Diabetes and hyperglycaemia among hospitalised patients with COVID-19 in Western Sydney: a retrospective cohort study.

BACKGROUND: Diabetes has been recognised as a major risk factor for COVID-19 mortality and hospital complications in earlier studies. AIMS: To examine the characteristics of hospitalised COVID-19 patients with diabetes and the impact of diabetes and hyperglycaemia on hospital outcomes. METHODS: This was a retrospective cohort study. Admission glucose levels, HbA1c, diabetes status and hospital outcomes were determined for subjects admitted from June to November 2021 by matching a pathology data set, a clinical data set and the hospital administrative database. The outcomes of interest were death, intensive care unit (ICU) admission and length of stay (LOS). RESULTS: There were 1515 individuals admitted with COVID-19 with 49 deaths (3.2%) and 205 (13.5%) ICU admissions. The median length of hospital stay was 3.7 days. Three hundred and ten patients (20%) had diabetes, with 46 (15%) newly diagnosed. Patients with diabetes had a higher mortality than patients who did not have diabetes (8% vs 2%, P < 0.001), were more likely to be admitted to ICU (20% vs 12%, P = 0.001) and have longer median LOS stay (6.6 (interquartile range (IQR) 2.9-12.5) vs 2.9 (IQR 0.5-7.1) days, P < 0.001). In multivariate models, neither diabetes nor admission glucose predicted death. Admission glucose level but not diabetes was an independent predictor of ICU admission and LOS. CONCLUSIONS: There is a high prevalence of diabetes among patients hospitalised with COVID-19, with worse outcomes. In contrast to previous studies, the association of diabetes with mortality was not significant when adjusted for other variables. This is possibly related to the benefits of vaccination and current medical and ICU interventions.

COVID-19 in Australia: our national response to the first cases of SARS-CoV-2 infection during the early biocontainment phase.

BACKGROUND: On 31 December 2019, the World Health Organization recognised clusters of pneumonia-like cases due to a novel coronavirus disease (COVID-19). COVID-19 became a pandemic 71 days later. AIM: To report the clinical and epidemiological features, laboratory data and outcomes of the first group of 11 returned travellers with COVID-19 in Australia. METHODS: This is a retrospective, multi-centre case series. All patients with confirmed COVID-19 infection were admitted to tertiary referral hospitals in New South Wales, Queensland, Victoria and South Australia. RESULTS: The median age of the patient cohort was 42 years (interquartile range (IQR), 24-53 years) with six men and five women. Eight (72.7%) patients had returned from Wuhan, one from Shenzhen, one from Japan and one from Europe. Possible human-to-human transmission from close family contacts in gatherings overseas occurred in two cases. Symptoms on admission were fever, cough and sore throat (n = 9, 81.8%). Co-morbidities included hypertension (n = 3, 27.3%) and hypercholesterolaemia (n = 2, 18.2%). No patients developed severe acute respiratory distress nor required intensive care unit admission or mechanical ventilation. After a median hospital stay of 14.5 days (IQR, 6.75-21), all patients were discharged. CONCLUSIONS: This is a historical record of the first COVID-19 cases in Australia during the early biocontainment phase of the national response. These findings were invaluable for establishing early inpatient and outpatient COVID-19 models of care and informing the management of COVID-19 over time as the outbreak evolved. Future research should extend this Australian case series to examine global epidemiological variation of this novel infection.

Effect of Vancomycin or Daptomycin With vs Without an Antistaphylococcal ß-Lactam on Mortality, Bacteremia, Relapse, or Treatment Failure in Patients With MRSA Bacteremia: A Randomized Clinical Trial.

