title: [Optimization of antibiotics in combination].
abstract: OBJECTIVE
  To evaluate the antibacterial activity of Ciprofloxacin, Amikacin in combination with beta-lactams against Pseudomonas aeruginosa strains in vitro, to optimize treatment regime for antibiotics on the basis of pharmacokinetics (PK)/pharmacodynamics (PD) and drug sensitivity tests. Methods With checkerboard titration method, the minimal inhibitory concentrations (MIC) of a combination of antibiotics in different concentrations for 33 clinically isolated Pseudomonas aeruginosa strains were determined by broth dilution. Fractional inhibitory concentrations (FIC) were calculated for judging synergic effect of antibiotics.
  
  
  RESULTS
  The combination of Amikacin and Ceftazidime showed synergic effects (accounting for 57.6%). The combinations of Ciprofloxacin with Ceftazidime, Cefepime, Imipenem/Cilastatin, Meropenem showed synergic or additive effect. In the study with PK/PD, C(max)/MIC was the principal parameters for evaluation of aminoglycoside and fluoroquinolone antibiotics, while T > MIC was the principal parameter to be used to evaluate beta-lactams antibiotics.
  
  
  CONCLUSIONS
  When antibiotics are used in combination, MICs can be reduced significantly and antibacterial activities are enhanced remarkably. The combination of antibiotics results mainly in synergic or additive effect, and no inhibitory effect is observed. PK/PD analysis plays an important role in planning optimal combination regime to raise clinical efficacy.
authors.affiliation: Department of Pharmacy, Third Affiliated Hospital of Inner Mongolia Medical College, Baotou 014010, PR China.
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Zhang
authors.forename: Ling-Feng
authors.initials: LF
authors.lastname: Wang
authors.forename: Zhao-Yan
authors.initials: ZY
authors.lastname: Meng
authors.forename: Qing-Ping
authors.initials: QP
authors.lastname: Yu
authors.forename: Bai-Qing
authors.initials: BQ
authors.lastname: Gao
authors.forename: Te
authors.initials: T
authors.lastname: Ba
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Wang
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Ma
authors.forename: Yao-Yu
authors.initials: YY
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000583:Amikacin / Q000493:pharmacokinetics / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D002053:Burn Units; D002939:Ciprofloxacin / Q000493:pharmacokinetics / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D006801:Humans; D007362:Intensive Care Units; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification; D047090:beta-Lactams / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D002939:Ciprofloxacin; D000583:Amikacin