The Effectiveness of Ultraviolet-C (UV-C) Irradiation on the Viability of Airborne Pseudomonas aeruginosa.

Pseudomonas aeruginosa (Pa) is the predominant bacterial pathogen in people with cystic fibrosis (CF) and can be transmitted by airborne droplet nuclei. Little is known about the ability of ultraviolet band C (UV-C) irradiation to inactivate Pa at doses and conditions relevant to implementation in indoor clinical settings. We assessed the effectiveness of UV-C (265 nm) at up to seven doses on the decay of nebulized Pa aerosols (clonal Pa strain) under a range of experimental conditions. Experiments were done in a 400 L rotating sampling drum. A six-stage Andersen cascade impactor was used to collect aerosols inside the drum and the particle size distribution was characterized by an optical particle counter. UV-C effectiveness was characterized relative to control tests (no UV-C) of the natural decay of Pa. We performed 112 tests in total across all experimental conditions. The addition of UV-C significantly increased the inactivation of Pa compared with natural decay alone at all but one of the UV-C doses assessed. UV-C doses from 246-1968 µW s/cm2 had an estimated effectiveness of approximately 50-90% for airborne Pa. The effectiveness of doses ≥984 µW s/cm2 were not significantly different from each other (p-values: 0.365 to ~1), consistent with a flattening of effectiveness at higher doses. Modelling showed that delivering the highest dose associated with significant improvement in effectiveness (984 µW s/cm2) to the upper air of three clinical rooms would lead to lower room doses from 37-49% of the 8 h occupational limit. Our results suggest that UV-C can expedite the inactivation of nebulized airborne Pa under controlled conditions, at levels that can be delivered safely in occupied settings. These findings need corroboration, but UV-C may have potential applications in locations where people with CF congregate, coupled with other indoor and administrative infection control measures.

Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults.

BACKGROUND: Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. METHODS: A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. RESULTS: The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. CONCLUSIONS: The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials.

Bacterial Profile, Multi-Drug Resistance and Seasonality Following Lower Limb Orthopaedic Surgery in Tropical and Subtropical Australian Hospitals: An Epidemiological Cohort Study.

We aimed to describe the epidemiology, multi-drug resistance and seasonal distribution of bacteria cultured within 12 months following lower limb orthopaedic surgery in tropical and subtropical Australian hospitals between 2010 and 2017. We collected data from four tropical and two subtropical hospitals. Categorical variables were examined using the Pearson Chi-squared test or Fisher's Exact test, and continuous variables with the Student t-test or Mann-Whitney U test. A Poisson regression model was used to examine the relationship between season, weather and the incidence of Staphylococcus and nonfermentative species. We found that at tropical sites, nonfermenters (Pseudomonas aeruginosa and Acinetobacter baumannii) were more common (28.7% vs. 21.6%, p = 0.018), and patients were more likely to culture multi-drug-resistant (MDR) nonfermenters (11.4% vs. 1.3%, p = 0.009) and MDR Staphylococcus aureus (35.9% vs. 24.6%, p = 0.006). At tropical sites, patients were more likely to be younger (65.9 years vs. 72.0, p = < 0.001), male (57.7% vs. 47.8%, p = 0.005), having knee surgery (45.3% vs. 34.5%, p = 0.002) and undergoing primary procedures (85.0% vs. 73.0%, p = < 0.001). Species were similar between seasons in both tropical and subtropical hospitals. Overall, we found that following lower limb orthopaedic surgery in tropical compared with subtropical Australia, patients were more likely to culture nonfermenters and some MDR species.

Locating "gold standard" evidence for simulation as a substitute for clinical practice in prelicensure health professional education: A systematic review.

AIMS AND OBJECTIVES: To extract, examine and report the highest available levels of evidence from healthcare disciplines in the use of simulation-based education as substitution for clinical placement in prelicensure programmes. BACKGROUND: Simulation is widely employed across prelicensure health professional education to create safe, realistic clinical learning experiences for students. Whether simulation can be employed to substitute for actual clinical placement, and if so, in what proportion, replacement ratio and duration, is unclear. METHODS: A systematic review and quality appraisal of primary studies related to prelicensure students in all health disciplines, guided by the PRISMA checklist. RESULTS: Ten primary studies were included, representing 2,370 students from three health disciplines in four countries. Nine studies were experimental and quasi-experimental and methodological quality was assessed as moderate to high with good to very good inter-rater agreement. Direct substitution of simulation for clinical practice ranged from 5% to 50%. With one exception, replacement ratios were 1:1 and duration of replacement ranged from 21 hr-2 years. Levels of evaluation included measures of reaction, knowledge and behaviour transfer; no negative outcomes were reported. We appraised practicalities for design of substitution, design limitations and knowledge transfer to accreditation standards for prelicensure programmes. CONCLUSIONS: This review synthesised highest levels and quality of available evidence for substitution of simulation for clinical placement in health professional education. Included studies were heterogenous in simulation interventions (proportion, ratio and duration) and in the evaluation of outcomes. Future studies should incorporate standardised simulation curricula, widen the health professions represented and strengthen experimental designs. RELEVANCE TO CLINICAL PRACTICE: Current evidence for clinical educational preparation does not appear to be translated into programme accreditation standards governing clinical practice experience for prelicensure programmes in relevant jurisdictions. Overall, a stronger evidence base is necessary to inform future curricula and policy development, to strengthen clinical practice in health.