Importance: Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with mortality of more than 20%. Combining standard therapy with a ß-lactam antibiotic has been associated with reduced mortality, although adequately powered randomized clinical trials of this intervention have not been conducted. Objective: To determine whether combining an antistaphylococcal ß-lactam with standard therapy is more effective than standard therapy alone in patients with MRSA bacteremia. Design, Setting, and Participants: Open-label, randomized clinical trial conducted at 27 hospital sites in 4 countries from August 2015 to July 2018 among 352 hospitalized adults with MRSA bacteremia. Follow-up was complete on October 23, 2018. Interventions: Participants were randomized to standard therapy (intravenous vancomycin or daptomycin) plus an antistaphylococcal ß-lactam (intravenous flucloxacillin, cloxacillin, or cefazolin) (n = 174) or standard therapy alone (n = 178). Total duration of therapy was determined by treating clinicians and the ß-lactam was administered for 7 days. Main Outcomes and Measures: The primary end point was a 90-day composite of mortality, persistent bacteremia at day 5, microbiological relapse, and microbiological treatment failure. Secondary outcomes included mortality at days 14, 42, and 90; persistent bacteremia at days 2 and 5; acute kidney injury (AKI); microbiological relapse; microbiological treatment failure; and duration of intravenous antibiotics. Results: The data and safety monitoring board recommended early termination of the study prior to enrollment of 440 patients because of safety. Among 352 patients randomized (mean age, 62.2 [SD, 17.7] years; 121 women [34.4%]), 345 (98%) completed the trial. The primary end point was met by 59 (35%) with combination therapy and 68 (39%) with standard therapy (absolute difference, -4.2%; 95% CI, -14.3% to 6.0%). Seven of 9 prespecified secondary end points showed no significant difference. For the combination therapy vs standard therapy groups, all-cause 90-day mortality occurred in 35 (21%) vs 28 (16%) (difference, 4.5%; 95% CI, -3.7% to 12.7%); persistent bacteremia at day 5 was observed in 19 of 166 (11%) vs 35 of 172 (20%) (difference, -8.9%; 95% CI, -16.6% to -1.2%); and, excluding patients receiving dialysis at baseline, AKI occurred in 34 of 145 (23%) vs 9 of 145 (6%) (difference, 17.2%; 95% CI, 9.3%-25.2%). Conclusions and Relevance: Among patients with MRSA bacteremia, addition of an antistaphylococcal ß-lactam to standard antibiotic therapy with vancomycin or daptomycin did not result in significant improvement in the primary composite end point of mortality, persistent bacteremia, relapse, or treatment failure. Early trial termination for safety concerns and the possibility that the study was underpowered to detect clinically important differences in favor of the intervention should be considered when interpreting the findings. Trial Registration: ClinicalTrials.gov Identifier: NCT02365493.

Combination of Vancomycin and ß-Lactam Therapy for Methicillin-Resistant Staphylococcus aureus Bacteremia: A Pilot Multicenter Randomized Controlled Trial.

BACKGROUND: In vitro laboratory and animal studies demonstrate a synergistic role for the combination of vancomycin and antistaphylococcal ß-lactams for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Prospective clinical data are lacking. METHODS: In this open-label, multicenter, clinical trial, adults with MRSA bacteremia received vancomycin 1.5 g intravenously twice daily and were randomly assigned (1:1) to receive intravenous flucloxacillin 2 g every 6 hours for 7 days (combination group) or no additional therapy (standard therapy group). Participants were stratified by hospital and randomized in permuted blocks of variable size. Randomization codes were kept in sealed, sequentially numbered, opaque envelopes. The primary outcome was the duration of MRSA bacteremia in days. RESULTS: We randomly assigned 60 patients to receive vancomycin (n = 29), or vancomycin plus flucloxacillin (n = 31). The mean duration of bacteremia was 3.00 days in the standard therapy group and 1.94 days in the combination group. According to a negative binomial model, the mean time to resolution of bacteremia in the combination group was 65% (95% confidence interval, 41%-102%; P = .06) that in the standard therapy group. There was no difference in the secondary end points of 28- and 90-day mortality, metastatic infection, nephrotoxicity, or hepatotoxicity. CONCLUSIONS: Combining an antistaphylococcal ß-lactam with vancomycin may shorten the duration of MRSA bacteremia. Further trials with a larger sample size and objective clinically relevant end points are warranted. Australian New Zealand Clinical Trials Registry: ACTRN12610000940077 (www.anzctr.org.au).

Rapid Detection of Methicillin-Resistant Staphylococcus aureus and Methicillin-Susceptible S. aureus Directly from Positive Blood Cultures by Use of the BD Max StaphSR Assay.

