillin Resistant Staphylococcus Aureus, Carrier state, and Methicillin
We report the complete genome sequence of the Campylobacter concisus type strain ATCC 33237 and the draft genome sequences of eight additional well-characterized C. concisus strains. C. concisus has been shown to be a genetically... more
We report the complete genome sequence of the Campylobacter concisus type strain ATCC 33237 and the draft genome sequences of eight additional well-characterized C. concisus strains. C. concisus has been shown to be a genetically heterogeneous species, and these nine genomes provide valuable information regarding the diversity within this taxon.
Research Interests:
Current culture methods to investigate changes in Escherichia coli community structure are often slow and laborious. Genes such as gnd (6-phosphogluconate dehydrogenase) have a highly variable nucleotide sequence and may provide a target... more
Current culture methods to investigate changes in Escherichia coli community structure are often slow and laborious. Genes such as gnd (6-phosphogluconate dehydrogenase) have a highly variable nucleotide sequence and may provide a target for E. coli microbiome analysis using culture-independent methods. Metabarcoded PCR primers were used to generate separate libraries from calf faecal samples for high throughput sequencing. Although a total of 348 separate gnd sequence types (gSTs) were identified, 188 were likely to be due to sequencing errors. Of the remaining 160 gSTs, 92 did not match those in a database of 319 separate gnd sequences. 'Animal' was the main determinant of E. coli diversity with limited impact of sample type or DNA extraction method on intra-host E. coli community variation from faeces and recto-anal mucosal swab samples. This culture-independent study has addressed the difficulties of quantifying bacterial intra-species diversity and revealed that, whilst...
Research Interests:
Legionella longbeachae serogroup 1, predominantly found in soil and composted plant material, causes the majority of cases of Legionnaires' disease (LD) in New Zealand. Here, we report the complete genome sequence of an L. longbeachae... more
Legionella longbeachae serogroup 1, predominantly found in soil and composted plant material, causes the majority of cases of Legionnaires' disease (LD) in New Zealand. Here, we report the complete genome sequence of an L. longbeachae serogroup 1 (sg1) isolate derived from a patient hospitalized with LD in Christchurch, New Zealand.
Research Interests:
Homologous recombination is a central feature of bacterial evolution, yet confounds traditional phylogenetic methods. While a number of methods specific to bacterial evolution have been developed, none of these permit joint inference of a... more
Homologous recombination is a central feature of bacterial evolution, yet confounds traditional phylogenetic methods. While a number of methods specific to bacterial evolution have been developed, none of these permit joint inference of a bacterial recombination graph and associated parameters. In this paper, we present a new method which addresses this shortcoming. Our method uses a novel Markov chain Monte Carlo algorithm to perform phylogenetic inference under the ClonalOrigin model of Didelot et al. (Genetics, 2010). We demonstrate the utility of our method by applying it to rMLST data sequenced from pathogenic and non-pathogenic Escherichia coli serotype O157 and O26 isolates collected in rural New Zealand. The method is implemented as an open source BEAST 2 package, Bacter, which is available via the project web page at http://tgvaughan.github.io/bacter.
Research Interests:
Hypotheses of hybrid origin are common. Here we use next generation sequencing to test a hybrid hypothesis for a non-model insect with a large genome. We compared a putative hybrid triploid stick insect species (Acanthoxyla geisovii) with... more
Hypotheses of hybrid origin are common. Here we use next generation sequencing to test a hybrid hypothesis for a non-model insect with a large genome. We compared a putative hybrid triploid stick insect species (Acanthoxyla geisovii) with its putative paternal diploid taxon (Clitarchus hookeri), a relationship that provides clear predictions for the relative genetic diversity within each genome. The parental taxon is expected to have comparatively low allelic diversity that is nested within the diversity of the hybrid daughter genome. The scale of genome sequencing required was conveniently achieved by extracting mRNA and sequencing cDNA to examine expressed allelic diversity. This allowed us to test hybrid-progenitor relationships among non-model organisms with large genomes and different ploidy levels. Examination of thousands of independent loci avoids potential problems produced by the silencing of parts of one or other of the parental genomes, a phenomenon sometimes associated ...
Research Interests:
Research Interests:
To quantify the numbers of live cattle, sheep and poultry imported into New Zealand and, where possible, their country of origin from 1860 to 1979. Information on the origin and number of live animal importations into New Zealand was... more
To quantify the numbers of live cattle, sheep and poultry imported into New Zealand and, where possible, their country of origin from 1860 to 1979. Information on the origin and number of live animal importations into New Zealand was collected for cattle, sheep and poultry for the period 1868-1979 from the annual reports compiled by the New Zealand Registrar General's Office, Government Statistician's Office, Census and Statistics Office, Census and Statistics Department, Customs Department and Department of Statistics. Census data from 1851 to 1871 were also used to estimate the livestock population during this period. The number of animals imported and the mean population for each species in a decade were determined, and the major countries of origin were identified. A large number of cattle (53,384) and sheep (604,525) were imported in the 1860s, and then there was a marked reduction in importations. Live poultry were imported in relatively small numbers (20,701) from 188...
