title: Long-term changes in human colonic Bifidobacterium populations induced by a 5-day oral amoxicillin-clavulanic acid treatment.
abstract: The objective of this study was to assess the possible modifications due to amoxicillin-clavulanic acid (AMC) treatment on total bacteria and on Bifidobacterium species balance in human colonic microbiota. Eighteen healthy volunteers (19 to 36 years old) were given a 875/125 mg dose of AMC twice a day for 5 days. Fecal samples were obtained before and after antibiotic exposure. After total DNA extraction, total bacteria and bifidobacteria were specifically quantified using real-time PCR. Dominant species were monitored over time using bacterial and bifidobacterial Temporal Temperature Gradient gel Electrophoresis (TTGE). At the end of AMC exposure, total bacterial concentrations as well as bifidobacteria concentrations were significantly reduced compared to before AMC exposure:10.7±0.1 log(10) 16S rRNA gene copies/g vs 11.1±0.1 log(10) (p = 0.003) and 8.1±0.5 log(10) 16S rRNA gene copies/g vs 9.4±0.3 log(10) (p = 0.003), respectively. At the same time, the mean similarity percentages of TTGE bacteria and TTGE bifidobacteria profiles were significantly reduced compared to before AMC exposure: 51.6%±3.5% vs 81.4%±2.1% and 55.8%±7.6% vs 84.5%±4.1%, respectively. Occurrence of B. adolescentis, B. bifidum and B. pseudocatenulatum/B. catenulatum species significantly decreased. Occurrence of B. longum remained stable. Moreover, the number of distinct Bifidobacterium species per sample significantly decreased (1.5±0.3 vs 2.3±0.3; p = 0.01). Two months after AMC exposure, the mean similarity percentage of TTGE profiles was 55.6% for bacteria and 62.3% for bifidobacteria. These results clearly demonstrated that a common antibiotic treatment may qualitatively alter the colonic microbiota. Such modifications may have potential long-term physiological consequences.
authors.affiliation: Laboratoire de Biologie, Conservatoire national des arts et métiers, Paris, France. irene.mangin@cnam.fr
authors.forename: Irène
authors.initials: I
authors.lastname: Mangin
authors.forename: Christophe
authors.initials: C
authors.lastname: Lévêque
authors.forename: Fabien
authors.initials: F
authors.lastname: Magne
authors.forename: Antonia
authors.initials: A
authors.lastname: Suau
authors.forename: Philippe
authors.initials: P
authors.lastname: Pochart
mesh_terms: D000328:Adult; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000008:administration & dosage*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001644:Bifidobacterium / Q000187:drug effects* / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis / Q000379:methods; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination / Q000379:methods*; D005243:Feces; D020459:Genes, rRNA; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D013045:Species Specificity; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D019980:Amoxicillin-Potassium Clavulanate Combination