Abstract

Ceftizoxime sodium is a new synthetic β-lactam antibiotic combining potent antibacterial activity with high stability to a wide range of bacterial β-lactamase. This experiment was achieved to evaluate the antibacterial activities of ceftizoxime sodium against. Gram negative enteric bacteria isolated from in outpatient visiting Yeungnam university hospital and to study the emergence of drug induced bacterial variants which resist to ceftizoxime in vitro. The antibacterial activity of the ceftizoxime was compared with that of antibiotics and its effect on population of normal intestinal flora in mice was observed. The results are summarized as follows: 1. Highly effective antibacterial activity of ceftizoxime against Gram negative enteric bacilli was demonstrated and this antibacterial activity was superior to that of ampicillin. 2. Several test strains shows multiple antibiotic resistance. Among 15 strains of Escherichia coli, 1 strain was resistant to ampicillin, cefadroxil, gentamicin, tetracycline, and 2 strains were resistant to ampicillin, cefadroxil, tetracycline, five strains of Escherichia coli and Enterobacter cloacae was resistant to ampicillin, tetracycline and Shigella dysenteriae was resistant to ampicillin, gentamicin, tetracycline. 3. The frequency of in vitro emergence of resistant variants among ceftizoxime sensitive bacteria in the presence of increasing concentrations of the compound was found to be low. 4. Plasmid was isolated in 6 of 9 strains (6 strains of Escherichia coli, Shigella dysenteriae, Enterobacter cloacae and Salmonella typhi). That showed different antibiotic resistance. They were 5 strains of Escherichia coli and 1 strain of Shigella dysenteriae. However, plasmid could not be considered as a hallmark for antibiotic resistance by this Further studies with curing experiment are to be accomplished for this purpose. 5. Changes in the bacterial count of normal intestinal flora following 25 mg/kg/day administration of ceftizoxime over 5 consecutive days were not significant. In conclusion, ceftizoxime appeared to be a drug of choice in the treatment of Gram negative enteric bacilli infection.