Search

Staphylococcus aureus and Streptococcus pyogenes are important contributors to disease in northern Australia. Both are opportunistic pathogens, frequently carried on the skin or in the respiratory tract in the absence of disease. A large proportion of the S. aureus strains causing infection in northern Australia possess the Panton Valentine (PVL) toxin, with ST93, ST5, and ST121 being significant. PVL+ strains are associated with both community- and healthcare-associated infections, and a large proportion are methicillin-resistant S. aureus (MRSA). MRSA strains known to be healthcare associated (ST239 and ST22) are not prevalent. CC1 PVL− MRSA continue to cause infections. The diversity of S. pyogenes emm types in northern Australia is high with skin tropic and non-tropic emm types predominating. This contrasts with other parts of Australia where emm diversity is lower and rates of pharyngitis higher. The high diversity raises concerns for the likely efficacy of vaccines based on the variable region of the M protein, the nucleotide sequence of which underpins emm typing. It is likely that complex interactions occur between these two important bacterial pathogens, and other important skin pathogens in the region such as the scabies mite.

There has been intense debate about student engagement and student voice in institutions of higher education in the past decade or so. Most of the discussion has been theoretical or based on a cause-and-effect research design. With the aim of gathering student perspectives on student voice and its related mechanisms, this study collected the voice of 13 students, the majority of whom were international students, from one UK university. Participants include undergraduate (n=1), postgraduate taught (n=7), and PhD (n=5) students who voluntarily agreed to have an online interview with the researcher, a PhD intern of the Student Voice team. Findings indicate that participants have an overall positive and supportive view of student voice mechanisms at this institution, although some understandings are not adequate or accurate. Participants’ attitudes towards some commonly used communication channels indicate that they prioritise an interactive and dynamic tool to initiate dialogue with the university. Suggestions are put forward for managerial strategies for a sustainable and inclusive student voice mechanism.

Abstract Background Nevus of Ota or “oculodermal melanocytosis” is a rare congenital hamartoma of dermal melanocytes causing a blue-gray hyperpigmentation of the eye and surrounding structures. The condition, originally described by Ota and Tanino in 1939, mainly affects the ophthalmic and maxillary divisions of the trigeminal nerve. We describe the first reported case of unilateral oculodermal melanocytosis in a Caucasian woman with oral buccal mucosal involvement. Oral involvement of nevus of Ota is very rare. Case presentation A 48-year-old Caucasian woman was referred by the dermatology division to the oral medicine department at the University of Liverpool School of Dentistry with new-onset oral pigmentation to the left buccal mucosa. The patient had a previous diagnosis of oculodermal nevus. Conclusion An incisional biopsy of the left buccal mucosa was completed. The report stated that histological and immunohistochemical features were in keeping with a blue nevus, but within the context of the preexisting occulodermal pigmentation, a diagnosis of oculodermal melanocytosis, also known as “nevus of Ota,” was made. The patient will be kept under review in the oral medicine department because the progression of the lesion on the left buccal mucosa requires active monitoring owing to the potential for malignant change. The patient also requires regular review in the dermatology and ophthalmology divisions.

Abstract Objectives: We report a cluster of acute rheumatic fever (ARF) cases and the public health response in a high‐burden Australian setting. Methods: The public health unit was notified of an increase in ARF cases in a remote Australian Aboriginal community. A multi‐disciplinary group coordinated the response. Household contacts were screened for ARF or group A Streptococcus (GAS) infection by questionnaire and swab collection, offered an echocardiogram if aged 5–20 years, and intramuscular benzathine benzylpenicillin if aged over one year or if less than one year with impetigo. Results: Fifteen definite and seven probable ARF cases were diagnosed in the community in July–December 2014 (all‐age incidence of definite ARF: 1,473/100,000). The public health response identified two additional cases of ARF. A total of 81 contacts were screened; GAS was detected in 3/76 (4%) throat swabs and 11/24 (46%) skin swabs. Molecular typing revealed high GAS strain diversity. Conclusions: The incidence of ARF during this cluster was very high. Carriage and infection with GAS was observed, but no outbreak strain identified. Implications for public health: A national public health guideline has since been developed that includes advice on the investigation of an ARF outbreak/cluster. Sustained efforts with strong community engagement are required to tackle high ARF rates.

