title: In vivo pharmacokinetics/pharmacodynamics of colistin and imipenem in Pseudomonas aeruginosa biofilm infection.
abstract: Many Pseudomonas aeruginosa isolates from the airways of patients with cystic fibrosis (CF) are sensitive to antibiotics in susceptibility testing, but eradication of the infection is difficult. The main reason is the biofilm formation in the airways of patients with CF. The pharmacokinetics (PKs) and pharmacodynamics (PDs) of antimicrobials can reliably be used to predict whether antimicrobial regimens will achieve the maximum bactericidal effect against infections. Unfortunately, however, most PK/PD studies of antimicrobials have been done on planktonic cells and very few PK/PD studies have been done on biofilms, partly due to the lack of suitable models in vivo. In the present study, a biofilm lung infection model was developed to provide an objective and quantitative evaluation of the PK/PD profile of antimicrobials. Killing curves were set up to detect the antimicrobial kinetics on planktonic and biofilm P. aeruginosa cells in vivo. Colistin showed concentration-dependent killing, while imipenem showed time-dependent killing on both planktonic and biofilm P. aeruginosa cells in vivo. The parameter best correlated to the elimination of bacteria in lung by colistin was the area under the curve (AUC) versus MIC (AUC/MIC) for planktonic cells or the AUC versus minimal biofilm inhibitory concentration (MBIC; AUC/MBIC) for biofilm cells. The best-correlated parameter for imipenem was the time that the drug concentration was above the MIC for planktonic cells (T(MIC)) or time that the drug concentration was above the MBIC (T(MBIC)) for biofilm cells. However, the AUC/MIC of imipenem showed a better correlation with the efficacy of imipenem for biofilm infections (R(2) = 0.89) than planktonic cell infections (R(2) = 0.38). The postantibiotic effect (PAE) of colistin and imipenem was shorter in biofilm infections than planktonic cell infections in this model.
authors.affiliation: Department of Clinical Microbiology, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark. whz2009@hotmail.com
authors.forename: Wang
authors.initials: W
authors.lastname: Hengzhuang
authors.forename: Hong
authors.initials: H
authors.lastname: Wu
authors.forename: Oana
authors.initials: O
authors.lastname: Ciofu
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Song
authors.forename: Niels
authors.initials: N
authors.lastname: Høiby
mesh_terms: D000464:Alginates / Q000737:chemistry; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D019540:Area Under Curve; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D018914:Cells, Immobilized; D003091:Colistin / Q000493:pharmacokinetics / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D015378:Imipenem / Q000493:pharmacokinetics / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D010933:Plankton / Q000187:drug effects* / Q000254:growth & development; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000464:Alginates; D000900:Anti-Bacterial Agents; D006603:Hexuronic Acids; D015378:Imipenem; D020723:Glucuronic Acid; D003091:Colistin