Infection In Australia Research Articles

Quantifying the Economic and Clinical Value of Reducing Antimicrobial Resistance in Gram-negative Pathogens Causing Hospital-Acquired Infections in Australia.

Antimicrobial resistance (AMR) is a global public health challenge requiring a global response to which Australia has issued a National Antimicrobial Resistance Strategy. The necessity for continued-development of new effective antimicrobials is required to tackle this immediate health threat is clear, but current market conditions may undervalue antimicrobials. We aimed to estimate the health-economic benefits of reducing AMR levels for drug-resistant gram-negative pathogens in Australia, to inform health policy decision-making. A published and validated-dynamic health economic model was adapted to the Australian setting. Over a 10-year time horizon, the model estimates the clinical and economic outcomes associated with reducing current AMR levels, by up to 95%, of three gram-negative pathogens in three hospital-acquired infections, from the perspective of healthcare payers. A willingness-to-pay threshold of AUD$15,000-$45,000 per quality-adjusted life-year (QALY) gained and a 5% discount rate (for costs and benefits) were applied. Over ten years, reducing AMR for gram-negative pathogens in Australia is associated with up to 10,251 life-years and 8924 QALYs gained, 9041 bed-days saved and 6644 defined-daily doses of antibiotics avoided. The resulting savings are estimated to be $10.5 million in hospitalisation costs, and the monetary benefit at up to $412.1 million. Our results demonstrate the clinical and economic value of reducing AMR impact in Australia. Of note, since our analysis only considered a limited number of pathogens in the hospital setting only and for a limited number of infection types, the benefits of counteracting AMR are likely to extend well beyond the ones demonstrated here. These estimates demonstrate the consequences of failure to combat AMR in the Australian context. The benefits in mortality and health system costs justify consideration of innovative reimbursement schemes to encourage the development and commercialisation of new effective antimicrobials.

Success of Debridement, Antibiotics, and Implant Retention in Prosthetic Joint Infection Following Primary Total Knee Arthroplasty: Results From a Prospective Multicenter Study of 189 Cases

BackgroundThis study aimed to identify the success rate of debridement, antibiotics, and implant retention (DAIR) for prosthetic joint infection (PJI) in a large prospective cohort of patients undergoing total knee arthroplasty (TKA). The ability for different PJI classification systems to predict success was assessed. MethodsProspective data recorded in the Prosthetic Joint Infection in Australia and New Zealand Observational study were analyzed. One hundred eighty-nine newly diagnosed knee PJIs were managed with DAIR between July 2014 and December 2017. Patients were prospectively followed up for 2 years. A strict definition of success was used, requiring the patient being alive with documented absence of infection, no ongoing antibiotics and the index prosthesis in place. Success was compared against the Coventry (early PJI ≤1 month), International Consensus Meeting (early ≤90 days), Auckland (early <1 year), and Tsukayama (early ≤1 month, hematogenous >1 month with <7 days symptoms, chronic >1 month with >7 days symptoms) classifications. ResultsDAIR success was 45% (85/189) and was highest in early PJIs defined according to the Coventry (adjusted odds ratio [aOR] = 3.9, P = .01), the International Consensus Meeting (aOR = 3.1, P = .01), and the Auckland classifications (aOR = 2.6, P = .01). Success was lower in both hematogenous (aOR = 0.4, P = .03) and chronic infections (aOR = 0.1, P = .003). ConclusionTime since primary TKA is an important predictor of DAIR success. Success was highest in infections occurring <1 month of the primary TKA and progressively decreased as time since the primary TKA increased.

Source attribution of campylobacteriosis in Australia, 2017-2019.

Campylobacter jejuni and Campylobacter coli infections are the leading cause of foodborne gastroenteritis in high-income countries. Campylobacter colonizes a variety of warm-blooded hosts that are reservoirs for human campylobacteriosis. The proportions of Australian cases attributable to different animal reservoirs are unknown but can be estimated by comparing the frequency of different sequence types in cases and reservoirs. Campylobacter isolates were obtained from notified human cases and raw meat and offal from the major livestock in Australia between 2017 and 2019. Isolates were typed using multi-locus sequence genotyping. We used Bayesian source attribution models including the asymmetric island model, the modified Hald model, and their generalizations. Some models included an "unsampled" source to estimate the proportion of cases attributable to wild, feral, or domestic animal reservoirs not sampled in our study. Model fits were compared using the Watanabe-Akaike information criterion. We included 612 food and 710 human case isolates. The best fitting models attributed>80%of Campylobacter cases to chickens, with a greater proportion of C. coli (>84%) than C. jejuni (>77%). The best fitting model that included an unsampled source attributed 14% (95% credible interval [CrI]: 0.3%-32%) to the unsampled source and only 2% to ruminants (95% CrI: 0.3%-12%) and 2% to pigs (95% CrI: 0.2%-11%) The best fitting model that did not include an unsampled source attributed 12% to ruminants (95% CrI:1.3%-33%) and 6% to pigs (95% CrI: 1.1%-19%). Chickens were the leading source of human Campylobacter infections in Australia in 2017-2019 and should remain the focus of interventions to reduce burden.

Virtual hospital-level care-feasibility, acceptability, safety and impact of a pilot Hospital-In-The-Home model for COVID-19 infection.

Hospital-in-the-Home (HITH) delivers hospital level care to patients in the comfort of their own home. Traditionally HITH involves clinicians travelling to patients' homes. We designed and implemented a virtual model of care leveraging a combination of virtual health modalities for children with COVID-19 in response to rising patient numbers, infection risk and pressures on protective equipment. In contrast to other models for COVID-19 infection in Australia at the time, our HITH service catered only for children who were unwell enough to meet criteria for hospitalisation (ie bed-replacement). To measure the feasibility, acceptability, safety and impact of a virtual model of care for managing children with COVID-19 infection requiring hospital-level care. Retrospective study of a new virtual model of care for all children admitted to the Royal Children's HITH service with COVID-19 infection between 7th October 2021 and 28th April 2022. The model consisted of at least daily video consultations, remote oximetry, symptom tracking, portal messaging and 24 h phone and video support. Patients were eligible if they met a certain level of severity (work of breathing, dehydration, lower oxygen saturations) without requiring intravenous fluids, oxygen support or intensive care. Online surveys were distributed to staff and consumers who experienced the model of care. 331 patients were managed through the virtual HITH program with a mean length of stay of 3.5 days. Of these, 331 (100%) engaged in video consultations, 192 (58%) engaged in the patient portal and completed the symptom tracker a total of 634 times and communicated via a total of 783 messages. Consumer satisfaction (n = 31) was high (4.7/5) with the most useful aspect of the model rated as video consultation. Clinician satisfaction (n = 9) was also high with a net promoter score of 8.9. There were no adverse events at home. Eight children (2.4%) represented to hospital, 7 (2.1%) of whom were readmitted. The impact is represented by a total of 1,312 hospital bed-days saved in the seven-month period (2,249 bed-days per year). In addition, 1,480 home visits (travel time/ protective equipment/ infection risk) were avoided. A virtual HITH program for COVID-19 in children is feasible, acceptable and safe and has a substantial impact on bed-days saved and nursing travel time. The implications for management of other acute respiratory viral illnesses that contribute to hospital bed pressure during winter months is immense. Virtual HITH is likely to be a key enabler of a sustainable healthcare system.

Optimizing point-of-care testing strategies for diagnosis and treatment of hepatitis C virus infection in Australia: a model-based cost-effectiveness analysis

Timely diagnosis and treatment of hepatitis C virus (HCV) is critical to achieve elimination goals. This study evaluated the cost-effectiveness of point-of-care testing strategies for HCV compared to laboratory-based testing in standard-of-care. Cost-effectiveness analyses were undertaken from the perspective of Australian Governments as funders by modelling point-of-care testing strategies compared to standard-of-care in needle and syringe programs, drug treatment clinics, and prisons. Point-of-care testing strategies included immediate point-of-care HCV RNA testing and combined point-of-care HCV antibody and reflex RNA testing for HCV antibody positive people (with and without consideration of previous treatment). Sensitivity analyses were performed to investigate the cost per treatment initiation with different testing strategies at different HCV antibody prevalence levels. The average costs per HCV treatment initiation by point-of-care testing, from A$890 to A$1406, were up to 35% lower compared to standard-of-care ranging from A$1248 to A$1632 depending on settings. The average costs per treatment initiation by point-of-care testing for three settings ranged from A$1080 to A$1406 for RNA, A$960-A$1310 for combined antibody/RNA without treatment history consideration, and A$890-A$1189 for combined antibody/RNA with treatment history consideration. When HCV antibody prevalence was <74%, combined point-of-care HCV antibody and point-of-care RNA testing were the most cost-effective strategies. Modest increases in treatment uptake by 8%-31% were required for immediate point-of-care HCV RNA testing to achieve equivalent cost per treatment initiation compared to standard-of-care. Point-of-care testing is more cost-effective than standard of care for populations at risk of HCV. Testing strategies combining point-of-care HCV antibody and RNA testing are likely to be cost-effective in most settings. National Health and Medical Research Council.

The burden of surgical site infections in Australia: A cost-of-illness study

ObjectiveTo estimate the cost of surgical site infections in Australian public hospitals in 2018–19, to demonstrate the economic burden of hospital-associated infection in a well-resourced health system. MethodsA cost-of-illness analysis was conducted over a 1-year time horizon based on data from published literature extrapolated using simulation techniques. The direct and indirect costs of SSI were estimated for Australia and each of its states and territories. ResultsAn estimated 16,541 cases of SSI occurred in Australian public hospitals in 2018–19, resulting in a total direct cost of A$323.5 million. The average cost per case was A$18,814, which was 2.5 times the average per capita spending on health. The indirect costs of absenteeism and premature death were valued at A$23.0 million and A$2 948.1 million per annum, respectively. ConclusionSSI is a significant but preventable cost with most of the financial burden coming from premature deaths but underreporting means our costs are likely underestimated.

Ciprofloxacin resistance and tolerance of Pseudomonas aeruginosa ocular isolates

PurposeTolerance to antibiotics may occur due to changes in bacterial growth patterns and can be a precursor to development of resistance. However, there is a lack of information on the ability of ocular bacteria isolates to develop tolerance. This paper explores the tolerance to 8 different antibiotics of 61 microbial keratitis isolates of Pseudomonas aeruginosa from Australia and India using the MBC/MIC ratio, with tolerance defined by a ratio ≥ 32, and tolerance to ciprofloxacin by an agar diffusion assay. MethodsAntibiotics used were ciprofloxacin, levofloxacin, gentamicin, tobramycin, piperacillin, imipenem, ceftazidime and polymyxin B. Isolates were sourced from microbial keratitis infections in Australia and India. Minimum bactericidal and minimum inhibitory concentration (MBC and MIC) were obtained using broth microdilution and compared to breakpoints from the Clinical Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) to determine bacterial susceptibility. Tolerance was assessed as MBC/MIC ≥ 32. An alternative method for tolerance detection (TD) was assessed with 13P. aeruginosa sensitive isolates by agar disk diffusion assay of ciprofloxacin followed by application of glucose to the agar and observation of re-growth of colonies. ResultsThirty-three isolates were resistant to imipenem, 20 to ciprofloxacin, 14 to tobramycin and piperacillin, 12 to levofloxacin and ceftazidime, 8 to gentamicin, and 5 to polymyxin B. The percentage of strains resistant to levofloxacin (7 vs 30 %; p = 0.023), gentamicin (0 vs 24 %; p = 0.005) and tobramycin (4 vs 33 %; p = 0.004) was significantly greater in isolates from India.On average, strains from India exhibited notably greater MIC and MBC values compared to strains obtained from Australia. Out of 61 isolates, none displayed an MBC/MIC ratio ≥ 32. However, three sensitive isolates had low tolerance, nine had medium tolerance and one had high tolerance to ciprofloxacin with the TDtest. ConclusionsThis study used two methods to determine whether P. aeruginosa strains could show tolerance to antibiotics. Using the MBC/MIC criteria no strain was considered tolerant to any of the eight antibiotics used. When 13 strains were tested for tolerance against ciprofloxacin, the most commonly used monotherapy for keratitis, one had high tolerance and nine had medium tolerance. This demonstrates the capacity of P. aeruginosa to develop tolerance which may result in therapeutic failures if inappropriate dosing regimens are used to treat keratitis.

