OBJECTIVE To determine in vitro antibiotic activity of cefminox and 14 other
antimicrobials against extended spectrum beta-lactamases
(ESBLs) producing and non-producing strains. METHODS MICs of cefminox and 14 other
antimicrobials were determined by agar dilution susceptibility test and (ESBLs) were screened and conformed by disk diffusion method according to NCCLS recommended. RESULTS (Against) 110 strains producing ESBLs Escherichia coli and Klebsiella
pneumoniae, none resistant strain was discovered to imipenem. Cefminox had lower resistance than other 13 antimicrobials excluded imipenem, its resistant rate was 7.3%. MIC_(50) and MIC_(90) value ranges of cefminox were 0.5-1 mg/L and 2-32 mg/L, respectively. Against 40 strains non-producing ESBLs E. coli and K. pneumoniae, cefminox had the same activity as cefmetazole, ceftazidime, cefotaxime, ceftriaxone, cefepime and imipenem, their susceptible rate was 100%, MIC_(50) and MIC_(90) value ranges were from (0.032) to 0.5 mg/L and from 0.064 to 4 mg/L. CONCLUSIONS Against (ESBLs-)producing E. coli and K. pneumoniae, cefminox is the highest active antibiotic except imipenem. Its activity is not only much better than other two cephamycins, but also more active than those of all beta-lactams, aminoglycosides and fluoroquinolones tested. Against producing ESBL-negative strains, cefminox has the same high activity as cefmetazole, ceftazidime, cefotaxime, ceftriaxone, cefepime and imipenem, no resistant strain is detected to those antimicrobials.