Abstract: OBJECTIVE To provide information for the rational use of antibacterials, the variation of gram-negative bacterial resistance as well as the relationship between the bacterial resistance rate (BRR) and defined daily doses (DDDs) of antibiotics were investigated. METHODS The original BRR of 4 gram negative bacteria for 9 antibiotics and the DDDs of 81 antibiotics from 2011 to 2013 were collected from the antibiotics monitoring and analyzing module in the hospital information system (HIS). Principal component analysis (PCA) was carried to visualize the bacterial resistance in our hospital. Multivariate regression model, which mapped the influence of DDDs to BRR, was established. RESULTS The BRR of Escherichia coli for imipenem/cilastatin showed the most significant upward trend, which was positively correlated with the DDDs of imipenem/cilastatin and azithromycin. CONCLUSION This case study demonstrates that the monitoring of the BRR of Escherichia coli for imipenem/cilastatin should be strengthened by hospital. The management of imipenem/cilastatin and azithromycin should also be further strengthened.