Protective role of intestinal flora against infection with Pseudomonas aeruginosa in mice: influence of antibiotics on colonization resistance.

摘要: Swiss white mice were given ampicillin, clindamycin, kanamycin, metronidazole, or streptomycin in drinking water for a period of 3 weeks. One week after the initiation antibiotic administration, treated and untreated control challenged orally with approximately 10(8) viable, streptomycin-resistant (SR) Pseudomonas aeruginosa isolates. All five antibiotics decreased resistance to intestinal colonization SR P. aeruginosa, as reflected by an increased fecal carriage organism increase population levels feces compared controls. Metronidazole was least effective this regard. The lowered dose that resulted implantation 50% ID50 various degrees. Administration streptomycin, most antibiotic, caused 10,000-fold decrease Oral inoculation organisms translocation mesenteric lymph nodes, spleens, livers 13 17 streptomycin-treated mice, 1 20 clindamycin-treated 14 metronidazole-treated mice. Translocation not observed, however, ampicillin- kanamycin-treated animals. Antibiotic activity detected cecal contents streptomycin-, but