Infective endocarditis outcomes at a tertiary hospital in Western Australia: a retrospective cohort study from 2016 to 2021.

BACKGROUND: Infective endocarditis (IE) is a severe infection with considerable mortality. It is associated with geographical variation, complicating diagnosis and treatment of patients in a standardised manner. AIM: To evaluate the characteristics and management outcomes of patients with IE in Royal Perth Hospital (RPH). METHODS: A single-centre, retrospective cohort study. Data were collected from medical records of 131 patients with a diagnosis of IE admitted to RPH between 2016 and 2021. RESULTS: Eighty-four patients with definite IE were included for analysis. The median age of patients was 51.5 years and 77.4% were male. Compared to the general Australian population, there was disproportionately greater representation of Indigenous Australians (21.4%), those with a history of injecting drug use (IDU) (27.4%), rheumatic heart disease (14.3%) and previous IE (13.1%). The most commonly affected valve was the mitral valve in 46.4% of patients, and the most common pathogen was Staphylococcus aureus in 47.6% of patients. Twelve-month mortality was 16.7%, with significantly increased mortality in those treated non-surgically (25.6% vs 7.3%, P = 0.025). Factors associated with undergoing surgery included the presence of aortic valve disease, perivalvular extension of infection and infection with Enterococcus faecalis, whereas IDU, tricuspid valve disease and S. aureus infection were associated with non-surgical management. Adherence to multidisciplinary team review was 75.0%, and surgical management was performed in 70.7% of patients meeting an indication for surgery. CONCLUSION: IE mortality rates remain high, particularly in patients who do not undergo surgical management. Streamlined MDT assessment and referral for surgical management where appropriate is necessary to improve outcomes.

Admissions for antibiotic-resistant infections in cancer patients during first year of cancer diagnosis: a cross-sectional study.

In this study, linked Western Australian health data were used to determine presence of an antibiotic-resistant infection (ABRI) for all people diagnosed with a primary invasive cancer in 2009. Of 10 858 cancer cases, 154 (1.42%) had an ABRI. Patients with an ABRI were older (71.5 vs 66 years), and more had died in the year following diagnosis (37.7 vs 20.2%, P < 0.001). The ABRI cohort had a higher proportion of colorectal, genitourinary and haematological cancers (19.5 vs 11.9%; 14.3 vs 9.7% and 16.9 vs 5.8%, respectively). Hospital admissions with an ABRI were longer (22.3 vs 2.9 days, P < 0.001) and had a higher proportion of unplanned admissions (60.3 vs 15.2%), admissions through emergency department (36.8 vs 8.3%) and intensive care admissions (14.9 vs 1.7%, P < 0.001). Patients with solid tumours who developed an ABRI were more likely to have received chemotherapy (35.9 vs 27.8%, P = 0.04). In haematological cancer patients, a greater proportion of the admissions with an ABRI occurred after radiation therapy or chemotherapy (P = 0.01 and P = 0.005, respectively). This study is the first to report population-level data on ABRI in cancer patients. Patients with an ABRI had more hospital admissions and poorer outcomes.

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).

Community-onset Staphylococcus aureus Surveillance Programme annual report, 2012.

In 2012, the Australian Group on Antimicrobial Resistance (AGAR) conducted a community-onset period-prevalence survey of clinical Staphylococcus aureus isolated from hospital outpatients and general practice patients including nursing homes, long term care facilities and hospice patients. Day surgery and dialysis patients were excluded. Twenty-nine medical microbiology laboratories from all state and mainland territories participated. Isolates were tested by Vitek2® (AST-P612 card). Results were compared with previous AGAR community surveys. Nationally, the proportion of S. aureus that were methicillin-resistant S. aureus (MRSA) increased significantly from 11.5% in 2000 to 17.9% in 2012 (P<0.0001). Resistance to the non-ß-lactam antimicrobials varied between regions. No resistance was detected to vancomycin, teicoplanin or linezolid. Resistance in methicillin susceptible S. aureus was rare apart from erythromycin (12.8%) and was absent for vancomycin, teicoplanin, linezolid and daptomycin. The proportion of S. aureus characterised as health care-associated MRSA (HA-MRSA) was 5.1%. Three HA-MRSA clones were characterised, with 72.9% and 26.4% of HA-MRSA classified as ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA) respectively. Multi-clonal community-associated MRSA (CA-MRSA) accounted for 12.5% of all S. aureus. Regional variation in resistance in MRSA was primarily due to the differential distribution of the 2 major HA-MRSA clones; ST239-III [3A] (Aus-2/3 EMRSA), which is resistant to multiple non-ß-lactam antimicrobials, and ST22-IV [2B] (EMRSA-15), which is resistant to ciprofloxacin and typically erythromycin. Although the majority of CA-MRSA were non-multi-resistant, a significant expansion of Panton-Valentine leukocidin (PVL) positive CA-MRSA clones has occurred nationally. The mean age of patients (31.7 years, 95% CI 28.9-34.5) with a PVL positive CA-MRSA infection was significantly lower (P<0.0001), than the mean age of patients with a PVL negative CA-MRSA infection (55.7 years, 95% CI 50.7-60.6). This shift in the molecular epidemiology of MRSA clones in the Australian community will potentially increase the number of young Australians with skin and soft tissue infections requiring hospitalisation.