Bacterial co-infection with H1N1 infection in patients admitted with community acquired pneumonia

• DOI: 10.1016/j.jinf.2012.04.009
• Publication Date: 2012-04-27T00:32:50Z
• Authors: Catia Cillóniz; Santiago Ewig; Rosario Menéndez; Miquel Ferrer; Eva Polverino; Soledad Reyes; Albert Gabarrús; Maria Angeles Marcos; Juan Cordoba; Josep Mensa; Antoni Torres
• Keywords: Adult; Aged, 80 and over; Male; Adolescent; Coinfection; Incidence; Bacterial Infections; Middle Aged; Article; Anti-Bacterial Agents; 3. Good health; Community-Acquired Infections; 03 medical and health sciences; Influenza A Virus, H1N1 Subtype; Logistic Models; 0302 clinical medicine; Risk Factors; Influenza, Human; Pneumonia, Bacterial; Humans; Female; Prospective Studies; Aged

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 A H1N1 pneumonia and bacterial co-infection.Prospective observational study of consecutive hospitalized patients with influenza A H1N1 virus and community-acquired pneumonia (CAP). We compared cases with and without bacterial co-infection.The incidence of influenza A H1N1 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 A H1N1 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.