The effect of pharmacokinetic/pharmacodynamic (PK/PD) parameters of gatifloxacin on its bactericidal activity and resistance selectivity against clinical isolates of Streptococcus pneumoniae

Ebisu, Hiroyuki; Kishii, Ryuta; Takei, Masaya; Fukuda, Hideyuki

doi:10.1007/s10156-003-0243-9

Cited by 4 publications

(4 citation statements)

References 16 publications

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“…It has been reported that the selection of resistance after exposure to gatifloxacin appeared to be mainly dependent on the C max /MIC ratio, and a C max /MIC ratio м 1.7 might be necessary to prevent the occurrence of a resistant strain. 31 However, the strain used in that study possessed no mutations in the QRDR of parC or gyrA. It would suggest that a larger C max /MIC ratio might be necessary to prevent the occurrence of a resistant strain, especially for a strain with mutations in the QRDR of parC or gyrA.…”

Section: Discussionmentioning

confidence: 97%

Pharmacodynamic evaluation of tosufloxacin against Streptococcus pneumoniae in an in vitro model simulating serum concentration

Fukuda

Takahata

Mitsuyama

2006

Journal of Infection and Chemotherapy

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Section: Discussionmentioning

confidence: 97%

Pharmacodynamic evaluation of tosufloxacin against Streptococcus pneumoniae in an in vitro model simulating serum concentration

Fukuda

Takahata

Mitsuyama

2006

Journal of Infection and Chemotherapy

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“…The in vitro PK model has been described previously (6). A dilutional in vitro PK model (PASS-400; Dainipponseiki, Kyoto, Japan) was used to simulate serum concentrations of ciprofloxacin on the basis of the PK parameters reported previously (17).…”

Section: Methodsmentioning

confidence: 99%

“…In vitro PK/PD analysis of antimicrobial agents offers an alternative method for the determination of an adequate clinical regimen and is useful for predicting the clinical efficacy of a given antibiotic against various bacteria (2,6,8,(14)(15)(16). Therefore, the in vitro PK model, which can simulate human PK, is rapidly becoming one of the most important examinations in the development of new antimicrobial agents.…”

mentioning

confidence: 99%

Cultivation of Neisseria gonorrhoeae in Liquid Media and Determination of Its In Vitro Susceptibilities to Quinolones

Takei

Yamaguchi²,

Fukuda³

et al. 2005

J Clin Microbiol

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The cultivation of Neisseria gonorrhoeae by use of fastidious broth (FB) was evaluated. FB was found to be able to support the growth of all N. gonorrhoeae strains tested in this study without a rapid decrease in the viable count after exponential growth. After 24 h of incubation at 35°C with 5% CO 2 , viable counts of all strains reached over 10 8 CFU/ml in FB. Similar growth of the wild-type strain and its target-altered quinoloneresistant derivatives was observed. The susceptibilities of laboratory-adapted strains and clinical isolates to quinolones were tested by the microdilution method using FB. The MICs determined by microdilution were not significantly different from those determined by the agar dilution method recommended by the CLSI (formerly National Committee for Clinical Laboratory Standards). Moreover, the concentration-dependent time-kill of quinolones such as gatifloxacin and ciprofloxacin was observed in FB. At 2 to 4 times the MIC, gatifloxacin and ciprofloxacin were predominantly bactericidal against N. gonorrhoeae WHO A. At the MIC, the activities of both quinolones ranged from bactericidal to bacteriostatic. At 0.25 to 0.5 times the MIC, gonococcal growth was comparable to that of the growth control. These results suggest that the cultivation of N. gonorrhoeae by use of FB may be useful for evaluation of the antibacterial effects of quinolones.Neisseria gonorrhoeae is one of the causatives of sexually transmitted diseases, and it is a fastidious organism. This organism is typically cultured using an agar medium such as chocolate agar plate (GCII agar base with 1% IsoVitaleX [BBL] and purified hemoglobin). The CLSI (formerly the National Committee for Clinical Laboratory Standards) recommends only the agar dilution procedure for antibacterial susceptibility testing of N. gonorrhoeae (20). Before the 1980s, a number of studies were published regarding the liquid culture methodology for N. gonorrhoeae (9,13,21,23,25). However, these reports demonstrated that the number of bacteria decreased rapidly after bacterial exponential growth, and broth microdilution methods for susceptibility testing of N. gonorrhoeae were reported to give higher MICs of ␤-lactam antibiotics against penicillinase-producing N. gonorrhoeae than agar dilution methods (7,22).Recently, the antibacterial activity of antigonococcal agents against clinical isolates of N. gonorrhoeae has been declining (1, 11, 24). Quinolones initially appeared to be promising agents for the treatment of N. gonorrhoeae infections; however, the extensive clinical use of quinolones carries the risk of the development of resistance, and indeed, there have been increasing numbers of recent isolates of N. gonorrhoeae that are highly resistant to quinolones, especially in Asia (11,24,27). Therefore, the evaluation of the antibacterial susceptibility of N. gonorrhoeae is important in the clinical setting. According to the CLSI (formerly NCCLS) procedure, the drug susceptibility of N. gonorrhoeae should be measured by the agar dilution method, and it is...

