title: Individualizing risk of multidrug-resistant pathogens in community-onset pneumonia.
abstract: BACKGROUND
  The diffusion of multidrug-resistant (MDR) bacteria has created the need to identify risk factors for acquiring resistant pathogens in patients living in the community.
  
  
  OBJECTIVE
  To analyze clinical features of patients with community-onset pneumonia due to MDR pathogens, to evaluate performance of existing scoring tools and to develop a bedside risk score for an early identification of these patients in the Emergency Department.
  
  
  METHODS
  This was an open, observational, prospective study of consecutive patients with pneumonia, coming from the community, from January 2011 to January 2013. The new score was validated on an external cohort of 929 patients with pneumonia admitted in internal medicine departments participating at a multicenter prospective study in Spain.
  
  
  RESULTS
  A total of 900 patients were included in the study. The final logistic regression model consisted of four variables: 1) one risk factor for HCAP, 2) bilateral pulmonary infiltration, 3) the presence of pleural effusion, and 4) the severity of respiratory impairment calculated by use of PaO2/FiO2 ratio. A new risk score, the ARUC score, was developed; compared to Aliberti, Shorr, and Shindo scores, this point score system has a good discrimination performance (AUC 0.76, 95% CI 0.71-0.82) and calibration (Hosmer-Lemeshow, χ2 = 7.64; p = 0.469). The new score outperformed HCAP definition in predicting etiology due to MDR organism. The performance of this bedside score was confirmed in the validation cohort (AUC 0.68, 95% CI 0.60-0.77).
  
  
  CONCLUSIONS
  Physicians working in ED should adopt simple risk scores, like ARUC score, to select the most appropriate antibiotic regimens. This individualized approach may help clinicians to identify those patients who need an empirical broad-spectrum antibiotic therapy.
authors: Department of Public Health and Infectious Diseases, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy; Department of Emergency Medicine, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Marco
authors: M
authors: Falcone
authors: Department of Public Health and Infectious Diseases, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Alessandro
authors: A
authors: Russo
authors: Unit of Infectious Diseases, Department of Medical and Surgical Sciences, St. Orsola-Malpighi Hospital, Alma Mater Studiorum University of Bologna, Bologna, Italy.
authors: Maddalena
authors: M
authors: Giannella
authors: Department of Internal Medicine and Medical Specialties, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Roberto
authors: R
authors: Cangemi
authors: Department of Emergency Medicine, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Maria Gabriella
authors: MG
authors: Scarpellini
authors: Department of Emergency Medicine, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Giuliano
authors: G
authors: Bertazzoni
authors: Department of Microbiology, General Hospital, Ciudad Real, Spain.
authors: José Martínez
authors: JM
authors: Alarcón
authors: Department of Clinical Medicine, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Gloria
authors: G
authors: Taliani
authors: Department of Public Health and Infectious Diseases, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Paolo
authors: P
authors: Palange
authors: Department of Public Health and Infectious Diseases-Statistics Section, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Alessio
authors: A
authors: Farcomeni
authors: Department of Public Health and Infectious Diseases-Statistics Section, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Annarita
authors: A
authors: Vestri
authors: Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors: Emilio
authors: E
authors: Bouza
authors: Department of Internal Medicine and Medical Specialties, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Francesco
authors: F
authors: Violi
authors: Department of Public Health and Infectious Diseases, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy.
authors: Mario
authors: M
authors: Venditti
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001419:Bacteria / Q000302:isolation & purification / Q000472:pathogenicity*; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D003710:Demography; D024901:Drug Resistance, Multiple, Bacterial; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D018410:Pneumonia, Bacterial / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D015995:Prevalence; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors