An overview of risk factors, management and prevention of cochlear implant infections

PURPOSE OF REVIEW

With cochlear implantation becoming increasingly performed worldwide, an understanding of the risk factors, preventive measures, and management of cochlear implant (CI) infection remains important given the significant morbidity and cost it conveys.

RECENT FINDINGS

At the turn of the 21st century there was a decrease in rates of CI infection, particularly meningitis, following the discontinuation of positioner use for CI. However, in more recent years rates of CI infection have remained largely static. Recently, studies evaluating preventive measures such as pneumococcal vaccination, S. aureus decolonization and surgical antibiotic prophylaxis have emerged in the literature.

SUMMARY

Prompt recognition of CI infection and appropriate investigation and management are key, however at present treatment is largely informed by cohort and case-control studies and expert opinion. Preventive measures including pneumococcal vaccination, S. aureus decolonization and preoperative antibiotic prophylaxis play a role in reducing rates of CI infection. However, there remains a need for well designed clinical trials to provide higher level evidence to better guide preventive measures for, and management decisions of, CI infections in the future.

Invasive aspergillosis in adult patients in Australia and New Zealand: 2017-2020

Background

New and emerging risks for invasive aspergillosis (IA) bring the need for contemporary analyses of the epidemiology and outcomes of IA, in order to improve clinical practice.

Methods

The study was a retrospective, multicenter, cohort design of proven and probable IA in adults from 10 Australasian tertiary centres (January 2017-December 2020). Descriptive analyses were used to report patients' demographics, predisposing factors, mycological characteristics, diagnosis and management. Accelerated failure-time model was employed to determine factor(s) associated with 90-day all-cause mortality (ACM).

Findings

Of 382 IA episodes, 221 (in 221 patients) fulfilled inclusion criteria - 53 proven and 168 probable IA. Median patient age was 61 years (IQR 51-69). Patients with haematologic malignancies (HM) comprised 49.8% of cases. Fifteen patients (6.8%) had no pre-specified immunosuppression and eleven patients (5.0%) had no documented comorbidity. Only 30% of patients had neutropenia. Of 170 isolates identified, 40 (23.5%) were identified as non-Aspergillus fumigatus species complex. Azole-resistance was present in 3/46 (6.5%) of A. fumigatus sensu stricto isolates. Ninety-day ACM was 30.3%. HM (HR 1.90; 95% CI 1.04-3.46, p = 0.036) and ICU admission (HR 4.89; 95% CI 2.93-8.17, p < 0.001) but not neutropenia (HR 1.45; 95% CI 0.88-2.39, p = 0.135) were associated with mortality. Chronic kidney disease was also a significant predictor of death in the HM subgroup (HR 3.94; 95% CI 1.15-13.44, p = 0.028).

Interpretation

IA is identified in high number of patients with mild/no immunosuppression in our study. The relatively high proportion of non-A. fumigatus species complex isolates and 6.5% azole-resistance rate amongst A. fumigatus sensu stricto necessitates accurate species identification and susceptibility testing for optimal patient outcomes.

Funding

This work is unfunded. All authors' financial disclosures are listed in detail at the end of the manuscript.

Consumer perspectives on simplified, layered consent for a low risk, but complex pragmatic trial

BACKGROUND

For decades, the research community has called for participant information sheets/consent forms (PICFs) to be improved. Recommendations include simplifying content, reducing length, presenting information in layers and using multimedia. However, there are relatively few studies that have evaluated health consumers' (patients/carers) perspectives on the type and organisation of information, and the level of detail to be included in a PICF to optimise an informed decision to enter a trial. We aimed to elicit consumers' views on a layered approach to consent that provides the key information for decision-making in a short PICF (layer 1) with additional optional information that is accessed separately (layer 2). We also elicited consumers' views on the optimal content and layout of the layered consent materials for a large and complex Bayesian adaptive platform trial (the SNAP trial).

METHODS

We conducted a qualitative multicentre study (4 focus groups and 2 semi-structured interviews) involving adolescent and adult survivors of Staphylococcus aureus bloodstream infection (22) and their carers (2). Interview transcripts were examined using inductive thematic analysis.

RESULTS

Consumers supported a layered approach to consent. The primary theme that emerged was the value of agency; the ability to exert some control over the amount of information read before the consent form is signed. Three other themes emerged; the need to prioritise participants' information needs; the importance of health literacy; the importance of information about a trial's benefits (over its risks) for decision-making and the interplay between the two.

CONCLUSIONS

Our findings suggest that consumers may challenge the one-size-fits-all approach currently applied to the development of PICFs in countries like Australia. Consumers supported a layered approach to consent that offers choice in the amount of information to be read before deciding whether to enter a trial. A 3-page PICF was considered sufficient for decision-making for the SNAP trial, provided that further information was available and accessible.

Urinary tract infections in children: building a causal model-based decision support tool for diagnosis with domain knowledge and prospective data

BACKGROUND

Diagnosing urinary tract infections (UTIs) in children in the emergency department (ED) is challenging due to the variable clinical presentations and difficulties in obtaining a urine sample free from contamination. Clinicians need to weigh a range of observations to make timely diagnostic and management decisions, a difficult task to achieve without support due to the complex interactions among relevant factors. Directed acyclic graphs (DAG) and causal Bayesian networks (BN) offer a way to explicitly outline the underlying disease, contamination and diagnostic processes, and to further make quantitative inference on the event of interest thus serving as a tool for decision support.

METHODS

We prospectively collected data on children present to ED with suspected UTIs. Through knowledge elicitation workshops and one-on-one meetings, a DAG was co-developed with clinical domain experts (the Expert DAG) to describe the causal relationships among variables relevant to paediatric UTIs. The Expert DAG was combined with prospective data and further domain knowledge to inform the development of an application-oriented BN (the Applied BN), designed to support the diagnosis of UTI. We assessed the performance of the Applied BN using quantitative and qualitative methods.

RESULTS

We summarised patient background, clinical and laboratory characteristics of 431 episodes of suspected UTIs enrolled from May 2019 to November 2020. The Expert DAG was presented with a narrative description, elucidating how infection, specimen contamination and management pathways causally interact to form the complex picture of paediatric UTIs. Parameterised using prospective data and expert-elicited parameters, the Applied BN achieved an excellent and stable performance in predicting Escherichia coli culture results, with a mean area under the receiver operating characteristic curve of 0.86 and a mean log loss of 0.48 based on 10-fold cross-validation. The BN predictions were reviewed via a validation workshop, and we illustrate how they can be presented for decision support using three hypothetical clinical scenarios.

