Post Antibiotic, Post β-lactamase Inhibitor and Post Antibiotic Sub-MIC Effect of Ceftriaxone/Tazobactam on β-lactamase-producing Escherichia coli in vitro
10.3969/j.issn.1672-173X.2009.06.023
- VernacularTitle:头孢曲松/他唑巴坦对产β-内酰胺酶大肠埃希菌后效应的研究
- Author:
Shou-Chai ZHANG
1
;
Ling-Ling ZHANG
;
Su-Wan CHEN
;
Hai-Yan WU
;
Xiao-Kang LIU
Author Information
1. 四川大学
- Keywords:
Ceftriaxone;
Tazobactam;
Escherichia coli;
PAE;
PLIE;
PASME
- From:
Journal of Sichuan University (Medical Sciences)
2009;40(6):1071-1074
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study post antibiotic effect (PAE), post β-lactamase inhibitor effect (PLIE) and post antibiotic sub-MIC effect (PASME) of ceftriaxone/tazobactam on β-lactamase-producing Escherichia coli in vitro. Methods The minimal inhibitory concentration (MIC) of ceftriaxone/tazobactam against 4 types of β lactamase producing E. colis strains, was measured by two-fold agar dilution method. The numbers of CFU on plates were counted by micro-inoculation colony counting method. The growth kinetics curves of the bacteria were drawn according to CFU counts, from which the PAE. PLIE and PASME were calculated. Results The MIC of the ceftriaxone/tazobactam combination was eight times more than ceftriaxone alone. No longer PAE (-0. 59-0. 85 h) was found in the ceftriaxone/tazobactam combination or any of them alone. The PLIE and PASME varied according to the type of β-lactamase but similar results were observed for the strains producing the same type β-lactamase. All PLIEs (0. 62-3. 22 h) and most PASMEs (0.12-5. 61 h) were longer than PAEs. The lower MIC of ceftriaxone the strain had, the longer the PAE, PLIE and PAMSE were. Conclusion The duration of PLIE and PASME may concerned with the type of β-lactamase. With both longer PLIE and PASME, longer dosing interval should be recommended. The PAE, PLIE and PASME provide an important instrument for pharmacodynamic studies of antibiotics, in particular for the design of dosing schedules.
