[Clinical laboratory approach for determination of effective dose of cefotiam. Observation from disc susceptibility test and MICs].

Reliability of cefotiam disc diffusion susceptibility test was investigated for determining whether the disc results correlate with minimal inhibitory concentration (MIC) or not. The results of Showa disc and Oxoid disc were well correlated. The inhibitory zone size of Showa disc and MIC were also well correlated, indicating reliability of the cefotiam disc test. The disc result, was observed over 84% of clinically isolated S. aureus, S. epidermidis, S. pneumoniae, S. pyogenes, E. coli, K. pneumoniae, P. mirabilis and H. influenzae. Their mean MICs were less than about 1.5 microgram/ml. Such a result should be useful for the determination of drug dose in various clinical conditions in order to obtain the proper drug levels in blood and tissues. The results of antibiotic disc diffusion susceptibility test with various bacteria isolated from clinical materials were compared. Cefotiam revealed a potent antimicrobial activity against Gram-positive cocci, showing a similar potency to that of cephalothin and cefazolin. However, it showed a stronger activity against Gram-negative bacilli than that of cephalothin, cefazolin, cephalexin and cefoxitin, revealing less resistant strains. Cephalosporins developed recently such as cefotaxime, cefoperazone, ceftizoxime, latamoxef etc. show very potent antimicrobial activity against Gram-negative bacilli, but their activity against S. aureus and S. epidermidis is weaker than that of cefotiam, cephalothin, cefazolin etc. Therefore, cefotiam can be considered as one of the drugs of first choice for surgical perioperative prophylaxis and blind therapy.