CONCLUSION

Causal BNs created from both expert knowledge and data can integrate case-specific information to provide individual decision support during the diagnosis of paediatric UTIs in ED. The model aids the interpretation of culture results and the diagnosis of UTIs, promising the prospect of improved patient care and judicious use of antibiotics.

A quality improvement study: Optimizing pneumococcal vaccination rates in children with cochlear implants

Children with cochlear implants are at increased risk of invasive pneumococcal disease, with national and international guidelines recommending additional pneumococcal vaccines for these children. This study aimed to examine the pneumococcal immunization status and rate of invasive pneumococcal disease in children with cochlear implants at a tertiary paediatric hospital over a 12-year period. Additionally, the impacts of vaccination reminders and a dedicated immunization clinic on pneumococcal vaccination rates were assessed. This quality improvement study included 200 children who had received a cochlear implant through the Children's Hearing Implant Program at a tertiary paediatric hospital servicing the state of Western Australia. The majority of children (88%) were not up to date with additionally recommended pneumococcal vaccinations. Over the 12-year study period, 2% of children developed invasive pneumococcal disease associated with cochlear implant infections. Generic and personalized electronic immunization reminders improved pneumococcal vaccine up-take in this paediatric cochlear implant setting from 12% (19/153) at baseline to 49% (75/153, p < 0.0001) post implementation. The value of a nurse-led dedicated immunization clinic was also demonstrated with all children (42/42, 100%) up to date with Prevenar13 and the majority (34/42, 81%) up to date with Pneumovax23 post initiation of this referral pathway. These data support the expansion of this model to other medically-at-risk paediatric groups that have been highlighted consistently to be under-vaccinated.

Infectious complications and optimising infection prevention for children with cochlear implants

AIM

To describe the clinical epidemiology of children receiving cochlear implants, as well as the management and outcomes of cochlear implant infections and adherence to infection prevention measures.

METHODS

A retrospective observational study was conducted in children ≤18 years who received cochlear implants in Western Australia's tertiary paediatric hospital. Information was obtained from medical and laboratory records regarding demographics, indication for implant, implant infection and preoperative Staphylococcus aureus screening/decolonisation. Immunisation history was examined using the Australian Immunisation Register.

RESULTS

Overall, 118 children received cochlear implants, with 158 devices inserted (599 cochlear implant insertion-years). An implant infection rate of 3.8% (6/158) was identified during the study period (four pneumococcal and two community-acquired methicillin resistant S. aureus infections). All required surgical management, with an overall median duration of antibiotic therapy of 37 days (interquartile range (IQR) 29-48) and median length of stay of 8 days (IQR 8-9.5). All devices were retained and there were no relapses or deaths. Half of the children who developed cochlear implant infections (50%, 3/6) were up-to-date with additional pneumococcal vaccinations and no children (0%, 0/118) received S. aureus screening/decolonisation before implant insertion.

CONCLUSIONS

Favourable outcomes were achieved with cochlear implant retention; however, the treatment was burdensome for families. We demonstrate significant scope to improve adherence to existing infection prevention strategies and provide direction for optimising preventative measures in the future. These include ensuring parental education, additional pneumococcal vaccinations and S. aureus decolonisation which are delivered as an infection prevention bundle to the growing population of infants receiving cochlear implants.

Measurement of Lepton-Jet Correlation in Deep-Inelastic Scattering with the H1 Detector Using Machine Learning for Unfolding

The first measurement of lepton-jet momentum imbalance and azimuthal correlation in lepton-proton scattering at high momentum transfer is presented. These data, taken with the H1 detector at HERA, are corrected for detector effects using an unbinned machine learning algorithm (multifold), which considers eight observables simultaneously in this first application. The unfolded cross sections are compared with calculations performed within the context of collinear or transverse-momentum-dependent factorization in quantum chromodynamics as well as Monte Carlo event generators.

Whole genome sequencing and molecular epidemiology of pediatric Staphylococcus aureus bacteremia

BACKGROUND

The role Staphylococcus aureus antimicrobial resistance genes and toxins play in disease severity, management and outcome in childhood is an emerging field requiring further exploration.

METHODS

A prospective multi-site study of Australian and New Zealand children hospitalized with S. aureus bacteremia (SAB), occurred over 24-months (2017-2018). Whole genome sequencing (WGS) data was paired with clinical information from the ISAIAH cohort.

RESULTS

353 SAB isolates were sequenced; 85% methicillin-susceptible S. aureus ([MSSA], 301/353); 15% methicillin-resistant S. aureus ([MRSA], 52/353). There were 92 sequence types (STs), most commonly; ST5 (18%) and ST30 (8%), grouped into 23 clonal complexes (CCs), most frequently CC5 (21%) and CC30 (12%). MSSA comprised the majority of healthcare-associated SAB (87%, 109/125), with principal clones CC15 (48%, 11/21) and CC8 (33%, 7/21). Panton Valentine Leukocidin (PVL)-positive SAB occurred in 22% (76/353); predominantly MSSA (59%, 45/76), community-onset (92%, 70/76) infections. For community-onset SAB, the only microbiological independent predictor of poor outcomes was PVL-positivity (aOR 2.6 [CI 1.0-6.2]).

CONCLUSION

From this WGS pediatric SAB data, we demonstrate the previously under-recognized role MSSA has in harboring genetic virulence and causing healthcare-associated infections. PVL-positivity was the only molecular independent predictor of poor outcomes in children. These findings underscore the need for further research to define the potential implications PVL-producing strains may have on approaches to S. aureus clinical management.

Re-examining Hepatitis B Postexposure Prophylaxis Following Pediatric Community-acquired Needle-stick Injury in an Era of a National Immunization Registry

BACKGROUND

Long-term hepatitis B immunity has been demonstrated following the completion of the primary vaccination series in childhood. Some guidelines recommend a hepatitis B surface antibody (anti-HBs) directed approach following community-acquired needle-stick injury (CANSI) to inform hepatitis B postexposure prophylaxis (PEP) management. We assessed the utility of anti-HBs testing post-CANSI, as well as the costing of, and adherence to PEP at a pediatric hospital.

