Serratia marcescens bacteremia at a medical center in southern Taiwan: high prevalence of cefotaxime resistance
Hsin-I Shih, Hsin-Chun Lee, Nan-Yao Lee, Chia-Ming Chang, Chi-Jung Wu, Li-Rong Wang, Nai-Ying Ko, Wen-Chien Ko
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan; Department of Medicine, National Cheng Kung University, Medical College, Tainan; Department of Pathology, National Cheng Kung University Hospital, Tainan; and Department of Nursing, National Cheng Kung University, Medical College, Tainan, Taiwan
Received: March 17, 2005 Revised: May 9, 2005 Accepted: July 19, 2005
Antimicrobial resistance of isolates and risk factors for mortality were retrospectively investigated in 71 adult patients with Serratia marcescens bacteremia. During the 4-year study period, 78 clinically significant episodes of S. marcescens bacteremia occurred in 71 patients. The mean age of the patients was 65 years (range, 25-86 years) with a male predominance (45 patients, 63%). Most of the bacteremic episodes were nosocomial (78%), and 34% were polymicrobial. The overall mortality rate within 2 weeks after the onset of bacteremia was 41%. The presence of malignancy and critical illness at initial presentation were independent risk factors for mortality. By disk susceptibility test, 72 isolates were resistant to cefotaxime (92%) but susceptible to ceftazidime (99%). All isolates were susceptible to meropenem. Among the 47 patients with monomicrobial S. marcescens bacteremia, the mortality rate within 5 days of onset in patients receiving appropriate empirical antimicrobial therapy was lower than that in patients receiving inappropriate therapy although this difference was not significant (14% vs 28%, p=0.27). Among the patients with cefotaxime-resistant but ceftazidime-susceptible S. marcescens bacteremia treated with ceftazidime, 6 of 7 patients (86%) survived for more than 2 weeks, suggesting the potential effectiveness of ceftazidime in the treatment of cefotaxime-resistant Serratia infections. Further clinical studies are required to delineate the clinical role of ceftazidime therapy for infections caused by S. marcescens with this resistant phenotype.
Bacteremia, cefotaxime, drug resistance, Serratia marcescens
J Microbiol Immunol Infect 2005;38:350-357.