Journal Article

Staphylococcus aureus Community-acquired Pneumonia: Prevalence, Clinical Characteristics, and Outcomes

Magill, Shelley, Williams, Derek J., Courtney, D. Mark, Fakhran, Sherene S., Casimir, Geoffrey, Jain, Seema, Self, Wesley H., Edwards, Kathryn M., Waterer, Grant W., Wunderink, Richard G., Zhu, Yuwei, Bramley, Anna, Grijalva, Carlos G., Anderson, Evan J., Chappell, James D., Balk, Robert A., Trabue, Christopher

2016

Overview

Background. Prevalence of Staphylococcus aureus community-acquired pneumonia (CAP) and its clinical features remain incompletely understood, complicating empirical selection of antibiotics. Methods. Using a multicenter, prospective surveillance study of adults hospitalized with CAP, we calculated the prevalence of methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) among all CAP episodes. We compared the epidemiologic, radiographic, and clinical characteristics of S. aureus CAP (per respiratory or blood culture) with those of pneumococcal (per respiratory or blood culture or urine antigen) and all-cause non-S. aureus CAP using descriptive statistics. Results. Among 2259 adults hospitalized for CAP, 37 (1.6%) had S. aureus identified, including 15 (0.7%) with MRSA and 22 (1.0%) with MSSA; 115 (5.1%) had Streptococcus pneumoniae. Vancomycin or linezolid was administered to 674 (29.8%) patients within the first 3 days of hospitalization. Chronic hemodialysis use was more common among patients with MRSA (20.0%) than pneumococcal (2.6%) and all-cause non-S. aureus (3.7%) CAP. Otherwise, clinical features at admission were similar, including concurrent influenza infection, hemoptysis, multilobar infiltrates, and prehospital antibiotics. Patients with MRSA CAP had more severe clinical outcomes than those with pneumococcal CAP, including intensive care unit admission (86.7% vs 34.8%) and in-patient mortality (13.3% vs 4.4%). Conclusions. Despite very low prevalence of S. aureus and, specifically, MRSA, nearly one-third of adults hospitalized with CAP received anti-MRSA antibiotics. The clinical presentation of MRSA CAP overlapped substantially with pneumococcal CAP, highlighting the challenge of accurately targeting empirical anti-MRSA antibiotics with currently available clinical tools and the need for new diagnostic strategies.

• Publisher: Oxford University Press,Infectious Diseases Society of America
• Subject: Adolescent / Adult / Aged / Aged, 80 and over / Anti-Bacterial Agents - therapeutic use / Antibiotics / ARTICLES AND COMMENTARIES / Blood / Centers for Disease Control and Prevention (U.S.) / Community-Acquired Infections - diagnosis / Community-Acquired Infections - epidemiology / Community-Acquired Infections - microbiology / Comparative analysis / Epidemiological Monitoring / Epidemiology / Female / Humans / Male / Methicillin-Resistant Staphylococcus aureus - drug effects / Middle Aged / Pneumonia / Pneumonia, Staphylococcal - diagnosis / Pneumonia, Staphylococcal - epidemiology / Pneumonia, Staphylococcal - microbiology / Prevalence / Prospective Studies / Staphylococcus aureus / Staphylococcus aureus - drug effects / Staphylococcus infections / Streptococcus pneumoniae / United States - epidemiology / Young Adult