METHODS

Children presenting to an Australian tertiary pediatric hospital post-CANSI (2014-2019) were identified retrospectively using medical and laboratory records. Immunization status was obtained from the Australian Immunisation Registry.

RESULTS

Fifty-six children with CANSI were identified. Of those with immunization records, all had completed hepatitis B vaccinations (n = 52). At presentation, 44% (n = 23) had anti-HBs <10 IU/L, which was more likely in older (≥6 years, 68%) versus younger children (OR 4.59, P < 0.02). HBIG and hepatitis B vaccine adherence was 65% (15/23) and 78% (18/23), respectively. All children (n = 14) with anti-HBs ≥4 weeks postvaccination ±HBIG, demonstrated an anamnestic response. No hepatitis B infections were detected. Using completed immunizations versus anti-HBs levels as a marker of immunity to direct PEP resulted in a projected cost savings of AUD$ 4234.

CONCLUSION

Anti-HBs levels <10 IU/L, despite previous vaccinations, were frequent in children post-CANSI, with many demonstrating an anamnestic response. Adherence to postexposure HBIG and hepatitis B vaccine was suboptimal using an anti-HBs directed approach. These data support re-evaluating PEP in an era of the national immunization registry; completion of hepatitis B vaccinations as a marker of immunity provides a practical approach, ensuring optimized care for pediatric CANSI.

A plant-infecting subviral RNA associated with poleroviruses produces a subgenomic RNA which resists exonuclease XRN1 in vitro

Subviral agents are nucleic acids which lack the features for classification as a virus. Tombusvirus-like associated RNAs (tlaRNAs) are subviral positive-sense, single-stranded RNAs that replicate autonomously, yet depend on a coinfecting virus for encapsidation and transmission. TlaRNAs produce abundant subgenomic RNA (sgRNA) upon infection. Here, we investigate how the well-studied tlaRNA, ST9, produces sgRNA and its function. We found ST9 is a noncoding RNA, due to its lack of protein coding capacity. We used resistance assays with eukaryotic Exoribonuclease-1 (XRN1) to investigate sgRNA production via incomplete degradation of genomic RNA. The ST9 3' untranslated region stalled XRN1 very near the 5' sgRNA end. Thus, the XRN family of enzymes drives sgRNA accumulation in ST9-infected tissue by incomplete degradation of ST9 RNA. This work suggests tlaRNAs are not just parasites of viruses with compatible capsids, but also mutually beneficial partners that influence host cell RNA biology.

Progress towards a coordinated, national paediatric antimicrobial resistance surveillance programme: Staphylococcus aureus, enterococcal and Gram-negative bacteraemia in Australia

BACKGROUND

There is increasing knowledge of antimicrobial usage in children yet limited availability of nationally representative paediatric-specific data on antimicrobial resistance.

OBJECTIVES

Paediatric data from this national surveillance programme are presented to explore differences between childhood and adult bloodstream infections and antimicrobial resistance surveillance.

METHODS

Using information collected from a prospective coordinated antimicrobial resistance surveillance programme, children ≤18 years and adults >18 years with a positive blood culture for Staphylococcus aureus, Enterococcus spp. or Gram-negative spp. presenting to one of 34 Australian hospitals during 2013-16 were evaluated. Consistent methodologies for key sepsis pathogens were employed and a comparative analysis between children and adults was conducted.

RESULTS

There are stark contrasts between children and adults in this national antimicrobial resistance (AMR) data set. Notable differences include lower rates of AMR, different clinical and molecular phenotypes and lower mortality amongst children. The burden of Gram-negative resistance is disproportionately experienced in children, with higher odds of death with an ESBL versus non-ESBL bacteraemia in comparison with adults.

CONCLUSIONS

These data support that children are not just 'little adults' in the AMR era, and analyses by age group are important to detect differences in antibiotic susceptibility, clinical phenotype and genetic virulence factors. Antimicrobial surveillance incorporated into routine laboratory practice is vital to inform an array of wider applications including antimicrobial guidelines, stewardship and direction for prioritization of novel antimicrobial development.

Pediatric Staphylococcus aureus bacteremia: clinical spectrum and predictors of poor outcome

BACKGROUND

Staphylococcus aureus is a common cause of bacteremia, yet the epidemiology, and predictors of poor outcome remain inadequately defined in childhood.

METHODS

ISAIAH is a prospective, cross-sectional study of S. aureus bacteremia (SAB), in children hospitalized in Australia and New Zealand, over 24-months (2017-2018).

RESULTS

Overall, 552 SABs were identified, (incidence 4.4/100,000/yr [95% confidence interval (CI) 2.2-8.8]), with methicillin-susceptible (84%), community onset (78%) infection predominating. Indigenous children (8.1/100,000/yr [CI 4.8-14.4]), those from lower-socioeconomic areas (5.5/100,000/yr [CI 2.8-10.2]) and neonates (6.6/100,000/yr (CI 3.4-11.7) were over-represented. Although 90-day mortality was infrequent, one-third experienced the composite of: length of stay >30 days (26%), ICU admission (20%), relapse (4%), or death (3%).Predictors of mortality included prematurity (aOR 16.8 [CI 1.6-296.9]), multifocal infection (aOR 22.6 [CI 1.4-498.5]), necrotizing pneumonia (aOR 38.9 [CI 1.7 - 1754.6]), multiorgan dysfunction (aOR 26.5 [CI 4.1-268.8]) and empiric-vancomycin (aOR 15.7 [CI 1.6-434.4]); whilst Infectious Diseases (ID) consultation (aOR 0.07 [CI 0.004-0.9]) was protective. Neither MRSA nor vancomycin trough-targets impacted survival; however, empiric-vancomycin was associated with significant nephrotoxicity (OR 3.1 [CI 1.3-8.1]).

CONCLUSIONS

High SAB incidence was demonstrated, with at-risk populations identified for future prioritized care. For the first time in a pediatric setting, necrotizing pneumonia and multifocal infection were predictors of mortality, whilst ID consultation was protective. The need to re-evaluate pediatric vancomycin trough-targets and limit unnecessary empiric-vancomycin exposure, to reduce poor outcomes and nephrotoxicity is highlighted. One in three children experienced considerable SAB morbidity, therefore pediatric inclusion in future SAB comparator trials is paramount to improve outcomes.

