Correlation between Carbapenem Prescription Trends and Imipenem Resistance in Acinetobacter baumannii at an Intensive Care Unit between 2006 and 2010

ABSTRACT

Carbapenem resistance in Acinetobacter baumannii has increased rapidly worldwide. It is generally assumed that carbapenem prescription in a hospital has a significant impact on imipenem resistance in A. baumannii. However, there are few studies validating these assumptions with statistical data. We performed a surveillance study to investigate the relationship between carbapenem prescription trends and the imipenem resistance rate of A. baumannii in an ICU. Carbapenem prescription data in the WHO anatomical therapeutic chemical (ATC)/defined daily dose (DDD) format for the period from 2006 to 2010 were obtained from the hospital electronic pharmacy records. In the same period, microbiologic data for the ICU were extracted from the laboratory information system. Imipenem resistance rates of A. baumannii increased from 4.3% in 2006 to 83.8% in 2010 (P <0.05; r2=0.85). Carbapenem prescription had increased from 19.71 DDD per 1,000 inpatient-days in 2006 to 36.99 DDD per 1,000 inpatient-days in 2010 (P <0.05; r2=0.95). Carbapenem prescription rate correlated with the imipenem resistance rate in A. baumannii (P <0.05; R=0.9). The results of our study demonstrated a correlation between carbapenem prescription trends and imipenem resistance in A. baumannii.