Publications by authors named "Philip M Giffard"

Article Synopsis
  • The study examines the genomic relationship between Streptococcus dysgalactiae subspecies equisimilis (SDSE) and Streptococcus pyogenes, focusing on how they share ecosystems and possibly diseases due to genetic similarities and horizontal gene transfer (HGT).
  • An analysis of genomes from 294 SDSE and 315 S. pyogenes samples collected in remote Australian First Nations communities reveals a significant overlap in transmission among households, suggesting independent transmission patterns without competition between the two species.
  • The research identifies mobile genetic elements linked to antimicrobial resistance and virulence in both pathogens, emphasizing the ongoing co-circulation of SDSE and S. pyogenes in these communities and highlighting the need
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Here, we present the R package, minSNPs. This is a re-development of a previously described Java application named Minimum SNPs. MinSNPs assembles resolution-optimised sets of single nucleotide polymorphisms (SNPs) from sequence alignments such as genome-wide orthologous SNP matrices.

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Article Synopsis
  • Streptococcus pyogenes (GAS) infections significantly impact Aboriginal Australians, leading to skin infections and serious health issues like rheumatic heart disease, but understanding their transmission has been challenging.
  • A genomic analysis of GAS isolates from a study on impetigo in remote Northern Territory communities revealed that asymptomatic throat carriage plays a larger role in GAS transmission compared to impetigo lesions.
  • Findings indicated households experienced prolonged GAS infections, often reinforced by factors like household size and the presence of other infections, complicating efforts to control these infections.
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  • Bacteria can develop resistance to antibiotics through various mechanisms, which can be monitored by laboratory tests.
  • This study identifies a specific resistance mechanism in Group A Streptococcus that uses a gene (thfT) to acquire nutrients from the host, allowing it to bypass the antibiotic sulfamethoxazole's effects.
  • Understanding these resistance mechanisms during infections is crucial to reduce ineffective antibiotic use and limit the spread of resistance among bacteria.
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CtGEM typing was developed to subdivide the bacterial species Chlamydia trachomatis on the basis of genome phylogeny and anatomical tropism. The rationale was facilitation of surveillance for ocular strains, although the method is applicable to essentially any C. trachomatis surveillance application that does not require high resolution.

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The prevalence of rheumatic heart disease (RHD) in the Aboriginal population of the Australian Northern Territory is high, and Streptococcus pyogenes skin infections likely contribute to this. A promising candidate S. pyogenes "30mer" vaccine is composed of 30 pharyngitis associated type-specific antigens from the S.

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Group A Streptococcus (GAS; Streptococcus pyogenes) is a bacterial pathogen for which a commercial vaccine for humans is not available. Employing the advantages of high-throughput DNA sequencing technology to vaccine design, we have analyzed 2,083 globally sampled GAS genomes. The global GAS population structure reveals extensive genomic heterogeneity driven by homologous recombination and overlaid with high levels of accessory gene plasticity.

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Chlamydia trachomatis infects the urogenital tract (UGT) and eyes. Anatomical tropism is correlated with variation in the major outer membrane protein encoded by ompA. Strains possessing the ocular ompA variants A, B, Ba and C are typically found within the phylogenetically coherent "classical ocular lineage".

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Background: The microbiome of built environment surfaces is impacted by the presence of humans. In this study, we tested the hypothesis that analysis of surface swabs from clinic toilet/bathroom yields results correlated with sexually transmitted infection (STI) notifications from corresponding human populations. We extended a previously reported study in which surfaces in toilet/bathroom facilities in primary health clinics in the Australian Northern Territory (NT) were swabbed then tested for nucleic acid from the STI agents and .

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Objectives: The detection of an STI agent in a urogenital tract (UGT) specimen from a young child is regarded as being indicative of sexual abuse. However, the probabilities of contamination events that could conceivably lead to STI positive specimens in the absence of sexual contact are unclear. The objective was to estimate the potential for fingers that have come in contact with positive urine to detectably contaminate negative urine.