SUCCESS OF DAIR VERSUS REVISION IN EARLY AND LATE PJIS IN PRIMARY TKA: A PROSPECTIVE STUDY OF 251 CASES

The optimum indications for debridement, antibiotics and implant retention (DAIR) are unclear. Previous studies have demonstrated higher success rate of DAIR within one year of the primary arthroplasty. This study aimed to compare the success rate of DAIR vs revision in “early” and “late” infections to provide guidance for clinical decision making.The Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort prospectively recorded PJIs between July 2014 and December 2017 in 27 hospitals. This study included PIANO patients with first time PJIs occurring after primary TKA. Treatment success was defined as the patient being alive, free from further revision and without clinical or microbiological evidence of reinfection at two years follow-up.“Early” and “late” infections were analyzed separately. Univariate analysis compared demographic and disease specific factors between the DAIR and Revision groups. Multivariate binary logistic regression identified whether treatment strategy and other risk factors were associated with treatment success in “early” and “late” infections.In 117 “early” (&lt;1 year) infections, treatment success rate was 56% in the DAIR group and 54% in the revision group (p=0.878). No independent risk factors were associated with treatment outcome on multivariate analysis.In 134 “late” (&gt;1 year) infections, treatment success rate was 34.4% in the DAIR group and 60.5% in the revision group (OR 3.07 p=0.006). On multivariate analysis, revision was associated with 2.47x higher odds of success (p=0.041) when compared to DAIR, patients with at least one significant co-morbidity (OR 2.27, p=0.045) or with Staphylococcus aureus PJIs (OR 2.5, p=0.042) had higher odds of failure.In “late” PJIs occurring &gt;1 year following primary TKA, treatment strategy with revision rather than DAIR was associated with greater success. Patients with significant comorbidities and Staphylococcus aureus PJIs were at higher risk of failure regardless of treatment strategy.

Blood parasites: morphological identification of filarial infections in blood smears

Identification of microfilaria seen in blood films may be the only method available to make a diagnosis of some filarial infections. The low incidence of these infections in Australia and lack of exposure to the features to identify microfilaria is becoming more challenging for microscopists. Images taken from case studies collected for more than 50 years have been compiled to show the differences between the morphology of different species of microfilaria in the blood.

Effectiveness of direct-acting antiviral therapy among Aboriginal and Torres Strait Islander peoples with HCV infection in Australia: A national real-world cohort (REACH-C).

Aboriginal and Torres Strait Islander peoples experience a disproportionate burden of hepatitis C virus (HCV) infection. This study assessed the effectiveness of direct-acting antiviral (DAA) therapy among Aboriginal peoples in the three years following universal access in Australia. REACH-C, a national multicentre prospective cohort study, evaluated HCV treatment outcomes from sequential DAA initiations across 33 health services between March 2016 and June 2019. DAA effectiveness was assessed by sustained virological response (SVR) in the total (full analysis set) and effectiveness (modified analysis set excluding those lost to follow-up) populations. Overall, 915 (10%) Aboriginal and 8095 (90%) non-Indigenous people commenced DAA therapy, of whom 30% and 16% reported current injecting drug use and 73% and 42% were treated in primary care, respectively. SVR in the total and effectiveness populations was 74% and 94% among Aboriginal people and 82% and 94% among non-Indigenous people, with loss to follow-up contributing to lower SVR in the total population analysis (22% Aboriginal, 13% non-Indigenous). Among Aboriginal people, returning for follow-up was positively associated with older age (aOR 1.20; 95% CI 1.04, 1.39) and SVR was negatively associated with cirrhosis (aOR 0.39; 95% CI 0.19, 0.80) and prior DAA treatment (aOR 0.14; 95% CI 0.04, 0.49). Factors reflecting higher vulnerability or inequity were not associated with returning for testing or SVR. DAA therapy was highly effective among Aboriginal peoples with HCV treated through primary and tertiary services. Tailored community-led interventions are necessary to optimize follow-up and engagement. Sustained DAA uptake and equitable access to care, treatment and prevention are required for HCV elimination.

Interim position statement on doxycycline post-exposure prophylaxis (Doxy-PEP) for the prevention of bacterial sexually transmissible infections in Australia and Aotearoa New Zealand - the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM).

Recent studies have provided evidence for the effectiveness of using doxycycline (Doxy-PEP) to prevent bacterial sexually transmissible infections (STI), namely chlamydia, gonorrhoea, and syphilis, among gay, bisexual, and other men who have sex with men who have experienced multiple STIs. However, there remain several unanswered questions around potential adverse outcomes from Doxy-PEP, including the possibility of inducing antimicrobial resistance in STIs and other organisms, and the possibility of disrupting the microbiome of people who choose to use Doxy-PEP. This interim position statement from the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine aims to outline the current evidence for Doxy-PEP, and to highlight potential adverse outcomes, to enable clinicians to conduct evidence-based conversations with patients in Australia and Aotearoa New Zealand who intend to use Doxy-PEP.

The chlamydia care cascade of young people attending Australian general practices; a descriptive study to assess gaps in care.

Most chlamydia infections in Australia are diagnosed in general practice. The care cascade concept (testing, treatment and re-testing) can be utilised to explore the management of chlamydia infections. We explored the chlamydia care cascade among young people attending general practices in Australia. We analysed de-identified electronic medical record data for 16-29-year-old individuals attending 70 Australian general practices between January 2018 and December 2020. Five outcomes: (1) chlamydia testing, (2) positivity, (3) treatment, (4) re-testing and (5) re-infection were summarised as annual counts and proportions per calendar year. Logistic regression was used to investigate the association of age, gender and clinic location with each outcome. During the study period, a total of 220909 clinical episodes involving 137358 16-29-year-olds were recorded. Of these episodes, 10.45% (n =23077, 95% CI 8.73-12.46) involved a chlamydia test. Of 1632 chlamydia cases, 88.79% (n =1449, 95% CI 86.37-90.82) had appropriate antibiotics recorded as defined in Australian sexually transmitted infection management guidelines. Of 183 chlamydia cases that did not have appropriate antibiotics recorded, 46.45% (n =85) had re-attended the clinic within 90days of diagnosis. Among 1068 chlamydia cases that had appropriate antibiotic recorded in 2018 and 2019, 22.57% (n =241, 95% CI 20.15-25.18) were re-tested within 6weeks to 4months of their diagnosis. One-third of episodes of chlamydia cases that did not have a re-test recorded (n =281) had re-attended the clinics within 4months of diagnosis. Our study provides insight into chlamydia management by analysing general practice medical records, indicating substantial gaps in testing and re-testing for 16-29-year-olds. These data can also be used to explore the impact of future interventions to optimise chlamydia management.

Predictive modelling of Ross River virus using climate data in the Darling Downs.

Ross River virus (RRV) is the most common mosquito-borne infection in Australia. RRV disease is characterised by joint pain and lethargy, placing a substantial burden on individual patients, the healthcare system and economy. This burden is compounded by a lack of effective treatment or vaccine for the disease. The complex RRV disease ecology cycle includes a number of reservoirs and vectors that inhabit a range of environments and climates across Australia. Climate is known to influence humans, animals and the environment and has previously been shown to be useful to RRV prediction models. We developed a negative binomial regression model to predict monthly RRV case numbers and outbreaks in the Darling Downs region of Queensland, Australia. Human RRV notifications and climate data for the period July 2001 - June 2014 were used for model training. Model predictions were tested using data for July 2014 - June 2019. The final model was moderately effective at predicting RRV case numbers (Pearson's r = 0.427) and RRV outbreaks (accuracy = 65%, sensitivity = 59%, specificity = 73%). Our findings show that readily available climate data can provide timely prediction of RRV outbreaks.

Incidence of primary hepatitis C virus infection among people who inject drugs in Australia pre- and post-unrestricted availability of direct acting antiviral therapies.

