Valéria Dos Santos Kênia, Diniz Cláudio Galuppo, Coutinho Simone Cristina, Apolônio Ana Carolina Morais, Geralda de Sousa-Gaia Luciana, Nicoli Jacques Robert, Farias Luiz de Macêdo, Roque de Carvalho Maria Auxiliadora
Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
J Med Microbiol. 2007 Jun;56(Pt 6):798-802. doi: 10.1099/jmm.0.47112-0.
Ertapenem and piperacillin/tazobactam are beta-lactam antibiotics with a broad spectrum of activity used for the treatment of mixed infections in which Bacteroides fragilis and Escherichia coli play an important aetiological role. In this study, the activities of piperacillin/tazobactam and ertapenem (MIC and time-kill kinetics) against these bacteria were compared. MICs were determined by the agar dilution method, and the time and slope of time-kill curves were analysed. In the in vitro pharmacodynamic assays, pure and mixed cultures of E. coli and B. fragilis were exposed to peak concentrations of ertapenem (8.0 microg ml(-1)) and piperacillin/tazobactam (64.0/8.0 microg ml(-1)) for 48 h. Treatment with ertapenem reduced the viability of E. coli and/or B. fragilis by 3 logs in all experiments, whereas piperacillin/tazobactam only affected the viability of B. fragilis. Both drugs exhibited their fastest rates of killing when bacteria were grown in mixed cultures. According to the results, ertapenem exhibited activity similar to that of piperacillin/tazobactam against B. fragilis alone or in mixed culture. However, ertapenem exhibited a markedly higher activity against E. coli alone or in combination with B. fragilis relative to piperacillin/tazobactam.
厄他培南和哌拉西林/他唑巴坦是具有广泛抗菌活性的β-内酰胺类抗生素，用于治疗以脆弱拟杆菌和大肠埃希菌为重要病因的混合感染。在本研究中，比较了哌拉西林/他唑巴坦和厄他培南对这些细菌的活性（最低抑菌浓度和时间杀菌动力学）。最低抑菌浓度采用琼脂稀释法测定，并分析了时间杀菌曲线的时间和斜率。在体外药效学试验中，将大肠埃希菌和脆弱拟杆菌的纯培养物及混合培养物暴露于厄他培南（8.0 μg/ml）和哌拉西林/他唑巴坦（64.0/8.0 μg/ml）的峰值浓度下48小时。在所有实验中，厄他培南治疗均使大肠埃希菌和/或脆弱拟杆菌的活力降低3个对数级，而哌拉西林/他唑巴坦仅影响脆弱拟杆菌的活力。当细菌在混合培养物中生长时，两种药物的杀菌速度最快。根据结果，厄他培南对单独或混合培养的脆弱拟杆菌的活性与哌拉西林/他唑巴坦相似。然而，相对于哌拉西林/他唑巴坦，厄他培南对单独或与脆弱拟杆菌联合的大肠埃希菌具有明显更高的活性。