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“…Data from in vitro, animal and clinical studies suggest that an fAUC 0-24h /MIC ratio between 25 and 34 is the target for fluoroquinolones to permit bacterial eradication in CAP caused by S. pneumoniae [13]. However, other authors suggest that for CAP due to this microorganism, an fAUC 0-24h /MIC ratio ≥30 is predictive of infection outcome [14][15][16][17][18][19]. 0924 Although the MIC is a good PD parameter to describe the antibacterial potency of a drug, it is a threshold concentration with poor precision, determined under static in vitro conditions.…”

Section: Introductionmentioning

confidence: 99%

Pharmacokinetic/pharmacodynamic modelling of the bactericidal activity of free lung concentrations of levofloxacin and gatifloxacin against Streptococcus pneumoniae

Tasso

Andrade

Costa

2011

International Journal of Antimicrobial Agents

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The aim of this work was to compare the pharmacological properties of levofloxacin and gatifloxacin against Streptococcus pneumoniae by pharmacokinetic/pharmacodynamic (PK/PD) modelling of the time-kill curves employing an E(max) model. An in vitro infection model was used to simulate free pulmonary fluctuating concentrations expected after multiple dosing regimens of both drugs in humans or constant multiples of the minimum inhibitory concentration. PK/PD parameters and PK/PD indices of the simulated dosing regimens were compared. The levofloxacin EC(50) (concentration producing 50% of the maximum effect) (mean ± standard deviation 3.57±2.16 mg/L) was higher than that for gatifloxacin (0.95±0.56 mg/L) when simulating multiple dosing regimens as well as constant concentrations (EC(50,levofloxacin)=2.75±0.45 mg/L; EC(50,gatifloxacin)=1.03±0.52 mg/L). The maximum killing rate constant (k(max)) was not statistically different for both drugs independent of fluctuating (k(max,levofloxacin)=0.40±0.19 h(-1); k(max,gatifloxacin)=0.48±0.15 h(-1)) or constant concentrations (k(max,levofloxacin)=0.34±0.06 h(-1); k(max,gatifloxacin)=0.39±0.23 h(-1)). The PK/PD model was able to describe the effect of levofloxacin and gatifloxacin against S. pneumoniae in vitro for all the simulations investigated. Gatifloxacin was more potent than levofloxacin, but both presented equivalent efficacy. The model can be used for simulating alternative regimens and optimising therapy to treat streptococcal infextions.

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The effect of pharmacokinetic/pharmacodynamic (PK/PD) parameters of gatifloxacin on its bactericidal activity and resistance selectivity against clinical isolates of Streptococcus pneumoniae

Cited by 4 publications

References 16 publications

Pharmacodynamic evaluation of tosufloxacin against Streptococcus pneumoniae in an in vitro model simulating serum concentration

Pharmacodynamic evaluation of tosufloxacin against Streptococcus pneumoniae in an in vitro model simulating serum concentration

Cultivation of Neisseria gonorrhoeae in Liquid Media and Determination of Its In Vitro Susceptibilities to Quinolones

Pharmacokinetic/pharmacodynamic modelling of the bactericidal activity of free lung concentrations of levofloxacin and gatifloxacin against Streptococcus pneumoniae

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