Antibacterial Efficacy of a Chitosan-Based Hydrogel Modified With Epsilon-Poly-l-Lysine Against Pseudomonas aeruginosa in a Murine-Infected Burn Wound Model.

INTRODUCTION: Because antibiotic resistance is increasing worldwide and the leading cause of death in burn patients is an infection, an urgent need exists for nonantibiotic approaches to eliminate multidrug-resistant bacteria from burns to prevent their systemic dissemination and sepsis. We previously demonstrated the significant antibiofilm activity of a chitosan (CS) hydrogel containing the antimicrobial peptide epsilon-poly-l-lysine (EPL) against multidrug-resistant Pseudomonas aeruginosa using ex vivo porcine skin. In this study, we evaluated the in vivo antibacterial efficacy of a CS/EPL hydrogel against P. aeruginosa in a murine burn wound infection model. MATERIALS AND METHODS: Full-thickness burns were created on the dorsum using a heated brass rod and were inoculated with bioluminescent, biofilm-forming P. aeruginosa (Xen41). Mice were treated with CS/EPL, CS, or no hydrogel applied topically 2 or 24 hours after inoculation to assess the ability to prevent or eradicate existing biofilms, respectively. Dressing changes occurred daily for 3 days, and in vivo bioluminescence imaging was performed to detect and quantitate bacterial growth. Blood samples were cultured to determine systemic infection. In vitro antibacterial activity and cytotoxicity against human primary dermal fibroblasts, keratinocytes, and mesenchymal stem cells were also assessed. RESULTS: CS/EPL treatment initiated at early or delayed time points showed a significant reduction in bioluminescence imaging signal compared to CS on days 2 and 3 of treatment. Mice administered CS/EPL had fewer bloodstream infections, lower weight loss, and greater activity than the untreated and CS groups. CS/EPL reduced bacterial burden by two orders of magnitude in vitro and exhibited low cytotoxicity against human cells. CONCLUSION: A topical hydrogel delivering the antimicrobial peptide EPL demonstrates in vivo efficacy to reduce but not eradicate established P. aeruginosa biofilms in infected burn wounds. This biocompatible hydrogel shows promise as an antimicrobial barrier dressing for the sustained protection of burn wounds from external bacterial contamination.

Health and economic burden of antimicrobial-resistant infections in Australian hospitals: a population-based model.

OBJECTIVE: To estimate the additional health and economic burden of antimicrobial-resistant (AMR) infections in Australian hospitals. METHODS: A simulation model based on existing evidence was developed to assess the additional mortality and costs of healthcare-associated AMR Escherichia coli (E. coli), Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium, and Staphylococcus aureus infections. SETTING: Australian public hospitals. FINDINGS: Australian hospitals spent an additional AUD$5.8 million (95% uncertainty interval [UI], $2.2-$11.2 million) per year treating ceftriaxone-resistant E.coli bloodstream infections (BSI), and an estimated AUD$5.5 million per year (95% UI, $339,633-$22.7 million) treating MRSA patients. There are no reliable estimates of excess morbidity and mortality from AMR infections in sites other than the blood and in particular for highly prevalent AMR E. coli causing urinary tract infections (UTIs). CONCLUSION: The limited evidence-base of the health impact of resistant infection in UTIs limits economic studies estimating the overall burden of AMR. Such data are increasingly important and are urgently needed to support local clinical practice as well as national and global efforts to curb the spread of AMR.

Evaluation of Volume of Intramuscular Injection into the Caudal Thigh Muscles of Female and Male BALB/c Mice (Mus musculus).

This study presents recommendations for intramuscular injection into the caudal thigh muscle of mice according to analysis of in vivo imaging of intramuscularly injected iohexol, a radiocontrast agent commonly used in CT imaging. An experienced laboratory animal technician using a Hamilton syringe intramuscularly injected iohexol into isoflurane-anesthetized female and male BALB/c mice. Injected volumes (25, 50, 100, and 200 µL) underwent CT scanning at 9 time points over a 3-h period. The distribution of the injectate in the muscles of the rear leg was examined over time for each volume group. Results indicated that 25- and 50-µL volumes remain intramuscularly. At 100 µL, mild to moderate leakage into the extramuscular tissues occurred. At 200 µL, leakage into the extramuscular tissues was moderate to severe. Our results suggest volumes of 50 µL or less are recommended for the caudal thigh muscles of mice when intramuscular pharmacokinetics are needed; volumes greater than 50 µL display variable distribution into extramuscular tissues, thus potentially yielding different pharmacokinetic profiles.

