Search

Objective: Estimate the presence of methicillin resistant Staphylococcus aureus (MRSA), extended beta‐lactamase (ESBL) producing Enterobacteriaceae, and vancomycin resistant enterococci (VRE) in bulk tank milk in dairy herds in New South Wales (NSW), Australia. Methods: Bulk tank milk samples (n = 80) were collected from dairy farms (n = 40, i.e. 2 per farm) in NSW during 2021. Bacteria were cultured using selective chromogenic indicator media with isolate identity confirmed using biochemical testing, Gram stain, and MALDI‐TOF mass spectroscopy. Antimicrobial resistance (AMR) was confirmed using antibiotic disk diffusion. Results: No samples tested positive to the targeted AMR organisms. Conclusion: The prevalence of MRSA, ESBL‐producing Enterobacteriaceae, and VRE is low in NSW dairy herds. [ABSTRACT FROM AUTHOR]

To support antimicrobial stewardship in livestock production, there is a growing array of point-of-care diagnostics to guide antimicrobial treatment. The primary objective of this observational study was to evaluate the diagnostic performance of 5 point-of-care tests currently available in Australia for guiding lactational treatment of nonsevere clinical mastitis. A secondary objective was to describe the pathogen profiles of mastitis-causing organisms in cows managed in barns ("intensive") and on pasture ("nonintensive"). Foremilk samples (n = 641) were collected by farm staff in dairy herds in Australia (n = 30) and tested at a university laboratory using a reference test and 5 index tests. The reference test was aerobic culture on trypticase soy agar with 5% sheep blood followed by MALDI-TOF for identification of isolates. The following point-of-care tests were evaluated as index tests: Accumast, biplate, Check-Up, Mastatest (with AUP3-2022 product), and 3M Petrifilm. We found that 23% of samples were contaminated, with the median herd contamination prevalence being 22%. After excluding contaminated samples, the most common diagnoses (according to the reference test) in intensive herds were no growth (31.7%), Klebsiella spp. (28.1%), Escherichia coli (15.0%), and Streptococcus uberis (8.4%). The most common diagnoses in noncontaminated samples from cows in nonintensive herds were Strep. uberis (35.0%), no growth (26.9%), and E. coli (13.3%). After 24 h of incubation, all index tests demonstrated limited diagnostic sensitivity for identification of pathogens of interest (range: 0.06-0.63). Diagnostic performance was better at the group-level, with sensitivity and specificity for identification of noncontaminated gram-positive growths (i.e., cases that are widely considered to be candidates for antimicrobial treatment) being 0.84 and 0.75, respectively (biplate), 0.76 and 0.90 (Accumast), 0.89 and 0.79 (Check-Up), 0.67 and 0.83 (Petrifilm), and 0.55 and 0.81 (Mastatest). In intensive herds, 22.7% to 40% of cases were classified as antimicrobial treatment candidates by index tests, which was less than for cows in nonintensive herds (41.3%-61.0%). Despite limited diagnostic reliability at the genus level and species level, and the need to ensure samples are collected aseptically, our findings indicate that implementation of selective treatment protocols using the tests evaluated in this study would likely reduce antimicrobial usage in Australian herds., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Aims: Increasing aortic dilation increases the risk of aortic dissection. Nevertheless, dissection occurs at dimensions below guideline-directed cut-offs for prophylactic surgery. Currently, there are no large-scale population imaging data assessing aortic dimensions before dissection., Methods and Results: Patients within the National Echo Database of Australia were stratified according to absolute, height-indexed, and body surface area (BSA)-indexed aortic dimensions. Fatal thoracic aortic dissections (ICD-10-AM Code I71) were identified via linkage with the National Death Index. A total of 524 994 individuals were assessed, comprising patients with normal aortic dimensions (n = 460 992), mild dilation (n = 53 402), moderate dilation (n = 10 029), and severe dilation (n = 572). A total of 274 992 (52.4%) were males, with a median age of 64 years and a median follow-up time of 6.9 years. Eight hundred and ninety-nine fatal aortic dissections occurred (normal diameter = 610, mildly dilated aorta = 215, moderately dilated = 53, and severely dilated = 21). Using normal aortas as the reference population, odds of fatal dissection increased with aortic diameter [mild = odds ratio (OR) 3.05, 95% confidence interval (CI) 2.61-3.56; moderate = OR 4.0, 95% CI 3.02-5.30; severe = OR 28.72, 95% CI 18.44-44.72]. Due to the much larger number of patients without severe aortic dilation, 97.7% of fatal aortic dissections occurred in non-severely dilated aortas. Following sensitivity analysis, severe