Ms Brigid O'Kane2, Ms Vivian Leung1,2, Ms Rica Tamala1, Ms Liz Orr1, A/Prof. Caroline Marshall1,2
1The Royal Melbourne Hospital, Melbourne, Australia, 2University of Melbourne, Melbourne, Australia
Biography:
Associate Professor Caroline Marshall is an infectious diseases physician at the Royal Melbourne Hospital where she is Head of the Infection Prevention and Surveillance Service. She is also Honorary Principal Research Fellow at the Department of Infectious Diseases at the University of Melbourne.
Abstract:
Introduction
Carbapenemase-producing organisms (CPOs) pose a major healthcare challenge due to limited treatment options, increased morbidity and mortality, and high transmission potential. In Victoria, CPOs have been notifiable since 2018, with coordinated investigation by the Department of Health, Microbiological Diagnostic Unit Public Health Laboratory, and Local Public Health Units. The Royal Melbourne Hospital (RMH) Infection Prevention and Surveillance Service (IPSS) has conducted surveillance since 2016. This study describes the epidemiology of CPO cases at RMH.
Methods
All confirmed CPO cases at RMH from 2016–2025 were analysed using prospectively collected data. Definitions aligned with the Victorian CPO guideline. Data sources included the IPSS REDCap database, infection prevention software, and electronic medical records. Patient- and episode-level descriptive analyses of demographic and epidemiological variables were performed in R.
Results
A total of 207 patients (254 episodes) were identified; over half were overseas born. Incidence increased more than sixfold over the study period. Most episodes (97%) involved carbapenemase-producing Enterobacterales with Escherichia coli (44.1%) most common, then Klebsiella pneumoniae (23.5%), then Enterobacter cloacae (14.2%). NDM (n=109) was the most common gene, followed by IMP (n=48).
Over half of cases (52.4%) were detected on admission, while 39.4% (n=100) were identified after 48 hours. Among 181 patients with risk data, 34.8% had prior overseas hospitalisation and 28.7% recent overseas travel or residence without hospitalisation.
Conclusion
CPO cases increased substantially, largely associated with overseas exposure, though local acquisition was also frequent. Ongoing surveillance is critical to enable appropriate isolation and prevent transmission. Recent domestic healthcare exposure may warrant expansion of screening criteria.