Pharmacokinetics of 2 Formulations of Transdermal Fentanyl in Cynomolgus Macaques (Macaca fascicularis).

Fentanyl is a µ-opioid agonist that often is used as the analgesic component for balanced anesthesia in both human and veterinary patients. Minimal information has been published regarding appropriate dosing, and the pharmacokinetics of fentanyl are unknown in NHP. The pharmacokinetic properties of 2 transdermal fentanyl delivery methods, a solution (2.6 and 1.95 mg/kg) and a patch (25 µg/h), were determined when applied topically to the dorsal scapular area of cynomolgus macaques (Macaca fascicularis). Serum fentanyl concentrations were analyzed by using liquid chromatography-mass spectrometry. Compared with the patch, the transdermal fentanyl solution generated higher drug concentrations over longer time. Adverse reactions occurred in the macaques that received the transdermal fentanyl solution at 2.6 mg/kg. Both preparations showed significant interanimal variability in the maximal serum drug levels, time to achieve maximal fentanyl levels, elimination half-life, and AUC values. Both the maximal concentration and the time at which this concentration occurred were increased in macaques compared with most other species after application of the transdermal fentanyl patch and compared with dogs after application of the transdermal fentanyl solution. The pharmacokinetic properties of transdermal fentanyl in macaques are markedly different from those in other veterinary species and preclude its use as a long-acting analgesic drug in NHP.

Clinical pathways for chronic cough in children.

BACKGROUND: Chronic cough (a cough lasting longer than four weeks) is a common problem internationally. Chronic cough has associated economic costs and is distressing to the child and to parents; ignoring cough may lead to delayed diagnosis and progression of serious underlying respiratory disease. Clinical guidelines have been shown to lead to efficient and effective patient care and can facilitate clinical decision making. Cough guidelines have been designed to facilitate the management of chronic cough. However, treatment recommendations vary, and specific clinical pathways for the treatment of chronic cough in children are important, as causes of and treatments for cough vary significantly from those in adults. Therefore, systematic evaluation of the use of evidence-based clinical pathways for the management of chronic cough in children would be beneficial for clinical practice and for patient care. Use of a management algorithm can improve clinical outcomes; such management guidelines can be found in the guidelines for cough provided by the American College of Chest Physicians (ACCP) and the British Thoracic Society (BTS). OBJECTIVES: To evaluate the effectiveness of using a clinical pathway in the management of children with chronic cough. SEARCH METHODS: The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE, review articles and reference lists of relevant articles were searched. The latest search was conducted in January 2014. SELECTION CRITERIA: All randomised controlled trials of parallel-group design comparing use versus non-use of a clinical pathway for treatment of chronic cough in children (< 18 years of age). DATA COLLECTION AND ANALYSIS: Results of searches were reviewed against predetermined criteria for inclusion. Two review authors independently selected studies and performed data extraction in duplicate. MAIN RESULTS: One study was included in the review. This multi-centre trial was based in five Australian hospitals and recruited 272 children with chronic cough. Children were randomly assigned to early (two weeks) or delayed (six weeks) referral to respiratory specialists who used a cough management pathway. When an intention-to-treat analysis was performed, clinical failure at six weeks post randomisation (defined as < 75% improvement in cough score, or total resolution for fewer than three consecutive days) was significantly less in the early pathway arm compared with the control arm (odds ratio (OR) 0.35, 95% confidence interval (CI) 0.21 to 0.58). These results indicate that one additional child will be cured for every five children treated via the cough pathway (number needed to treat for an additional beneficial outcome (NNTB) = 5, 95% CI 3 to 9) at six weeks. Cough-specific parent-reported quality of life scores were significantly better in the early-pathway group; the mean difference (MD) between groups was 0.60 (95% CI 0.19 to 1.01). Duration of cough post randomisation was significantly shorter in the intervention group (early-pathway arm) compared with the control group (delayed-pathway arm) (MD -2.70 weeks, 95% CI -4.26 to -1.14). AUTHORS' CONCLUSIONS: Current evidence suggests that using a clinical algorithm for the management of children with chronic cough in hospital outpatient settings is more effective than providing wait-list care. Futher high-quality randomised controlled trials are needed to perform ongoing evaluation of cough management pathways in general practitioner and other primary care settings.

