Prevalence and risk factors for antibiotic-resistant community-associated bloodstream infections

ABSTRACT

Antibiotic resistance is increasing in many community settings. The purpose of this study was to determine the proportion of antibiotic resistant community-associated bloodstream infections [CA-BSIs] present on hospital admissions to identify risk factors for acquiring resistant versus susceptible CA-BSIs and to describe the incidence of concurrent infections with CA-BSIs. We conducted a retrospective cohort study of patients discharged from one community, one pediatric, and two tertiary/quaternary care hospitals within an academically affiliated network in the borough of Manhattan in New York, NY, from 2006 to 2008. The CA-BSIs present at hospital admission were defined as BSIs occurring within the first 48 h of hospitalization. Infections and patient characteristics were identified using data available from patients' electronic medical records and discharge records. In total, 1677 CA-BSIs were identified. Staphylococcus aureus had the largest proportion of resistance [41.2%], followed by enterococcal species [24.3%], Pseudomonas aeruginosa [20.2%], Streptococcus pneumoniae [16.6%], Acinetobacter baumannii [10.0%], and Klebsiella pneumoniae [9.9%]. Significant predictors of resistance were prior residence in a skilled nursing facility [OR, 2.55; 95% Cl, 1.39-4.70], advanced age [1.01; 1.002-1.02], presence of malignancy [0.58; 0.37-0.91], prior hospitalization [1.62; 1.17-2.23], a weighted Charlson score [1.09; 1.02-1.17] for S. aureus, presence of malignancy [1.82; 1.004-3.30], prior hospitalizations [2.03; 1.12-3.38] for enterococcal species, and younger age for S. pneumoniae [p = 0.02]. Urinary tract infections were the most common concurrent infection [n = 45/87, 51.7%]. Over 27% of the CA-BSIs present on admission were antibiotic resistant. Understanding the prevalence and risk factors for CA-BSIs may help improve empiric antibiotic therapy and outcomes for patients with community-onset infections