Long-term cultivation-independent microbial diversity analysis demonstrates that bacterial communities infecting the adult cystic fibrosis lung show stability and resilience.
BACKGROUND
Culture-independent analysis of the respiratory secretions of people with cystic fibrosis (CF) has identified many bacterial species not previously detected using culture in this context. However, little is known about their clinical significance or persistence in CF airways.


METHODS
The authors characterised the viable bacterial communities in the sputum collected from 14 patients at monthly intervals over 1 year using a molecular community profiling technique-terminal restriction fragment length polymorphism. Clinical characteristics were also collected, including lung function and medications. Ecological community measures were determined for each sample. Microbial community change over time within subjects was defined using ecological analytical tools, and these measures were compared between subjects and to clinical features.


RESULTS
Bacterial communities were stable within subjects over time but varied between subjects, despite similarities in clinical course. Antibiotic therapy temporarily perturbed these communities which generally returned to pretreatment configurations within 1 month. Species usually considered CF pathogens and those not previously regarded as such exhibited similar patterns of persistence. Less diverse sputum bacterial communities were correlated to lung disease severity and relative abundance of Pseudomonas aeruginosa.


CONCLUSIONS
Whilst not true in all cases, the microbial communities that chronically infect the airways of patients with CF can vary little over a year despite antibiotic perturbation. The species present tended to vary more between than within subjects, suggesting that each CF airway infection is unique, with relatively stable and resilient bacterial communities. The inverse relationship between community richness and disease severity is similar to findings reported in other mucosal infections.
Molecular Microbiology Research Laboratory, Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, Franklin-Wilkins Building, London SE1 9NH, UK.
Franziska Anne
FA
Stressmann
Geraint B
GB
Rogers
Christopher J
CJ
van der Gast
Peter
P
Marsh
Louic S
LS
Vermeer
Mary P
MP
Carroll
Lucas
L
Hoffman
Thomas W V
TW
Daniels
Nilesh
N
Patel
Benjamin
B
Forbes
Kenneth Deans
KD
Bruce
D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D058491:Bacterial Load / Q000187:drug effects; D044822:Biodiversity; D003550:Cystic Fibrosis / Q000188:drug therapy / Q000382:microbiology* / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D054892:Metagenome; D012150:Polymorphism, Restriction Fragment Length; D025341:Principal Component Analysis; D012137:Respiratory System / Q000382:microbiology*; D013183:Sputum / Q000382:microbiology*
D000900:Anti-Bacterial Agents