Retrospective review of 200 children hospitalised with acute asthma. Identification of intervention points: a single centre study.

AIM: Indigenous Australians with asthma have higher morbidity and mortality compared with non-Indigenous Australians. In children hospitalised with acute asthma, we aimed to (i) determine if acute severity, risk factors and management differed between Indigenous and non-Indigenous children; and (ii) identify intervention points to reduce morbidity and mortality of asthma. METHODS: Retrospective review of 200 children hospitalised to Royal Darwin Hospital with asthma. We compared admission characteristics, severity indices, treatment, discharge plans and readmissions in Indigenous and non-Indigenous children. RESULTS: Median age was 3.6 years (interquartile range 2.2, 6.8). A significantly higher proportion of Indigenous children (95.2%) were exposed to tobacco smoke compared with non-Indigenous children (45.7%). The difference in proportions was -0.41 (95% confidence interval (CI) -0.60, -0.22). Other risk factors, asthma severity (moderate 83.9% vs. 83.3%; severe 16% vs. 16.1%), length of stay (1.9 vs. 1.3 days) and readmission rate (27.4% vs. 27.5%) were similar between Indigenous and non-Indigenous children. Indigenous children were significantly more likely to be followed up in a community clinic (difference in proportions = 0.10, 95% CI 0.1, 0.17) and less likely by a paediatrician. Only 62.5% of all children had an asthma action plan on discharge. CONCLUSION: Unlike other common respiratory diseases requiring hospitalisation, biological factors are unlikely major contributors to the known gap in asthma outcomes between Indigenous and non-Indigenous children. Intervention points include better identification, documentation and management of tobacco smoke exposure, delivery of salbutamol and discharge planning (including education and utilisation of asthma action plans).

Effect of FLT3 ligand on survival and disease phenotype in murine models harboring a FLT3 internal tandem duplication mutation.

Many of the mutations contributing to leukemogenesis in acute myeloid leukemia have been identified. A common activating mutation is an internal tandem duplication (ITD) mutation in the FLT3 gene that is found in approximately 25% of patients and confers a poor prognosis. FLT3 inhibitors have been developed and have some efficacy, but patients often relapse. Levels of FLT3 ligand (FL) are significantly elevated in patients during chemotherapy and may be an important component contributing to relapse. We used a mouse model to investigate the possible effect of FL expression on leukemogenesis involving FLT3-ITD mutations in an in vivo system. FLT3(ITD/ITD) FL(-/-) (knockout) mice had a statistically significant increase in survival compared with FLT3(ITD/ITD) FL(+/+) (wildtype) mice, most of which developed a fatal myeloproliferative neoplasm. These findings suggest that FL levels may have prognostic significance in human patients. We also studied the effect of FL expression on survival in a FLT3-ITD NUP98-HOX13 (NHD13) fusion mouse model. These mice develop an aggressive leukemia with short latency. We asked whether FL expression played a similar role in this context. The NUP98-HOX13 FLT3(ITD/wt) FL(-/-) mice did not have a survival advantage, compared with NUP98-HOX13 FLT3(ITD/wt) FL(+/+) mice (normal FL levels). The loss of the survival advantage of the FL knockout group in the NUP98-HOX13 model suggests that adding a second mutation changes the effect of FL expression in the context of more aggressive disease.

Antibiotics for bronchiectasis exacerbations in children: rationale and study protocol for a randomised placebo-controlled trial.

