Bloodstream infections caused by Enterobacter species: predictors of 30-day mortality rate and impact of broad-spectrum cephalosporin resistance on outcome.
BACKGROUND
Enterobacter species have become increasingly important nosocomial pathogens. However, resistance to cephalosporins often complicates the treatment of Enterobacter infection. This study was conducted to evaluate the predictors of mortality and the impact of cephalosporin resistance on outcome in patients with Enterobacter bacteremia.


METHODS
A total of 183 patients with Enterobacter bacteremia were retrospectively analyzed. Broad-spectrum cephalosporin resistance was defined as in vitro resistance to cefotaxime or ceftazidime. The main outcome measure was the 30-day mortality rate.


RESULTS
Of 183 patients, 86 (47%) had bacteremia caused by broad-spectrum cephalosporin-resistant Enterobacter species, and their infections were classified as resistant. The 30-day mortality rate of patients with resistant infections (the resistant group) was significantly higher than that of patients with susceptible infections (the susceptible group) (33.7% vs. 18.6%; P=.021). When the 30-day mortality rates were compared according to the primary sites of infection and underlying conditions, the 30-day mortality rates of the resistant group were significantly higher than those of the susceptible group, in patients with an unknown primary site of infection, or in patients with septic shock. Multivariate analysis showed that broad-spectrum cephalosporin resistance was one of the independent risk factors associated with 30-day mortality (odds ratio [OR], 3.69; 95% confidence interval [CI], 1.01-13.52; P=.049). Presentation with septic shock and an increasing Acute Physiology and Chronic Health Evaluation II score were also independent risk factors for mortality (OR, 59.91 [95% CI, 14.93-240.15; P<.001] and 1.52 [95% CI, 1.24-1.86; P<.001], respectively).


CONCLUSIONS
Broad-spectrum cephalosporin resistance adversely affects the outcome of patients with Enterobacter bacteremia, especially those with an unknown primary site of infection and those with septic shock.
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
Cheol-In
CI
Kang
Sung-Han
SH
Kim
Wan Beom
WB
Park
Ki-Deok
KD
Lee
Hong-Bin
HB
Kim
Myoung-don
MD
Oh
Eui-Chong
EC
Kim
Kang-Won
KW
Choe
D018806:APACHE; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000188:drug therapy* / Q000401:mortality; D002439:Cefotaxime / Q000627:therapeutic use; D002442:Ceftazidime / Q000627:therapeutic use; D018550:Cephalosporin Resistance; D003428:Cross Infection / Q000188:drug therapy* / Q000401:mortality; D004754:Enterobacter / Q000187:drug effects*; D004756:Enterobacteriaceae Infections / Q000188:drug therapy* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis
D002442:Ceftazidime; D002439:Cefotaxime