Research Interests: Commerce, Livestock, Sheep, Animals, New Zealand, and 3 morePoultry, Cattle, and Veterinary Sciences
Research Interests: Biology and Campylobacter
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Three strains of Geobacillus stearothermophilus (designated A1, P3, and D1) were isolated from a New Zealand milk powder manufacturing plant. Here, we describe their draft genome sequences. This information provided the first genomic... more
Three strains of Geobacillus stearothermophilus (designated A1, P3, and D1) were isolated from a New Zealand milk powder manufacturing plant. Here, we describe their draft genome sequences. This information provided the first genomic insights into the nature of G. stearothermophilus strains present in the milk powder manufacturing environment.
Page 1. 11 MOUSE MODELS OF CANCER Debrah M. Thompson, Louise van der Weyden, Patrick J. Biggs, Yeun-Jun Chung, and Allan Bradley INTRODUCTION Mouse models of cancer have both enhanced and driven research into the molecular basis of human... more
Page 1. 11 MOUSE MODELS OF CANCER Debrah M. Thompson, Louise van der Weyden, Patrick J. Biggs, Yeun-Jun Chung, and Allan Bradley INTRODUCTION Mouse models of cancer have both enhanced and driven research into the molecular basis of human cancers. ...
Research Interests:
Research Interests:
Isolation of wildlife into fragmented populations as a consequence of anthropogenic-mediated environmental change may alter host-pathogen relationships. Our understanding of some of the epidemiological features of infectious disease in... more
Isolation of wildlife into fragmented populations as a consequence of anthropogenic-mediated environmental change may alter host-pathogen relationships. Our understanding of some of the epidemiological features of infectious disease in vulnerable populations can be enhanced by the use of commensal bacteria as a proxy for invasive pathogens in natural ecosystems. The distinctive population structure of a well-described meta-population of a New Zealand endangered flightless bird, the takahe (Porphyrio hochstetteri), provided a unique opportunity to investigate the influence of host isolation on enteric microbial diversity. The genomic epidemiology of a prevalent rail-associated endemic commensal bacterium was explored using core genome and ribosomal multilocus sequence typing (rMLST) of 70 Campylobacter sp. nova 1 isolated from one third of the takahe population resident in multiple locations. While there was evidence of recombination between lineages, bacterial divergence appears to have occurred and multivariate analysis of 52 rMLST genes revealed location-associated differentiation of C. sp. nova 1 sequence types. Our results indicate that fragmentation and anthropogenic manipulation of populations can influence host-microbial relationships, with potential implications for niche adaptation and the evolution of micro-organisms in remote environments. This study provides a novel framework in which to explore the complex genomic epidemiology of micro-organisms in wildlife populations.
Research Interests:
Genetic variation in an infectious disease pathogen can be driven by ecological niche dissimilarities arising from different host species and different geographical locations. Whole genome sequencing was used to compare E. coli O157... more
Genetic variation in an infectious disease pathogen can be driven by ecological niche dissimilarities arising from different host species and different geographical locations. Whole genome sequencing was used to compare E. coli O157 isolates from host reservoirs (cattle and sheep) from Scotland and to compare genetic variation of isolates (human, animal, environmental/food) obtained from Scotland, New Zealand, Netherlands, Canada and the USA. Nei's genetic distance calculated from core genome single nucleotide polymorphisms (SNPs) demonstrated that the animal isolates were from the same population. Investigation of the Shiga toxin bacteriophage and their insertion sites (SBI typing) revealed that cattle and sheep isolates had statistically indistinguishable rarefaction profiles, diversity and genotypes. In contrast, isolates from different countries exhibited significant differences in Nei's genetic distance and SBI typing. Hence, after successful international transmission, which has occurred on multiple occasions, local genetic variation occurs, resulting in a global patchwork of continental and trans-continental phylogeographic clades. These findings are important for three reasons: first, understanding transmission and evolution of infectious diseases associated with multiple host reservoirs and multi-geographic locations; second, highlighting the relevance of the sheep reservoir when considering farm based interventions; and third, improving our understanding of why human disease incidence varies across the world.
Research Interests:
Hereditary cylindromatosis is a rare autosomal dominant disease characterised by the development of multiple benign neoplasms of the skin. We recently localised the gene responsible for this disease (cyld1) to chromosome 16q12-q13 and... more
Hereditary cylindromatosis is a rare autosomal dominant disease characterised by the development of multiple benign neoplasms of the skin. We recently localised the gene responsible for this disease (cyld1) to chromosome 16q12-q13 and provided evidence that it is a tumour suppressor gene (Biggs et al., 1995). We have now examined polymorphic markers on every chromosome, some of which are close to known tumour suppressor genes, in 25 tumours from 4 individuals with familial cylindromatosis. No loss of heterozygosity (LOH) was detected other than at loci on chromosome 16q. This observation suggests that the cyld1 gene may be the only tumour suppressor gene implicated in the development of cylindromas. We have also demonstrated LOH using markers on chromosome 16q in 8/14 (57%) sporadic cylindromas, indicating that the cyld1 gene is likely to be involved in the genesis of both familial and sporadic cylindromas.