The parasitic mite Sarcoptes scabiei is an economically highly significant parasite of the skin of humans and animals worldwide. In humans, this mite causes a neglected tropical disease (NTD), called scabies. This disease results in major morbidity, disability, stigma and poverty globally and is often associated with secondary bacterial infections. Currently, anti-scabies treatments are not sufficiently effective, resistance to them is emerging and no vaccine is available. Here, we report the first high-quality genome and transcriptomic data for S. scabiei. The genome is 56.6 Mb in size, has a a repeat content of 10.6% and codes for 9,174 proteins. We explored key molecules involved in development, reproduction, host-parasite interactions, immunity and disease. The enhanced 'omic data sets for S. scabiei represent comprehensive and critical resources for genetic, functional genomic, metabolomic, phylogenetic, ecological and/or epidemiological investigations, and will underpin the design and development of new treatments, vaccines and/or diagnostic tests.

Abstract Background Scabies is worldwide one of the most common, yet neglected, parasitic skin infections, affecting a wide range of mammals including humans. Limited treatment options and evidence of emerging mite resistance against the currently used drugs drive our research to explore new therapeutic candidates. Previously, we discovered a multicopy family of genes encoding cysteine proteases with their catalytic sites inactivated by mutation (SMIPP-Cs). This protein family is unique in parasitic scabies mites and is absent in related non-burrowing mites. We postulated that the SMIPP-Cs have evolved as an adaptation to the parasitic lifestyle of the scabies mite. To formulate testable hypotheses for their functions and to propose possible strategies for translational research we investigated whether the SMIPP-Cs are common to all scabies mite varieties and where within the mite body as well as when throughout the parasitic life-cycle they are expressed. Results SMIPP-C sequences from human, pig and dog mites were analysed bioinformatically and the phylogenetic relationships between the SMIPP-C multi-copy gene families of human, pig and dog mites were established. Results suggest that amplification of the SMIPP-C genes occurred in a common ancestor and individual genes evolved independently in the different mite varieties. Recombinant human mite SMIPP-C proteins were produced and used for murine polyclonal antibody production. Immunohistology on skin sections from human patients localised the SMIPP-Cs in the mite gut and in mite faeces within in the epidermal skin burrows. SMIPP-C transcription into mRNA in different life stages was assessed in human and pig mites by reverse transcription followed by droplet digital PCR (ddPCR). High transcription levels of SMIPP-C genes were detected in the adult female life stage in comparison to all other life stages. Conclusions The fact that the SMIPP-Cs are unique to three Sarcoptes varieties, present in all burrowing life stages and highly expressed in the digestive system of the infective adult female life stage may highlight an essential role in parasitism. As they are excreted from the gut in scybala they presumably are able to interact or interfere with host proteins present in the epidermis.

Epidemiological studies link Sarcoptes scabiei infection and impetigo. Scabies mites can promote Streptococcus pyogenes (Group A Streptococcus) and Staphylococcus aureus infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. However, little is known about the composition and the function of the scabies-associated microbiota. Here, high-throughput whole-metagenome sequencing was used to explore the scabies-associated microbiome. Scabies mites including their immediate microenvironments were isolated from two patients with severe scabies in Northern Australia. Two ~45–50 million paired-end reads Illumina libraries were generated of which ~2 (5.1%) and 0.7 million (1.3%) microbial reads were filtered out by mapping to human (hg19) and mite draft genomes. Taxonomic profiling revealed a microbial community dominated by the phylum Firmicutes (A: 79% and B: 59%) and genera that comprise Streptococcus, Staphylococcus, Acinetobacter, and Corynebacterium. Assembly of the metagenome reads resulted in genome bins representing reference genomes of Acinetobacter baumannii, Streptococcus dysgalactiae (Group C/G), Proteus mirablis and Staphylococcus aureus. The contigs contained genes relevant to pathogenicity and antibiotics resistance. Confocal microscopy of a patient skin sample confirmed A. baumannii, Streptococci and S. aureus in scabies mite gut and faeces and the surrounding skin. The study provides fundamental evidence for the association of opportunistic pathogens with scabies infection.