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is the world's most prevalent bacterial sexually transmitted infection and leading infectious cause of blindness, yet it is one of the least understood human pathogens, in part due to the difficulties of in vitro culturing and the lack of available tools for genetic manipulation. Genome sequencing has reinvigorated this field, shedding light on the contemporary history of this pathogen. Here, we analyze 563 full genomes, 455 of which are novel, to show that the history of the species comprises two phases, and conclude that the currently circulating lineages are the result of evolution in different genomic ecotypes.

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We report two cases of severe pneumonia due to clone ST93 methicillin-resistant (MRSA) presenting from a remote Australian Indigenous community within a 2-week period, and the utilization of whole genome sequences to determine whether these were part of an outbreak. was isolated from 12 of 92 nasal swabs collected from 25 community households (including the two index households); one isolate was ST93. Three of five skin lesion isolates obtained at the community were ST93.

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Chlamydia trachomatis causes sexually transmitted infections and the blinding disease trachoma. Current data on C. trachomatis phylogeny show that there is only a single trachoma-causing clade, which is distinct from the lineages causing urogenital tract (UGT) and lymphogranuloma venerum diseases.

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Objectives: The objective was to determine the frequency of trachoma genotypes of Chlamydia trachomatis-positive urogenital tract (UGT) specimens from remote areas of the Australian Northern Territory (NT).

Setting: The setting was analysis of remnants of C. trachomatis positive primarily UGT specimens obtained in the course of clinical practice.

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Background: Despite a high burden of staphylococcal skin disease in children and high incidence of Staphylococcus aureus bacteremia in adult Indigenous populations in northern Australia, there are few studies describing incidence or clinical information of invasive S aureus (ISA) infections in children.

Methods: We conducted a retrospective review for all cases of S aureus bacteremia and sterile site infections, for children under 15 years, in northern Australia over a 4-year period (2007-2010). Cases were categorized as neonatal (<28 days) and pediatric (≥28 days).

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Background: The detection of a sexually transmitted infection (STI) agent in a urine specimen from a young child is regarded as an indicator of sexual contact. False positives may conceivably arise from the transfer of environmental contaminants in clinic toilet or bathroom facilities into urine specimens.

Methods: The potential for contamination of urine specimens with environmental STI nucleic acid was tested empirically in the male and female toilets or bathrooms at 10 Northern Territory (Australia) clinics, on 7 separate occasions at each.

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We define two novel species of the genus Staphylococcus that are phenotypically similar to and have near identical 16S rRNA gene sequences to Staphylococcus aureus. However, compared to S. aureus and each other, the two species, Staphylococcus argenteus sp.

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Melioidosis is a potentially fatal disease caused by the saprophytic bacterium Burkholderia pseudomallei. Resistance to gentamicin is generally a hallmark of B. pseudomallei, and gentamicin is a selective agent in media used for diagnosis of melioidosis.

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The Indigenous population of the Northern Territory of Australia (NT) suffers from a very high burden of Streptococcus pyogenes disease, including cardiac and renal sequelae. The aim of this study was to determine if S. pyogenes isolated from this population represent NT endemic strains, or conversely reflect strains with global distribution.

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Staphylococcus aureus clonal complex 75 (herein referred to as S. argenteus) lacks the carotenoid pigment operon, crtOPQMN, responsible for production of the putative virulence factor, staphyloxanthin. Although a common cause of community-onset skin infections among Indigenous populations in northern Australia, this clone is infrequently isolated from hospital-based patients with either bacteremic or nonbacteremic infections.

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High-resolution melting (HRM) analysis uses real-time PCR instrumentation to interrogate DNA sequence variation and is a low-cost, single-step, closed-tube method. Here we describe HRM technology and provide examples of varied clinical microbiological applications to highlight the strengths and limitations of HRM analysis.

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