Accuracy of American Thoracic Society/Infectious Diseases Society of America criteria in predicting infection or colonization with multidrug-resistant bacteria at intensive-care unit admission.

The aim of this prospective observational study was to determine the accuracy of American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) criteria in predicting infection or colonization related to multidrug-resistant (MDR) bacteria at intensive-care unit (ICU) admission. MDR bacteria were defined as methicillin-resistant Staphylococcus aureus, ceftazidime-resistant or imipenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and extended-spectrum β-lactamase-producing Gram-negative bacilli. Screening for MDR bacteria (using nasal and rectal swabs and tracheal aspirates from intubated patients) was performed at ICU admission. Risk factors for infection or colonization with MDR bacteria at ICU admission were determined using univariate and multivariate analyses. The accuracy of ATS/IDSA criteria in predicting infection or colonization with these bacteria at ICU admission was calculated. Eighty-three (13%) of 625 patients were infected or colonized with MDR bacteria at ICU admission. Multivariate analysis allowed identification of prior antimicrobial treatment (OR 2.3, 95% CI 1.2-4.3; p 0.008), residence in a nursing home (OR 2, 95% CI 1.1-3.7; p <0.001), and prior hospitalization (OR 3.9, 95% CI 1.7-8.8; p <0.001) as independent predictors of infection or colonization with MDR bacteria at ICU admission. Although sensitivity (89%) and negative predictive values (96%) were high, low specificity (39%) and a positive predictive value (18%) were found when ATS/IDSA criteria were used in predicting infection or colonization with MDR bacteria at ICU admission. In patients with pneumonia, adherence to guidelines was associated with increased rates of appropriate initial antibiotic treatment and de-escalation. ATS/IDSA criteria had an excellent negative predictive value and a low positive predictive value concerning infection or colonization with MDR bacteria at ICU admission.