Burden of paediatric pyoderma and scabies in <scp>N</scp>orth <scp>W</scp>est <scp>Q</scp>ueensland

Whitehall, John; Kuzulugil, Deniz; Sheldrick, Kyle; Wood, Angela

doi:10.1111/jpc.12095

Cited by 36 publications

(25 citation statements)

References 9 publications

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“…The annual incidence of bacteremia due to S. aureus is six times higher in the Australian Aboriginal population than the rest of the Australian population [9]. More recently, methicillin resistant S. aureus (MRSA) has been reported in 64% of children presented with scabies in a regional hospital of North West Queensland [10]. While epidemiological evidence has been well-established that bacterial infections are closely linked with scabies, and mechanical damage of the upper epidermal layers by the mites is one obvious prerequisite, the relationship itself, between host, mites and bacteria, is poorly understood.…”

Section: Introductionmentioning

confidence: 99%

A Scabies Mite Serpin Interferes with Complement-Mediated Neutrophil Functions and Promotes Staphylococcal Growth

Swe

Fischer

2014

PLoS Negl Trop Dis

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BackgroundScabies is a contagious skin disease caused by the parasitic mite Sarcoptes scabiei. The disease is highly prevalent worldwide and known to predispose to secondary bacterial infections, in particular by Streptococcus pyogenes and Staphylococcus aureus. Reports of scabies patients co-infected with methicillin resistant S. aureus (MRSA) pose a major concern for serious down-stream complications. We previously reported that a range of complement inhibitors secreted by the mites promoted the growth of S. pyogenes. Here, we show that a recently characterized mite serine protease inhibitor (SMSB4) inhibits the complement-mediated blood killing of S. aureus.Methodology/Principal FindingsBlood killing of S. aureus was measured in whole blood bactericidal assays, counting viable bacteria recovered after treatment in fresh blood containing active complement and phagocytes, treated with recombinant SMSB4. SMSB4 inhibited the blood killing of various strains of S. aureus including methicillin-resistant and methicillin-sensitive isolates. Staphylococcal growth was promoted in a dose-dependent manner. We investigated the effect of SMSB4 on the complement-mediated neutrophil functions, namely phagocytosis, opsonization and anaphylatoxin release, by flow cytometry and in enzyme linked immuno sorbent assays (ELISA). SMSB4 reduced phagocytosis of S. aureus by neutrophils. It inhibited the deposition of C3b, C4b and properdin on the bacteria surface, but did not affect the depositions of C1q and MBL. SMSB4 also inhibited C5 cleavage as indicated by a reduced C5b-9 deposition.Conclusions/SignificanceWe postulate that SMSB4 interferes with the activation of all three complement pathways by reducing the amount of C3 convertase formed. We conclude that SMSB4 interferes with the complement-dependent killing function of neutrophils, thereby reducing opsonization, phagocytosis and further recruitment of neutrophils to the site of infection. As a consequence secreted scabies mites complement inhibitors, such as SMSB4, provide favorable conditions for the onset of S. aureus co-infection in the scabies-infected microenvironment by suppressing the immediate host immune response.

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Section: Introductionmentioning

confidence: 99%

A Scabies Mite Serpin Interferes with Complement-Mediated Neutrophil Functions and Promotes Staphylococcal Growth

Swe

Fischer

2014

PLoS Negl Trop Dis

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“…Similarly, scabies is very common in tropical environments particularly amongst children with population prevalence in excess of 10% in many Asian, Pacific Island and Central and South American countries[2]. Community based skin infection prevalence studies from Aboriginal populations in northern Australia demonstrate some of the highest prevalence rates of scabies and impetigo in the world[5, 6]. …”

Section: Introductionmentioning

confidence: 99%

Are scabies and impetigo “normalised”? A cross-sectional comparative study of hospitalised children in northern Australia assessing clinical recognition and treatment of skin infections

