Updated Parameters for Listeria monocytogenes Dose-Response Model Considering Pathogen Virulence and Age and Sex of Consumer.

Better knowledge regarding the Listeria monocytogenes dose-response (DR) model is needed to refine the assessment of the risk of foodborne listeriosis. In 2018, the European Food Safety Agency (EFSA) derived a lognormal Poisson DR model for 14 different age-sex sub-groups, marginally to strain virulence. In the present study, new sets of parameters are developed by integrating the EFSA model for these sub-groups together with three classes of strain virulence characteristics ("less virulent", "virulent", and "more virulent"). Considering classes of virulence leads to estimated relative risks (RRs) of listeriosis following the ingestion of 1000 bacteria of "less virulent" vs. "more virulent" strains ranging from 21.6 to 24.1, depending on the sub-group. These relatively low RRs when compared with RRs linked to comorbidities described in the literature suggest that the influence of comorbidity on the occurrence of invasive listeriosis for a given exposure is much more important than the influence of the virulence of the strains. The updated model parameters allow better prediction of the risk of invasive listeriosis across a population of interest, provided the necessary data on population demographics and the proportional contribution of strain virulence classes in food products of interest are available. An R package is made available to facilitate the use of these dose-response models.

Microbiological Quality of Australian Beef, Sheep and Pork Carcases, Cuts and Offals.

A one-year survey was undertaken of the microbiological quality of carcases and the derived primal cuts, manufacturing meat and offals at twelve Australian export establishments (six beef, three sheep/lamb and three pork). A total of 27,157 microbiological results for aerobic plate count (APC) and generic Escherichia coli were gathered, 15,155 from beef, 8405 from sheep and 3597 from pig establishments. The mean log10 APCs on beef, sheep and pig carcases were 0.84, 1.60 and 1.30 log10 cfu/cm2, respectively. For primals, the mean log10 APC was higher for beef but was similar for sheep and pork primals, with 'outside' cuts having higher counts. For manufacturing meat, the concentration was 2-3 log10 cfu/g, irrespective of species. The prevalence (%) of generic E. coli from beef, sheep and pork was 2.3, 28.4 and 5.4 on carcases; 7.0, 20.6 and 3.2 on primals; and 5.8, 33.6 and 6.1 on manufacturing meat, respectively. The mean log10 APCs of beef, sheep and pork offal were 3.23, 3.18 and 3.37 log10 cfu/g, with tripes and tongues having APCs 1-2 log10 units higher than organ offals. The results reflect improvements in total bacterial loadings compared with previous national baseline surveys.

Risk Assessment of Pectenotoxins in New Zealand Bivalve Molluscan Shellfish, 2009-2019.

Pectenotoxins (PTXs) are produced by Dinophysis spp., along with okadaic acid, dinophysistoxin 1, and dinophysistoxin 2. The okadaic acid group toxins cause diarrhetic shellfish poisoning (DSP), so are therefore regulated. New Zealand currently includes pectenotoxins within the DSP regulations. To determine the impact of this decision, shellfish biotoxin data collected between 2009 and 2019 were examined. They showed that 85 samples exceeded the DSP regulatory limit (0.45%) and that excluding pectenotoxins would have reduced this by 10% to 76 samples. The incidence (1.3%) and maximum concentrations of pectenotoxins (0.079 mg/kg) were also found to be low, well below the current European Food Safety Authority (EFSA) safe limit of 0.12 mg/kg. Inclusion within the DSP regulations is scientifically flawed, as pectenotoxins and okadaic acid have a different mechanism of action, meaning that their toxicities are not additive, which is the fundamental principle of grouping toxins. Furthermore, evaluation of the available toxicity data suggests that pectenotoxins have very low oral toxicity, with recent studies showing no oral toxicity in mice dosed with the PTX analogue PTX2 at 5000 µg/kg. No known human illnesses have been reported due to exposure to pectenotoxins in shellfish, a fact which combined with the toxicity data indicates that they pose negligible risk to humans. Regulatory policies should be commensurate with the level of risk, thus deregulation of PTXs ought to be considered, a stance already adopted by some countries.

The Normal Fetal Cephalic Index in the Second and Third Trimesters of Pregnancy.

