Association Between Minimum Inhibitory Concentration, Beta-lactamase Genes and Mortality for Patients Treated With Piperacillin/Tazobactam or Meropenem From the MERINO Study.

INTRODUCTION: This study aims to assess the association of piperacillin/tazobactam and meropenem minimum inhibitory concentration (MIC) and beta-lactam resistance genes with mortality in the MERINO trial. METHODS: Blood culture isolates from enrolled patients were tested by broth microdilution and whole genome sequencing at a central laboratory. Multivariate logistic regression was performed to account for confounders. Absolute risk increase for 30-day mortality between treatment groups was calculated for the primary analysis (PA) and the microbiologic assessable (MA) populations. RESULTS: In total, 320 isolates from 379 enrolled patients were available with susceptibility to piperacillin/tazobactam 94% and meropenem 100%. The piperacillin/tazobactam nonsusceptible breakpoint (MIC >16 mg/L) best predicted 30-day mortality after accounting for confounders (odds ratio 14.9, 95% confidence interval [CI] 2.8-87.2). The absolute risk increase for 30-day mortality for patients treated with piperacillin/tazobactam compared with meropenem was 9% (95% CI 3%-15%) and 8% (95% CI 2%-15%) for the original PA population and the post hoc MA populations, which reduced to 5% (95% CI -1% to 10%) after excluding strains with piperacillin/tazobactam MIC values >16 mg/L. Isolates coharboring extended spectrum ß-lactamase (ESBL) and OXA-1 genes were associated with elevated piperacillin/tazobactam MICs and the highest risk increase in 30-day mortality of 14% (95% CI 2%-28%). CONCLUSIONS: After excluding nonsusceptible strains, the 30-day mortality difference from the MERINO trial was less pronounced for piperacillin/tazobactam. Poor reliability in susceptibility testing performance for piperacillin/tazobactam and the high prevalence of OXA coharboring ESBLs suggests that meropenem remains the preferred choice for definitive treatment of ceftriaxone nonsusceptible Escherichia coli and Klebsiella.

Microbial biofilms associated with intravascular catheter-related bloodstream infections in adult intensive care patients.

Catheter-related bloodstream infection (CRBSI) is one of the most serious complications in hospitalised patients, leading to increased hospitalisation, intensive care admissions, extensive antibiotic treatment and mortality. A greater understanding of these bacterial infections is needed to improve the prevention and the management of CRBSIs. We describe here the systematic culture-independent evaluation of intravascular catheter (IVC) bacteriology. Twelve IVCs (6 central venous catheters and 6 arterial catheters) were collected from 6 patients. By using traditional culture methods, 3 patients were diagnosed with catheter colonisation including 1 patient who also had CRBSI, and 3 had no colonisation. From a total of 839,539 high-quality sequence reads from high-throughput sequencing, 8 microbial phyla and 76 diverse microbial genera were detected. All IVCs examined in this study were colonised with complex microbial communities including "non-colonised IVCs," as defined using traditional culture methods. Two main community types were observed: Enterobacteriaceae spp., dominant in patients without colonisation or CRBSI; and Staphylococcus spp., dominant in patients with colonisation and CRBSI. More diverse pathogens and a higher microbial diversity were present in patients with IVC colonisation and CRBSI. Community composition did not appear to be affected by patients' antibiotic treatment or IVC type. Characterisation of these communities is the first step in elucidating roles of these pathogens in disease progression, and to ultimately facilitate the improved prevention, refined diagnosis and management of CRBSI.

Rates of neutropenia in adults with influenza A or B: a retrospective analysis of hospitalised patients in South East Queensland during 2015.

Neutropenia in adult patients is often attributed to intercurrent viral infections; however, there are limited data describing the frequency or natural history of this phenomenon. We examined all patients presenting to three large hospitals in the Metro South region of South East Queensland with laboratory-confirmed influenza A or B throughout the 2015 influenza season (January-October). Four hundred and thirty-six patients were studied and 15.3% of this cohort were neutropenic (absolute neutrophil count <2.0 × 109 /L) with no identifiable cause other than the influenza. Importantly, the majority of cases were mild, with absolute neutrophil count remaining >1.0 × 109 /L. The incidence of neutropenia was significantly higher in association with influenza B than influenza A (18.3% vs 10.3%). We conclude that mild, transient neutropenia is common among patients with influenza infection and advise that it should not cause alarm or invite specific investigation unless severe or prolonged.

Analysis of knowledge and attitude surveys to identify barriers and enablers of appropriate antimicrobial prescribing in three Australian tertiary hospitals.

BACKGROUND: Antimicrobial stewardship programmes aim to optimise use of antibiotics and are now mandatory in all Australian hospitals. AIM: We aimed to identify barriers to and enablers of appropriate antimicrobial prescribing among hospital doctors. METHODS: Two paper-based and one web-based surveys were administered at three Australian university teaching hospitals from March 2010 to May 2011. The 18-item questionnaire recorded doctors' level of experience, their knowledge regarding the use of common antimicrobials and their attitudes regarding antimicrobial prescribing. Local survey modifications allowed inclusion of specific questions on: infections in intensive care unit patients, clinical microbiology and use of local guidelines. RESULTS: The respondents (n = 272) were comprised of 96 (35%) registrars, 67 (25%)residents, 57 (21%) interns and 47 (17%) consultant hospital doctors. Forty-one per cent were working in a medical specialty. Identified barriers included: gaps in antimicrobial prescribing knowledge (especially among interns), a lack of awareness about which antimicrobials were restricted and a reliance on senior colleagues to make antimicrobial prescribing decisions. Enablers of optimal prescribing included: an acknowledgement of the need for assistance in prescribing and reported readiness to consult national prescribing guidelines. These results were used to help guide and prioritise interventions to improve prescribing practices. CONCLUSION: A transferable knowledge and attitudes survey tool can be used to highlight barriers and facilitators to optimal hospital antimicrobial prescribing in order to inform tailored antimicrobial stewardship interventions.

Two rare severe and fulminant presentations of Q fever in patients with minimal risk factors for this disease.

We described two rare severe and fulminant clinical presentations of acute Q fever. The first patient had severe multiorgan failure. The second patient had fever and severe cholera-like diarrhoea. Coxiella burnetii polymerase chain reaction on blood or serum can be clinically useful in the diagnosis of acute Q fever before seroconversion.