title: Antibiotic-induced enterococcal expansion in the mouse intestine occurs throughout the small bowel and correlates poorly with suppression of competing flora.
abstract: To test the hypothesis that establishing gastrointestinal colonization with multiresistant Enterococcus faecium (VRE) C68 results from expansion of the enterococcal population in the upper small bowel, we compared VRE quantities recovered from the proximal, middle, and distal segments of the small bowel from mice treated with different antimicrobial agents. Antibiotics associated with high-level VRE fecal colonization (cefotetan, ceftriaxone, clindamycin, and ticarcillin-clavulanic acid) increased VRE quantities in all small-bowel segments, whereas cefepime and piperacillin-tazobactam did not. Enterococcal expansion did not correlate with reductions in numbers of native gram-negative or anaerobic flora. Green fluorescence protein-expressing E. faecium bacteria were found adjacent to the small bowel epithelial lining in colonized mice. These data indicate that enterococcal bowel colonization begins within the proximal small bowel and does not correlate with inhibition of other cultivable flora. Host or enterococcal factors induced by exposures to certain antibiotics may play a role in facilitating E. faecium colonization of the mammalian gastrointestinal tract.
authors.affiliation: Medical Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA.
authors.forename: Viera
authors.initials: V
authors.lastname: Lakticová
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hutton-Thomas
authors.forename: Matthew
authors.initials: M
authors.lastname: Meyer
authors.forename: Evren
authors.initials: E
authors.lastname: Gurkan
authors.forename: Louis B
authors.initials: LB
authors.lastname: Rice
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology; D002969:Clavulanic Acids / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D016984:Enterococcus faecium / Q000187:drug effects* / Q000254:growth & development*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D007421:Intestine, Small / Q000187:drug effects* / Q000382:microbiology*; D008795:Metronidazole / Q000494:pharmacology; D051379:Mice; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D000077725:Piperacillin, Tazobactam Drug Combination; D013982:Ticarcillin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002969:Clavulanic Acids; D008795:Metronidazole; D049452:Green Fluorescent Proteins; D000077725:Piperacillin, Tazobactam Drug Combination; D002981:Clindamycin; C043215:ticarcillin-clavulanic acid; D010397:Penicillanic Acid; D013982:Ticarcillin; D010878:Piperacillin