The BD Max StaphSR assay is an automated qualitative in vitro diagnostic test for the direct detection and differentiation of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA). A total of 460 specimens were tested, and the results were compared with standard culture-based identification. MRSA was detected in 48 samples (sensitivity of 100%; positive predictive value [PPV] of 100%). MSSA was detected in 112 samples (sensitivity of 99.1%; PPV of 100%), and 299 samples containing coagulase-negative staphylococcus and nonstaphylococcal species were negative by the BD Max StaphSR assay (specificity of 100%; negative predictive value [NPV] of 99.7 to 100%).

Genetic and molecular predictors of high vancomycin MIC in Staphylococcus aureus bacteremia isolates.

An elevated vancomycin MIC is associated with poor outcomes in Staphylococcus aureus bacteremia (SAB) and is reported in patients with methicillin-susceptible S. aureus (MSSA) bacteremia in the absence of vancomycin treatment. Here, using DNA microarray and phenotype analysis, we investigated the genetic predictors and accessory gene regulator (agr) function and their relationship with elevated vancomycin MIC using blood culture isolates from a multicenter binational cohort of patients with SAB. Specific clonal complexes were associated with elevated (clonal complex 8 [CC8] [P < 0.001]) or low (CC22 [P < 0.001], CC88 [P < 0.001], and CC188 [P = 0.002]) vancomycin MIC. agr dysfunction (P = 0.014) or agr genotype II (P = 0.043) were also associated with an elevated vancomycin MIC. Specific resistance and virulence genes were also linked to an elevated vancomycin MIC, including blaZ (P = 0.002), sea (P < 0.001), clfA (P < 0.001), splA (P = 0.001), and the arginine catabolic mobile element (ACME) locus (P = 0.02). These data suggest that inherent organism characteristics may explain the link between elevated vancomycin MICs and poor outcomes in patients with SAB, regardless of the antibiotic treatment received. A consideration of clonal specificity should be included in future research when attempting to ascertain treatment effects or clinical outcomes.

Software for selecting the most informative sets of genomic loci for multi-target microbial typing.

BACKGROUND: High-throughput sequencing can identify numerous potential genomic targets for microbial strain typing, but identification of the most informative combinations requires the use of computational screening tools. This paper describes novel software-- Automated Selection of Typing Target Subsets (AuSeTTS)--that allows intelligent selection of optimal targets for pathogen strain typing. The objective of this software is to maximise both discriminatory power, using Simpson's index of diversity (D), and concordance with existing typing methods, using the adjusted Wallace coefficient (AW). The program interrogates molecular typing results for panels of isolates, based on large target sets, and iteratively examines each target, one-by-one, to determine the most informative subset. RESULTS: AuSeTTS was evaluated using three target sets: 51 binary targets (13 toxin genes, 16 phage-related loci and 22 SCCmec elements), used for multilocus typing of 153 methicillin-resistant Staphylococcus aureus (MRSA) isolates; 17 MLVA loci in 502 Streptococcus pneumoniae isolates from the MLVA database (http://www.mlva.eu) and 12 MLST loci for 98 Cryptococcus spp. isolates.The maximum D for MRSA, 0.984, was achieved with a subset of 20 targets and a D value of 0.954 with 7 targets. Twelve targets predicted MLST with a maximum AW of 0.9994. All 17 S. pneumoniae MLVA targets were required to achieve maximum D of 0.997, but 4 targets reached D of 0.990. Twelve targets predicted pneumococcal serotype with a maximum AW of 0.899 and 9 predicted MLST with maximum AW of 0.963. Eight of the 12 MLST loci were sufficient to achieve the maximum D of 0.963 for Cryptococcus spp. CONCLUSIONS: Computerised analysis with AuSeTTS allows rapid selection of the most discriminatory targets for incorporation into typing schemes. Output of the program is presented in both tabular and graphical formats and the software is available for free download from http://www.cidmpublichealth.org/pages/ausetts.html.

Vancomycin AUC/MIC ratio and 30-day mortality in patients with Staphylococcus aureus bacteremia.

A ratio of the vancomycin area under the concentration-time curve to the MIC (AUC/MIC) of ≥ 400 has been associated with clinical success when treating Staphylococcus aureus pneumonia, and this target was recommended by recently published vancomycin therapeutic monitoring consensus guidelines for treating all serious S. aureus infections. Here, vancomycin serum trough levels and vancomycin AUC/MIC were evaluated in a "real-world" context by following a cohort of 182 patients with S. aureus bacteremia (SAB) and analyzing these parameters within the critical first 96 h of vancomycin therapy. The median vancomycin trough level at this time point was 19.5 mg/liter. There was a significant difference in vancomycin AUC/MIC when using broth microdilution (BMD) compared with Etest MIC (medians of 436.1 and 271.5, respectively; P < 0.001). Obtaining the recommended vancomycin target AUC/MIC of ≥ 400 using BMD was not associated with lower 30-day all-cause or attributable mortality from SAB (P = 0.132 and P = 0.273, respectively). However, an alternative vancomycin AUC/MIC of >373, derived using classification and regression tree analysis, was associated with reduced mortality (P = 0.043) and remained significant in a multivariable model. This study demonstrated that we obtained vancomycin trough levels in the target therapeutic range early during the course of therapy and that obtaining a higher vancomycin AUC/MIC (in this case, >373) within 96 h was associated with reduced mortality. The MIC test method has a significant impact on vancomycin AUC/MIC estimation. Clinicians should be aware that the current target AUC/MIC of ≥ 400 was derived using the reference BMD method, so adjustments to this target need to be made when calculating AUC/MIC ratio using other MIC testing methods.

Quantitative estimation of the stability of methicillin-resistant Staphylococcus aureus strain-typing systems by use of Kaplan-Meier survival analysis.

Knowledge concerning stability is important in the development and assessment of microbial molecular typing systems and is critical for the interpretation of their results. Typing system stability is usually measured as the fraction of isolates that change type after several in vivo passages, but this does not necessarily reflect in vivo stability. The aim of this study was to utilize survival analysis to provide an informative quantitative measure of in vivo stability and to compare the stabilities of various techniques employed in typing methicillin-resistant Staphylococcus aureus (MRSA). We identified 100 MRSA pairs (isolated from the same patient ≥ 1 month apart) and typed them using multilocus sequence typing (MLST), phage-derived open reading frame (PDORF) typing, toxin gene profiling (TGP), staphylococcal cassette chromosome mec (SCCmec) subtyping, pulsed-field gel electrophoresis (PFGE), and spa sequence typing. Discordant isolate pairs, belonging to different MLST clonal complexes, were excluded, leaving 81 pairs for analysis. The stabilities of these methods were examined using Kaplan-Meier survival analysis, and discriminatory power was measured by Simpson's index of diversity. The probability percentages that the type remained unchanged at 6 months for spa sequence typing, TGP, multilocus variable number of tandem repeats analysis (MLVA), SCCmec subtyping, PDORF typing, and PFGE were 95, 95, 88, 82, 71, and 58, respectively, while the Simpson's indices of diversity were 0.48, 0.47, 0.70, 0.72, 0.89, and 0.88, respectively. Survival analysis using sequential clinical isolates adds an important quantitative dimension to the measurement of stability of a microbial typing system. Of the methods compared here, PDORF typing provides high discriminatory power, comparable with that of PFGE, and a level of stability suitable for MRSA surveillance and outbreak investigations.

National surveillance of methicillin-resistant Staphylococcus aureus in China highlights a still-evolving epidemiology with 15 novel emerging multilocus sequence types.