BACKGROUND: Despite bronchiectasis being increasingly recognised as an important cause of chronic respiratory morbidity in both indigenous and non-indigenous settings globally, high quality evidence to inform management is scarce. It is assumed that antibiotics are efficacious for all bronchiectasis exacerbations, but not all practitioners agree. Inadequately treated exacerbations may risk lung function deterioration. Our study tests the hypothesis that both oral azithromycin and amoxicillin-clavulanic acid are superior to placebo at improving resolution rates of respiratory exacerbations by day 14 in children with bronchiectasis unrelated to cystic fibrosis. METHODS: We are conducting a bronchiectasis exacerbation study (BEST), which is a multicentre, randomised, double-blind, double-dummy, placebo-controlled, parallel group trial, in five centres (Brisbane, Perth, Darwin, Melbourne, Auckland). In the component of BEST presented here, 189 children fulfilling inclusion criteria are randomised (allocation-concealed) to receive amoxicillin-clavulanic acid (22.5 mg/kg twice daily) with placebo-azithromycin; azithromycin (5 mg/kg daily) with placebo-amoxicillin-clavulanic acid; or placebo-azithromycin with placebo-amoxicillin-clavulanic acid for 14 days. Clinical data and a paediatric cough-specific quality of life score are obtained at baseline, at the start and resolution of exacerbations, and at day 14. In most children, blood and deep nasal swabs are also collected at the same time points. The primary outcome is the proportion of children whose exacerbations have resolved at day 14. The main secondary outcome is the paediatric cough-specific quality of life score. Other outcomes are time to next exacerbation; requirement for hospitalisation; duration of exacerbation; and spirometry data. Descriptive viral and bacteriological data from nasal samples and blood markers will also be reported. DISCUSSION: Effective, evidence-based management of exacerbations in people with bronchiectasis is clinically important. Yet, there are few randomised controlled trials (RCTs) in the neglected area of non-cystic fibrosis bronchiectasis. Indeed, no published RCTs addressing the treatment of bronchiectasis exacerbations in children exist. Our multicentre, double-blind RCT is designed to determine if azithromycin and amoxicillin-clavulanic acid, compared with placebo, improve symptom resolution on day 14 in children with acute respiratory exacerbations. Our planned assessment of the predictors of antibiotic response, the role of antibiotic-resistant respiratory pathogens, and whether early treatment with antibiotics affects duration and time to the next exacerbation, are also all novel. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Register (ANZCTR) number ACTRN12612000011886.

Risks of severity and readmission of Indigenous and non-Indigenous children hospitalised for bronchiolitis.

OBJECTIVE: To describe the characteristics of children admitted to Royal Darwin Hospital with bronchiolitis, and to compare the severity of illness and incidence of subsequent readmission in Indigenous and non-Indigenous children. DESIGN, SETTING AND PARTICIPANTS: Retrospective study of 101 children (aged

Culture-specific programs for children and adults from minority groups who have asthma.

BACKGROUND: People with asthma who come from minority groups have poorer asthma outcomes and more asthma related visits to Emergency Departments (ED). Various programmes are used to educate and empower people with asthma and these have previously been shown to improve certain asthma outcomes. Models of care for chronic diseases in minority groups usually include a focus of the cultural context of the individual and not just the symptoms of the disease. Therefore, questions about whether culturally specific asthma education programmes for people from minority groups are effective at improving asthma outcomes, are feasible and are cost-effective need to be answered. OBJECTIVES: To determine whether culture-specific asthma programmes, in comparison to generic asthma education programmes or usual care, improve asthma related outcomes in children and adults with asthma who belong to minority groups. SEARCH STRATEGY: We searched the Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE, review articles and reference lists of relevant articles. The latest search was performed in May 2008. SELECTION CRITERIA: All randomised controlled trials (RCTs) comparing the use of culture-specific asthma education programmes with generic asthma education programmes, or usual care, in adults or children from minority groups who suffer from asthma. DATA COLLECTION AND ANALYSIS: Two review authors independently selected, extracted and assessed the data for inclusion. We contacted authors for further information if required. MAIN RESULTS: Four studies were eligible for inclusion in the review. A total of 617 patients, aged from 5 to 59 years were included in the meta-analysis of data. Use of a culture-specific programme was superior to generic programmes or usual care, in improving asthma quality of life scores in adults, pooled WMD 0.25 (95% CI 0.09 to 0.41), asthma knowledge scores in children, WMD 3.30 (95% CI 1.07 to 5.53), and in a single study, reducing asthma exacerbation in children (risk ratio for hospitalisations 0.32, 95%CI 0.15, 0.70). AUTHORS' CONCLUSIONS: Current limited data show that culture-specific programmes for adults and children from minority groups with asthma, are more effective than generic programmes in improving most (quality of life, asthma knowledge, asthma exacerbations, asthma control) but not all asthma outcomes. This evidence is limited by the small number of included studies and the lack of reported outcomes. Further trials are required to answer this question conclusively.

