Related Experiment Videos
Surgical sepsis: constancy of antibiotic susceptibility of causative organisms
C J Krepel1, C M Gohr, C E Edmiston
1Surgical Microbiology Research Laboratory, Medical College of Wisconsin, Milwaukee, USA.
Background:
It is well documented that antibiotic therapy exerts selective pressure on bacteria. Conversion of bacteria from susceptible to resistant to antibiotics has been observed often during antimicrobial therapy. It has been postulated that human intestinal reservoirs facilitate communication of transposons that can transfer resistance determinants among various bacterial species.
Methods:
This study examined the susceptibilities of organisms isolated from infected abdomens to a number of antibiotic agents during a 12-year time interval. Analysis included 1102 isolates recovered from 255 specimens, representing the following genera: Bacteroides, Clostridium, Gemella, Fusobacterium, Peptostreptococcus, Porphyromonas, Prevotella, Enterococcus, Staphylococcus, Streptococcus, Pseudomonas, and Enterobacteriaceae. Strains were tested against beta-lactam agents, beta-lactams in combination with beta-lactamase inhibitors, first, second, and third generation cephalosporins, aminoglycosides, clindamycin, metronidazole, chloramphenicol, and imipenem.
Results:
The results indicated that during a time period of more than a decade essentially no change occurred in the antibiotic susceptible fraction of all species tested.
Conclusions:
Abdominal sepsis is caused by leakage of endogenous intestinal flora. This study suggests that the intestinal flora is not permanently affected by short-term antibiotic therapy and that older antibiotics are appropriate first-line therapeutic agents for community-acquired infections caused by normal intestinal flora.
Insights
Antibiotic resistance in intestinal bacteria did not change significantly over a decade. This suggests short-term antibiotic use doesn't permanently alter gut flora, supporting older antibiotics for common infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Antibiotic therapy drives bacterial resistance.
- Intestinal bacteria may transfer resistance genes.
- Understanding resistance shifts is crucial for effective treatment.
Purpose of the Study:
- To assess changes in antibiotic susceptibility of abdominal sepsis isolates over 12 years.
- To evaluate the long-term impact of antibiotic selective pressure on intestinal flora.
Main Methods:
- Analyzed 1102 isolates from 255 abdominal sepsis specimens.
- Tested bacterial susceptibility to various antibiotic classes including beta-lactams, cephalosporins, and aminoglycosides.
- Covered genera such as Bacteroides, Enterococcus, Staphylococcus, and Enterobacteriaceae.
Main Results:
- No significant change in antibiotic susceptibility was observed across all tested species over the 12-year period.
- Bacterial resistance patterns remained stable despite ongoing antibiotic use.
Conclusions:
- Intestinal flora is resilient to short-term antibiotic therapy.
- Established antibiotics remain effective for community-acquired abdominal infections.
- The study supports the continued use of older antibiotics as first-line agents.