Synergistic Effect of Combination Interventions for Methicillin-resistant Staphylococcus aureus Transmission Control in Nursing Homes: A Computation Modelling Evaluation with Heterogeneous Contact Mixing

Abstract Background The endemic threat of Methicillin-Resistant Staphylococcus aureus (MRSA) in nursing homes pose a serious and escalating challenge to public health administration in infection control. Nursing homes are considered as major reservoirs for MRSA colonization, with considerable high levels of colonization prevalence. Aim Direct contact is the major transmission mode of MRSA colonization. This study employed a computation model to evaluate the effect of 3 intervention scenarios on MRSA colonization prevalence rate in nursing homes. Methods Simulations were conducted using a deterministic compartmental model featuring heterogeneous contact matrix between residents and health-care workers (HCWs). Contact parameters were derived from a nursing home survey. Three intervention scenarios were simulated: (1) hand-hygiene compliance by HCWs, (2) screening-and-isolation upon admission, and (3) implementing both interventions at the same time. Results For every 10% reduction in average contamination duration in HCWs, the estimated average reduction in prevalence rate is 1.29 percentage point compared with the prevalence rate before the intervention was implemented. Screening-and-isolation intervention results in an average reduction of 19.04 percentage point in prevalence rate (s.d. = 1.58; 95% CI = 18.90-19.18) compared with the prevalence rate before the intervention was implemented. In intervention scenario 3, synergistic effects were observed when implementing hand-hygiene compliance by HCWs and screening-and-isolation together. Conclusion Our results provide quantitative data for nursing home administrators in interventions planning, design, adjustment, effect estimation and comparison.