Do rapid diagnostic methods improve antibiotic prescribing in paediatric bacteraemia?

AIM

Rapid blood culture pathogen identification facilitated by matrix-assisted laser desorption ionisation time-of-flight and GeneXpert has the potential to improve antibiotic prescribing. This study investigates the impact of these rapid diagnostics on the timeliness of effective and optimal antibiotic prescribing in paediatric patients with bacteraemia.

METHODS

A single centre retrospective cohort study was performed comparing paediatric bacteraemia cases pre- and post-rapid diagnostic implementation. Primary outcomes were the proportion of cases receiving, and median time to administration of effective and optimal antibiotics from blood culture collection. Secondary outcomes included hospital length of stay, intensive care unit admissions, and all-cause mortality.

RESULTS

A total of 255 bacteraemia cases were subject to final data analysis, 129 in the control cohort (pre-implementation of rapid diagnostics) and 126 in the rapid diagnostics cohort. The median time to effective (2.3 vs. 1.8 h, P = 0.20) and optimal therapy (44.4 vs. 39.1 h, P = 0.66) did not differ significantly between the cohorts. There was also no significant difference found in the number of cases reaching effective (120 vs. 116, P = 0.77) and optimal therapy (66 vs. 62, P = 0.76), length of stay (7 vs. 9 days), all-cause mortality (1.6 vs. 1.6%) and number of intensive care unit admissions (20 vs. 15).

CONCLUSION

The implementation of rapid diagnostics, when used in isolation, resulted in no improvement in antibiotic prescribing or patient clinical outcomes. To be effective, rapid diagnostics must be coupled with active real-time antimicrobial stewardship promotion, de-escalation or modification based on early laboratory results.

Pre- and post-intervention study examining immunisation rates, documentation, catch-up delivery and the impact of a dedicated immunisation service at a tertiary paediatric hospital

AIM

To explore immunisation rates and catch-up delivery to children admitted to hospital before and after an immunisation service was commenced.

METHODS

This pre- and post-intervention study examined 300 admissions prior to (cohort 1) and 300 following (cohort 2) the introduction of an immunisation service. Immunisation rates, documentation, catch-up delivery and accuracy of the Australian Immunisation Register (AIR) were examined.

RESULTS

On admission, 75% (cohort 1) and 89% (cohort 2) were up-to-date with immunisations. Immunisation history was documented in the medical record in 78% and requirement for catch-up documented in 10%. AIR was incorrect in one-third of cases. By 3 months following discharge, 28% (cohort 1) and 64% (cohort 2) of patients were immunised.

CONCLUSIONS

Children admitted to hospital have lower immunisation rates than the national average. Documentation was poor, opportunities for catch-up were missed and AIR is error-prone. Catch-up rates increased following the introduction of an immunisation service.

Case Report: Neonatal Varicella Acquired From Maternal Zoster

The incidence of neonatal varicella has decreased dramatically since the introduction of the varicella vaccination. Although the varicella zoster virus is often associated with a mild infection, it may cause severe morbidity and mortality, particularly in the neonatal period and immunocompromised hosts. We report a case of neonatal varicella acquired from maternal zoster in a mother on biological immunosuppressive therapy. Following the diagnosis, the baby improved on antiviral therapy without any neurological sequelae. This case highlights the limited published data on neonatal varicella following herpes zoster reactivation to inform practice. This includes the role of varicella zoster immunoglobulin in neonates exposed to maternal zoster, the degree of trans-placental immunity and optimum antiviral dosing and duration.

Clinical Management of Staphylococcus aureus Bacteremia in Neonates, Children, and Adolescents

Staphylococcus aureus is a common cause of community and health care-associated bacteremia, with authors of recent studies estimating the incidence of S aureus bacteremia (SAB) in high-income countries between 8 and 26 per 100 000 children per year. Despite this, <300 children worldwide have ever been randomly assigned into clinical trials to assess the efficacy of treatment of SAB. A panel of infectious diseases physicians with clinical and research interests in pediatric SAB identified 7 key clinical questions. The available literature is systematically appraised, summarizing SAB management in children in relation to these priority clinical questions. The management of neonates, children, and adolescents with SAB is predominantly based on clinical experience and trial data extrapolated from adult studies, with limited high-quality evidence available to guide management. The optimal, comprehensive management strategies for SAB in children will remain unknown until the questions outlined are answered through prospective observational cohorts and inclusion of children with SAB in clinical trials.

Pollen Loads of Flower Visitors to Açaí Palm (Euterpe oleracea) and Implications for Management of Pollination Services

Understanding the functional roles of different pollinator species is crucial to the development of sustainable farming practices in pollinator-dependent crops. However, this can be challenging for crop plants in tropical regions with hyper-diverse pollinator communities. Here, we assess pollen loads of different insect visitors to inflorescences of açaí palm (Euterpe oleracea), the most important native crop in the Amazon estuary region. Flower-visiting insects were collected from pistillate (female) inflorescences at eight sites, including four managed floodplain forests and four plantations. Pollinator Importance Value Index (PIVI) and Relative Importance (RI) scores were calculated for common visitor taxa (≥ 10 individuals) using sum visit frequencies and median pollen loads. Pollen load analyses revealed that over seventy insect taxa, including bees, flies, beetles, wasps and ants, were effective vectors of E. oleracea pollen. Native bees, including both solitary and eusocial taxa, were the most efficient pollen vectors, with median pollen loads at least eight times higher than those of the next best insect group (flies). Insect pollen loads were at their highest between 0800 and 1300 hours, and four insect taxa had RI scores > 0.05, including two meliponine bees belonging to the Trigona genus (Trigona branneri Cockerell and Trigona pallens Fabricius) and two halictid bee genera (Augochloropsis and Dialictus). Our results suggest that native bees play an important role in açaí pollination and should be the primary focus of pollinator management in açaí production systems.

Spotting sporotrichosis skin infection: The first Australian paediatric case series

AIM

Sporotrichosis is a dermatomycosis caused by the dimorphic fungus, Sporothrix schenckii, with various outbreaks across Australia attributed to mouldy hay. Our objective was to investigate the clinical presentation and management of cutaneous sporotrichosis in a paediatric population of Western Australia.

