Detection of Anaerobic Bacteria in High Numbers in Sputum from Patients with Cystic Fibrosis

Rationale: Pulmonary infection in cystic ?brosis (CF) is polymicrobial and it is possible that anaerobic bacteria, not detected by routine aerobic culture methods, reside within infected anaerobic airway<br/>mucus.<br/>Objectives: To determine whether anaerobic bacteria are present in the sputum of patients with CF.<br/>Methods: Sputum samples were collected from clinically stable adults with CF and bronchoalveolar lavage ?uid (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 quanti?ed and identi?ed.<br/>Measurements and Main Results: Anaerobic species primarily within the genera Prevotella,Veillonella, Propionibacterium, andActinomyces were isolated in high numbers from 42 of 66 (64%) sputum samples from adult patients with CF. Colonization with Pseudomonas aeruginosa signi?cantly increased the likelihood that anaerobic bacteria would be present in the sputum. Similar anaerobic species were identi?ed 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<br/>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.<br/>Conclusions: A range of anaerobic species are present in large numbers in the lungs of patients with CF. If these anaerobic bacteria are contributing signi?cantly to infection and in?ammation in the CF<br/>lung, informed alterations to antibiotic treatment to target anaerobes, in addition to the primary infecting pathogens, may improve management.