1982 Volume 1 Issue 1 Pages 25-37
The results of the studies described in this communication indicate that antimicrobials cause suppression of normal aerobic and anaerobic flora in a variety of ways. In conclusion, it is summarized that: (i) Changes in the intestinal microflora are the reflection of the antibacterial spectrum and activity specific to the antibiotic administered.(ii) Degrees of alteration in the flora correlate well to concentrations of drug in the intestinal contents, and particularly, with the antibiotics of parenteral administration, they depend on the concentrations excreted in the bile.(iii) Changes in the flora take place within 24 hr of drug administration, and at least 2 weeks and usually 3 to 4 weeks are required for recovery of flora to normal levels.(iv) When bacteria that harbor R plasmids mediating resistance to the antibiotic used exist in the flora, the drug is inactivated, resulting in selective overgrowth of the resistant organisms. After withdrawal of the drug the resistant organisms may disappear or decrease in number.(v) Bifidobacteria are generally very sensitive to most of the antibiotics tested.(vi) Overgrowth of yeasts is seen during the course of drug administration.(vii) No adverse consequences ascribable to the direct effects of changes in the flora are observed.
