title: Validation of a clinical score for assessing the risk of resistant pathogens in patients with pneumonia presenting to the emergency department.
abstract: BACKGROUND
  Resistant organisms (ROs) are increasingly implicated in pneumonia in patients presenting to the emergency department (ED). The concept of healthcare-associated pneumonia (HCAP) exists to help identify patients infected with ROs but may be overly broad. We sought to validate a previously developed score for determining the risk for an RO and to compare it with the HCAP definition.
  
  
  METHODS
  We evaluated adult patients admitted via the ED with bacterial pneumonia (January-December 2010). We defined methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and extended-spectrum β-lactamases as ROs. The risk score was as follows: 4, recent hospitalization; 3, nursing home; 2, chronic hemodialysis; 1, critically ill. We evaluated the screening value of the score and of HCAP by determining their areas under the receiver-operating characteristic (AUROC) curves for predicting ROs.
  
  
  RESULTS
  The cohort included 977 patients, and ROs were isolated in 46.7%. The most common organisms included MRSA (22.7%), P. aeruginosa (19.1%), and Streptococcus pneumoniae (19.1%). The risk score was higher in those with an RO (median score, 4 vs 1; P < .001). The AUROC for HCAP equaled 0.62 (95% confidence interval [CI], .58-.65) versus 0.71 (95% CI, .66-.73) for the risk score. As a screening test for ROs, a score > 0 had a high negative predictive value (84.5%) and could lead to fewer patients unnecessarily receiving broad-spectrum antibiotics.
  
  
  CONCLUSIONS
  ROs are common in patients presenting to the ED with pneumonia. A simple clinical risk score performs moderately well at classifying patients regarding their risk for an RO.
authors: Department of Medicine, Pulmonary and Critical Care Medicine Division, Washington Hospital Center, Washington, District of Columbia 20010, USA. afshorr@dnamail.com
authors: Andrew F
authors: AF
authors: Shorr
authors: Marya D
authors: MD
authors: Zilberberg
authors: Richard
authors: R
authors: Reichley
authors: Jason
authors: J
authors: Kan
authors: Alex
authors: A
authors: Hoban
authors: Justin
authors: J
authors: Hoffman
authors: Scott T
authors: ST
authors: Micek
authors: Marin H
authors: MH
authors: Kollef
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification* / Q000472:pathogenicity; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification* / Q000472:pathogenicity; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D013296:Streptococcus pneumoniae / Q000302:isolation & purification / Q000472:pathogenicity; D014861:Washington / Q000453:epidemiology; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D001618:beta-Lactamases