The global spread of methicillin-resistant Staphylococcus aureus (MRSA) is a serious problem, particularly in mainland China. In order to better understand the national molecular epidemiology and resistance profiles of hospital-associated MRSA (HA-MRSA) in China, a laboratory-based multicenter surveillance study was conducted. Sixty-nine hospitals in 45 large cities in 27 provinces were involved, and a total of 1,141 HA-MRSA isolates were collected during the 6-month study period in 2011. All MRSA isolates were characterized by multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, spa typing, detection of the Panton-Valentine leukocidin (PVL) locus (lukS-PV and lukF-PV), and antibiogram analysis. ST239-III-t030, ST239-III-t037, and ST5-II-t002 were the predominant HA-MRSA clones (overall prevalence rates, 57.1%, 12.9%, and 8.1%, respectively), although the prevalence rates of these major clones varied markedly in different administrative regions. Of note, 6.6% of the HA-MRSA isolates were found to belong to ST59, which had typical community-associated MRSA (CA-MRSA) features, including carriage of SCCmec type IV or V and PVL and less antimicrobial resistance than other major HA-MRSA clones. Moreover, among 36 MLST sequence types (STs) identified, 15 STs, accounting for 3.5% of total isolates, were novel. A novel ST designated ST2590, which is a single-locus variant of ST5-II-t002, was identified in three hospitals in two large cities, with a total of 17 isolates. To further monitor trends in HA-MRSA prevalence, epidemic clonal shifts, clone emergence, and transmission between community and health care settings, longitudinal national MRSA surveillance is required.

A Randomized Trial of Nafamostat for Covid-19.

BACKGROUND: Nafamostat mesylate is a potent in vitro antiviral agent that inhibits the host transmembrane protease serine 2 enzyme used by severe acute respiratory syndrome coronavirus 2 for cell entry. METHODS: This open-label, pragmatic, randomized clinical trial in Australia, New Zealand, and Nepal included noncritically ill hospitalized patients with coronavirus disease 2019 (Covid-19). Participants were randomly assigned to usual care or usual care plus nafamostat. The primary end point was death (any cause) or receipt of new invasive or noninvasive ventilation or vasopressor support within 28 days after randomization. Analysis was with a Bayesian logistic model in which an adjusted odds ratio <1.0 indicates improved outcomes with nafamostat. Enrollment was closed due to falling numbers of eligible patients. RESULTS: We screened 647 patients in 21 hospitals (15 in Australia, 4 in New Zealand, and 2 in Nepal) and enrolled 160 participants from May 2021 to August 2022. In the intention-to-treat population, the primary end point occurred in 8 (11%) of 73 patients with usual care and 4 (5%) of 82 with nafamostat. The median adjusted odds ratio for the primary end point for nafamostat was 0.40 (95% credible interval, 0.12 to 1.34) with a posterior probability of effectiveness (adjusted odds ratio <1.0) of 93%. For usual care compared with nafamostat, hyperkalemia occurred in 1 (1%) of 67 and 7 (9%) of 78 participants, respectively, and clinically relevant bleeding occurred in 1 (1%) of 73 and 7 (8%) of 82 participants. CONCLUSIONS: Among hospitalized patients with Covid-19, there was a 93% posterior probability that nafamostat reduced the odds of death or organ support. Prespecified stopping criteria were not met, precluding definitive conclusions. Hyperkalemia and bleeding were more common with nafamostat. (Funded by ASCOT and others; ClinicalTrials.gov number, NCT04483960.)

Prospective genotyping of hospital-acquired methicillin-resistant Staphylococcus aureus isolates by use of a novel, highly discriminatory binary typing system.

In settings of high methicillin-resistant Staphylococcus aureus (MRSA) prevalence, detection of nosocomial transmission events can be difficult without strain typing. Prospective typing of all MRSA isolates could potentially identify transmission in a timely fashion, making infection control responses to outbreaks more effective. We describe the development and evaluation of a novel 19-target binary typing system for MRSA using the multiplex-PCR/reverse line blot hybridization platform. Pulse-field gel electrophoresis (PFGE), spa typing, and phage-derived open reading frame (PDORF) typing were performed for comparison. The system was utilized to identify transmission events in three general surgical wards over a 12-month period. Initial MRSA isolates from 273 patients were differentiated into 55 unique binary types. One or more potential contacts colonized with the same MRSA strain were identified in 69 of 87 cases (79%) in which definite or possible nosocomial MRSA acquisition had occurred. The discriminatory power of the typing system was similar to that of PFGE (Simpson's index of diversity [D] = 0.994, versus 0.987) and higher than that of spa typing (D = 0.926). Strain typing reduced the total number of potential MRSA-colonized source contacts from 859 to 212 and revealed temporal clustering of transmission events. Prospective MRSA typing using this novel binary typing method can rapidly identify nosocomial transmission events, even in high-prevalence settings, which allows timely infection control interventions. The system is rapid, inexpensive, discriminatory, and suitable for routine, high-throughput use in the hospital microbiology laboratory.