The 2016 Global Health Sector Strategy (GHSS) on viral hepatitis aims to reduce new hepatitis C virus (HCV) infections by 80% by 2030, including a 30% reduction by 2020. This study aimed to estimate primary HCV incident infection among a national sample of people who inject drugs (PWID) before and after the introduction of unrestricted access to HCV direct-acting antiviral (DAA) therapy via Australia's Pharmaceutical Benefits Scheme in 2016. A simple deterministic linkage method identified repeat respondents in serial cross-sectional surveys conducted among PWID. Two separate retrospective cohorts of HCV antibody-negative respondents were created, corresponding to the pre- (2010-15) and post- (2016-21) DAA time-periods. This study took place in Australia. Among 757 PWID retained (376 pre-DAA, 381 post-DAA), more than half were male (60%), the majority were heterosexual (80%), the median age was 40 years (interquartile range = 33-46 years) and the predominant drugs last injected were heroin (24%), pharmaceutical opioids (27%) and methamphetamine (41%). The primary outcome was HCV seroconversion, defined as a negative HCV antibody test result followed by a positive HCV antibody result. Time to primary incident HCV infection was estimated using the person-years (PY) method. A total 97 of 376 (2010-15) and 41 of 381 (2016-21) HCV seroconversions were identified. Primary HCV incidence more than halved, from 13.6 per 100 PY [95% confidence intervals (CI) = 11.2, 16.6] in 2010-15 to 5.4 per 100 PY (95% CI =3.9, 7.3) in 2016-21. The decline was independent of observed differences in demographic and drug use characteristics over the two time-periods (adjusted hazard ratio =0.47, 95% CI =0.31-0.69, P<0.001). Australia has had a 53% reduction in primary hepatitis C virus (HCV) incidence among people who inject drugs following unrestricted availability of HCV direct acting antiviral therapy in March 2016. Given that PWID are the predominant population at risk of HCV infection in Australia, findings add to the evidence that Australia has probably met its 2020 Global Health Sector Strategy subtarget of a 30% decline in new infections.

Characteristics and outcomes of culture-negative prosthetic joint infections from the Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort study.

Introduction: Culture-negative (CN) prosthetic joint infections (PJIs) account for approximately 10 % of all PJIs and present significant challenges for clinicians. We aimed to explore the significance of CN PJIs within a large prospective cohort study, comparing their characteristics and outcomes with culture-positive (CP) cases. Methods: The Prosthetic joint Infection in Australia and New Zealand Observational (PIANO) study is a prospective, multicentre observational cohort study that was conducted at 27 hospitals between 2014 and 2017. We compared baseline characteristics and outcomes of all patients with CN PJI from the PIANO cohort with those of CP cases. We report on PJI diagnostic criteria in the CN cohort and apply internationally recognized PJI diagnostic guidelines to determine optimal CN PJI detection methods. Results: Of the 650 patients with 24-month outcome data available, 55 (8.5 %) were CN and 595 were CP. Compared with the CP cohort, CN patients were more likely to be female (32 (58.2 %) vs. 245 (41.2 %); 0.016), involve the shoulder joint (5 (9.1 %) vs. 16 (2.7 %); 0.026), and have a lower mean C-reactive protein (142 mg L vs. 187 mg L ; 0.016). Overall, outcomes were superior in CN patients, with culture negativity an independent predictor of treatment success at 24 months (adjusted odds ratio, aOR, of 3.78 and 95 %CI of 1.65-8.67). Suboptimal diagnostic sampling was common in both cohorts, with CN PJI case detection enhanced using the Infectious Diseases Society of America PJI diagnostic guidelines. Conclusions: Current PJI diagnostic guidelines vary substantially in their ability to detect CN PJI, with comprehensive diagnostic sampling necessary to achieve diagnostic certainty. Definitive surgical management strategies should be determined by careful assessment of infection type, rather than by culture status alone.

Detection and characterisation of Bordetella hinzii in line-related bacteraemia and respiratory tract infection in Australia

