Piperacillin-Tazobactam (TZP) Resistance in Escherichia coli Due to Hyperproduction of TEM-1 β-Lactamase Mediated by the Promoter Pa/Pb

This study was approved by the ethics committee of Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China and the Review Board exempted the requirement for written informed consent because this retrospective study only focused on bacteria and did not affect the patients. Bacterial Strains and Growth Condition The clinical strain E. coli RJ904 was obtained from the blood specimen of a hospitalized patient in Shanghai, China (Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University) in 2005. Ceftazidime was used for the medication. The patient’s condition improved after the treatment and the patient was discharged. The isolate was identified using VITEK2 automated systems (BioMérieux, France). All of the plasmids used in this study are listed in Supplementary Table S1. All cloning procedures were carried out in E. coli (DH5α), and antibiotics were used with suitable concentrations for plasmid selection when necessary. All the E. coli strains were routinely grown in Luria-Bertani (LB) broth (Oxoid) and incubated overnight at 35°C. Antimicrobial Susceptibility Testing Susceptibility testing of all the antibiotics for the clinical strain RJ904, transconjugant RJ904C, and recombinant vectors RJ904-PA/PB was determined using the E-test (bioMérieux, France). The antibiotic susceptibility of the strains to piperacillin with a fixed concentration of tazobactam (TZP, 4 mg/L) was determined using three methods:...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research