Activities of doripenem against nosocomial bacteremic drug-resistant Gram-negative bacteria in a medical center in Taiwan

Shao-Xing Dong, Jann-Tay Wang, Shan-Chwen Chang


Received: April 30, 2011    Revised: August 1, 2011    Accepted: August 31, 2011   

Corresponding author. Division of Infectious Diseases, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 100, Taiwan.

The majority of nosocomial infections in Taiwan hospitals are caused by drug-resistant Gram-negative bacteria (GNB), including Pseudomonas aeruginosa, Acinetobacter baumannii, and various species of Enterobacteriaceae. Carbapenems are important agents for treating infections caused by these GNB. Recently, doripenem was approved for use in Taiwan in August 2009. However, data on its in vitro activity against nosocomial GNB isolated from Taiwan remain limited. The study was designed to look into this clinical issue.

A total of 400 nonduplicated nosocomial blood isolates isolated in 2009, inclusive of P. aeruginosa (n = 100), A. baumannii(n = 100), and Enterobacteriaceae (n = 200), were randomly selected from the bacterial bank preserved at National Taiwan University Hospital. Susceptibilities of these 400 isolates to various antibiotics, including doripenem, imipenem, meropenem, ceftazidime, amikacin, ciprofloxacin, colistin, and tigecycline were determined by using Etest.

Doripenem demonstrated similar in vitro activity to imipenem and meropenem against P. aeruginosa (87%, vs. 85% and 89%), A. baumannii (56%, vs. 60% and 60%), and Enterobacteriaceae (100%, vs. 98.5% and 99.5%). The prevalence of carbapenem-resistant (any one of three tested carbapenems) P. aeruginosa, A. baumannii, and Enterobacteriaceae isolates was 15%, 44%, and 0.5%, respectively.

Doripenem was as effective as imipenem and meropenem in our study. However, there was a significant proportion of carbapenem resistance among the tested isolates. Hence, longitudinal surveillance is necessary to monitor the resistance trend.

Acinetobacter baumannii, Activity, Carbapenems, Doripenem, Enterobacteriaceae, Pseudomonas aeruginosa