aortic dilation was responsible for at most 24.4% of fatal aortic dissections. The results were robust for absolute, height-indexed, or BSA-indexed aortic measurements., Conclusion: Although severe aortic dilatation is associated with a near-30-fold increase in fatal dissections, severely dilated aortas are implicated in only 2.3-24.4% of fatal dissections. This highlights the 'aortic paradox' and limitations of current guidelines. Future studies should seek to refine risk predictors in patients without severe aortic dilation., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Bovine digital dermatitis (BDD) is an important cause of lameness in dairy cows worldwide. However, very little is known about this disease in Australian herds, which are predominantly managed on pasture. The primary objectives of this cross-sectional study were to describe the presence and prevalence of BDD in Australian dairy herds and to characterize the microbiota of healthy skin and M4 lesions of BDD-affected, pasture-managed cows. Cows from 71 dairy herds were examined at milking time to identify the presence of BDD lesions. True prevalence was estimated using Bayesian methods with informative priors for sensitivity and specificity. Biopsy samples (n = 60) were collected from cows with and without BDD lesions in 7 pasture-based herds. The microbiota in the superficial and deep strata of each tissue biopsy were characterized via sequencing of the V3-V4 region of the bacterial ribosomal RNA gene. Lesions were detected in 1,817 (11.5%) of 15,813 cows and in 68 of 71 (95.8%) herds. The median herd-level apparent and true prevalences of BDD were 8.5% and 18.1%, respectively, but prevalences varied considerably between farms. On farms with BDD, M4 lesions accounted for 70% to 100% of all lesions (interquartile range = 95.1%-100%, median = 100%); M2 lesions (i.e., large ulcerative lesions) were observed at low prevalence (<2.2%) in the few herds (7/71, 9.9%) where they were found. There was a significant difference in the composition of the microbiota between healthy skin and M4 lesions but not between superficial and deep tissue layers. Several gut- and effluent-associated bacterial taxa, including Lentimicrobium and Porphyromonas, which have previously been associated with BDD, were abundant in BDD lesions but not in control biopsies. Our study supports the idea that such taxa are involved in, although possibly not essential to, lesion development and persistence in pasture-managed cows in Australia. Our results also suggest that Dichelobacter may contribute to the disease process. We conclude that BDD is likely to occur in most Australian dairy farms, but that further studies are needed to identify its effect on cow welfare and productivity. Further investigation of the etiology of BDD in Australian dairy herds is also necessary to inform prevention and control strategies., (© 2024, The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The mechanisms driving dynamics of many epidemiologically important mosquito-borne pathogens are complex, involving combinations of vector and host factors (e.g., species composition and life-history traits), and factors associated with transmission and reporting. Understanding which intrinsic mechanisms contribute most to observed disease dynamics is important, yet often poorly understood. Ross River virus (RRV) is Australia's most important mosquito-borne disease, with variable transmission dynamics across geographic regions. We used deterministic ordinary differential equation models to test mechanisms driving RRV dynamics across major epidemic centers in Brisbane, Darwin, Mandurah, Mildura, Gippsland, Renmark, Murray Bridge, and Coorong. We considered models with up to two vector species (Aedes vigilax, Culex annulirostris, Aedes camptorhynchus, Culex globocoxitus), two reservoir hosts (macropods, possums), seasonal transmission effects, and transmission parameters. We fit models against long-term RRV surveillance data (1991-2017) and used Akaike Information Criterion to select important mechanisms. The combination of two vector species, two reservoir hosts, and seasonal transmission effects explained RRV dynamics best across sites. Estimated vector-human transmission rate (average β = 8.04x10-4per vector per day) was similar despite different dynamics. Models estimate 43% underreporting of RRV infections. Findings enhance understanding of RRV transmission mechanisms, provide disease parameter estimates which can be used to guide future research into public health improvements and offer a basis to evaluate mitigation practices., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Koolhof et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform., (© 2023 The Authors. Australian Veterinary Journal published by John Wiley & Sons Australia, Ltd on behalf of Australian Veterinary Association.)

