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Qualitative and quantitative composition of gut microbiota from cystic fibrosis patients

Abstract number: P639

Sánchez-Calvo J.M., Garcia-Castillo M., Lamas A., Rodriguez-Baños M., Baquero F., Suárez L., Cantón R., del Campo R.

Objective: To analysed the gut microbiota of cystic fibrosis (CF) patients by classical culture-based methods and also by non-culture molecular approaches.

Methods: Faecal samples from 18 CF-patients and also from 20 healthy volunteers (HV) were seeded in selective agar plates including: M-Enterococcus, manitol-salt, MacConkey, MRS, and ESBL. An additional blood-Columbia agar plate was including in order to estimate the aerobic bacterial concentration in faeces, and also the organims not recovered on selective plates. Five different colonies per morphology was subculture in the corresponding plates, and their clonal relationship was assessed by PFGE. Antimicrobial susceptibility was tested in the different PFGE pattern clones by agar dilution method. Total DNA was obtained from the faeces (QuiAmp minikit, Quiagen) and quantitative-PCR experiments were conducted in order to know the bacterial density for the BacteroidesPrevotellaPorphyromonas, Fusobacterium, and Lactic Acid Bacteria (LAB) groups. PCR-DGGE was performed with universal primers sets (V2-V3 region of 16S) and also with the described bacterial groups.

Results: Considering the blood-Columbia agar plate, lower bacterial charge was found in the CF faecal samples than in the HV. Curiously, Gram-negative bacteria were not detected in CF samples, neither in the selective mediums (MacConkey and ESBL) nor in the blood-Columbia agar. Enterococcal and staphylococcal clones were detected only in 10 and 9 CF patients, respectively, whereas for HV these genera were represented in all subjects. Several LAB genera as Lactococcus, Lactobacillus, and Pediococcus were detected in almost 50% of the CF samples. Multirresistance to four or more antibiotic families were corroborated in all CF isolates. Quantitative-PCR results showed statistical differences among the density proportions of the bacterial groups in the CF-patients versus the HV: BacteroidesPrevotellaPorphyromonas (6:1), Fusobacterium (1.8:1), and LAB (2:1) groups. DGGE-experiments showed particular bands associated only to CF-patients.

Conclusion: Qualitative and Quantitative significant differences were detected in the CF gut microbiota when comparing with that of HV, being relevant the higher amounts of anaerobes in the CF faces and the absence of Gram-negative cultivable organism. These differences can be related with antimicrobial selective pressure and particular gut mucosal conditions in CF patients.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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