|Topic:||19. Lung Infection (Non-Mycobacterial, i.e., Bacterial, Viral, Fungal, HIV, etc.) / Adult / Clinical Studies / Microbiology, Tuberculosis and Pulmonary Infections (MTPI)|
|Authors:||T. Rahman, R. Cavallazzi, J.D. Price, R.Y.H. Kim, Y. Kothari, A. Bhatt, N. Maniar, R. Pearce; Louisville, KY/US|
Rationale: Methicillin-resistant Staphylococcus aureus (MRSA) pneumonia causes significant morbidity and mortality and may have varying risk factors. In this study, we intended to identify risk factors that may be specifically associated with MRSA infection in the hospitalized patient with community-acquired pneumonia (CAP) or health-care associated pneumonia (HCAP).
Methods: This is a case-control study. Cases were inpatients with a positive blood or sputum culture for MRSA and who met criteria for CAP or HCAP. Controls were inpatients admitted with CAP or HCAP who did not have MRSA infection. We assessed a number of risk factors for MRSA infection. We carried out multivariate logistic regression analysis to assess the independent effect of risk factors for MRSA infection. To build a model, we selected variables based on statistical significance and biological plausibility.
Results: We included 36 cases and 74 controls. The following risk factors were associated with MRSA infection on multivariate logistic regression: bilateral infiltrate in chest radiograph (odds ratio [OR]: 4.3; 95% CI: 1.6 to 11.5; P value = 0.003), tracheostomy (OR: 6.8; 95% CI: 1.5 to 30.3; P value = 0.012), history of intravenous drug use (OR: 10.4; 95% CI: 1.4 to 77.8; P value = 0.022), and female gender (OR: 0.2; 95% CI: 0.07 to 0.62; P value = 0.005).
Conclusion: We identified history of intravenous drug use, bilateral infiltrates on the chest radiograph, and the presence of tracheostomy as risk factors associated with higher odds of MRSA infection in patients with CAP or HCAP. On the other hand, female gender was associated with lower odds of MRSA infection. Identifying risk factors for MRSA infection is clinically relevant because it can aid in the initial antimicrobial choice.