METHODS

A retrospective case review was performed for S. schenckii infections in children below 18 years, between January 2000 and November 2017. Cases were identified from the state-wide laboratory database and additional clinical data obtained from medical records.

RESULTS

Thirty-two cases of microbiologically proven S. schenckii infection were identified, mostly from rural areas (n = 20, 63%). Complete clinical data were available for 11 cases (34%). The most common risk factors were exposure to farm animals and hay, arthropod bites and outdoor activities. The median duration from symptom onset to correct diagnosis was 6 weeks (interquartile range: 4-7 weeks). Most cases were initially treated with multiple, broad-spectrum antibacterial agents (n = 7, 64%). Targeted therapy (itraconazole) was used in all cases once the diagnosis was made, with a median treatment duration of 5 months (interquartile range: 4-6 months). Morbidity included scarring (n = 4, 31%), itraconazole associated diarrhoea (n = 1, 8%) and mild hepatotoxicity (n = 1, 8%).

CONCLUSION

Summarising the clinical experience of these cases is a useful guide for clinical recognition and may serve to shorten the interval between onset and diagnosis, and avoid the need for antibacterial therapy. These data highlight the importance of recognising Sporotrichosis in children outside an outbreak setting, leading to timely diagnosis and appropriate treatment with antifungal agents.

Adjunctive protein synthesis inhibitor antibiotics for toxin suppression in Staphylococcus aureus infections: a systematic appraisal

Protein synthesis inhibitor antibiotics inhibit synthesis of new proteins, including exotoxins and other important virulence determinants in Staphylococcus aureus. A summary of the literature regarding the use of adjunctive protein synthesis inhibitors for toxin suppression in the setting of S. aureus infections is presented.

CASSETTE-clindamycin adjunctive therapy for severe Staphylococcus aureus treatment evaluation: study protocol for a randomised controlled trial

BACKGROUND

Exotoxins are important virulence factors in Staphylococcus aureus. Clindamycin, a protein synthesis inhibitor antibiotic, is thought to limit exotoxin production and improve outcomes in severe S. aureus infections. However, randomised prospective data to support this are lacking.

METHODS

An open-label, multicentre, randomised controlled trial (RCT) will compare outcome differences in severe S. aureus infection between standard treatment (flucloxacillin/cefazolin in methicillin-susceptible S. aureus; and vancomycin/daptomycin in methicillin-resistant S. aureus) and standard treatment plus an additional clindamycin given for 7 days. We will include a minimum of 60 participants (both adult and children) in the pilot study. Participants will be enrolled within 72 h of an index culture. Severe infections will include septic shock, necrotising pneumonia, or multifocal and non-contiguous skin and soft tissue/osteoarticular infections. Individuals who are immunosuppressed, moribund, with current severe diarrhoea or Clostridiodes difficile infection, pregnant, and those with anaphylaxis to β-lactams or lincosamides will be excluded. The primary outcomes measure is the number of days alive and free (1 or 0) of systemic inflammatory response syndrome (SIRS) within the first 14 days post randomisation. The secondary outcomes measure will include all-cause mortality at 14, 42, and 90 days, time to resolution of SIRS, proportion with microbiological treatment failure, and rate of change of C-reactive protein over time. Impacts of inducible clindamycin resistance, strain types, methicillin susceptibility, and presence of various exotoxins will also be analysed.

DISCUSSION

This study will assess the effect of adjunctive clindamycin on patient-centred outcomes in severe, toxin-mediated S. aureus infections. The pilot study will provide feasibility for a much larger RCT.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12617001416381p . Registered on 6 October 2017.

Lessons learned from a hospital-wide review of blood stream infections for paediatric central line-associated blood stream infection prevention

AIM

Bacteraemia episodes were assessed to calculate a hospital-wide central line-associated blood stream infection (CLABSI) rate per 1000 catheter-days. Secondary objectives were to describe risk factors, microbiology and outcomes of children with CLABSI.

METHODS

A retrospective study was conducted at an Australian tertiary paediatric hospital in children <18 years who had blood culture sampling during the 2-year period, 2014-2015. All blood culture results were extracted from the hospital's laboratory information system. National Healthcare Safety Network Centres for Disease Control and Prevention definitions for bacteraemia classification were used. Central venous access device (CVAD) insertion and removal dates were obtained from a surgical electronic database and anaesthetic records and then manually validated.

RESULTS

Of 11 774 processed blood culture bottles, 207 episodes of blood stream infection were observed. Eighty-five (41%) episodes were community-acquired bacteraemia (CA-B) and 122 (59%) health care-associated bacteraemia (HA-B), of which 73 (35%) were CLABSI. The hospital-wide CLABSI rate was 0.62 per 1000 catheter-days (95% confidence interval: 0.49-0.77). Conditions associated with CLABSI were malignancy (n = 45, 62%) and gastrointestinal failure (n = 6, 8%). Thirty-three (45%) CLABSI episodes developed in an outpatient setting.

CONCLUSIONS

HA-B has a significant impact on child health, exceeding the number of CA-B at our hospital. Children with CVADs are vulnerable in both the inpatient and outpatient settings. Collecting robust data for a hospital-wide CLABSI rate is important to understand the full spectrum of paediatric CLABSI. The value of validating data using both electronic and manual methods is demonstrated.

Infectious Diseases Clinician's Variation in the Management of Pediatric Staphylococcus aureus Bacteraemia and Equipoise for Clinical Trials

Background: Pediatric Staphylococcus aureus bacteraemia is one of the leading causes of community-acquired blood-stream infection in the developed world; however, our understanding of management practices by treating clinicians is limited. Methods: The authors designed a web-based clinician survey with support from the Australian and New Zealand Pediatric Infectious Diseases group, of the Australasian Society of Infectious Diseases. Clinicians were presented with three pediatric cases of varying severity. Antibiotic choice, durations of intravenous and oral therapy and research priorities for pediatric S. aureus bacteraemia trials were gauged. Results and Conclusion: Large variation in antibiotic prescribing amongst clinicians is demonstrated and increased, corresponding with escalating case complexity and persisting MRSA bacteraemia. Most clinicians chose defining optimal duration of therapy for S. aureus bacteraemia as their top clinical trial priority. These findings highlight the importance of prioritizing pediatric S. aureus bacteraemia clinical trials, to inform guidelines and best practice management.

