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This audit reviewed the impact on access to routine medical care and adverse outcomes in patients with suspected SARS-CoV-2 infection managed on a 'COVID-19' (CV) ward compared with a general medicine ward at Box Hill Hospital, Victoria. Data were collected at two time points to capture changes associated with onsite testing. We found no healthcare delays from admission to CV wards and observed faster exits from CV wards with improved testing efficiency. This critical finding is relevant as Victoria manages a third wave of infections.

Background Healthcare workers (HCW) are exposed to an increased risk of COVID-19 through direct contact with patients and patient environments. We calculated the; seroprevalence of SARS-CoV-2 in HCW at Eastern Health, a tertiary healthcare network in Victoria, and assessed associations with demographics, work location and role. Methods A cross-sectional cohort study of HCW at Eastern Health was conducted. Serum was analysed for the presence of antibodies to SARS-CoV-2, and all participants completed; an online survey collecting information on demographics, place of work, role, and exposures; to COVID-19. Seroprevalence was calculated as the proportion participants with SARS-CoV-2; antibodies out of all tested individuals. Results The crude seroprevalence of SARS-CoV-2 antibodies in this study was 2.17% (16/736). Thirteen of the 16 (81.2%) positive cases had previously been diagnosed with COVID-19 by PCR: the seroprevalence in the group not previously diagnosed with COVID by PCR was 0.42% (3/720). Having direct contact with COVID-19 patients did not increase the likelihood of having positive serology. A prior history of symptoms consistent with COVID-19 was associated with a higher likelihood of having positive serology (OR 17.2, p = 0.006, 95%CI: 2.25–131.55). Conclusion Our calculated seroprevalence of 2.17% is higher than estimated in the general Australian population, but lower than that reported in HCW internationally. The; majority of those with positive serology in our study had previously been diagnosed with COVID-19 by PCR based testing. Seropositivity was not associated with interaction with COVID-19 positive patients, highlighting effective infection prevention and control practices within the workplace.

Background Periprosthetic joint infection (PJI) is a devastating condition and there is a lack of evidence to guide its management. We hypothesized that treatment success is independently associated with modifiable variables in surgical and antibiotic management. Methods The is a prospective, observational study at 27 hospitals across Australia and New Zealand. Newly diagnosed large joint PJIs were eligible. Data were collected at baseline and at 3, 12, and 24 months. The main outcome measures at 24 months were clinical cure (defined as all of the following: alive, absence of clinical or microbiological evidence of infection, and not requiring ongoing antibiotic therapy) and treatment success (clinical cure plus index prosthesis still in place). Results Twenty-four-month outcome data were available for 653 patients. Overall, 449 patients (69%) experienced clinical cure and 350 (54%) had treatment success. The most common treatment strategy was debridement and implant retention (DAIR), with success rates highest in early postimplant infections (119 of 160, 74%) and lower in late acute (132 of 267, 49%) and chronic (63 of 142, 44%) infections. Selected comorbidities, knee joint, and Staphylococcus aureus infections were independently associated with treatment failure, but antibiotic choice and duration (including rifampicin use) and extent of debridement were not. Conclusions Treatment success in PJI is associated with (1) selecting the appropriate treatment strategy and (2) nonmodifiable patient and infection factors. Interdisciplinary decision making that matches an individual patient to an appropriate management strategy is a critical step for PJI management. Randomized controlled trials are needed to determine the role of rifampicin in patients managed with DAIR and the optimal surgical strategy for late-acute PJI.

