903. Etiology of Community-Acquired Pneumonia in Iceland, a One Year Population-Based Prospective Study
Session: Poster Abstract Session: Respiratory Infections
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C

Pneumonia is a common cause of mortality and hospital admission worldwide. Many pathogens can cause pneumonia, but in clinical practice most cases lack etiologic diagnosis.


Patients requiring hospital admission with community-acquired pneumonia were prospectively enrolled into the study during a 12 month period, December 2008-November 2009. This period encompassed the 2009 influenza A pandemic. All patients had a new infiltrate on chest x-ray and fulfilled clinical criteria. Etiologic testing was performed using blood and sputum-cultures, as well as urine antigen testing for Streptococcus pneumoniae and Legionella pneumophila. Polymerase chain reaction (PCR) testing was performed on upper airway samples for seasonal and pandemic influenza and Legionella species in addition to a multiplex PCR testing for multiple pathogens (adenovirus; bocavirus; influenza A & B; metapneumovirus; parainfluenzavirus 1,2,3; respiratory syncytial virus (RSV); enterovirus; coronaviruses  OC43, NL63, 229E and HKU1; M. pneumoniae and C. pneumoniae).


Overall, 310 patients were enrolled, 95% of eligible patients. An etiologic agent was found in 152 cases (49%) and >1 pathogen  was found in 24 patients. The most common bacteria were S. pneumoniae (27% of diagnosed cases, n=42), M. pneumoniae (24%, n=36), and Haemophilus influenzae (12%, n=18)). Viruses accounted for 27% of cases, including influenza A (18%, n=27), RSV (4%, n=6), rhinovirus (4%, n=6), metapneumovirus (2%, n=3) and single cases of coronavirus, parainfluenza and bocavirus. Combinations of pathogens found in more than one case were S. pneumoniae and a virus (n=6) (influenza or rhinovirus) and H. Influenzae and a virus (n=4) (rhinovirus or RSV) as well as the combination of S. pneumoniae and H. influenzae or Moraxella catarrhalis (n=4). Total in-house mortality was 3%.


Our results confirm the importance of S. pneumoniae as a major cause of pneumonia but also demonstrate the high frequency and potential importance of viral coinfections in this patient population. Respiratory viruses as a group were detected at a similar rate as S. pneumoniae in our study.

Agnar Bjarnason, MD1,2, Johan Westin, MD, PhD3, Magnus Lindh, MD, PhD3, Lars-Magnus Andersson, MD, PhD3, Karl G. Kristinsson, MD, PhD1,4, Arthur Löve, MD, PhD1,5, Olafur Baldursson, MD, PhD6 and Magnus Gottfredsson, MD, PhD7,8, (1)Faculty of Medicine, University of Iceland, Reykjavik, Iceland, (2)Dept of Infectious Diseases, Sahlgrenska University Hospital, Gothenburg, Sweden, (3)Dept of Infectious Diseases/Virology, Sahlgrenska University Hospital, Gothenburg, Sweden, (4)Clinical Microbiology, Landspitali University Hospital, Reykjavik, Iceland, (5)Virology, Landspitali University Hospital, Reykjavik, Iceland, (6)Pulmonary Medicine, Landspitali University Hospital, Reykjavik, Iceland, (7)Infectious Diseases, Landspitali University Hospital, Reykjavik, Iceland, (8)Faculty Of Medicine, University of Iceland, Reykjavik, Iceland


A. Bjarnason, None

J. Westin, None

M. Lindh, None

L. M. Andersson, None

K. G. Kristinsson, None

A. Löve, None

O. Baldursson, None

M. Gottfredsson, None

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