Infection characteristics and treatment of Staphylococcus aureus bacteraemia at a tertiary children's hospital

BACKGROUND

Staphylococcus aureus bacteraemia (SAB) causes considerable morbidity and mortality in children. Despite this, its epidemiology and risk factors are poorly understood, with minimal paediatric clinical trial data available to guide clinicians in management. We conducted a pilot study to characterise SAB and validate a severity classification for use in future clinical trials.

METHODS

Patients with SAB were prospectively identified at Princess Margaret Hospital for Children (Perth, Western Australia) from May 2011 to December 2013. Retrospective data were collected from clinical and laboratory records. Cases were classified based on a priori defined criteria as simple (single or contiguous, peripheral site focus) or complex (multi-site, deep tissue, no focus or sepsis) and tested against risk factors and markers of severity of infection.

RESULTS

There were 49 cases of SAB (median age 7.7 years), with classification as simple (n = 30, 61%) and complex (n = 19, 39%) respectively. There were no deaths or relapses in our cohort. Only 10% of isolates were methicillin resistant S. aureus (MRSA), and none of these were healthcare-associated. Age, gender, Indigenous status, MRSA and healthcare-associated infections were not predictive of complex infection. Pre-existing malignancy was a risk factor for complex infection (p = 0.02). Complex infections were associated with a higher median maximum C reactive protein (216 mg/L vs 50 mg/L, p = < 0.001), longer median length of stay (42 vs 10 days, p = < 0.001) and longer duration of antibiotic therapy (43 vs 34 days, p = 0.03).

DISCUSSION

This is the first attempt to categorise paediatric SAB as simple versus complex, to guide clinicians in decision making.

CONCLUSIONS

There is a wide spectrum of disease severity in paediatric SAB, with maximum CRP, length of stay, and duration of therapy greater in those with complex disease. Distinct cohorts with simple and complex courses which may be a target for future clinical trials have been described.

Manual therapy, exercise therapy, or both, in addition to usual care, for osteoarthritis of the hip or knee. 2: economic evaluation alongside a randomized controlled trial

OBJECTIVE

To evaluate the cost effectiveness of manual physiotherapy, exercise physiotherapy, and a combination of these therapies for patients with osteoarthritis of the hip or knee.

METHODS

206 Adults who met the American College of Rheumatology criteria for hip or knee osteoarthritis were included in an economic evaluation from the perspectives of the New Zealand health system and society alongside a randomized controlled trial. Resource use was collected using the Osteoarthritis Costs and Consequences Questionnaire. Quality-adjusted life years (QALYs) were calculated using the Short Form 6D. Willingness-to-pay threshold values were based on one to three times New Zealand's gross domestic product (GDP) per capita of NZ$ 29,149 (in 2009).

RESULTS

All three treatment programmes resulted in incremental QALY gains relative to usual care. From the perspective of the New Zealand health system, exercise therapy was the only treatment to result in an incremental cost utility ratio under one time GDP per capita at NZ$ 26,400 (-$34,081 to $103,899). From the societal perspective manual therapy was cost saving relative to usual care for most scenarios studied. Exercise therapy resulted in incremental cost utility ratios regarded as cost effective but was not cost saving. For most scenarios combined therapy was not as cost effective as the two therapies alone.

CONCLUSIONS

In this study, exercise therapy and manual therapy were more cost effective than usual care at policy relevant values of willingness-to-pay from both the perspective of the health system and society. Trial registration number Australian New Zealand Clinical Trials Registry ACTRN12608000130369.

Age, cohort and period effects on hip fracture incidence: analysis and predictions from New Zealand data 1974-2007

Hip fractures are substantial problem worldwide. The increase in rate with age does not continue into very old age. Rates decline in successive birth cohorts. If the increasing trend in period effect continues, there will be a substantial increase in hip fracture incidence.

INTRODUCTION

The purpose of this study is to (1) determine incidence rates for fracture neck of femur (FNF) for the period 1974-2007, (2) estimate age, cohort, and period effects, and (3) predict the burden of FNF in 2025.

METHODS

Age adjusted incidence rates were estimated using New Zealand hospital discharge data for 1974-2007. Age-period-cohort modeling was used to estimate individual effects of these factors after adjusting for the other two factors. Future fracture burden was estimated under two scenarios.

RESULTS

Age-adjusted rates for women increased from 1974 to 1987 whereas rates for men have increased from 1974 until 2007. Risk increased from 70 years of age but dropped among the very elderly. Period effects showed a steady increase in risk throughout 1974-2007. In contrast, the risk was lower in later cohorts. If there is no change in the period effect from 2007 we estimate a reduction in the burden of illness from FNF, especially for women. However if the period effect continues to increase, there will be substantial increases in FNF incidence, especially for men.

CONCLUSIONS

The effect of population aging on FNF incidence is predictable because projections are based on an existing population. The increasing health and improvement in measures of physical status of older people through the last century, explain the decline in FNF incidence in later cohorts. The steady increase in period effect may be due to increased survival of the very frail. This burden of illness resulting from FNFs must be addressed by population based, research proven approaches to fall and fracture prevention.

A High-Pressure Test of Birch's Law

The compressional wave velocities of polycrystalline NaCl and KCl have been measured to over 17 gigapascals, with the use of Brillouin scattering and the diamond anvil cell. This pressure corresponds to 40% compression for NaCl and 60% compression for KCl (including the volume change across the B1-B2 transition). The data obey Birch's Law, which predicts that the velocity of each material is linear with density, except across the B1-B2 phase transition in KCl. This deviation from Birch's Law can be rationalized in terms of an interatomic potential model wherein the vibrational frequencies of the nearest neighbor bonds decrease when going to the eight-coordinated B2 structure from the six-coordinated B1 structure.

Continuous positive airway pressure in heart failure patients with obstructive sleep apnoea

BACKGROUND

The aim of the study was to study the effect of 6 months of continuous positive airway pressure (CPAP) in community heart failure (HF) patients with obstructive sleep apnoea (OSA).

METHODS

Clinically stable outpatients with HF and OSA (left ventricular ejection fraction (LVEF) <45%, apnoea/hypopnoea index >15/h, n = 19) treated with CPAP and a control group (LVEF <45%, apnoea/hypopnoea index <10/h, n = 7) were compared at baseline and at 6 months by Minnesota heart failure score, Epworth sleepiness score, shuttle walk distance, brain natriuretic peptide, urinary catecholamines and echocardiographic indices using paired t-test, McNemar's tests and effect sizes.

