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[Antibiotic susceptibility of bacteria isolated from surgical infections (first report)]
Abstract:
In vitro activities of several antimicrobial agents against bacterial pathogens isolated from patients with primary and postoperative infections were investigated in 1982 and 1983. Antimicrobial agents examined were as follows: sulbenicillin (SBPC), piperacillin (PIPC), cephalothin (CET), cefazolin (CEZ), cefmetazole (CMZ), cefotiam (CTM), cefoperazone (CPZ), cefotaxime (CTX), ceftizoxime (CZX), cefmenoxime (CMX), latamoxef (LMOX), lincomycin (LCM), gentamicin (GM) and amikacin (AMK). Specimens for bacterial isolation included plus, fluid drawn by centesis, or bile. Blood samples of septicemia were excluded. The antimicrobial activities of these drugs were determined by the agar plate dilution method of the Japanese Society of Chemotherapy. There were 123 strains obtained in the 1982 survey and 252 strains in the 1983 survey. Little or no differences were seen in frequencies of isolation between the isolates of principal species in 1982 and those in 1983. Isolation frequencies of pathogens in primary infections were, in an order of decreasing frequency, E. coli (25.6%), anaerobes (21.1%), Streptococcus sp. (14.3%), Staphylococcus sp. (11.3%); in postoperative infections, Streptococcus sp. was most frequent (28.6%), followed by Pseudomonas sp. (17.6%), anaerobes (12.6%), E. coli (10.9%), Staphylococcus (10.1%). Against S. aureus, CEZ, CTM, LCM and GM had similar degree of activity with CET being somewhat more active. CMX was the most active drug among the third generation cephems tested against S. aureus. No strain was CTM, CEZ, and LCM-resistant at the same time. Over 90% of E. coli, were sensitive to CTX, CZX and CMX, inhibited by 0.10 microgram/ml, while E. coli were slightly less susceptible to CPZ and LMOX. Penicillins were not very active against K. pneumoniae, and only 60% of K. pneumoniae were inhibited by PIPC at concentrations of 12.5 micrograms/ml. Third generation cephems, CTX, CMX and CZX, proved highly active against K. pneumoniae; over 90% of K. pneumoniae was inhibited by CTX, CMX and CZX at a concentration of 0.10 microgram/ml. About 60% of P. aeruginosa was inhibited by 3.13 micrograms/ml of PIPC and GM but was resistant to SBPC. This survey should be very useful for the selection of an appropriate drug for prophylaxis if the frequencies of incidences of pathogens in postoperative infections are taken into account in selecting the most active antibiotic agent(s) against the most frequent genus, genera and species of pathogens.
Insights
This study evaluated antimicrobial activities against common bacterial pathogens from primary and postoperative infections. Third-generation cephalosporins demonstrated high efficacy against E. coli and K. pneumoniae, guiding antibiotic selection.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Bacterial infections remain a significant challenge in both primary and postoperative settings.
- Understanding the in vitro susceptibility patterns of common pathogens is crucial for effective treatment and prophylaxis.
- This study addresses the need for updated antimicrobial activity data against prevalent bacterial strains.
Purpose of the Study:
- To investigate the in vitro antimicrobial activities of various agents against bacterial pathogens from primary and postoperative infections.
- To compare the efficacy of different antibiotic classes, including penicillins, cephalosporins, and aminoglycosides.
- To provide data to guide the selection of appropriate antimicrobial agents for prophylaxis and treatment.
Main Methods:
- Bacterial pathogens were isolated from patient specimens (excluding blood) in 1982 and 1983.
- A panel of 14 antimicrobial agents was tested, including sulbenicillin, piperacillin, cephalothin, cefazolin, cefmetazole, cefotiam, cefoperazone, cefotaxime, ceftizoxime, cefmenoxime, latamoxef, lincomycin, gentamicin, and amikacin.
- Antimicrobial activity was determined using the agar plate dilution method, following guidelines from the Japanese Society of Chemotherapy.
Main Results:
- Escherichia coli was the most frequent pathogen in primary infections (25.6%), while Streptococcus sp. predominated in postoperative infections (28.6%).
- Third-generation cephalosporins (cefotaxime, ceftizoxime, cefmenoxime) showed high activity against E. coli and Klebsiella pneumoniae, with over 90% sensitivity at 0.10 microgram/ml.
- Pseudomonas aeruginosa showed resistance to sulbenicillin but moderate susceptibility to piperacillin and gentamicin.
Conclusions:
- Third-generation cephalosporins are highly effective against key Gram-negative pathogens like E. coli and K. pneumoniae.
- The study highlights the importance of considering pathogen prevalence in postoperative infections when selecting prophylactic antibiotics.
- The findings provide valuable insights for optimizing antimicrobial therapy and combating bacterial resistance.