In vitro Antibacterial Activity of Doripenem against Gram-Negative Blood Isolates in a Korean Tertiary Care Center.
BACKGROUND
Doripenem is the most recently introduced antimicrobial agent of the carbapenem class. It is a valuable therapeutic option in the context of increasing antimicrobial resistance to imipenem and meropenem among gram-negative bacilli (GNB) clinical isolates. However, clinicians are usually reluctant to prescribe doripenem, because susceptibility to doripenem is not automatically reported by most clinical laboratories and the in vitro activity of doripenem against clinically significant GNB isolates remains uncertain.


METHODS
We investigated the in vitro antibacterial activity of doripenem in GNB blood isolates in a tertiary care center. Over a period of 10 months, 212 adult bacteremia cases were treated at the study hospital. Doripenem susceptibility testing was performed for the 212 blood isolates by the disk diffusion method, and clinical data were collected.


RESULTS
Among the blood isolates, the rate of doripenem resistance (7.5%) was lower than that of imipenem (12.9%) or other anti-GNB antimicrobial agents, except amikacin (2.1%). Almost all imipenem-susceptible GNB blood isolates (181/182, 99.5%) were susceptible to doripenem. Whereas doripenem resistance was rarely observed in Enterobacteriaceae (2/181, 1.1%), it was frequently observed in patients with non-fermentatative GNB (12/27, 44.4%), hospital-acquired infections (7/27, 25.9%), and pneumonia (11/49, 22.4%).


CONCLUSIONS
Doripenem exhibited more potent in vitro activity against GNB blood isolates than other anti-GNB antimicrobial agents in a tertiary care center where it was infrequently prescribed compared with other carbapenems. However, its clinical utility may be limited due to the increasing number of carbapenem-resistant non-fermentative GNB infections.
Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
Seong-Ho
SH
Choi
Division of Infectious Diseases, Department of Internal Medicine, Severance Hospital, Seoul, Korea.
Mi Young
MY
Ahn
Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
Jin-Won
JW
Chung
Department of Laboratory Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
Mi-Kyung
MK
Lee
Bacteremia; Doripenem; Gram-negative bacteria