The cephalic index (CI) is used in the evaluation of individuals with craniosynostosis. There is little agreement as to the normal range and stability of the CI during the fetal period, partly due to limited literature. We sought to determine the range, distribution and stability of the fetal CI in the second half of pregnancy. We also aimed to identify any relationship to delivery complications such as obstructed labor and malpresentation.The fetal head circumference, biparietal diameter (BPD) and occipitofrontal diameter (OFD) measurements were obtained from standard ultrasound images. Each of 4304 fetuses had measurements taken at morphology scan performed between 17 and 22 weeks' gestation, and at growth scanning at 28 to 33 weeks' gestation. The cephalic index was calculated using the formula: CI = BPD/OFD × 100. The distribution of the CI at both scans is very close to a normal distribution. The mean CI at 17 to 22 weeks was 75.9 (SD, 3.7); the mean CI at 28 to 33 weeks was 77.8 (SD, 3.5). The mean change in CI was 1.9 (SD, 4.28), which is not statistically significantly different from zero (t = 0.656, P = 0.512, 95% confidence interval). No relationship was found between the CI in normal fetuses and delivery complications. There is a wide variation in the change in CI in the third trimester. A value below the normal range in the third trimester or a progressive reduction in CI during the latter half of pregnancy should provoke detailed scanning of the fetal cranial sutures to check for craniosynostosis.

Sonographic indicators of isolated fetal sagittal craniosynostosis during pregnancy.

INTRODUCTION: The antenatal diagnosis of sagittal craniosynostosis can be challenging, but there are several published papers describing a traumatic outcome to both the affected fetus and the mother during delivery of a scaphocephalic child. The antenatal imaging from affected children was collected along with the mother's obstetric history. The aim of this study was to identify antenatal ultrasound features that may assist the diagnosis of sagittal synostosis before birth, to enable appropriate delivery planning and avoid both maternal and fetal trauma during birth. METHODS: Antenatal ultrasound scans in both the second and third trimesters were traced for 36 children with sagittal synostosis. The initially diagnostic CT scans were also sourced. A delivery history was collected from the hospital case notes where available. RESULTS: The affected group showed a statistically significant reduction in cephalic index during the second half of pregnancy compared with the normal population which became slightly more brachycephalic (P = 0.001). Regression analysis showed an average reduction in cephalic index of 0.57 units per month. There was also a much higher rate of malpresentation and surgical deliveries in the affected group than the normal population. There was a relationship between sagittal craniosynostosis and breech presentation and an associated higher rate of surgical deliveries. CONCLUSION: It is possible to detect sagittal synostosis in the third trimester of pregnancy which may assist with delivery planning.

Regional versus metropolitan pancreaticoduodenectomy mortality in Australia.

BACKGROUND: This retrospective, population-based cohort study aims to determine if differences in the regional distribution of procedures or variation in regional mortality contributes to the variable pancreaticoduodenectomy (PD) mortality between Australian states and territories. METHODS: De-identified procedural data from public hospitals between 1 July 2005 and 30 June 2015 from the Australian Institute of Health and Welfare were analysed. The regional distribution of procedures and variation in perioperative mortality rate (POMR) were investigated in New South Wales (NSW), Victoria and Queensland (QLD) using logistic regression analysis. RESULTS: NSW performed the highest proportion of city-based procedures (93.8%) while QLD performed the highest proportion of regional procedures (15.3%). QLD demonstrated the lowest city mortality (1.9%) and lowest POMR overall (2.0%). City, regional and state-wide mortality was highest in NSW (5.0%, 8.4% and 5.3%). No significant difference in POMR was demonstrated between regional and city hospitals in each of the states (P = 0.46) or across all states (P = 0.50). CONCLUSION: This study demonstrates comparable regional PD distribution across Australia. The difference in PD POMR between city and regional areas was not found to be statistically significant. NSW exhibited the highest city, regional and overall PD POMR, potentially warranting further investigation.

Comparison of postmortem inspection procedures for detecting caseous lymphadenitis of Australian sheep and goats.

Alternative postmortem inspection procedures for the detection of gross abnormalities due to Caseous Lymphadenitis (CLA) of sheep and goats were compared quantitatively against the current Australian Standard (AS4696). Studies on sheep and goats in Australia during 2016 addressed data gaps regarding current prevalence, combinations of multiple lesions within affected carcases and sensitivity of inspection procedures enabling a comparison of alternative with current procedures. Using these contemporary inspection data from 54 915 sheep and 48 577 goats a desktop study estimated the effect of implementing alternative procedures of reduced palpation from eleven carcase sites to the four sites most commonly affected. Under current procedures it was estimated that 86 sheep and 34 goat carcases with CLA lesions are missed per 10,000 carcases. Under alternative procedures it is estimated that an additional 48.4 sheep and 10.5 goat carcases with CLA lesions would be missed per 10 000 carcases. Of these, 38.2 sheep and 5.6 goat per 10 000 carcases would contain CLA only in routinely discarded, non-edible tissue sites. Hence, only an additional 10.2 sheep and 4.9 goat carcases per 10 000 inspected, with CLA in edible tissue sites are estimated to be missed. These alternative procedures have now been officially implemented in the Australian domestic standard.

Panoramic radiography is of limited value in the evaluation of maxillary sinus disease.

OBJECTIVES: The aim of this study was to determine (1) the diagnostic efficacy of orthopantomography (OPG) in the diagnosis of sinus diseases by using cone beam computed tomography (CBCT) as the imaging gold standard, (2) which diseases can be diagnosed by using panoramic radiography or CBCT, and (3) the interobserver agreement of 2 experienced dental radiologists. STUDY DESIGN: The images of 714 individuals who underwent OPG and CBCT on the same day were assessed separately by 2 dental radiologists. The results were compared by using Gwet's AC1 statistical methods. RESULTS: In total, 1322 maxillary sinuses were imaged. The sensitivity of OPG for the detection of any maxillary sinus pathology was poor compared with CBCT, but the specificity was high. The sensitivity of OPG for detecting mucosal thickening was 36.7%. The positive predictive value of OPG for diagnosing mucosal thickening was 79.9 %, but the negative predictive value was 51.9%. Interobserver agreement was strong (≥0.912) for all lesions except mucosal thickening. CONCLUSIONS: Panoramic imaging has low efficacy in the diagnosis of sinus disease, even when examined by experienced dental radiologists. OPG can be useful in excluding disease, but 3-dimensional scanning is necessary for the definitive investigation of sinus lesions.

Quantitative Microbial Risk Assessment of Salmonellosis from the Consumption of Australian Pork: Minced Meat from Retail to Burgers Prepared and Consumed at Home.

Pork burgers could be expected to have an elevated risk of salmonellosis compared to other pork products due to their comminuted nature. A stochastic risk assessment was performed to estimate the risk of salmonellosis from Australian pork burgers and considered risk-affecting factors in the pork supply chain from retail to consumption at home. Conditions modeled included prevalence and concentration of Salmonella in pork mince, time and temperature effects during retail, consumer transport, and domestic storage and the effect of cooking, with the probability of illness from consumption estimated based on these effects. The model was two-dimensional, allowing for the separation of variability and uncertainty. Potential changes to production practices and consumer behaviors were examined through alternative scenarios. Under current conditions in Australia, the mean risk of salmonellosis from consumption of 100 g pork burgers was estimated to be 1.54 × 10 - 8 per serving or one illness per 65,000,000 servings consumed. Under a scenario in which all pork mince consumed is served as pork burgers, and with conservative (i.e., worst-case) assumptions, 0.746 cases of salmonellosis per year from pork burgers in Australia were predicted. Despite the adoption of several conservative assumptions to fill data gaps, it is predicted that pork burgers have a low probability of causing salmonellosis in Australia.

Perioperative Mortality Following Oesophagectomy and Pancreaticoduodenectomy in Australia.