Antibiotic choice may not explain poorer outcomes in patients with Staphylococcus aureus bacteremia and high vancomycin minimum inhibitory concentrations.

BACKGROUND: There are concerns about reduced efficacy of vancomycin in patients with Staphylococcus aureus bacteremia (SAB), especially when the minimum inhibitory concentration (MIC) nears the upper limit of the susceptible range. METHODS: We examined the relationship between antibiotic treatment, 30-day mortality, and microbiologic parameters in a large Australasian cohort of patients with SAB. RESULTS: We assessed 532 patients with SAB from 8 hospitals. All patients with methicillin-resistant S. aureus (MRSA) bacteremia were treated with vancomycin, and patients with methicillin-susceptible S. aureus (MSSA) bacteremia received either flucloxacillin or vancomycin. Increasing vancomycin MIC was associated with increased mortality in vancomycin-treated patients. However, even in patients with MSSA bacteremia treated with flucloxacillin, mortality was also higher if the vancomycin Etest MIC of their isolate was >1.5 µg/mL, compared with those with lower MIC isolates (26.8% vs 12.2%; P < .001). After adjustment in a multivariate model, age, hospital-onset SAB and vancomycin MIC were independently associated with mortality, but methicillin resistance and antibiotic choice were not. CONCLUSIONS: We have confirmed an association between higher vancomycin MIC and increased mortality in patients with SAB, but surprisingly this relationship was not related to the antibiotic treatment received, suggesting that the use of vancomycin per se is not responsible for the poorer outcome.

ASCOT ADAPT study of COVID-19 therapeutics in hospitalised patients: an international multicentre adaptive platform trial.

BACKGROUND: SARS-CoV-2 infection is associated with a significant risk of hospitalisation, death, and prolonged impact on quality of life. Evaluation of new treatment options and optimising therapeutic management of people hospitalised with SARS-CoV-2 infection remains essential, but rapid changes in pandemic conditions and potential therapies have limited the utility of traditional approaches to randomised controlled trials. METHODS: ASCOT ADAPT is an international, investigator-initiated, adaptive platform, randomised controlled trial of therapeutics for non-critically ill patients hospitalised with COVID-19. The study design is open label and pragmatic. Potential participants are hospitalised adults with PCR confirmed, symptomatic, SARS-CoV-2 infection, within 14 days of symptom onset. Domains include antiviral, antibody and anticoagulant interventions, with a composite primary outcome of 28-day mortality or progression to intensive-care level respiratory or haemodynamic support. Initial interventions include intravenous nafamostat and variable dose anticoagulation. A range of secondary endpoints, and substudies for specific domains and interventions are outlined. DISCUSSION: This paper presents the trial protocol and management structure, including international governance, remote site monitoring and biobanking activities and provides commentary on ethical and pragmatic considerations in establishing the ASCOT ADAPT trial under pandemic conditions. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry (ACTRN12620000445976) and ClinicalTrials.gov (NCT04483960).

Seroprevalence of Severe Acute Respiratory Syndrome Coronavirus 2-Specific Antibodies in Australia After the First Epidemic Wave in 2020: A National Survey.

BACKGROUND: As of mid-2021, Australia's only nationwide coronavirus disease 2019 (COVID-19) epidemic occurred in the first 6 months of the pandemic. Subsequently, there has been limited transmission in most states and territories. Understanding community spread during the first wave was hampered by initial limitations on testing and surveillance. To characterize the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody seroprevalence generated during this time, we undertook Australia's largest national SARS-CoV-2 serosurvey. METHODS: Between June 19 and August 6, 2020, residual specimens were sampled from people undergoing general pathology testing (all ages), women attending antenatal screening (20-39 years), and blood donors (20-69 years) based on the Australian population's age and geographic distributions. Specimens were tested by Wantai total SARS-CoV-2-antibody assay. Seroprevalence estimates adjusted for test performance were produced. The SARS-CoV-2 antibody-positive specimens were characterized with microneutralization assays. RESULTS: Of 11 317 specimens (5132 general pathology; 2972 antenatal; 3213 blood-donors), 71 were positive for SARS-CoV-2-specific antibodies. Seroprevalence estimates were 0.47% (95% credible interval [CrI], 0.04%-0.89%), 0.25% (CrI, 0.03%-0.54%), and 0.23% (CrI, 0.04%-0.54%), respectively. No seropositive specimens had neutralizing antibodies. CONCLUSIONS: Australia's seroprevalence was extremely low (<0.5%) after the only national COVID-19 wave thus far. These data and the subsequent limited community transmission highlight the population's naivety to SARS-CoV-2 and the urgency of increasing vaccine-derived protection.