et al. 2017

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BackgroundComplications of scabies and impetigo such as glomerulonephritis and invasive bacterial infection in Australian Aboriginal children remain significant problems and the overall global burden of disease attributable to these skin infections remains high despite the availability of effective treatment. We hypothesised that one factor contributing to this high burden is that skin infection is under-recognised and hence under-treated, in settings where prevalence is high.MethodsWe conducted a prospective, cross-sectional study to assess the burden of scabies, impetigo, tinea and pediculosis in children admitted to two regional Australian hospitals from October 2015 to January 2016. A retrospective chart review of patients admitted in November 2014 (mid-point of the prospective data collection in the preceding year) was performed. Prevalence of documented skin infection was compared in the prospective and retrospective population to assess clinician recognition and treatment of skin infections.Results158 patients with median age 3.6 years, 74% Aboriginal, were prospectively recruited. 77 patient records were retrospectively reviewed. Scabies (8.2% vs 0.0%, OR N/A, p = 0.006) and impetigo (49.4% vs 19.5%, OR 4.0 (95% confidence interval [CI 2.1–7.7) were more prevalent in the prospective analysis. Skin examination was only documented in 45.5% of cases in the retrospective review. Patients in the prospective analysis were more likely to be prescribed specific treatment for skin infection compared with those in the retrospective review (31.6% vs 5.2%, OR 8.5 (95% CI 2.9–24.4).ConclusionsScabies and impetigo infections are under-recognised and hence under-treated by clinicians. Improving the recognition and treatment of skin infections by clinicians is a priority to reduce the high burden of skin infection and subsequent sequelae in paediatric populations where scabies and impetigo are endemic.

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“…Secondary bacterial skin infections commonly associated with scabies infestations are primarily caused by two clinically important pathogens, i.e. Streptococcus pyogenes and Staphylococcus aureus , including methicillin-resistant and methicillin-sensitive strains [8], [15]. These bacterial pathogens potentially cause life-threatening invasive infections, if left untreated.…”

Section: Introductionmentioning

confidence: 99%

Scabies Mites Alter the Skin Microbiome and Promote Growth of Opportunistic Pathogens in a Porcine Model

et al. 2014

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BackgroundThe resident skin microbiota plays an important role in restricting pathogenic bacteria, thereby protecting the host. Scabies mites (Sarcoptes scabiei) are thought to promote bacterial infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. Epidemiological studies in humans confirm increased incidence of impetigo, generally caused by Staphylococcus aureus and Streptococcus pyogenes, secondary to the epidermal infestation with the parasitic mite. It is therefore possible that mite infestation could alter the healthy skin microbiota making way for the opportunistic pathogens. A longitudinal study to test this hypothesis in humans is near impossible due to ethical reasons. In a porcine model we generated scabies infestations closely resembling the disease manifestation in humans and investigated the scabies associated changes in the skin microbiota over the course of a mite infestation.Methodology/Principal FindingsIn a 21 week trial, skin scrapings were collected from pigs infected with S. scabies var. suis and scabies-free control animals. A total of 96 skin scrapings were collected before, during infection and after acaricide treatment, and analyzed by bacterial 16S rDNA tag-encoded FLX-titanium amplicon pyrosequencing. We found significant changes in the epidermal microbiota, in particular a dramatic increase in Staphylococcus correlating with the onset of mite infestation in animals challenged with scabies mites. This increase persisted beyond treatment from mite infection and healing of skin. Furthermore, the staphylococci population shifted from the commensal S. hominis on the healthy skin prior to scabies mite challenge to S. chromogenes, which is increasingly recognized as being pathogenic, coinciding with scabies infection in pigs. In contrast, all animals in the scabies-free cohort remained relatively free of Staphylococcus throughout the trial.Conclusions/SignificanceThis is the first experimental in vivo evidence supporting previous assumptions that establishment of pathogens follow scabies infection. Our findings provide an explanation for a biologically important aspect of the disease pathogenesis. The methods developed from this pig trial will serve as a guide to analyze human clinical samples. Studies building on this will offer implications for development of novel intervention strategies against the mites and the secondary infections.

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Burden of paediatric pyoderma and scabies in North West Queensland

Abstract: Pyoderma and scabies are major health burdens in North West Queensland, requiring organised community-based prevention. The number of repeat admissions emphasises the futility of individual treatment.

Cited by 36 publications

References 9 publications

A Scabies Mite Serpin Interferes with Complement-Mediated Neutrophil Functions and Promotes Staphylococcal Growth

A Scabies Mite Serpin Interferes with Complement-Mediated Neutrophil Functions and Promotes Staphylococcal Growth

Are scabies and impetigo “normalised”? A cross-sectional comparative study of hospitalised children in northern Australia assessing clinical recognition and treatment of skin infections

Scabies Mites Alter the Skin Microbiome and Promote Growth of Opportunistic Pathogens in a Porcine Model

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