Staphylococcus aureus Community-acquired Pneumonia: Prevalence, Clinical Characteristics, and Outcomes.
Clin Infect Dis. 2016 May 8;
Authors: Self WH, Wunderink RG, Williams DJ, Zhu Y, Anderson EJ, Balk RA, Fakhran SS, Chappell JD, Casimir G, Courtney DM, Trabue C, Waterer GW, Bramley A, Magill S, Jain S, Edwards KM, Grijalva CG
Abstract
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 2,259 adults hospitalized for CAP, 37 (1.6%) had S. aureus identified, including 15 (0.7%) with MRSA and 22 (1.0%) with MSSA, and 115 (5.1%) had S. pneumoniae Vancomycin or linezolid was administered to 674 (29.8%) patients within the first three 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 pre-hospital antibiotics. Patients with MRSA CAP had more severe clinical outcomes than pneumococcal CAP, including ICU 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.
PMID: 27161775 [PubMed - as supplied by publisher]