The utility of SARS-CoV-2-specific serology in COVID-19 diagnosis.

INTRODUCTION: In May 2020, The Communicable Diseases Network of Australia (CDNA) case definition introduced serological criteria to support the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We present findings that support the utility of SARS-CoV-2-specific serology for public health investigations. METHODS: From 24 January to 31 July 2020, the following information was collected from individuals with positive SARS-CoV-2-specific immunofluorescence antibody tests: history of contact with COVID-19 cases; recent travel; symptoms consistent with COVID-19; and SARS-CoV-2 nucleic acid testing (NAT) results. Individuals were classified as confirmed or probable by CDNA criteria or additionally as possible (SARS-CoV-2-specific IgG positive with compatible symptoms or epidemiologic risk) or indeterminate (SARS-CoV-2-specific IgA/IgM positive only) cases. RESULTS: A total of 10,595 individuals were tested in the six-month period. Of these, 9.8% (1,037) individuals had positive SARS-CoV-2-specific serology of which 566 (53.6%) were NAT-confirmed COVID-19 cases and 286 (27.6%) were part of a cruise ship outbreak sero-survey. The remaining 185 individuals (NAT negative) were individually classified as serologically confirmed (4, 0.4%), probable (72, 6.9%) possible (66, 6.4%) and indeterminate (38, 3.7%) cases. Maternal antibody transfer was inferred in one infant and four were unclassified. CONCLUSION: SARS-CoV-2-specific serology is a key diagnostic tool for retrospective identification of COVID-19 infection. Implications for public health: SARS-CoV-2 specific serology can enhance the ability to find cases, link missing cases in clusters of infection and identify the epidemiological extent of SARS-CoV-2 outbreaks. A combination of epidemiological criteria, clinical criteria and a quantitative serological test can be used as an adjunct to classify SARS-CoV-2 cases. Our study confirms the low level of community transmission in NSW during the first year of the COVID-19 pandemic.

Outbreak of community-acquired Staphylococcus aureus skin infections in an Australian professional football team.

OBJECTIVES: Skin and soft tissue infections commonly affect athletes and can lead to cluster outbreaks if not managed appropriately. We report the findings of an investigation into an outbreak of community-acquired Staphylococcus aureus infection in an Australian professional football team. DESIGN: Retrospective cross-sectional study. METHODS: Nose, axilla, groin and throat swab were collected from 47 participants. MRSA and MSSA isolates underwent antibiotic susceptibility testing, binary typing and whole genome sequencing. Infection control practitioners (ICPs) investigated the training grounds for risk factors in the transmission of S. aureus. RESULTS: Almost half of the participants (n=23, 48.9%) were found to be colonised with MSSA. An outbreak cluster of MRSA ST5 closely related to the fusidic acid-resistant New Zealand NZAK3 clone was identified in a group of four players. MSSA ST15 and MSSA ST291 strains were found to have colonised and spread between two and five players, respectively. All participants were advised to undergo decolonisation treatment consisting of 4% chlorhexidine body wash and mupirocin nasal ointment for ten days. The ICP team identified several unhygienic practices within the club's shared facilities that may have played a role in the transmission of S. aureus. CONCLUSIONS: We report for the first time a community-associated S. aureus outbreak involving the highly successful fusidic acid-resistant MRSA ST5 clone in a professional football club associated with inadequate hygiene procedures. Management and prevention of S. aureus relies heavily on hygiene education and adherence to personal and environmental hygiene practices and policies.