Bordetella hinzii has emerged as an unusual cause of infection in immunocompromised patients, previously linked to zoonotic transmission. Antimicrobial susceptibility and genetic diversity of B.hinzii are poorly understood. This study reports phenotypic and genomic characteristics of the first four Australian isolates of B.hinzii obtained from elderly immunocompromised patients. Bordetella hinzii isolates were identified by MALDI-TOF and whole genome sequencing (WGS). Antibiotic susceptibility testing was performed using disk diffusion or E-test. Genomes of B.hinzii were analysed in global context. A phylogenetic tree was constructed of all isolates using Roary and a maximum-likelihood tree was generated from the core-snp alignment. Bordetella hinzii minimum inhibitory concentrations (MICs) were largely uniform with high MICs to ampicillin, ceftriaxone and ciprofloxacin and low MICs to meropenem and piperacillin-tazobactam. Genomic analysis of isolate sequences divided strains analysed into two phylogenetically distinct groups, with one Australian B.hinzii isolate (AUS-4) assigned to Group 1, and the remaining isolates (AUS1-AUS3 and AUS-5) to Group 2. Single nucleotide polymorphism (SNP) analysis revealed two isolates, AUS-1 and AUS-2, were closely related with 14 SNP differences between them. All other Australian isolates were unrelated to each and all other isolates from the international dataset. Bordetella hinzii appears to pose a risk to immunocompromised individuals but remains susceptible to extended spectrum β-lactam and carbapenem antibiotics. Genomic analysis suggested a dissemination of genetically distinct strains.

Disease burden, associated mortality and economic impact of antimicrobial resistant infections in Australia

SummaryBackgroundThe growing spread of antimicrobial resistance (AMR) is accepted as a threat to humans, animals and the environment. This threat is considered to be both country specific and global, with bacteria resistant to antibiotic treatment geographically dispersed. Despite this, we have very few Australian estimates available that use national surveillance data supplemented with measures of risk, to generate reliable and actionable measures of AMR impact. These data are essential to direct policies and programs and support equitable healthcare resource utilisation. Importantly, such data can lead to implementation of programs to improved morbidity and mortality of patients with a resistant infection.MethodsUsing data from a previous case-cohort study, we estimated the AMR-associated health and economic impact caused by five hospital-associated AMR pathogens (Enterococcus spp., E. coli, K. pneumoniae, P. aeruginosa and S. aureus) in patients with a bloodstream, urinary tract, or respiratory tract infection in Australia in 2020. We estimated disease burden based on the counterfactual scenario in which all AMR infections were replaced by no infection.We used a population-level simulation model to compute AMR-associated mortality, loss of quality-adjusted life years and costs.FindingsIn 2020, there were 1,031 AMR-associated deaths (95% uncertainty interval [UI] 294, 2,615) from the five resistant hospital-associated infections in Australia. The greatest odds of dying were from respiratory infections (ceftazidime-resistant P. aeruginosa) and bloodstream infections, both resulting in high hospital and premature death costs. MRSA bacteraemia contributed the most to hospital costs (measured as bed-days) as patients with this infection resulted in additional 12,818 (95% UI 7246, 19966) hospital bed-days and cost the hospitals an extra $24,366,741 (95%UI $13,774,548, $37,954,686) per year. However, the cost of premature death from five resistant pathogens was $438,543,052, which was by far greater than the total hospital cost ($71,988,858). We estimate a loss of 27,705 quality-adjusted life years due to the five AMR pathogens.InterpretationThese are the first Australian estimates of AMR-associated health and economic impact. Country-level estimates of AMR impact are needed to provide local evidence to better inform programs and health policies to reduce morbidity and mortality associated with infection. The burden in hospital is likely an underestimate of the impact of AMR due to community-associated infections where data are limited, and the AMR burden is high. This should now be the focus of future study in this area.FundingTMW was supported by the Australian Partnership for Preparedness Research on Infectious Disease Emergencies (APPRISE) (grant number GNT1116530) Fellowship.

Modelling SARS‐CoV‐2 disease progression in Australia and New Zealand: an account of an agent‐based approach to support public health decision‐making

