Double-blind study to compare the selection of antibiotic resistance by amoxycillin or cephradine in the commensal flora.
Elderly patients with acute urinary infections were treated in a double-blind study with either amoxycillin or cephradine. In 52 patients who had received amoxycillin for one week about a third of all intestinal Escherichia coli were highly resistant to amoxycillin, and many were resistant to tetracycline, trimethoprim, or chloramphenicol. Cephradine selected less resistance. At a week after completion of chemotherapy, cephradine-resistant E coli were replaced by sensitive cultures at a greater frequency than were amoxycillin-resistant E coli. Neither antibiotic altered the skin flora. Amoxycillin, but not cephradine, selected for Enterobacteriaceae in the saliva. The propensity of amoxycillin to select resistance in E coli will limit its usefulness in treating urinary infections.
D000208:Acute Disease; D000368:Aged; D000658:Amoxicillin / Q000494:pharmacology* / Q000627:therapeutic use; D002511:Cephalosporins / Q000494:pharmacology*; D002515:Cephradine / Q000494:pharmacology* / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000188:drug therapy; D005260:Female; D006801:Humans; D007422:Intestines / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D010403:Penicillin Resistance; D011897:Random Allocation; D012463:Saliva / Q000382:microbiology; D012867:Skin / Q000382:microbiology; D014552:Urinary Tract Infections / Q000188:drug therapy
D002511:Cephalosporins; D000658:Amoxicillin; D002515:Cephradine