RESULTS

In HF patients with OSA, CPAP improved LVEF (35.9 +/- 6.1% to 40.6 +/- 8.0%, P = 0.015), decreased LV end-systolic volume (152 +/- 74 to 135 +/- 62 cm(3), P = 0.03), systolic blood pressure (P = 0.04) and sleepiness (Epworth sleepiness score 8.8 +/- 4.8 to 6.3 +/- 3.2, P = 0.01), whereas walk distance, catecholamines, brain natriuretic peptide levels and symptoms were unchanged. These outcomes did not change in the HF control group.

CONCLUSION

In community HF patients with OSA, CPAP therapy over 6 months improved LVEF, systolic blood pressure and sleepiness, but not sympathetic activation, brain natriuretic peptide or exercise levels. Acceptance was relatively low, potentially limiting therapeutic effectiveness.

Reducing hazard related falls in people 75 years and older with significant visual impairment: how did a successful program work?

BACKGROUND

In a randomized controlled trial testing a home safety program designed to prevent falls in older people with severe visual impairment, it was shown that the program, delivered by an experienced occupational therapist, significantly reduced the numbers of falls both at home and away from home.

OBJECTIVES

To investigate whether the success of the home safety assessment and modification intervention in reducing falls resulted directly from modification of home hazards or from behavioral modifications, or both.

METHODS

Participants were 391 community living women and men aged 75 years and older with visual acuity 6/24 meters or worse; 92% (361 of 391) completed one year of follow up. Main outcome measures were type and number of hazards and risky behavior identified in the home and garden of those receiving the home safety program, compliance with home safety recommendations reported at six months, location of all falls for all study participants during the trial, and environmental hazards associated with each fall.

RESULTS

The numbers of falls at home related to an environmental hazard and those with no hazard involved were both reduced by the home safety program (n = 100 participants) compared with the group receiving social visits (n = 96) (incidence rate ratios = 0.40 (95% confidence interval, 0.21 to 0.74) and 0.43 (0.21 to 0.90), respectively).

CONCLUSIONS

The overall reduction in falls by the home safety program must result from some mechanism in addition to the removal or modification of hazards or provision of new equipment.

An observational study of changes to long-term medication after admission to an intensive care unit

Many patients admitted to intensive care units consume long-term medication. New drugs may be commenced during intensive care intended for the short term or longer. Patients are often cared for by several teams during hospital admission and long-term medication may inadvertently be permanently discontinued. Following admission, new therapies relevant only in the short term could be continued beyond intensive care and hospital discharge. We conducted a retrospective analysis of drug prescription by examining patients' notes and charts before, during and after intensive care admission. Of 197 drugs prescribed up to intensive care admission to 59 patients, 112 (57%) were stopped. Ninety-nine of these were not reintroduced by intensive care discharge and 34 were not reintroduced by hospital discharge. Of 154 drugs commenced during intensive care, 96 (62%) had no listed reason for their introduction. Twenty-eight were continued beyond hospital discharge, some without apparent ongoing indication. Reliable mechanisms to prevent prescription errors are required.

Continuous positive airway pressure reduces daytime sleepiness in mild to moderate obstructive sleep apnoea: a meta-analysis

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) affects an estimated 2-4% of the middle aged population. Meta-analyses of randomised controlled trials have shown that the severe presentation of the syndrome (apnoea hypopnoea index (AHI) >30/hour) is effectively treated with continuous positive airway pressure (CPAP). Until recently there have been insufficient data to determine whether CPAP improves sleepiness in the larger subgroup with mild to moderate OSAS (AHI 5-30/hour).

METHODS

A systematic search of Medline and a hand search identified seven randomised controlled trials where CPAP was compared with either a placebo or with conservative management in the treatment of mild to moderate OSAS (AHI 5-30/hour). All trials used the Epworth Sleepiness Scale (ESS), four used the Multiple Sleep Latency Test (MSLT), and three used the Maintenance of Wakefulness Test (MWT) to measure sleepiness.

RESULTS

Meta-analyses indicated that CPAP significantly reduced subjective daytime sleepiness (ESS) by 1.2 points (95% CI 0.5 to 1.9, p = 0.001), improved objective daytime wakefulness (MWT) by 2.1 minutes (95% CI 0.5 to 3.7, p = 0.011), but did not affect objective daytime sleepiness (MSLT, mean benefit -0.2 minutes, 95% CI -1.0 to 0.6, p = 0.6). The two significant effects were small (effect size <0.30).

CONCLUSIONS

CPAP elicits small improvements in subjective sleepiness and objective wakefulness in people with mild to moderate OSAS. However, the effects on sleepiness are of limited clinical significance.

Randomised controlled crossover trial of humidified continuous positive airway pressure in mild obstructive sleep apnoea

BACKGROUND

It is unclear whether continuous positive airway pressure (CPAP), the treatment of choice for severe obstructive sleep apnoea (OSA), is effective at improving outcomes in mild OSA.

METHODS

To help define the role of humidified CPAP in mild OSA, a randomised crossover study was undertaken of patients with an apnoea hypopnoea index (AHI) of 5-30/hour. Subjective sleepiness, objective wakefulness, mood, reaction time, and quality of life were measured at baseline, after 3 weeks treatment with humidified CPAP and 3 weeks sham CPAP (2 week washout).

RESULTS

Twenty nine of 31 enrolled patients (age 25-67 years, seven women, mean (SD) body mass index 31.5 (6) kg/m2) completed the protocol. Humidified CPAP improved polysomnographic indices of OSA and Epworth Sleepiness Scale (2.4 points (95% CI 0.6 to 4.2)). Objective wakefulness (modified maintenance of wakefulness test) showed a trend towards improvement (5.2 minutes (95% CI -0.6 to 11)). Mood (Hospital Anxiety and Depression Scale), quality of life (SF 36, Functional Outcomes of Sleep Questionnaire), and reaction times (Psychomotor Vigilance Task) were not improved more than sham CPAP. Compliance with humidified and sham CPAP both averaged 4.9 hours/night. Placebo effects were evident in many outcomes and there was no clear treatment preference.