Objectives: To assess the safety, feasibility and independent predictors of next day discharge (NDD) in patients undergoing minimalist transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) in a real-world Australian population., Methods: This single centre study reviewed 135 consecutive patients who underwent minimalist transfemoral TAVI from June 2020 to February 2022. Baseline demographics, procedural characteristic and outcomes were obtained. All patients were assessed by the local protocol for NDD. Patients were then divided into two groups: those who achieved next day discharge (NDD) and those requiring >1 overnight hospital stay. Univariate, bivariate and stepwise multivariate logistic regression modelling was used to identify the predictors of successful next day discharge., Results: The mean age of the cohort was 82.9±5.7 years with 62.3% patients male, the average STS score was 4.1±2.4. All 135 patients underwent a successful transfemoral TAVI procedure, with 131 (97%) receiving a balloon-expandable valve. Ninety-seven (97) (71.9%) patients achieved NDD. Thirty (30)-day outcomes were excellent with a 30-day mortality of 0.7%, transient ischaemic attack/cardiovascular accident (TIA/CVA) 1.5%, major vascular complication 1.5% and 11.4% need for permanent pacemaker (PPM). In patients not achieving NDD, the average length of stay (LOS) was 3.0 days. Baseline characteristics demonstrated pre-existing first degree atrioventricular (AV) block and right bundle branch block (RBBB) as statistically significant negative predictors of NDD on univariate analysis. Next day discharge was achievable in only 50% of patients who suffered any minor or major procedural complication (15/30). Stepwise multivariate logistic regression modelling demonstrated female gender (OR 3.094, 95% CI 1.141-8.391, p=0.026), smaller aortic valve area (AVA) (OR 48.265, 95% CI 2.269-102.6, p=0.013), the presence of diabetes mellitus (OR 0.594, 95% CI 0.356-0.991, p=0.046) and a longer procedure time (OR 0.960, 95% CI 0.935-0.986, p=0.002) as statistically significant negative predictors of NDD. In addition, there was no difference in 30-day readmission rates between the NDD and non-NDD cohort (7.2% vs 10.5%, p=0.386)., Conclusion: Next day discharge is safe and feasible in almost three quarters of patients undergoing minimalist TAVI for severe AS in a predominantly balloon expandable valve cohort, with a very low rate of 30-day readmission. NDD provides advantages for hospital efficiency and improved cost-effectiveness. Female gender, smaller AVA, the presence of diabetes mellitus and a longer procedure time were independent negative predictors of successful NDD., (Copyright © 2022 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Toxic epidermal necrolysis (TEN) is a rare and life-threatening mucocutaneous disease triggered by a reaction to a drug. Despite reported mortality of 30%, management differs between healthcare settings. Our hospital was established in February 2015 becoming the new state burns centre in Western Australia (WA). Following this, we collaborated on comprehensive multidisciplinary guidelines for the management of TEN. These guidelines are updated annually to reflect the weight of emerging evidence in managing TEN. Our aim was to review the management and outcomes of TEN patients presenting to our hospital between February 2015 and May 2021 (inclusive). We collected data for 10 patients on year, age, ethnicity, gender, medical history, culprit drug and exposure, SCORTEN, length of stay, maximum percentage of skin detachment, mucosal surface involvement, ophthalmic amniotic membrane transplant, burns unit input/admission, intensive care unit admission, weight, systemic treatment(s), complications and outcome. We excluded 7 out of 17 flagged patients who did not strictly meet the definition of TEN as greater than 30% epidermal detachment, with epidermal detachment defined as bullae, erosions, and/or positive Nikolsky. We found that the mortality rate in WA from TEN is improving compared with two previous WA studies, with a mortality rate in our study of 20% (2 deaths). Though limited by small sample size and retrospective design, our study suggests a shift towards at least one systemic therapy per patient (most commonly cyclosporine), the growing use of etanercept and the ophthalmic use of amniotic membrane transplants. It demonstrates the importance of burns unit input and the utility of comprehensive multidisciplinary guidelines. While the management and outcomes of TEN patients in WA are continuing to improve, we support calls for large registry data to facilitate evidence growth and collaboration for this rare life-threatening condition., (© 2022 Australasian College of Dermatologists.)