Research Interests:
A novel, fatal neurological disease of the Australian brushtail possum (Trichosurus vulpecula) was first identified in 1995 in a research facility and subsequently in free-living possums in New Zealand and termed wobbly possum disease... more
A novel, fatal neurological disease of the Australian brushtail possum (Trichosurus vulpecula) was first identified in 1995 in a research facility and subsequently in free-living possums in New Zealand and termed wobbly possum disease (WPD). The results of previous transmission studies suggested that the aetiological agent of WPD is most likely a virus. However, the identity of the presumed viral agent had not been elucidated. In the current report, we describe identification of a novel virus from tissues of WPD-affected possums using a combination of next generation sequencing and traditional molecular methods. The proportion of possums positive for the novel virus by PCR was significantly higher (p<0.0001) among animals with WPD than clinically healthy possums, strongly suggesting an aetiological involvement of the virus in WPD. Analysis of the partial genomic sequence of the putative WPD virus indicated that it is a novel nidovirus, most closely related to the current members ...
Research Interests:
There is much interest in using high-throughput DNA sequencing methodology to monitor microorganisms, complex plant and animal communities. However, there are experimental and analytical issues to consider before applying a sequencing... more
There is much interest in using high-throughput DNA sequencing methodology to monitor microorganisms, complex plant and animal communities. However, there are experimental and analytical issues to consider before applying a sequencing technology, which was originally developed for genome projects, to ecological projects. Many of these issues have been highlighted by recent microbial studies. Understanding how high-throughput sequencing is best implemented is important for the interpretation of recent results and the success of future applications. Addressing complex biological questions with metagenomics requires the interaction of researchers who bring different skill sets to problem solving. Educators can help by nurturing a collaborative interdisciplinary approach to genome science, which is essential for effective problem solving. Educators are in a position to help students, teachers, the public and policy makers interpret the new knowledge that metagenomics brings. To do this,...
Research Interests:
Theory on the Cryptosporidium life cycle predicts genetic diversity of sporozoites within the host. Nevertheless, the Cryptosporidium intra-host genetic diversity is difficult to be studied using conventional Sanger sequencing or... more
Theory on the Cryptosporidium life cycle predicts genetic diversity of sporozoites within the host. Nevertheless, the Cryptosporidium intra-host genetic diversity is difficult to be studied using conventional Sanger sequencing or electrophoretic resolution of amplicons, due to the methods' inability to resolve mixtures of templates. We analysed the within-isolate genetic diversity of two Cryptosporidium parvum isolates sharing common descent, by combining the use of Next Generation Sequencing and cloning of PCR amplicons with database searches. The analysis concentrated on the single-copy 70kDa heat shock protein (HSP70) and the 60kDa surface glycoprotein (gp60) genes, which allowed any diversity to be ascribed to the presence of a heterogeneous population of sporozoites. The results indicated an unprecedented intra-host genetic diversity, with two HSP70 and 10 gp60 alleles in these isolates, in spite of the initial resolution of one allele per locus using Sanger sequencing. At ...
Research Interests:
Campylobacter jejuni is a thermophilic species that grows well at 42°C, a temperature associated with the avian body, and does not actively grow below 30°C, excluding C. jejuni subsp. doylei. We examined the phenotypic pattern of six... more
Campylobacter jejuni is a thermophilic species that grows well at 42°C, a temperature associated with the avian body, and does not actively grow below 30°C, excluding C. jejuni subsp. doylei. We examined the phenotypic pattern of six Campylobacter sequence types (ST) that are associated with different hosts, at two temperatures, 22°C and 42°C. ST42 has been isolated worldwide and is associated with ruminants and human disease. The ST2381 clonal complex has not yet been reported outside of New Zealand, and is associated with two species of indigenous New Zealand birds and with surface water. The genome of each isolate was sequenced. Using a phenotypic microarray (Omnilog system) we examined the carbon utilisation pattern of isolates from ST42 and the ST2381 clonal complex. The genomes were used to identify the genetic components of phenotypic differences. In general, isolates utilised fewer carbon sources at 22°C and these are a subset of those utilisedat 42°C by the same isolate. ST...
Research Interests:
Research Interests:
Correct rooting of the angiosperm radiation is both challenging and necessary for understanding the origins and evolution of physiological and phenotypic traits in flowering plants. The problem is known to be difficult due to the large... more
Correct rooting of the angiosperm radiation is both challenging and necessary for understanding the origins and evolution of physiological and phenotypic traits in flowering plants. The problem is known to be difficult due to the large genetic distance separating flowering plants from other seed plants and the sparse taxon sampling among basal angiosperms. Here, we provide further evidence for concern over substitution model misspecification in analyses of chloroplast DNA sequences. We show that support for Amborella as the sole representative of the most basal angiosperm lineage is founded on sequence site patterns poorly described by time-reversible substitution models. Improving the fit between sequence data and substitution model identifies Trithuria, Nymphaeaceae, and Amborella as surviving relatives of the most basal lineage of flowering plants. This finding indicates that aquatic and herbaceous species dominate the earliest extant lineage of flowering plants. [; ; ; ; ; .].