Bacterial co-infection with H1N1 infection in patients admitted with community acquired pneumonia.
Cillóniz C, Ewig S, Menéndez R, Ferrer M, Polverino E, Reyes S, Gabarrús A, Marcos MA, Cordoba J, Mensa J, Torres A.
Department of Pneumology, Institut del Tórax, Hospital Clinic, IDIBAPS, University of Barcelona, Villarroel 170, 08036, Spain; Centro de Investigación Biomédica En Red-Enfermedades Respiratorias (CibeRes, CB06/06/0028).
Bacterial co-infection is an important contributor to morbidity and mortality during influenza pandemics .We investigated the incidence, risk factors and outcome of patients with influenza AH1N1 pneumonia and bacterial co-infection.
Prospective observational study of consecutive hospitalized patients with influenza AH1N1 virus and community-acquired pneumonia (CAP). We compared cases with and without bacterial co-infection.
The incidence of influenza AH1N1 infection in CAP during the pandemic period was 19% (n, 667). We studied 128 patients; 42(33%) had bacterial co-infection. The most frequently isolated bacterial pathogens were Streptococcus pneumoniae (26, 62%) and Pseudomonas aeruginosa (6, 14%). Predictors for bacterial co-infection were chronic obstructive pulmonary disease (COPD) and increase of platelets count. The hospital mortality was 9%. Factors associated with mortality were age ≥ 65 years, presence of septic shock and the need for mechanical ventilation. Although patients with bacterial co-infection presented with higher Pneumonia Severity Index risk class, hospital mortality was similar to patients without bacterial co-infection (7% vs. 11%, respectively, p=0.54).
Bacterial co-infection was frequent in influenza AH1N1 pneumonia, with COPD and increased platelet count as the main predictors. Although associated with higher severe scales at admission, bacterial co-infection did not influence mortality of these patients.