INTRODUCTION: Oesophagectomy (OG) and pancreaticoduodenectomy (PD) remain associated with significant perioperative mortality rates (POMR). Improved outcomes in high-volume centres have led to these procedures being centralised in some countries. This retrospective, population-based cohort study was conducted to determine the Australian national, and state and territory based POMR associated with OG and PD, and assess trends over time. METHODS: Logistic regression analysis was performed using de-identified procedural data between 1 July 2005 and 30 June 2013 from the Australian Institute of Health and Welfare. Codes relating to OG and PD contained in the Australian Classification of Health Interventions were used to extract patient data. Mortality rates were risk adjusted for age, gender and urgency of admission. Temporal trends and differences between states/territories were investigated. RESULTS: The average Australian POMR throughout the study period was 3.5 and 3.0% for OG and PD, respectively. OG POMR showed no significant change over time (P = 0.30) or variation between states (P = 0.079). The annual POMR associated with PD, however, showed a significant decrease during the study period (P = 0.01) with variation in PD POMR outcomes evident amongst different regions (P = 0.0004). CONCLUSION: This study demonstrates a comparable Australian PD and OG POMR when correlated with international studies. National PD POMR improved throughout the study with consistent improvement across the states and territories. This study does, however, show variation in PD POMR between states and territories. Potential intra-state variation merits further investigation.

Perioperative Mortality Following Bariatric Surgery in Australia.

BACKGROUND: Bariatric surgery is the most effective method of sustainable weight loss for the treatment of morbid obesity. Low mortality associated with these procedures has been reported internationally; however, Australian outcomes are yet to be published. Despite its efficacy, limited access to bariatric surgery exists in Australian public hospitals. This retrospective data analysis was conducted for two reasons. Firstly, to determine the perioperative mortality rate (POMR) associated with bariatric procedures in Australia, and secondly, to compare public and private hospital bariatric surgery admission demographics and outcomes. METHOD: A retrospective review of de-identified patient data from the National Hospital Morbidity Database, held by the Australian Institute of Health and Welfare (AIHW), was conducted using codes relating to bariatric procedures. POMR calculations were established using AIHW admission data from 1 July 2005 to 30 June 2013. RESULTS: From 1 July 2005 to 30 June 2013, 113,929 patient admissions occurred for patients undergoing a bariatric procedure. Thirty-nine deaths occurred nationally, with an overall average POMR of 0.03%. A higher POMR was associated with public admissions and secondary procedures. A higher proportion of secondary procedures were performed in public hospitals. Primary bariatric procedure incidence increased throughout the study period while secondary bariatric procedure incidence decreased. CONCLUSION: This study demonstrates the Australian bariatric procedure POMR to be substantially lower than internationally reported figures. Public hospitals were shown to perform far fewer bariatric procedures at a higher POMR than private hospitals. Public hospitals performed a higher proportion of secondary revision procedures.

Spatial and Temporal Distribution of Norovirus and E. coli in Sydney Rock Oysters Following a Sewage Overflow into an Estuary.

This paper reports a study of norovirus (NoV) GII distribution and persistence in Sydney rock oysters (SRO) (Saccostrea glomerata) located in an estuary after a pump station sewage overflow. SRO were strategically placed at six sites spanning the length of the estuary from the pump station to the sea. The spatial and temporal distribution of NoV, hepatitis A virus (HAV) and Escherichia coli (E. coli) in oysters was mapped after the contamination event. NoV GI and GII, HAV and E. coli were quantified for up to 48 days in oysters placed at six sites ranging from 0.05 to 8.20 km from the sewage overflow. NoV GII was detected up to 5.29 km downstream and persisted in oysters for 42 days at the site closest to the overflow. NoV GII concentrations decreased significantly over time; a reduction rate of 8.5% per day was observed in oysters (p < 0.001). NoV GII concentrations decreased significantly as a function of distance at a rate of 5.8% per km (p < 0.001) and the decline in E. coli concentration with distance was 20.1% per km (p < 0.001). HAV and NoV GI were not detected. A comparison of NoV GII reduction rates from oysters over time, as observed in this study and other published research, collectively suggest that GII reduction rates from oysters may be broadly similar, regardless of environmental conditions, oyster species and genotype.

National surgical mortality audit may be associated with reduced mortality after emergency admission.

