Comparative "in vitro" activity of ciprofloxacin (Bay o9867) and other antimicrobial agents against urinary bacterial isolates
Piccolomini, R.; Ravagnan, G.
Chemioterapia International Journal of the Mediterranean Society of ChemoTherapy 5(4): 249-256
1986
ISSN/ISBN: 0392-906X PMID: 3769047 Document Number: 285208
Ciprofloxacin (Bay o9867) is a new quinolone derivative. Its activity against 537 urinary bacterial isolates was compared with those of ampicillin, amikacin, carbenicillin, cefazolin, cefotaxime, cefoxitin, ceftazidime, nalidixic and oxolinic acids, norfloxacin, trimethoprim, and other antimicrobial agents, when appropriate. It inhibited 90% of Citrobacter freundii, Enterobacter spp., E. coli, Klebsiella spp., Proteus spp., and Serratia spp. at 0.78 microgram/ml. The majority of Pseudomonas aeruginosa, including gentamicin-resistant strains, was inhibited by 0.78 microgram/ml. The minimal inhibitory concentrations of ciprofloxacin for 90% of Staphylococcus aureus, including methicillin-resistant strains, and Streptococcus faecalis were 0.78 microgram/ml and 1.56 micrograms/ml respectively. Ciprofloxacin inhibited organisms resistant to ampicillin, carbenicillin, cefazolin, nalidixic and oxolinic acids, and trimethoprim. Ciprofloxacin was less active in urine at pH 5.8 than in broth, but serum did not decrease minimal inhibitory concentrations or minimal bactericidal concentrations. There was no major difference between minimal inhibitory concentrations and minimal bactericidal concentrations. Spontaneous rates of mutation to resistance of representative urinary bacteria were studied. For ciprofloxacin these rates ranged from 8.2 X 10(-9) to 1.5 X 10(-11).