CONCLUSIONS

Humidified CPAP improves subjective sleepiness and possibly objective wakefulness but not reaction times, quality of life, or mood. These results do not support the routine use of CPAP in all patients with mild OSA, but offers some support for the trialling of CPAP in those with severe sleepiness.

Favourable outcome for patients with myeloid disorders treated with fludarabine-melphalan reduced-intensity conditioning and allogeneic bone marrow stem cell transplantation without the use of T-lymphocyte-depleting antibodies

We report the use of reduced-intensity conditioning (RIC)-matched sibling allogeneic bone marrow stem cell transplantation as a method of establishing a graft-vs.-leukaemia (GvL) effect against myeloid disorders using a fludarabine-melphalan protocol without the use of T-lymphocyte-depleting antibodies. The 16 patients in this group had predominantly poor-risk acute myeloid leukaemia (AML) (n=10), AML/myelodysplasia (MDS) (n=2) and MDS (n=4). All but one patient achieved full haematopoietic engraftment. Thirteen of 16 patients are alive and in continued complete remission on completion of this study with a median follow-up of 426 d (range 83-1524). The actuarial 4 yr disease-free and overall survival is 79% for both. Only one patient relapsed following transplant, giving a relapse rate of 6% during the study period. The treatment-related mortality was 13% (n= 2). Overall, acute graft-vs.-host disease (GvHD) occurred in 53% (8/15), with acute GvHD grade II or above occurring in 47% (7/15). In the 13 evaluable patients, chronic GvHD occurred in 46% (6/13), with this being extensive in three patients. These results suggest that a GvL effect can be delivered against poor-risk myeloid disorders with a low non-relapse mortality using this fludarabine-melphalan RIC protocol.

Fractal characteristics of breath to breath timing in sleeping infants

We examined interbreath interval (IBI) time series of 19 term infants during active and quiet sleep for fractal properties using Fano factor analysis. For each time series we calculated the fractal exponent (alpha), comparing alpha for the original time series with two forms of surrogate data, a temporally independent surrogate set and an autoregressive surrogate set. alpha values were normally distributed between 0.79 and -0.22, and did not differ with sleep state. The fractal characteristics of the original time series were not retained in the temporally independent surrogate time series indicating that the distribution of intervals alone was not fractal, but were retained using autoregressive surrogates with an order of 10, suggesting that the fractal properties of the IBI time series were related to correlations between successive breaths. These observations suggest that some of the respiratory variability that occurs during sleep in infants, which in the past has been regarded as stochastic noise, may be the product of deterministic processes.

Humidified nasal continuous positive airway pressure in obstructive sleep apnoea

Heated humidification of nasal continuous positive airway pressure (nCPAP) reduces upper airway symptoms and improves initial use in obstructive sleep apnoea syndrome (OSAS). The present study aimed to assess the effect of heated humidification of nCPAP on upper airway symptoms and initial use in obstructive sleep apnoea. This study was of a randomised, crossover design. Subjects with polysomnographically confirmed OSAS were randomised to 3 weeks nCPAP treatment with heated humidification (nCPAP-humid) or placebo humidification (nCPAP pl-humid). Objective and subjective nCPAP use, upper airway symptoms, and treatment satisfaction were compared. Thirty seven of 42 patients completed the protocol. nCPAP-humid reduced the frequency of adverse upper airway symptoms. nCPAP use over 3 weeks was greater with nCPAP-humid compared with nCPAP pl-humid. No difference was found between the treatment arms in terms of subjective treatment satisfaction or alertness. Heated humidification of nasal continuous positive airway pressure reduces upper airway symptoms and is associated with a small increase in initial use but not subjective sleepiness or treatment satisfaction. The results support the use of heated humidification as a strategy to reduce side-effects related to continuous positive airway pressure but not routine initial use.

Economic evaluation of a community based exercise programme to prevent falls

OBJECTIVE

To assess the incremental costs and cost effectiveness of implementing a home based muscle strengthening and balance retraining programme that reduced falls and injuries in older women.

DESIGN

An economic evaluation carried out within a randomised controlled trial with two years of follow up. Participants were individually prescribed an exercise programme (exercise group, n=116) or received usual care and social visits (control group, n=117).

SETTING

17 general practices in Dunedin, New Zealand.

PARTICIPANTS

Women aged 80 years and older living in the community and invited by their general practitioner to take part.

MAIN OUTCOME MEASURES

Number of falls and injuries related to falls, costs of implementing the intervention, healthcare service costs resulting from falls and total healthcare service costs during the trial. Cost effectiveness was measured as the incremental cost of implementing the exercise programme per fall event prevented.

MAIN RESULTS

27% of total hospital costs during the trial were related to falls. However, there were no significant differences in health service costs between the two groups. Implementing the exercise programme for one and two years respectively cost $314 and $265 (1995 New Zealand dollars) per fall prevented, and $457 and $426 per fall resulting in a moderate or serious injury prevented.

CONCLUSIONS

The costs resulting from falls make up a substantial proportion of the hospital costs for older people. Despite a reduction in falls as a result of this home exercise programme there was no significant reduction in healthcare costs. However, the results reported will provide information on the cost effectiveness of the programme for those making decisions on falls prevention strategies.

Biphasic response of NK cells expressing both activating and inhibitory killer Ig-like receptors

NK cells can co-express inhibitory and activating killer Ig-like receptors (KIR) recognizing the same HLA class I ligand. We present evidence from experiments with NK cells expressing both activating (KIR2DS2) and inhibitory (KIR2DL2 and KIR2DL3) receptors that the activating KIR can function without apparent interference from the inhibitory KIR. These studies used CD158b mAb that is equally reactive with KIR2DS2, KIR2DL2 and KIR2DL3. First, we show using plastic-immobilized CD158b mAb that the activating KIR2DS2 is stimulated, resulting in NK cell division and degranulation. Second, we show using soluble CD158b mAb and FcRII (+) P815 cells that high concentrations of CD158b mAb trigger the inhibitory KIR, whereas low concentrations stimulate the activating KIR2DS2 resulting in NK cell division and cytolysis. These results demonstrate that the activating KIR2DS2 can function on cells co-expressing the inhibitory KIR2DL2 and/or KIR2DL3, indicating the potential for independent function of activating KIR with natural ligand.