Culture-specific programs for children and adults from minority groups who have asthma.

BACKGROUND: People with asthma who come from minority groups have poorer asthma outcomes and more asthma related visits to Emergency Departments (ED). Various programmes are used to educate and empower people with asthma and these have previously been shown to improve certain asthma outcomes. Models of care for chronic diseases in minority groups usually include a focus of the cultural context of the individual and not just the symptoms of the disease. Therefore, questions about whether culturally specific asthma education programmes for people from minority groups are effective at improving asthma outcomes, are feasible and are cost-effective need to be answered. OBJECTIVES: To determine whether culture-specific asthma programmes, in comparison to generic asthma education programmes or usual care, improve asthma related outcomes in children and adults with asthma who belong to minority groups. SEARCH STRATEGY: We searched the Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE, review articles and reference lists of relevant articles. The latest search was performed in May 2008. SELECTION CRITERIA: All randomised controlled trials (RCTs) comparing the use of culture-specific asthma education programmes with generic asthma education programmes, or usual care, in adults or children from minority groups who suffer from asthma. DATA COLLECTION AND ANALYSIS: Two review authors independently selected, extracted and assessed the data for inclusion. We contacted authors for further information if required. MAIN RESULTS: Four studies were eligible for inclusion in the review. A total of 617 patients, aged from 5 to 59 years were included in the meta-analysis of data. Use of a culture-specific programme was superior to generic programmes or usual care, in improving asthma quality of life scores in adults, pooled WMD 0.25 (95% CI 0.09 to 0.41), asthma knowledge scores in children, WMD 3.30 (95% CI 1.07 to 5.53), and in a single study, reducing asthma exacerbation in children (risk ratio for hospitalisations 0.32, 95%CI 0.15, 0.70). AUTHORS' CONCLUSIONS: Current limited data show that culture-specific programmes for adults and children from minority groups with asthma, are more effective than generic programmes in improving most (quality of life, asthma knowledge, asthma exacerbations, asthma control) but not all asthma outcomes. This evidence is limited by the small number of included studies and the lack of reported outcomes. Further trials are required to answer this question conclusively.

Does the time-point of relapse influence outcome in pediatric rhabdomyosarcomas?

BACKGROUND: Childhood rhabdomyosarcoma (RMS), a soft tissue malignant tumor of skeletal muscle origin, accounts for approximately 3.5% of the cases of cancer among children 0-14 years and 2% of the cases among adolescents and young adults 15-19 years of age. PROCEDURE: We evaluated survival (SUR) after first relapse depending on the time to relapse (TTR) in RMSs of childhood and adolescence. Early, intermediate, and late relapsing patients were evaluated for prognostic risk factors. RESULTS: Two hundred thirty-four patients with RMS enrolled in the German sarcoma trial CWS-81, CWS-86, CWS-91, and CWS-96 met selection criteria. Of the 234 patients, 35%, 32%, and 33% relapsed within 6 (early), 6-12 (intermediate), and more than 12 (late) months respectively after the end of primary therapy. Four-year SUR was 12%, 21%, and 41% for early, intermediate, and late relapse respectively (P < 0.001). Four-year SUR after local relapse was 18% (early), 38% (intermediate), and 49% (late). Embryonal RMS showed four year SUR of 16%, 30%, and 46% (P < 0.001) whereas alveolar histology showed four year SUR of 8%, 6%, and 23% (P < 0.01) for early, intermediate, and late relapse respectively. CONCLUSION: TTR has significant influence on prognosis in relapsed RMS. It influences SUR independent of other features such as type of relapse, histology, tumor site, primary treatment time or irradiation in primary treatment.