MRSA Transmission Dynamics Among Interconnected Acute, Intermediate-Term, and Long-Term Healthcare Facilities in
Angela Chow1,2, Vanessa W Lim1, Ateeb Khan3
1Departments of Clinical Epidemiology and.
Background:
Methicillin-resistant Staphylococcus aureus (MRSA) is the most common healthcare-associated multidrug-resistant organism. Despite the interconnectedness between acute care hospitals (ACHs) and intermediate- and long-term care facilities (ILTCFs), the transmission dynamics of MRSA between healthcare settings is not well understood.
Methods:
We conducted a cross-sectional study in a network comprising an ACH and 5 closely affiliated ILTCFs in Singapore. A total of 1700 inpatients were screened for MRSA over a 6-week period in 2014. MRSA isolates underwent whole-genome sequencing, with a pairwise single-nucleotide polymorphism (Hamming distance) cutoff of 60 core genome single-nucleotide polymorphisms used to define recent transmission clusters (clades) for the 3 major clones.
Results:
MRSA prevalence was significantly higher in intermediate-term (29.9%) and long-term (20.4%) care facilities than in the ACH (11.8%) (P < .001). The predominant clones were sequence type [ST] 22 (n = 183; 47.8%), ST45 (n = 129; 33.7%), and ST239 (n = 26; 6.8%), with greater diversity of STs in ILTCFs relative to the ACH. A large proportion of the clades in ST22 (14 of 21 clades; 67%) and ST45 (7 of 13; 54%) included inpatients from the ACH and ILTCFs. The most frequent source of the interfacility transmissions was the ACH (n = 28 transmission events; 36.4%).
Conclusions:
MRSA transmission dynamics between the ACH and ILTCFs were complex. The greater diversity of STs in ILTCFs suggests that the ecosystem in such settings might be more conducive for intrafacility transmission events. ST22 and ST45 have successfully established themselves in ILTCFs. The importance of interconnected infection prevention and control measures and strategies cannot be overemphasized.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) spreads between hospitals and long-term care facilities, with higher prevalence in the latter. The acute care hospital was the most frequent source of MRSA transmission events between facilities.
Area of Science:
- Infectious Diseases
- Epidemiology
- Genomics
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a leading healthcare-associated multidrug-resistant organism.
- Understanding MRSA transmission dynamics between acute care hospitals (ACHs) and intermediate- and long-term care facilities (ILTCFs) is crucial due to their interconnectedness.
Purpose of the Study:
- To investigate the transmission dynamics of MRSA between an ACH and affiliated ILTCFs.
- To identify the prevalence and predominant clones of MRSA in different healthcare settings.
Main Methods:
- A cross-sectional study screened 1700 inpatients in an ACH and 5 ILTCFs in Singapore over 6 weeks.
- Whole-genome sequencing was performed on MRSA isolates.
- Recent transmission clusters (clades) were defined using a core genome single-nucleotide polymorphism cutoff of 60.
Main Results:
- MRSA prevalence was significantly higher in ILTCFs (29.9% intermediate-term, 20.4% long-term) compared to the ACH (11.8%).
- Predominant clones were ST22, ST45, and ST239, with greater diversity of sequence types (STs) observed in ILTCFs.
- The ACH was the most frequent source of interfacility MRSA transmissions, contributing to numerous transmission events involving ST22 and ST45.
Conclusions:
- MRSA transmission between ACHs and ILTCFs is complex.
- ILTCFs may be more conducive to intrafacility MRSA transmission, with ST22 and ST45 clones well-established in these settings.
- Integrated infection prevention and control strategies are essential to manage MRSA spread across interconnected healthcare facilities.
