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We describe the demographics, clinical and molecular epidemiology of extended-spectrum β-lactamase (ESBL) Escherichia coli bloodstream infections (BSI) in Central Australia. All ESBL-producing E. coli bloodstream isolates from January 2018 to December 2020 were retrospectively identified. Demographic and clinical information was extracted by chart review. Whole-genome sequencing was performed for multi-locus sequence typing, antibiotic-resistance genes, and phylogenetic relationships. We identified 41 non-duplicate episodes of ESBL E. coli BSI. Median age was 55 years (IQR 47-63), 78% were female, 93% were Aboriginal, and half came from a remote community. Infections were predominantly urinary (68%, 28/41). In the 12 months prior, 70% (26/37) of identified patients had been hospitalised and 81% (30/37) prescribed antibiotics. Meropenem and piperacillin-tazobactam susceptibility was maintained in 100% and 95% of isolates, respectively. Co-resistance to non-β-lactam antibiotics was 32% to gentamicin, 61% to trimethoprim/sulfamethoxazole, and 68% to ciprofloxacin. For sequenced isolates, 41% (16/35) were sequence type 131 (ST131). Mean acquired antibiotic-resistance genes for each isolate was 12.3 (SD 3.1). Four isolates carried an OXA-1 gene. Only non-ST131 isolates carried AmpC and acquired quinolone-resistance genes. There was some evidence of clustering of closely related strains, but no evidence of community or healthcare admission overlap. ESBL rates are rapidly rising in Central Australia, which is a conducive environment for antibiotic resistance development (e.g., overcrowding, socioeconomic disadvantages, high healthcare exposure and high antibiotic use). Future research is required to explore resistance-transmission dynamics in this unique setting., (Copyright © 2024 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)

Staphylococcus aureus bacteraemia is associated with a high morbidity and mortality. Time to effective antibiotics is key to reducing mortality. Current practices yield preliminary susceptibilities approximately 16-18 h after blood culture positivity. Molecular diagnostics could reduce the time from blood culture positivity to organism identification as MRSA or MSSA. The objective was to assess the performance of the GeneXpert in identifying MRSA/MSSA from blood culture bottles in the BACT/ALERT VIRTUO system. Eighty-eight blood culture bottles with Gram-positive cocci resembling staphylococci were analysed at Pathology Queensland using the Cepheid Xpert MRSA/SA BC system. The identification and susceptibilities from standard operating procedures were compared with the results from the Xpert MRSA/SA Blood Culture assay and routine laboratory practice. The overall positive percent agreement between the GeneXpert and standard laboratory practice was 94.1% (95% CI 85.6-98.37%) and the negative percent agreement was 100% (95% CI 83.16-100%). The Cepheid Xpert accurately identifies MRSA, MSSA and coagulase-negative staphylococci. The discordant results were from rarely occurring clinical isolates and were expected limitations of the assay. This kit has the potential to reduce the time to effective antibiotics and minimise the use of unnecessary antibiotics and associated costs., (Copyright © 2022 Royal College of Pathologists of Australasia. All rights reserved.)

Purpose of Review: This article aims to give a state-of-the-art assessment of treatment options for bloodstream infection because of ceftriaxone-resistant Gram-negative bacilli, especially those caused by extended-spectrum beta-lactamase (ESBL) or AmpC-producing Enterobacteriaceae. In particular, this review assesses whether current data support 'carbapenem-sparing options' for treatment of these serious infections., Recent Findings: The MERINO trial refuted earlier observational studies some of which showed equivalence in outcomes between beta-lactam/beta-lactamase inhibitor combinations and carbapenems for treatment of bloodstream infection because of ceftriaxone-resistant Escherichia coli or Klebsiella spp. Although numerous factors influence mortality following bloodstream infection, the variability in piperacillin/tazobactam MICs observed in the MERINO trial make this a less secure option than meropenem. However, the search for carbapenem-sparing options continues with four randomized controlled trials (RCTs) in progress and a number of other options in clinical development., Summary: Hard outcomes from RCTs are still needed before intravenous carbapenems can be displaced as the treatment of choice for ceftriaxone-resistant Gram-negative bacilli.