Published ahead of print on February 8, 2008, doi:10.1164/rccm.200708-1151OC
© 2008 American Thoracic Society doi: 10.1164/rccm.200708-1151OC
Detection of Anaerobic Bacteria in High Numbers in Sputum from Patients with Cystic Fibrosis1 School of Pharmacy, Medical Biology Centre, and 2 School of Medicine and Dentistry, Queen's University Belfast, Belfast, United Kingdom; 3 Department of General and Environmental Hygiene, Eberhard-Karls-Universtät, Hygiene-Institut, Tübingen, Germany; and Departments of 4 Pediatrics and 5 Microbiology and Immunology, 6 Cystic Fibrosis and Pulmonary Research and Treatment Center, and 7 Department of Medicine, University of North Carolina, Chapel Hill, North Carolina Correspondence and requests for reprints should be addressed to Michael M. Tunney, B.Sc., Ph.D., School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK. E-mail: m.tunney{at}qub.ac.uk Rationale: Pulmonary infection in cystic fibrosis (CF) is polymicrobial and it is possible that anaerobic bacteria, not detected by routine aerobic culture methods, reside within infected anaerobic airway mucus. Objectives: To determine whether anaerobic bacteria are present in the sputum of patients with CF. Methods: Sputum samples were collected from clinically stable adults with CF and bronchoalveolar lavage fluid (BALF) samples from children with CF. Induced sputum samples were collected from healthy volunteers who did not have CF. All samples were processed using anaerobic bacteriologic techniques and bacteria within the samples were quantified and identified. Measurements and Main Results: Anaerobic species primarily within the genera Prevotella, Veillonella, Propionibacterium, and Actinomyces were isolated in high numbers from 42 of 66 (64%) sputum samples from adult patients with CF. Colonization with Pseudomonas aeruginosa significantly increased the likelihood that anaerobic bacteria would be present in the sputum. Similar anaerobic species were identified in BALF from pediatric patients with CF. Although anaerobes were detected in induced sputum samples from 16 of 20 volunteers, they were present in much lower numbers and were generally different species compared with those detected in CF sputum. Species-dependent differences in the susceptibility of the anaerobes to antibiotics with known activity against anaerobes were apparent with all isolates susceptible to meropenem. Conclusions: A range of anaerobic species are present in large numbers in the lungs of patients with CF. If these anaerobic bacteria are contributing significantly to infection and inflammation in the CF lung, informed alterations to antibiotic treatment to target anaerobes, in addition to the primary infecting pathogens, may improve management.
Key Words: cystic fibrosis • anaerobe • infection • pathogenesis
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