Tonsils at Telethon: developing a standardised collection of tonsil photographs for group A streptococcal (GAS) research.

Introduction: Group A streptococcus (GAS) infections, such as pharyngitis and impetigo, can lead to rheumatic fever and rheumatic heart disease (RHD). Australian Aboriginal and Torres Strait Islander populations experience high rates of RHD and GAS skin infection, yet rates of GAS pharyngitis are unclear. Anecdotally, clinical presentations of pharyngitis, including tonsillar hypertrophy and sore throat, are uncommon. This study aimed to develop a standardised set of tonsil photographs and determine tonsil size distribution from an urban paediatric population. Methods: A prospective cohort of children aged 3-15 years were recruited at the public events "Discover Day" and "Telethon Weekend" (October 2017) in Perth, Western Australia, Australia. Tonsil photographs, symptomatology, and GAS rapid antigen detection tests (RADT) were collected. Tonsil size was graded from the photographs using the Brodsky Grading Scale of tonsillar hypertrophy (Brodsky) by two independent clinicians, and inter-rater reliability calculated. Pharyngitis symptoms and GAS RADT were correlated, and immediate results provided. Results: Four hundred and twenty-six healthy children participated in the study over three days. The median age was seven years [interquartile range (IQR) 5.9-9.7 years]. Tonsil photographs were collected for 92% of participants, of which 62% were rated as good-quality photographs and 79% were deemed of adequate quality for assessment by both clinicians. When scored by two independent clinicians, 57% received the same grade. Average Brodsky grades (between clinicians) were 11%, 35%, 28%, 22% and 5% of grades 0,1,2,3 and 4, respectively. There was moderate agreement in grading using photographs, and minimal to weak agreement for signs of infection. Of 394 participants, 8% reported a sore throat. Of 334 GAS RADT performed, <1% were positive. Discussion: We report the first standardised use of paediatric tonsil photographs to assess tonsil size in urban-living Australian children. This provides a proof of concept from an urban-living cohort that could be compared with children in other settings with high risk of GAS pharyngitis or rheumatic fever such as remote-living Australian Indigenous populations.

A population pharmacokinetic study of benzathine benzylpenicillin G administration in children and adolescents with rheumatic heart disease: new insights for improved secondary prophylaxis strategies.

BACKGROUND: Benzathine benzylpenicillin G (BPG) is recommended as secondary prophylaxis to prevent recurrence of acute rheumatic fever and subsequent rheumatic heart disease (RHD). Following intramuscular injection, BPG is hydrolysed to benzylpenicillin. Little is known of the pharmacokinetics of benzylpenicillin following BPG in populations at risk of RHD. METHODS: We conducted a longitudinal pharmacokinetic study of children and adolescents receiving secondary prophylaxis throughout six monthly cycles of BPG. Dried blood spot samples were assayed with LC-MS/MS. Benzylpenicillin concentrations were analysed using non-linear mixed-effects modelling with subsequent simulations based on published BMI-for-age and weight-for-age data. RESULTS: Eighteen participants contributed 256 concentrations for analysis. None had benzylpenicillin concentrations >0.02 mg/L for the full time between doses. The median duration above this target was 9.8 days for those with a lower BMI (<25 kg/m2), who also had lower weights, and 0 days for those with a higher BMI (≥25 kg/m2). Although fat-free mass was a key determinant of benzylpenicillin exposure after a standard dose of BPG, having a higher BMI influenced absorption and almost doubled (increase of 86%) the observed t½. CONCLUSIONS: Few children and adolescents receiving BPG as secondary prophylaxis will achieve concentrations >0.02 mg/L for the majority of the time between injections. The discordance of this observation with reported efficacy of BPG to prevent rheumatic fever implies a major knowledge gap relating to pharmacokinetic/pharmacodynamic relationships between benzylpenicillin exposure and clinical outcomes.

The development and testing of a skin tear risk assessment tool.

The aim of the present study is to develop a reliable and valid skin tear risk assessment tool. The six characteristics identified in a previous case control study as constituting the best risk model for skin tear development were used to construct a risk assessment tool. The ability of the tool to predict skin tear development was then tested in a prospective study. Between August 2012 and September 2013, 1466 tertiary hospital patients were assessed at admission and followed up for 10 days to see if they developed a skin tear. The predictive validity of the tool was assessed using receiver operating characteristic (ROC) analysis. When the tool was found not to have performed as well as hoped, secondary analyses were performed to determine whether a potentially better performing risk model could be identified. The tool was found to have high sensitivity but low specificity and therefore have inadequate predictive validity. Secondary analysis of the combined data from this and the previous case control study identified an alternative better performing risk model. The tool developed and tested in this study was found to have inadequate predictive validity. The predictive validity of an alternative, more parsimonious model now needs to be tested.

Identification of risk factors associated with the development of skin tears in hospitalised older persons: a case-control study.

To identify the risk factors associated with the development of skin tears in older persons four hundred and fifty three patients (151 cases and 302 controls) were enrolled in a case-control study in a 500-bed metropolitan tertiary hospital in Western Australia between December 2008 and June 2009. Case eligibility was defined by a skin tear on admission, which had occurred in the last 5 days; or, a skin tear developed during hospitalisation. For each case, two controls who did not have a skin tear and had been admitted within 1 day of the case, were also enrolled. Data collected from the nursing staff and inpatient medical records included characteristics known, or hypothesised, to be associated with increased vulnerability to skin tears. Data analysis included a series of multivariate stepwise regressions to identify a number of different potential explanatory models. The most parsimonious model for predicting skin tear development comprised six variables: ecchymosis (bruising); senile purpura; haematoma; evidence of a previously healed skin tear; oedema; and inability to reposition oneself independently. The ability of these six characteristics to predict who among older patients could subsequently develop a skin tear now needs to be determined by a prospective study.

The effectiveness of a twice-daily skin-moisturising regimen for reducing the incidence of skin tears.

A cluster randomised controlled trial was conducted to evaluate the effectiveness of a twice-daily moisturising regimen as compared to 'usual' skin care for reducing skin tear incidence. Aged care residents from 14 Western Australian facilities (980 beds) were invited to participate. The facilities were sorted into pairs and matched in terms of bed numbers and whether they provided high or low care. One facility from each matched pair was randomised to the intervention group. Consenting residents in an intervention facility received a twice-daily application of a commercially available, standardised pH neutral, perfume-free moisturiser on their extremities. Residents in the control facilities received ad hoc or no standardised skin-moisturising regimen. Participant numbers were sufficient to detect a 5% difference in incidence rate between the two groups with 80% power and a significance level of P = 0·05, and the inter-cluster correlation coefficient was 0·034. Data were collected over 6 months. A total of 1396 skin tears on 424 residents were recorded during the study. In the intervention group, the average monthly incidence rate was 5·76 per 1000 occupied bed days as compared to 10·57 in the control group. The application of moisturiser twice daily reduced the incidence of skin tears by almost 50% in residents living in aged care facilities.

Uncontrolled, open-label, pilot study of tea tree (Melaleuca alternifolia) oil solution in the decolonisation of methicillin-resistant Staphylococcus aureus positive wounds and its influence on wound healing.

Many complementary and alternative products are used to treat wounds. The essential oil of Melaleuca alternifolia, tea tree oil, has proven antimicrobial and anti-inflammatory properties, may be useful in methicillin-resistant Staphylococcus aureus (MRSA) decolonisation regimens and is reputed to have 'wound-healing' properties, but more data are required to support these indications. The primary aim of this uncontrolled case series was to assess whether a tea tree oil solution used in a wound cleansing procedure could decolonise MRSA from acute and chronic wounds of mixed aetiology. The secondary aim was to determine if the tea tree oil solution influenced wound healing outcomes. Nineteen participants with wounds suspected of being colonised with MRSA were enrolled in a pilot study. Seven were subsequently shown not to have MRSA and were withdrawn from the study. As many as 11 of the remaining 12 participants were treated with a water-miscible tea tree oil (3·3%) solution applied as part of the wound cleansing regimen at each dressing change. Dressing changes were three times per week or daily as deemed necessary by the study nurse following assessment. One participant withdrew from the study before treatment. No participants were MRSA negative after treatment. After treatment had been implemented, 8 of the 11 treated wounds had begun to heal and reduced in size as measured by computer planimetry. Although this formulation and mode of delivery did not achieve the primary aim of the study, tea tree oil did not appear to inhibit healing and the majority of wounds reduced in size after treatment.

Assessing bacterial burden in wounds: comparing clinical observation and wound swabs.

A randomised controlled trial (RCT) was conducted to compare the efficacy of nanocrystalline silver and cadexomer iodine dressings in healing chronic lower leg ulcers. The relationships between wound swab culture results and nurses' clinical assessments of critical colonisation, and between bacterial burden and healing rate, were also examined. There were 281 individuals with leg ulcers recruited. The bacterial burden of wounds was assessed using semi-quantitative wound swabs collected at baseline and intervals during the study. The study found no relationship between the nurses' clinical assessments and bacterial burden as identified from wound swabs in the wounds. A significant difference in wound healing was found with the use of nanocrystalline silver as compared to cadexomer iodine in the first 2 weeks of treatment when nil or low levels of leukocytes, gram positive bacilli, gram positive cocci or gram negative cocci were reported. This study has raised a number of questions regarding the need for further investigation into methods of assessing wound bacterial burden as well as the impact of wound biofilms on wound assessment and treatment.

A randomized-controlled trial comparing cadexomer iodine and nanocrystalline silver on the healing of leg ulcers.

Chronic leg ulcers are a debilitating, often painful, and costly condition. Leg ulcer healing may be impaired by bacterial colonization, which, unless effective intervention is instigated, can lead to infection. Although it is generally agreed that an antimicrobial dressing is clinically indicated when a wound becomes critically colonized, there is currently no agreement on what constitutes the best practice in the use of antimicrobials. This research compared the effectiveness of two commonly used antimicrobials: nanocrystalline silver and cadexomer iodine. A randomized-controlled trial was conducted in which 281 community nursing clients with leg ulcers compromised by bacterial burden were randomly assigned to have their wounds treated with either silver or iodine dressings. Sixty-four percent of ulcers healed within 12 weeks. The performance of each of the two antimicrobials was comparable in terms of overall healing rate and the number of wounds healed. However, use of silver compounds was associated with a quicker healing rate during the first 2 weeks of treatment and in wounds that were larger, older, and had more exudate. This trial provides some insights as to circumstances in which one product may be preferred over the other.