BACKGROUND: The Western Australian Audit of Surgical Mortality was established in 2002. A 10-year analysis suggested it was the primary driver in the subsequent fall in surgeon-related mortality. Between 2004 and 2010 the Royal Australasian College of Surgeons established mortality audits in other states. The aim of this study was to examine national data from the Australian Institute of Health and Welfare (AIHW) to determine if a similar fall in mortality was observed across Australia. METHOD: The AIHW collects procedure and outcome data for all surgical admissions. AIHW data from 2005/2006 to 2012/2013 was used to assess changes in surgical mortality. RESULTS: Over the 8 years surgical admissions increased by 23%, while mortality fell by 18% and the mortality per admission fell by 33% (P < 0.0001). A similar decrease was seen in all regions. The mortality reduction was overwhelmingly observed in elderly patients admitted as an emergency. CONCLUSION: The commencement of this nation-wide mortality audit was associated with a sharp decline in perioperative mortality. In the absence of any influences from other changes in clinical governance or new quality programmes it is probable it had a causal effect. The reduced mortality was most evident in high-risk patients. This study adds to the evidence that national audits are associated with improved outcomes.

Perioperative Mortality Rates in Australian Public Hospitals: The Influence of Age, Gender and Urgency.

INTRODUCTION: A decline in surgical deaths has been observed in Australia since the introduction of the Australian and New Zealand Audit of Surgical Mortality (ANZASM). The current study was conducted to determine whether the perioperative mortality rate (POMR) has also declined. METHODS: This study is a retrospective review of the POMR for surgical procedures in Australian public hospitals between July 2009 and June 2013, using data obtained from the Australian Institute of Health and Welfare. Operative procedures contained in the Australian Refined Diagnosis Related Groups were selected and the POMR was modelled using urgency of admission, age and gender as explanatory covariates. RESULTS: The POMR in Australian public hospitals reduced by 15.4 % over the 4-year period. The emergency admissions POMR dropped from 1.40 to 1.12 %, and the elective admissions POMR from 0.09 to 0.08 %. The binary logistic regression model used to predict patient mortality showed emergency admissions to have a higher POMR than elective, being more evident at older ages. For emergency admissions, the difference in POMR between females and males increased with age, from about 55 years onwards, with females being lower. For elective surgeries, the difference between males and females was of little practical importance across ages. CONCLUSIONS: The reduction in the POMR in Australia confirms the reduction in surgical deaths reported to ANZASM. Continuing to monitor POMR will be important to ensure the safest surgery in Australia. Further investigations into case-mix will allow better risk adjustment and comparison between regions and time-periods, to facilitate continuous quality improvement.

Australian seafood compositional profiles: A pilot study. Vitamin D and mercury content.

Given the scarcity of comprehensive nutritional data for Australia's >400 commercially produced seafood species a pilot study was undertaken to collect and analyse 22 species of wild and aquaculture seafood in order to develop a model for future comprehensive surveys. The species analysed were: Atlantic salmon, Australian sardine, prawn (six species), barramundi, abalone (three species), blue sprat, burrowing blackfish, gummy shark, oyster (four species), ocean trout and yellowtail kingfish. The analyses undertaken in this pilot study were: moisture, protein, total fat, cholesterol, fatty acids, vitamin C, vitamins A and D, and 21 mineral elements (including total mercury and methyl mercury). The data reported here are for vitamin D and mercury only. Comprehensive data have already been published elsewhere. Issues identified that should be addressed prior to undertaking a more extensive and representative study of the remaining major edible commercial Australian seafood species include: choice of samples and nutrients for analysis, facilities for sample handling and storage, data management and scrutiny, and laboratory quality control.

Effect of Sampling Plans on the Risk of Escherichia coli O157 Illness.

Australia exports about 150,000 to 200,000 tons of manufacturing beef to the United States annually. Each lot is tested for Escherichia coli O157 using the N-60 sampling protocol, where 60 small pieces of surface meat from each lot of production are tested. A risk assessment of E. coli O157 illness from the consumption of hamburgers made from Australian manufacturing meat formed the basis to evaluate the effect of sample size and amount on the number of illnesses predicted. The sampling plans evaluated included no sampling (resulting in an estimated 55.2 illnesses per annum), the current N-60 plan (50.2 illnesses), N-90 (49.6 illnesses), N-120 (48.4 illnesses), and a more stringent N-60 sampling plan taking five 25-g samples from each of 12 cartons (47.4 illnesses per annum). While sampling may detect some highly contaminated lots, it does not guarantee that all such lots are removed from commerce. It is concluded that increasing the sample size or sample amount from the current N-60 plan would have a very small public health effect.

