title: Risk factors associated with potentially antibiotic-resistant pathogens in community-acquired pneumonia.
abstract: BACKGROUND
  To identify pathogens that require different treatments in community-acquired pneumonia (CAP), we propose an acronym, "PES" (Pseudomonas aeruginosa, Enterobacteriaceae extended-spectrum β-lactamase-positive, and methicillin-resistant Staphylococcus aureus).
  
  
  OBJECTIVE
  To compare the clinical characteristics and outcomes between patients with CAP caused by PES versus other pathogens, and to identify the risk factors associated with infection caused by PES.
  
  
  METHODS
  We conducted an observational prospective study evaluating only immunocompetent patients with CAP and an established etiological diagnosis. We included patients from nursing homes. We computed a score to identify patients at risk of PES pathogens.
  
  
  RESULTS
  Of the 4,549 patients evaluated, we analyzed 1,597 who presented an etiological diagnosis. Pneumonia caused by PES was identified in 94 (6%) patients, with 108 PES pathogens isolated (n = 72 P. aeruginosa, n = 15 Enterobacteriaceae extended-spectrum β-lactamase positive, and n = 21 methicillin-resistant Staphylococcus aureus). These patients were older (P = 0.001), had received prior antibiotic treatment more frequently (P < 0.001), and frequently presented with acute renal failure (P = 0.004). PES pathogens were independently associated with increased risk of 30-day mortality (adjusted odds ratio = 2.51; 95% confidence interval = 1.20-5.25; P = 0.015). The area under the curve for the score we computed was 0.759 (95% confidence interval, 0.713-0.806; P < 0.001).
  
  
  CONCLUSIONS
  PES pathogens are responsible for a small proportion of CAP, resulting in high mortality. These pathogens require a different antibiotic treatment, and identification of specific risk factors could help to identify these microbial etiologies.
authors.affiliation: 1 Servei de Pneumologia, Institut del Torax, Hospital Clinic, IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Prina
authors.forename: Otavio T
authors.initials: OT
authors.lastname: Ranzani
authors.forename: Eva
authors.initials: E
authors.lastname: Polverino
authors.forename: Catia
authors.initials: C
authors.lastname: Cillóniz
authors.forename: Miquel
authors.initials: M
authors.lastname: Ferrer
authors.forename: Laia
authors.initials: L
authors.lastname: Fernandez
authors.forename: Jorge
authors.initials: J
authors.lastname: Puig de la Bellacasa
authors.forename: Rosario
authors.initials: R
authors.lastname: Menéndez
authors.forename: Josep
authors.initials: J
authors.lastname: Mensa
authors.forename: Antoni
authors.initials: A
authors.lastname: Torres
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D019540:Area Under Curve; D001987:Bronchiectasis / Q000453:epidemiology; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D015897:Comorbidity; D003244:Consciousness Disorders / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000302:isolation & purification / Q000502:physiology; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D005334:Fever / Q000453:epidemiology; D006801:Humans; D007121:Immunocompetence; D008297:Male; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification / Q000502:physiology; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents
keywords: antibiotic therapy; community-acquired pneumonia; infection