The objectives of this exploratory study were to (1) describe the association between herd-level udder hygiene and clinical mastitis and (2) investigate how sample size and milking stage affect the accuracy and precision of herd udder hygiene assessments made at milking time. A prospective longitudinal study was conducted in a dairy herd in Northern Australia as part of a previously published clinical trial of premilking teat disinfection. Video footage from 35 afternoon milkings was used to conduct 12,544 udder hygiene scores from 504 cows during an 89-d period and measure udder hygiene of the herd (proportion of cows with udder hygiene ≥3 out of 4). Linear interpolation was used to estimate herd udder hygiene on the days that were not scored, such that a herd-level udder hygiene measure was available for all cow-days in the study. Clinical mastitis events occurring during the study period were detected and recorded by farm staff according to a standardized definition. The relationship between herd udder hygiene on each of 1, 2, and 3 d before each study day (d -1, -2, and -3, respectively) and clinical mastitis at the cow level on each study day (each in turn being set as d 0) was determined using multivariable generalized estimating equations (family = Poisson, link = log), with the unit of analysis being the cow-day, adjusting for potential confounders and the clustering within the data. In addition, sampling strategies were evaluated by simulating herd udder hygiene assessments using a subset of cows in the herd. Herd udder hygiene from d -1, -2, and -3 was positively associated with clinical mastitis on d 0 (incidence rate ratio = 1.4 per 10-point increase in the percentage of cows with poor udder hygiene). Sampling strategy simulation found that at least 80 cows needed to be scored to achieve sufficiently precise estimations of herd udder hygiene. Furthermore, cows scored later during milking were slightly more likely to have poor udder hygiene than those scored earlier (risk ratio = 1.02 for cows that were 10% later in the milking order). More research is needed to evaluate risk factors for poor udder hygiene and potential interventions in pasture-based dairy cows., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Plastic sanitary sheaths over artificial insemination (AI) guns have been used at the time of AI to improve hygiene at AI and fertility in cattle, but fertility responses have been variable in studies when AI was performed by professional inseminators. The aims of this study were to investigate whether the use of a sanitary sheath at the time of AI carried out by nonprofessional (do-it-yourself, or DIY) inseminators improves pregnancy rates to AI in pasture-based dairy cows and whether effects of sheaths are greater in cows with contaminated vulvas and in cows at increased risk of extended calving to conception intervals. Lactating dairy cows located in 10 pasture-based herds in a subtropical region of northern Australia were inseminated by herd-based DIY inseminators and assigned to be inseminated with (n = 3,655) or without (n = 3,969) a sanitary sheath, with potential effects assessed using multivariable logistic regression. Overall, use of a sheath at the time of AI did not significantly affect pregnancy rates to AI (36.3% for those inseminated without a sheath vs. 36.8% for those inseminated with a sheath; odds ratio: 1.02; 95% confidence interval: 0.92-1.11). Effects of using a sheath on pregnancy rates to AI varied by herd, with lower pregnancy rates with the use of sheaths in 1 herd and some evidence of increases in 3 herds. Unexpectedly, there was evidence that the effect of sheath on pregnancy rates was less positive (or more negative) when the vulva was classified as dirty before any cleaning of the vulva before insemination compared with when the vulva was classified as clean (interaction odds ratio: 0.75; 95% CI: 0.56-1.00). Interactions between sheath and other explanatory variables that could affect fertility were not significant; thus, there was no compelling evidence that the effect of using a sheath was modified by any of these variables. We conclude that the use of sheaths during AI of pasture-based dairy cows by DIY inseminators does not, on average, markedly improve pregnancy rates to AI. However, responses may vary between herds, and the response to sheaths may be inferior (i.e., less positive or more negative) when a cow's vulva is contaminated with feces or discharge at the time of AI compared with when the vulva is clean., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Background: A large outbreak of hepatitis A affected individuals in several Australian states in 2009, resulting in a 2-fold increase in cases reported to state health departments compared with 2008. Two peaks of infection occurred (April-May and September-November), with surveillance data suggesting locally acquired infections from a widely distributed food product., Methods: Two case-control studies were completed. Intensive product trace-back and food sampling was undertaken. Genotyping was conducted on virus isolates from patient serum and food samples. Control measures included prophylaxis for close contacts, public health warnings, an order by the chief health officer under the Victorian Food Act 1984, and trade-level recalls on implicated batches of semidried tomatoes., Results: A multijurisdictional case-control study in April-May found an association between illness and consumption of semidried tomatoes (odds ratio [OR], 3.0; 95% CI 1.4-6.7). A second case-control study conducted in Victoria in October-November also implicated semidried tomatoes as being associated with illness (OR, 10.3; 95% CI, 4.7-22.7). Hepatitis A RNA was detected in 22 samples of semidried tomatoes. Hepatitis A virus genotype IB was identified in 144 of 153 (94%) patients tested from 2009, and partial sequence analysis showed complete identity with an isolate found in a sample of semidried tomatoes., Conclusions: The results of both case-control studies and food testing implicated the novel vehicle of semidried tomatoes as the cause of this hepatitis A outbreak. The outbreak was extensive and sustained despite public health interventions, the design and implementation of which were complicated by limitations in food testing capability and complex supply chains.