title: Alterations in intestinal microbiota of elderly Irish subjects post-antibiotic therapy.
abstract: OBJECTIVE
  The human intestinal microbiota composition alters naturally with age, but is unusually perturbed by antibiotic therapy. The impact of antibiotic therapy on the composition of the intestinal microbiota of a cross-section of elderly Irish subjects (n = 185, ≥ 65 years) was investigated, taking into consideration their residence location.
  
  
  METHODS
  Forty-two of the 185 elderly subjects were treated with at least one antibiotic within 1 month prior to faecal microbiota profiling. The residence locations of the subjects varied from long-term nursing care and rehabilitation wards to day hospitals and the community.
  
  
  RESULTS
  Culture-dependent methods indicated that faecal Bifidobacterium spp. numbers were significantly reduced following antibiotic treatment (P = 0.004, 7-fold reduction), while levels of Lactobacillus spp. and Enterobacteriaceae were unaffected. The largest decrease in Bifidobacterium spp. numbers was linked to the administration of nucleic acid synthesis inhibitors (P = 0.004, 23-fold reduction). Microbiota profiling revealed a significant compositional change across nine genera following antibiotic therapy, including a relative increase in Lactobacillus spp. (P = 0.031), as well as a decrease in the number of genera identified in the antibiotic-treated subjects (n = 58), when compared with untreated subjects (n = 79). More alterations in the intestinal microbiota were observed post-nucleic acid synthesis inhibitor therapy, most notably a decrease in relative Faecalibacterium spp. numbers (P < 0.001).
  
  
  CONCLUSIONS
  The impact of antibiotic therapy on the intestinal microbiota in the elderly should be considered for long-term health effects, and differential susceptibility may require the development of products (e.g. prebiotics and probiotics) for at-risk subjects.
authors.affiliation: Teagasc Food Research Centre, Moorepark, Fermoy, Co Cork, Ireland.
authors.forename: Orla
authors.initials: O
authors.lastname: O'Sullivan
authors.forename: Mairéad
authors.initials: M
authors.lastname: Coakley
authors.forename: Bhuvaneswari
authors.initials: B
authors.lastname: Lakshminarayanan
authors.forename: Susana
authors.initials: S
authors.lastname: Conde
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Claesson
authors.forename: Siobhán
authors.initials: S
authors.lastname: Cusack
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Fitzgerald
authors.forename: Paul W
authors.initials: PW
authors.lastname: O'Toole
authors.forename: Catherine
authors.initials: C
authors.lastname: Stanton
authors.forename: R Paul
authors.initials: RP
authors.lastname: Ross
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D005243:Feces / Q000382:microbiology*; D005260:Female; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000382:microbiology*; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008297:Male; D054892:Metagenome / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents