title: Bacteremia caused by Escherichia coli producing extended-spectrum beta-lactamase: a case-control study of risk factors and outcomes.
abstract: A case-control study was conducted in order to identify the risk factors associated with bloodstream infection caused by Escherichia coli producing extended-spectrum beta-lactamase (ESBL) and to determine the outcomes of infected patients. Risk factors associated with ESBL production, according to univariate analysis, included a history of recent hospitalization [odds ratio (OR) 4.3, 95% confidence interval (CI) 2.1-8.9; p < 0.001], severe underlying diseases (OR 15, 95% CI 4.4-51.5; p < 0.001), prior exposure to urinary catheters (OR 8.3, 95% CI 3.2-21.7; p < 0.001) and nosocomial (OR 14.1, 95% CI 6.1-32.8; p < 0.001) or urinary (OR 3.6, 95% CI 1.7-7.4; p < 0.001) origin of the bacteria. Multivariate analysis revealed that severe underlying diseases (OR 31.2, 95% CI 6.7-144; p < 0.001) and nosocomial (OR 16.5, 95% CI 5.6-49; p < 0.001) and urinary origins (OR 7.8, 95% CI 2.6-23.8; p < 0.001) of the bacteria were independently associated with ESBL production in bacteremic E. coli. Crude mortality in case patients was more than twice as high as that in controls (p = 0.04). Production of ESBL increased the risk of inappropriate initial therapy (OR 95.6, 95% CI 27.4-334.2; p < 0.001). Treatment failed in 4/7 case patients treated with ceftazidime to which the isolate was susceptible in vitro. Our findings have implications for the choice of empirical therapy in nosocomial urinary tract infection.
authors.affiliation: plho@hkucc.hku.hk
authors.forename: Pak-Leung
authors.initials: PL
authors.lastname: Ho
authors.forename: Wai-Ming
authors.initials: WM
authors.lastname: Chan
authors.forename: Kenneth W T
authors.initials: KW
authors.lastname: Tsang
authors.forename: Samson S Y
authors.initials: SS
authors.lastname: Wong
authors.forename: Karl
authors.initials: K
authors.lastname: Young
mesh_terms: D017677:Age Distribution; D000900:Anti-Bacterial Agents; D016470:Bacteremia / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D016001:Confidence Intervals; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008826:Microbial Sensitivity Tests; D015999:Multivariate Analysis; D011336:Probability; D012307:Risk Factors; D017678:Sex Distribution; D015996:Survival Rate; D016896:Treatment Outcome; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases