@article{mbs:/content/journal/jmm/10.1099/jmm.0.47112-0, author = "Valéria dos Santos, Kênia and Diniz, Cláudio Galuppo and Coutinho, Simone Cristina and Apolônio, Ana Carolina Morais and Geralda de Sousa-Gaia, Luciana and Nicoli, Jacques Robert and Farias, Luiz de Macêdo and Roque de Carvalho, Maria Auxiliadora", title = "In vitro activity of piperacillin/tazobactam and ertapenem against Bacteroides fragilis and Escherichia coli in pure and mixed cultures", journal= "Journal of Medical Microbiology", year = "2007", volume = "56", number = "6", pages = "798-802", doi = "https://doi.org/10.1099/jmm.0.47112-0", url = "https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.47112-0", publisher = "Microbiology Society", issn = "1473-5644", type = "Journal Article", keywords = "LLA, lower limit of accuracy", abstract = "Ertapenem and piperacillin/tazobactam are β-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 μg ml−1) and piperacillin/tazobactam (64.0/8.0 μg 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.", }