The emergence of multi-resistant organisms (MROs) in hospitals places a large burden on patient care. MROs are most often detected when they present clinically in patients or in targeted screening practices in critical care wards. However, it is known that there are undisclosed reservoirs of MROs in hospitals. This study sought to establish the true prevalence of MROs in the John Hunter Hospital (JHH), the principal referral centre for Newcastle, The Hunter and northern NSW.
A point prevalence study was conducted at JHH to investigate MRO carriage in adult inpatients and the hospital environment. The study targeted the major MROs of concern in the JHH, particularly Vancomycin-resistant enterococci (VRE) and Carbapenem-producing Enterobacteriaceae (CPE). VRE and CPE are among the most critical opportunistic pathogens at the centre of antibiotic resistance, with the World Health Organization citing these pathogens as high and critical priority, respectively. Genomic analysis of the patient and environmental samples was conducted to identify potential transmission events and define the sequence types, antibiotic resistance genes and mobile genetic elements that may be contributing to the persistence of these bacteria in the hospital.
The study found that 12% (19/156) of patients produced an MRO positive swab. Seventeen patients were colonised with only VRE, one patient was carrying only carbapenemase-producing Pseudomonas aeruginosa harbouring the Guiana extended-spectrum beta-lactamase (GES) gene, and one patient carried both of these MROs. Genome sequencing of the patient VRE samples identified two major sequence types (STs), ST78 and ST1424.
VRE and Pseudomonas aeruginosa were also found in the environmental samples. VRE isolates (n=13) were found on various surfaces including bedside tables, call devices, bed rails, sinks, nursing station computers and pan washing machines. Sequencing of these isolates showed a prominence of the same STs seen in patients, suggesting environmental/patient transmission. Current investigations are examining the potential for resistance transfer from large recombination events that occurred between strains of different STs.