Detection of anaerobic bacteria in high numbers in sputum from patients with cystic fibrosis.
BACKGROUND
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.


OBJECTIVE
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.


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.
Tunney
Michael M
MM
School of Pharmacy, Medical Biology Centre, Queen's University Belfast, Belfast, United Kingdom. m.tunney@qub.ac.uk
Field
Tyler R
TR
Moriarty
Thomas F
TF
Patrick
Sheila
S
Doering
Gerd
G
Muhlebach
Marianne S
MS
Wolfgang
Matthew C
MC
Boucher
Richard
R
Gilpin
Deirdre F
DF
McDowell
Andrew
A
Elborn
J Stuart
JS
D000293:Adolescent; D000328:Adult; D001421:Bacteria, Anaerobic / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D001431:Bacteriological Techniques; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications / Q000382:microbiology* / Q000503:physiopathology; D005541:Forced Expiratory Volume; D006801:Humans; D008875:Middle Aged; D012307:Risk Factors; D013183:Sputum / Q000382:microbiology*