[Replacement of third-generation cephalosporins by piperacillin-tazobactam decreases colonization of extended-spectrum beta-lactamases-producing intestinal Escherichia coli].

OBJECTIVE: To investigate the role of replacement of third-generation cephalosporins by piperacillin-tazobactam (pip-tazo) in influencing the colonization of extended-spectrum beta-lactamases (ESBLs)-producing Escherichia coli (E. coli) in intestinal tract.

METHODS: The study was divided into two phases lasting altogether 9 months, namely the pre-replacement phase (phase I, 3 months) and replacement phase (phase II, 6 months). In the latter phase, third-generation cephalosporins was restricted and replaced by pip-tazo. In phase I and phase IIb (the last 3 months of phase II), clinical data and rectal swab were taken for E. coli isolation as follow: within 24 hrs after admission (baseline screening), every week and 48 hrs before discharge. ESBLs production was detected with double disc test. Acquisition rate of ESBLs-producing E. coli were calculated both in ES1 group (patients' rectal swab collected and tests at least 2 times) and ES2 group (ES1 but with negative ESBLs either at the time of screening on admission or at anytime during the hospital stay). Continuous variable was compared using unpaired t-test and categorical variables was compared using Pearson Chi square test. Fisher's exact test was used in the two phases.

RESULTS: In phase IIb, as compared with in phase I, the total consumption of antibiotics other than pip-tazo was reduced by 38.40%, the third-generation cephalosporins consumption was reduced by 70.11%, but pip-tazo consumption was raised by 895.35%. Meanwhile, the acquisition rate of ESBLs-producing E. coli in rectal swab was significantly decreased in phase IIb as compared with phase I (11.4% vs 24.0%) in ES1 group and the same is true in ES2 group (11.8% vs 27.9%).

CONCLUSION: Replacement of third-generation cephalosporin with pip-tazo can reduce colonization of ESBLs--producing E. coli in intestinal tract.