ObjectiveIn 2020, we developed a public health decision‐support model for mitigating the spread of SARS‐CoV‐2 infections in Australia and New Zealand. Having demonstrated its capacity to describe disease progression patterns during both countries’ first waves of infections, we describe its utilisation in Victoria in underpinning the State Government's then ‘RoadMap to Reopening’. MethodsKey aspects of population demographics, disease, spatial and behavioural dynamics, as well as the mechanism, timing, and effect of non‐pharmaceutical public health policies responses on the transmission of SARS‐CoV‐2 in both countries were represented in an agent‐based model. We considered scenarios related to the imposition and removal of non‐pharmaceutical interventions on the estimated progression of SARS‐CoV‐2 infections. ResultsWave 1 results suggested elimination of community transmission of SARS‐CoV‐2 was possible in both countries given sustained public adherence to social restrictions beyond 60 days’ duration. However, under scenarios of decaying adherence to restrictions, a second wave of infections (Wave 2) was predicted in Australia. In Victoria’s second wave, we estimated in early September 2020 that a rolling 14‐day average of <5 new cases per day was achievable on or around 26 October. Victoria recorded a 14‐day rolling average of 4.6 cases per day on 25 October. ConclusionsElimination of SARS‐CoV‐2 transmission represented in faithfully constructed agent‐based models can be replicated in the real world. Implications for public healthAgent‐based public health policy models can be helpful to support decision‐making in novel and complex unfolding public health crises.

Burden of five healthcare associated infections in Australia

BackgroundHealthcare associated infections are of significant burden in Australia and globally. Previous estimates in Australia have relied on single-site studies, or combinations thereof, which have suggested the burden of these infections is high in Australia. Here, we estimate the burden of five healthcare associated infections (HAIs) in Australian public hospitals using a standard international framework, and compare these estimates to those observed in Europe.MethodsWe used data from an Australian point prevalence survey to estimate the burden of HAIs amongst adults in Australian public hospitals using an incidence-based approach, introduced by the ECDC Burden of Communicable Diseases in Europe.ResultsWe estimate that 170,574 HAIs occur in adults admitted to public hospitals in Australia annually, resulting in 7583 deaths. Hospital acquired pneumonia is the most frequent HAI, followed by surgical site infections, and urinary tract infections. We find that blood stream infections contribute a small percentage of HAIs, but contribute the highest number of deaths (3207), more than twice that of the second largest, while pneumonia has the higher impact on years lived with disability.ConclusionThis study is the first time the national burden of HAIs has been estimated for Australia from point prevalence data collected using validated surveillance definitions. Per-capita, estimates are similar to that observed in Europe, but with significantly higher occurrences of bloodstream infections and healthcare-associated pneumonia, primarily amongst women. Overall, the estimated burden is high and highlights the need for continued investment in HAI prevention.

Epidemiology and long-term neurological sequelae of childhood herpes simplex CNS infection.

AimHerpes simplex CNS infection is a rare but important cause of neurological disability. Long term outcomes after HSV CNS infection in Australia have not yet been fully described. We sought to provide a comprehensive review of HSV CNS infection in children using a retrospective 13‐year evaluation of statewide laboratory and clinical records and a parent survey conducted at least one year after the initial infection.MethodsAll positive PCR HSV 1 and 2 results from cerebrospinal fluid (CSF) or brain tissue were obtained from Queensland pathology providers for children aged 0–16 years between 1 January 2005 and 31 December 2017. Clinical data were obtained from patient records and longer‐term outcomes via parent survey at least 1 year after initial infection.ResultsForty‐three children were identified over the 13‐year period, 17 (39.5%) neonates and 26 (60.4%) non‐neonates. The annual incidence for HSV CNS infection in Queensland children aged ≤16 years was 0.3/100 000 (95% confidence intervals (CIs): 0.2–0.4) with neonates at highest risk (incidence 2.5/100 000 live births, 95% CI: 1.5–3.9). HSV 1 was the predominant serotype in both neonates and non‐neonates (9/17, 52.9% neonates and 19/26, 73.1% non‐neonates). Seven (16.3%) children died, five (5/17, 29.4% neonates), directly attributable to HSV CNS infection (all neonates). Twenty‐five (58.1%) had neurological morbidity at discharge (9/17 neonates (52.9%) vs. 16/26 (61.5%) non‐neonates) and 20/27 (74.1%) reported long‐term neurological morbidity at follow‐up (5/9 neonates (55.6%) vs. 15/18 non‐neonates (83.3%)). Seven children (two neonates and four non‐neonates) with long‐term neurological sequelae had no neurological morbidity identified at discharge.ConclusionSignificant long‐term neurologic sequelae were seen in children with HSV CNS infection even in children with no neurological disability identified at discharge from hospital. Careful neurodevelopmental follow‐up of all children is recommended.