Cystic fibrosis pathogens survive for extended periods within cough-generated droplet nuclei.

The airborne route is a potential pathway in the person-to-person transmission of bacterial strains among cystic fibrosis (CF) populations. In this cross-sectional study, we investigate the physical properties and survival of common non-Pseudomonas aeruginosa CF pathogens generated during coughing. We conclude that Gram-negative bacteria and Staphylococcus aureus are aerosolised during coughing, can travel up to 4 m and remain viable within droplet nuclei for up to 45 min. These results suggest that airborne person-to-person transmission is plausible for the CF pathogens we measured.

Estimation of the Blood Pressure Response With Exercise Stress Testing.

BACKGROUND: The blood pressure response to exercise has been described as a significant increase in systolic BP (sBP) with a smaller change in diastolic BP (dBP). This has been documented in small numbers, in healthy young men or in ethnic populations. This study examines these changes in low to intermediate risk of myocardial ischaemia in men and women over a wide age range. METHODS: Consecutive patients having stress echocardiography were analysed. Ischaemic tests were excluded. Manual BP was estimated before and during standard Bruce protocol treadmill testing. Patient age, sex, body mass index (BMI), and resting and peak exercise BP were recorded. RESULTS: 3,200 patients (mean age 58±12years) were included with 1,123 (35%) females, and 2,077 males, age range 18 to 93 years. Systolic BP increased from 125±17mmHg to 176±23mmHg. The change in sBP (ΔsBP) was 51mmHg (95% CI 51,52). The ΔdBP was 1mmHg (95% CI 1, 1), from 77 to 78mmHg, p<0.001). The upper limit of normal peak exercise sBP (determined by the 90th percentile) was 210mmHg in males and 200mmHg in females. The upper limit of normal ΔsBP was 80mmHg in males and 70mmHg in females. The lower limit of normal ΔsBP was 30mmHg in males and 20mmHg in females. CONCLUSIONS: In this large cohort, sBP increased significantly with exercise. Males had on average higher values than females. Similar changes were seen with the ΔsBP. The upper limit of normal for peak exercise sBP and ΔsBP are reported by age and gender.

Hysterosalpingo-foam sonography (HyFoSy): Tolerability, safety and the occurrence of pregnancy post-procedure.

BACKGROUND: Fallopian tube patency testing is an essential part of infertility evaluation. Hysterosalpingo-contrast sonography (HyCoSy) has been described as reliable, well tolerated and safe compared to other modalities such as laparoscopy and a dye test or hysterosalpingography. Limited availability of the previously used contrast has led to the introduction of a foam contrast agent as an alternative. AIMS: To assess the tolerability, safety and occurrence of pregnancy post-procedure of hysterosalpingo-foam sonography (HyFoSy). MATERIALS AND METHODS: A retrospective cohort study of women who had a HyFoSy at Queensland Ultrasound for Women from March 2013 to February 2015. A questionnaire was sent to their referring doctor to identify any complications or subsequent pregnancies with or without artificial reproductive technology (ART) within six months of the HyFoSy. RESULTS: Of 200 women, four cases were abandoned due to difficulty introducing the intracervical catheter, severe discomfort or a vasovagal episode. Response from referring doctors for 155 women reported no post-procedural complication. One hundred and eleven women were followed up for at least six months. Twenty-four out of 59 women (40.7%) who had ART and 24 out of 52 women (46.2%) who did not have ART conceived. Fifty percent of women who were nulligravida at the time of investigation, found to have at least one patent fallopian tube, whose partner had a normal semen analysis, spontaneously conceived within the time of follow up. CONCLUSIONS: HyFoSy is well tolerated and safe. A preponderance of pregnancies in the first month after HyFoSy suggests that a therapeutic effect may exist.

Determinants of Outcomes Following Resection for Pancreatic Cancer-a Population-Based Study.

BACKGROUND: Patient and health system determinants of outcomes following pancreatic cancer resection, particularly the relative importance of hospital and surgeon volume, are unclear. Our objective was to identify patient, tumour and health service factors related to mortality and survival amongst a cohort of patients who underwent completed resection for pancreatic cancer. METHODS: Eligible patients were diagnosed with pancreatic adenocarcinoma between July 2009 and June 2011 and had a completed resection performed in Queensland or New South Wales, Australia, with either tumour-free (R0) or microscopically involved margins (R1) (n = 270). Associations were examined using logistic regression (for binary outcomes) and Cox proportional hazards or stratified Cox models (for time-to-event outcomes). RESULTS: Patients treated by surgeons who performed <4 resections/year were more likely to die from a surgical complication (versus ≥4 resections/year, P = 0.04), had higher 1-year mortality (P = 0.03), and worse overall survival up to 1.5 years after surgery (adjusted hazard ratio 1.58, 95 % confidence interval 1.07-2.34). Amongst patients who had ≥1 complication within 30 days of surgery, those aged ≥70 years had higher 1-year mortality compared to patients aged <60 years. Adjuvant chemotherapy treatment improved recurrence-free survival (P = 0.01). There were no significant associations between hospital volume and mortality or survival. CONCLUSIONS: Systems should be implemented to ensure that surgeons are completing a sufficient number of resections to optimize patient outcomes. These findings may be particularly relevant for countries with a relatively small and geographically dispersed population.