Principal Component Analysis of Factors Affecting Methicillin-Resistant Staphylococcus aureus Isolation Rates

Abstract

  Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogenic bacterium causing nosocomial infections. Using data from patients hospitalized between April 2012 and June 2013 in our hospital, we examined how the use of antibiotics and hand disinfectants affected the MRSA isolation rates. The antimicrobial use density (AUD), use of disinfectants, and MRSA isolation rates from all samples and blood culture samples were correlated for disinfectants (r=−0.34). Higher AUD of carbapenem (r=0.61), first-generation cephalosporin (r=0.59), and quinolone (r=0.48) were also correlated with increased MRSA isolation rates. Multidimensional analysis was performed to evaluate contribution to MRSA isolation rates. In the first analysis, the disinfectant had a contribution ratio of 20.7%. In the second analysis, the AUD of carbapenem had a contribution ratio of 12.7%. The cumulative contribution ratio of disinfectant plus AUD of carbapenem was 86.7%. This new analytic method allowed visualization and has contributed to reducing MRSA isolation rates.