[Comparison of in vitro activities of first, second and third generation cephem antibiotics against various pathogens isolated from clinical material in 1985]
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Abstract:
In vitro susceptibilities of 2,133 strains of various pathogens isolated from clinical materials in 1985 to various cephem antibiotics were studied using the Showa disk diffusion test. The following antibiotics were evaluated: cephalexin (CEX), cephalothin (CET), cefazolin (CEZ), cefotiam (CTM), cefoxitin (CFX), cefmetazole (CMZ), cefotaxime (CTX), cefoperazone (CPZ), ceftizoxime (CZX), cefmenoxime (CMX), latamoxef (LMOX) and cefsulodin (CFS). S. aureus: Susceptible strains to CET, CEZ, CTM, CFX and CMZ with MICs less than 15 micrograms/ml accounted for 93, 73, 94, 80 and 96% of the strains tested respectively, while those susceptible to CTX, CPZ, CZX, CMX, LMOX and CFS accounted for 91, 65, 53, 96, 65 and 95%, respectively. Susceptible strains to CEX at MICs less than or equal to 20 micrograms/ml were 52%. Prevalence of bacterial resistance to CEX and CEZ, which have been used extensively, was greater than that to CET, CTM or CMZ, showing a bimodal distribution of MICs. The third generation cephems studied, in general, also showed bimodal distributions of MICs. S. epidermidis: Susceptible strains to CET, CEZ, CTM, CMZ, CTX, CPZ and CMX with MICs less than 15 micrograms/ml were more than 82% of the strains tested. S. pyogenes: All strains studied were susceptible to CET, CEZ, CTM, CFX, CMZ, CTX, CPZ, CZX and CMX at MICs less than or equal to 15 micrograms/ml. However, susceptible strains to either LMOX or CFS accounted for 95%, while those to CEX at MICs less than or equal to 20 micrograms/ml accounted for 95%.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
This study evaluated 2,133 clinical pathogen strains against 12 cephem antibiotics in 1985. Newer cephems showed higher susceptibility, while older ones like cephalexin (CEX) and cefazolin (CEZ) exhibited increased resistance in Staphylococcus aureus.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Cephem antibiotics are crucial in treating bacterial infections.
- Understanding in vitro antibiotic susceptibility is vital for effective treatment strategies.
- Monitoring antimicrobial resistance patterns is essential for public health.
Purpose of the Study:
- To assess the in vitro activity of various cephem antibiotics against clinically relevant pathogens.
- To compare the susceptibility profiles of different cephem generations against common bacteria.
- To identify emerging resistance trends in bacterial pathogens.
Main Methods:
- Disk diffusion test (Showa) was employed to determine minimum inhibitory concentrations (MICs).
- 2,133 bacterial strains isolated from clinical materials in 1985 were tested.
- Twelve cephem antibiotics, including first, second, and third-generation agents, were evaluated.
Main Results:
- Staphylococcus aureus showed high susceptibility (>90%) to cefmetazole (CMZ), cefotiam (CTM), and cefmenoxime (CMX).
- Resistance to older cephems like cephalexin (CEX) and cefazolin (CEZ) was more prevalent in S. aureus.
- Staphylococcus epidermidis and Staphylococcus pyogenes generally exhibited high susceptibility to most tested cephems.
Conclusions:
- Third-generation cephems demonstrated broad in vitro activity against the studied pathogens.
- Increased resistance to older cephems like CEX and CEZ was observed, highlighting the need for ongoing surveillance.
- The findings underscore the importance of selecting appropriate antibiotics based on susceptibility data.