Background Periprosthetic joint infection (PJI) is a devastating complication of joint replacement surgery. Most observational studies of PJI are retrospective or single-center, and reported management approaches and outcomes vary widely. We hypothesized that there would be substantial heterogeneity in PJI management and that most PJIs would present as late acute infections occurring as a consequence of bloodstream infections. Methods The Prosthetic joint Infection in Australia and New Zealand, Observational (PIANO) study is a prospective study at 27 hospitals. From July 2014 through December 2017, we enrolled all adults with a newly diagnosed PJI of a large joint. We collected data on demographics, microbiology, and surgical and antibiotic management over the first 3 months postpresentation. Results We enrolled 783 patients (427 knee, 323 hip, 25 shoulder, 6 elbow, and 2 ankle). The mode of presentation was late acute (>30 days postimplantation and 30 days postimplantation with ≥30 days of symptoms; 148, 19%). Debridement, antibiotics, irrigation, and implant retention constituted the commonest initial management approach (565, 72%), but debridement was moderate or less in 142 (25%) and the polyethylene liner was not exchanged in 104 (23%). Conclusions In contrast to most studies, late acute infection was the most common mode of presentation, likely reflecting hematogenous seeding. Management was heterogeneous, reflecting the poor evidence base and the need for randomized controlled trials., We enrolled 783 patients in a prospective, observational binational study of peri-prosthetic joint infection. Late, acute infections were the commonest mode of presentation. Microbiological causes differed according to affected joint and the timing of the infection. Management approaches were heterogeneous.

We compared the identification of Clostridium species using mass spectrometry by two different Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) platforms (Bruker MS and Vitek MS) against 16S rRNA sequencing as the reference standard. We then examined the impact of different sample preparations and (on one of those platforms) age of bacterial colonial growth on the performance of the MALDI-TOF MS systems. We identified 10 different species amongst the 52 isolates by 16S rRNA sequencing, with Clostridium perfringens the most prevalent (n=30). Spectrometric analysis using Vitek MS correctly speciated 47/52 (90.4%) isolates and was not affected by the sample preparation used. Performance of the Bruker MS was dependent on sample preparation with correct speciation obtained for 36 of 52 (69.2%) isolates tested using the Direct Transfer [DT] protocol, but all 52 (100%) isolates were correctly speciated using either an Extended Direct Transfer [EDT] or a Full Formic Extraction [EX] protocol. We then examined the effect of bacterial colonial growth age on the performance of Bruker MS and found substantial agreement in speciation using DT (Kappa=0.62, 95% CI: 0.46-0.75), almost perfect agreement for EDT (Kappa=0.94, 95% CI: 0.86-1.00) and exact agreement for EX (Kappa=1.00) between different days.

In late 2009 transplant organizations recommended that kidney recipients be vaccinated for pandemic H1N1 influenza (pH1N1); however, the vaccine efficacy was unknown. We had offered a monovalent non-adjuvanted pH1N1 vaccine to transplant recipients. Here we compared the pre- and post-vaccination seroresponses of 151 transplant recipients to that of 71 hemodialysis patients and 30 healthy controls. Baseline seroprotection was similar between groups but was significantly different at 1 month (44, 56, and 87%, respectively). Seroconversion was significantly less common for transplant recipients (32%) than dialysis patients (45%) and healthy controls (77%). After adjusting for age and gender, dialysis patients were significantly more likely (2.7-fold) to achieve new seroprotection than transplant recipients. The likelihood of seroprotection in transplant recipients was significantly reduced by mycophenolate use (adjusted odds ratio 0.24), in a dose-dependent manner, and by reduced eGFR (adjusted odds ratio 0.16 for worst to best). Seroprotection and geometric mean antibody titers increased substantially in 49 transplant recipients who subsequently received the 2010 seasonal influenza vaccine. Thus, patients requiring renal replacement therapy had reduced seroresponses to vaccination with the monovalent vaccine compared with healthy controls. Transplant recipient responses were further reduced if they were receiving mycophenolate or had significantly lower graft function.

Vaccine-preventable diseases cause significant mortality and morbidity. Immunisation of healthcare workers (HCW) plays a significant role in preventing nosocomial transmission in healthcare settings. Non-immune HCW put themselves, their contacts and patients at risk of preventable diseases. Achieving 100% protection for HCW and patients should be an achievable target; however, voluntary vaccination programs fail to achieve this rate of protection. This is true in the case of influenza, which contributes to the highest mortality and morbidity of any vaccine-preventable disease. Despite available safe, effective vaccines for seasonal influenza and recommendations by local and international authoritative bodies, the annual influenza vaccination rates amongst HCW remain disappointingly low despite recommendations by local and international authoritative bodies. Voluntary strategies of increasing access, offers of free vaccines, education, and highly visible publicity campaigns have had limited success. In the US, more innovative ideas have been proposed to complement these steps.We discuss such strategies including mandatory influenza vaccination and its possible implementation.