In the publication of this article [1], the figures were accidentally omitted due to an error. This has now been updated in the original article within the Case presentation section.

Introduction: Parasitic infections can adversely impact health, nutritional status and educational attainment. This study investigated hookworm and other intestinal parasites in an Aboriginal community in Australia from 1994 to 1996. Methods: Seven surveys for intestinal parasites were conducted by a quantitative formol-ether method on faecal samples. Serological testing was conducted for Strongyloides stercoralis and Toxocara canis IgG by enzyme-linked immunosorbent assays. Results: Of the 314 participants, infections were as follows: Trichuris trichiura (86%); hookworm, predominantly Ancylostoma duodenale (36%); Entamoeba spp. (E. histolytica complex [E. histolytica, E. dispar and E. moskovski], E. coli and E. hartmanni) (25%); S. stercoralis (19%); Rodentolepis nana (16%); and Giardia duodenalis (10%). Serological diagnosis for 29 individuals showed that 28% were positive for S. stercoralis and 21% for T. canis. There was a decrease in the proportion positive for hookworm over the two-year period but not for the other parasite species. The presence of hookworm, T. trichiura and Entamoeba spp. was significantly greater in 5–14 year olds (n = 87) than in 0–4 year olds (n = 41), while the presence of S. stercoralis, R. nana, G. duodenalis and Entamoeba spp. in 5–14 year olds was significantly greater than 15–69 year olds (n = 91). Discussion: Faecal testing indicated a very high prevalence of intestinal parasites, especially in schoolchildren. The decrease in percentage positive for hookworm over the two years was likely due to the albendazole deworming programme, and recent evidence indicates that the prevalence of hookworm is now low. However there was no sustained decrease in percentage positive for the other parasite species.

The scabies mite, Sarcoptes scabiei, is an obligate parasite of the skin that infects humans and other animal species, causing scabies, a contagious disease characterized by extreme itching. Scabies infections are a major health problem, particularly in remote Indigenous communities in Australia, where co-infection of epidermal scabies lesions by Group A Streptococci or Staphylococcus aureus is thought to be responsible for the high rate of rheumatic heart disease and chronic kidney disease. We collected and separately sequenced mite DNA from several pools of thousands of whole mites from a porcine model of scabies (S. scabiei var. suis) and two human patients (S. scabiei var. hominis) living in different regions of northern Australia. Our sequencing samples the mite and its metagenome, including the mite gut flora and the wound micro-environment. Here, we describe the mitochondrial genome of the scabies mite. We developed a new de novo assembly pipeline based on a bait-and-reassemble strategy, which produced a 14 kilobase mitochondrial genome sequence assembly. We also annotated 35 genes and have compared these to other Acari mites. We identified single nucleotide polymorphisms (SNPs) and used these to infer the presence of six haplogroups in our samples, Remarkably, these fall into two closely-related clades with one clade including both human and pig varieties. This supports earlier findings that only limited genetic differences may separate some human and animal varieties, and raises the possibility of cross-host infections. Finally, we used these mitochondrial haplotypes to show that the genetic diversity of individual infections is typically small with 1-3 distinct haplotypes per infestation.

Permethrin is the active component of topical creams widely used to treat human scabies. Recent evidence has demonstrated that scabies mites are becoming increasingly tolerant to topical permethrin and oral ivermectin. An effective approach to manage pesticide resistance is the addition of synergists to counteract metabolic resistance. Synergists are also useful for laboratory investigation of resistance mechanisms through their ability to inhibit specific metabolic pathways.To determine the role of metabolic degradation as a mechanism for acaricide resistance in scabies mites, PBO (piperonyl butoxide), DEF (S,S,S-tributyl phosphorotrithioate) and DEM (diethyl maleate) were first tested for synergistic activity with permethrin in a bioassay of mite killing. Then, to investigate the relative role of specific metabolic pathways inhibited by these synergists, enzyme assays were developed to measure esterase, glutathione S-transferase (GST) and cytochrome P450 monooxygenase (cytochrome P450) activity in mite extracts. A statistically significant difference in median survival time of permethrin-resistant Sarcoptes scabiei variety canis was noted when any of the three synergists were used in combination with permethrin compared to median survival time of mites exposed to permethrin alone (p