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. 2008 Aug 6;3(8):e2908.
doi: 10.1371/journal.pone.0002908.

Molecular detection of multiple emerging pathogens in sputa from cystic fibrosis patients

Fadi Bittar  1 , Hervé Richet, Jean-Christophe Dubus, Martine Reynaud-Gaubert, Nathalie Stremler, Jacques Sarles, Didier Raoult, Jean-Marc Rolain
Affiliations

Molecular detection of multiple emerging pathogens in sputa from cystic fibrosis patients

Fadi Bittar et al. PLoS One. .

Abstract

Background: There is strong evidence that culture-based methods detect only a small proportion of bacteria present in the respiratory tracts of cystic fibrosis (CF) patients.

Methodology/principal findings: Standard microbiological culture and phenotypic identification of bacteria in sputa from CF patients have been compared to molecular methods by the use of 16S rDNA amplification, cloning and sequencing. Twenty-five sputa from CF patients were cultured that yield 33 isolates (13 species) known to be pathogens during CF. For molecular cloning, 760 clones were sequenced (7.2+/-3.9 species/sputum), and 53 different bacterial species were identified including 16 species of anaerobes (30%). Discrepancies between culture and molecular data were numerous and demonstrate that accurate identification remains challenging. New or emerging bacteria not or rarely reported in CF patients were detected including Dolosigranulum pigrum, Dialister pneumosintes, and Inquilinus limosus.

Conclusions/significance: Our results demonstrate the complex microbial community in sputa from CF patients, especially anaerobic bacteria that are probably an underestimated cause of CF lung pathology. Metagenomic analysis is urgently needed to better understand those complex communities in CF pulmonary infections.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Bacteria identified by the conventional culture methods in children (A) and in adults (B).
Figure 2
Figure 2. Box plot graph representing the number of detected bacterial species in the two groups of patients.
Group 1 = patients to whom 24 clones from their sputa have been sequenced; Group 2 = patients to whom 40 clones from their sputa have been sequenced.
Figure 3
Figure 3. Comparison between phenotypic and genotypic detection and identification.
The number in the box indicates the number of clones obtained for each bacterial species in each sputum. C1, C2, C3, and C4 were control analysis. Blue color box = concordant results between PCR-cloning and culture; red color box = negative PCR-cloning and positive culture; green color box = positive PCR-cloning and negative culture; yellow color box = misidentified bacteria.
See this image and copyright information in PMC

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