The etiology of culture-negative septic arthritis is poorly characterised in persons infected with human immunodeficiency virus (HIV). New molecular methods may assist in the investigation of culture-negative infections of sterile sites, including septic arthritis. We describe the first case of septic arthritis due to the cause of rat bite fever (RBF), Streptobacillus moniliformis, confirmed by 16S rRNA sequence analysis, in a patient with newly diagnosed HIV infection.

Introduction We compared the identification of 52 Clostridium species from 52 incident bacteraemic patients using phenotypic analysis, two MALDI-TOF mass spectrometry platforms and molecular sequencing. We also examined the impact of different sample preparations and (on one platform) days of colonial growth on the performance of MALDI-TOF systems. Result 16S rRNA PCR accurately identified 10 Clostridium species amongst the 52 isolates. Combination phenotypic methods identified 44/52 (84.6%) to species level. Spectrometric analysis using Vitek MS yielded 47/52 (90.4%) species using direct transfer (DT), whilst analysis using Bruker MS yielded correct identification dependent on sample preparation [69.2% for DT protocol, 100% for extended direct transfer (EDT) protocol and 100% for full formic extraction (EX) protocol]. Sample preparation didn’t impact the Vitek MS. There was at least moderate agreement in performance for DT, EDT and EX between different days for the Bruker MS. Conclusion Phenotypic identification required numerous methods to accurately identified Clostridium species. Vitek MALDI-TOF MS performed better with the DT protocol compared to the Bruker MS, but the latter yielded correct identification in all samples tested with EDT and EX protocol. Sample preparations did not impact the Vitek MS. On the Bruker MS, the testing cycle can begin upon view of colonial growth.

Introduction 16S rRNA polymerase chain reaction (PCR) can result in accurate identification of many bacteria, but is not helpful in non-sterile specimens. We postulated specific toxin genes critically important in disease pathogenesis as alternative organism-specific targets in Clostridium perfringens, C. septicum and C. sordellii. We tested this theory using a 10-year single-institution Clostridium spp. bacteraemia series to investigate if there is any relatedness of presence of toxin genes to speciation of organism. Results Of 52 incident cases of blood cultures positive with Clostridium spp., there were 30 C. perfringens, six C. septicum and one C sordellii identified by 16S rRNA PCR. All 30 C. perfringens tested positive for plc genes by PCR, whilst two control isolates of C. septicum tested negative. All six C. septicum were also positive for csa gene, whilst the control C. sordellii did not produce a band. The single C. sordellii isolate tested did not generate a product specific for the tcsL or tcsH gene, the two major virulence determinants of this bacterium, but did result in an expected 450 bp sdlO fragment. Summary Toxigenic gene analysis can potentially be used to identify limited but important species of Clostridia when specific syndromes and aetiologies are suspected. Further work needs to be undertaken to further proof this.

Background Syphilis is primarily diagnosed serologically. Poly-merase chain reaction (PCR) is increasingly used as an adjunct in diagnosis. We describe the first case of using polA syphilis-specific PCR to make the diagnosis of syphilis aortitis. Case A 36-year-old Indian male had a 2 day history of fever and back pain. Examination revealed severe aortic regurgitation. Transoesophageal echocardiography demonstrated coronary cusp destruction with severe aortic regurgitation. Multiple blood cultures and investigations for ‘culture-negative endocarditis’ were unhelpful. Computed tomography of the thorax revealed normal thickness aorta. An empiric endocarditis antibiotics regimen was initiated and the patient had a mechanical St Jude’s aortic valve replacement. Histology of aortic intima and aortic valve revealed acute on chronic inflammation and prominent plasma cells. 16S rRNA PCR didn’t yield a bacterial sequence. Syphilis serology revealed positive Syphilis TP (Architect), Treponema pallidum particle agglutination (TPPA), total antibody enzyme immunoassay (EIA) and IgM EIA; whilst rapid plasma reagin (RPR) reactive, titre 1:64. Treponemal pallidum polA PCR was retrospectively performed on aortic intima and returned positive. The patient had his empiric antibiotics ceased and completed 15 days of IV penicillin. Conclusion The correct use of organism-specific targets in PCR can be considered to aid diagnosis. This is a proof of concept testing that may help certain cases of syphilis diagnosis in the future.