Risk Factors for Infection and Treatment Outcome of Bloodstream Infections due to Extended Spectrum beta-Lactamases Producing Klebsiella pneumoniae

Kang, Cheol In; Kim, Sung Han; Bang, Ji Whan; Kim, Hong Bin; Park, Sang Won; Choe, Young Ju; Oh, Myoung don; Kim, Eui Chong; Choe, Kang Won

Abstract

BACKGROUND: This study was conducted to evaluate risk factors for infection and treatment outcome of bloodstream infection due to extended spectrum beta-lactamases(ESBL)-producing K. pneumoniae.
METHODS
ESBL production was evaluated by NCCLS guidelines and/or double-disk synergy test in K. pneumoniae blood isolates stored from January, 1998 to April, 2002. Sixty patients with bloodstream infection due to ESBL-producing K. pneumoniae (case patients) were compared with 159 matched control patients with bloodstream infection of non-ESBL-producing K. pneumoniae. Retrospective case-control study was performed.
RESULTS
There were no significant differences in age, sex, APACHE II score, and the primary site of infection between the case and control groups. In multivariate analysis, significant independent risk factors associated with bloodstream infection due to ESBL-producing K. pneumoniae were urinary catheterization, invasive procedure within previous 72 hours, and the number of antibiotics administered within previous 30 days. In clinical response at 72 hours after initial antibiotic treatment, complete response rate was higher in the controls (13.3% vs. 40.3%, respectively, P<0.001), however, treatment failure rate was higher in the cases (33.3% vs. 11.9%, respectively, P<0.001). Overall 7- day mortality rates in the cases and the controls were was 20% (12/60) and 15.7% (25/159) (P= 0.451), respectively, and overall 30-day mortality rates were 30% (18/60) and 24.5% (39/159), respectively (P=0.410). When the patients with bloodstream infection of ESBL-producing organism were evaluated and the patients who received inadequate definitive antibiotic treatment were excluded, delayed effective antibiotic treatment was found to be not associated with higher mortality.
CONCLUSION
In patients infected with ESBL-producing K. pneumoniae bacteremia, clinical response rate at 72 hours after antimicrobial therapy was lower, but the increase of mortality rate was not significant. Delayed effective antibiotic treatment was not associated with higher mortality, when definitive appropriate antibiotic treatment was prescribed.