Risk Assessment of Escherichia coli O157 illness from consumption of hamburgers in the United States made from Australian manufacturing beef.

We analyze the risk of contracting illness due to the consumption in the United States of hamburgers contaminated with enterohemorrhagic Escherichia coli (EHEC) of serogroup O157 produced from manufacturing beef imported from Australia. We have used a novel approach for estimating risk by using the prevalence and concentration estimates of E. coli O157 in lots of beef that were withdrawn from the export chain following detection of the pathogen. For the purpose of the present assessment an assumption was that no product is removed from the supply chain following testing. This, together with a number of additional conservative assumptions, leads to an overestimation of E. coli O157-associated illness attributable to the consumption of ground beef patties manufactured only from Australian beef. We predict 49.6 illnesses (95%: 0.0-148.6) from the 2.46 billion hamburgers made from 155,000 t of Australian manufacturing beef exported to the United States in 2012. All these illness were due to undercooking in the home and less than one illness is predicted from consumption of hamburgers cooked to a temperature of 68 °C in quick-service restaurants.

A national survey of marine biotoxins in wild-caught abalone in Australia.

The first national survey of Australian wild-caught abalone was conducted between September 2012 and December 2013. The aim of the survey was to determine the presence of paralytic shellfish toxins (PSTs), amnesic shellfish toxins (ASTs), and diarrhetic shellfish toxins (DSTs) in wild-caught abalone at levels above the current Codex marine biotoxin limits during the 2013 fishing season. Abalone (n = 190) were collected from 68 abalone-fishing blocks for which the combined annual harvest accounts for 80 % of Australian production. Concurrent seawater samples were collected and enumerated for potentially toxic phytoplankton. The foot and viscera tissues of each abalone sample were analyzed separately for PSTs, ASTs, and DSTs. No samples (abalone foot or viscera) contained toxins at levels exceeding the marine biotoxin limits stipulated by Codex. The resulting prevalence estimate suggests that less than 1.6 % of the commercially caught wild abalone population in Australia were contaminated with marine biotoxins at levels above the regulatory limit during the survey period. ASTs were detected at very low (trace) levels in the foot and viscera tissue of four and three abalone samples, respectively. To our knowledge, this represents the first reported detection of domoic acid in Australian abalone. PSTs also were detected at very low levels in 17 samples of abalone foot tissue and 6 samples of abalone viscera. The association between the low levels of ASTs and PSTs detected in abalone and the presence of potential toxin-producing phytoplankton in seawater samples was weak. DSTs were not detected in any abalone despite the detection of very low levels of DST-producing phytoplankton in a small number (9 of 77) of seawater samples. The results of this survey should be useful for public health risk assessments and provide additional evidence that the prevalence of marine biotoxins in Australian wild-caught abalone is very low.

A survey of Australian oysters for the presence of human noroviruses.

Impending international policies for norovirus in oysters and the lack of Australian data suggested there was a need to undertake a national survey of norovirus in oysters. Two geographically distinct oyster-growing areas from each of three Australian states were sampled on 4 occasions during 2010 and 2011. The sites selected were considered by state shellfish authorities to be the most compromised with respect to the potential for human faecal contamination as identified by shoreline surveys. The oysters were tested for norovirus GI, GII and Escherichia coli. Norovirus GII was detected in two of 120 (1.7%) samples and norovirus GI was not detected. One of the norovirus positive samples was cloned and sequenced as GII.3. Five of 120 (4.2%) samples were found to have more than the guidance concentration of 230 E. coli per 100 g of shellfish but these samples did not contain detectable concentrations of norovirus. The apparently low prevalence of norovirus in oysters from Australian growing areas supports epidemiological data that suggests norovirus contamination of Australian oysters is rare. The results from this study emphasise the need for future norovirus control measures for shellfish to be commensurate with the risk associated with the growing area.