Distinct Epidemiology and Temporal Trends of Multidrug-Resistant Organisms in a Newly Established Hospital: A Five-Year Surveillance Study.

Background

Antimicrobial resistance is a major global health challenge, with multidrug-resistant organisms (MDROs) emerging faster than new antimicrobial agents are being developed. The epidemiology of MDROs varies substantially across healthcare settings; however, newly established hospitals remain understudied. This study aimed to characterise the epidemiology and temporal trends of MDROs in a newly established tertiary hospital.

Methods

A five-year retrospective longitudinal surveillance study was conducted from 2019 to 2023 in a newly established tertiary hospital in Southern China. Clinical isolates were collected from intensive care unit (ICU) and non-ICU wards. Nine major MDROs were investigated, including extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) and Escherichia coli (ESBL-ECO); carbapenem-resistant Klebsiella pneumoniae (CRKP), Escherichia coli (CRECO), Acinetobacter baumannii (CRAB), and Pseudomonas aeruginosa (CRPA); methicillin-resistant Staphylococcus aureus (MRSA); and vancomycin-resistant Enterococcus faecium (VREfm) and Enterococcus faecalis (VREfa).

Results

A total of 1533 MDRO isolates were identified during the study period. The predominant pathogens were ESBL-ECO (48.1%), ESBL-KP (16.4%), MRSA (11.4%), and CRPA (11.1%). Most isolates were recovered from non-ICU wards (85.4%), and more than half (51.5%) were community-onset. Isolation rates of ESBL-ECO, CRECO, CRAB, and CRPA were significantly higher in the ICU than in non-ICU wards (all p < 0.05). The incidence density rate of hospital-acquired infections caused by ESBL-KP, CRAB, and CRPA was also significantly higher in the ICU (all p < 0.05). Longitudinal analysis revealed divergent trends among MDROs. While most MDRO isolation rates remained below provincial and national benchmark levels, CRKP and CRAB showed significant increasing trends. CRPA exhibited a distinct pattern, increasing rapidly during the early years after hospital opening, exceeding both provincial and national benchmarks by the second year and remaining elevated thereafter.

Conclusions

MDRO epidemiology during the first five complete calendar years after hospital opening was characterised by a predominance of ESBL-ECO, ESBL-KP, MRSA, and CRPA, together with substantial non-ICU and community-onset burdens and heterogeneous temporal patterns across organisms. CRPA increased rapidly and remained above the available external benchmark thereafter. These findings highlight the need for hospital-wide, organism-specific MDRO surveillance, while maintaining intensified infection prevention and control in ICUs and continued vigilance for carbapenem-resistant pathogens, particularly CRPA.