Analysis of 4758 Escherichia coli bacteraemia episodes: predictive factors for isolation of an antibiotic-resistant strain and their impact on the outcome.
OBJECTIVE
To describe the predictive factors for the isolation of fluoroquinolone-resistant or extended- spectrum beta-lactamase (ESBL)-producing Escherichia coli and their impact on bacteraemia outcome.


METHODS
Analysis of E. coli bacteraemia episodes prospectively collected through a blood culture surveillance programme from January 1991 to December 2007.


RESULTS
Out of 18 080 episodes, 4758 (26%) E. coli bacteraemias were reported in the period of study. Mortality was noted in 440 cases (9%). Fluoroquinolone-resistant strains were reported in 1300 (27%) cases and ESBL-producing strains in 211 cases (4%). One hundred and seventy-eight strains out of 211 (84%) ESBL-producing E. coli were isolated since 2001. The two main independent risk factors for mortality were shock (OR: 10.28, P < 0.001) and inappropriate empirical therapy (OR: 4.83, P < 0.001). Inappropriate empirical therapy was significantly more frequent for infections caused by fluoroquinolone-resistant strains (n = 203, 16%, P < 0.001) and ESBL-producing strains (n = 110, 52%, P < 0.001). Independent factors associated with the isolation of a fluoroquinolone-resistant strain were: nosocomial origin (OR: 1.61, P < 0.001); urinary catheterization (OR: 2.44, P < 0.001); and previous therapy with a fluoroquinolone (OR: 7.41, P < 0.001). The independent risk factors associated with the isolation of an ESBL-producing strain were: nosocomial origin (OR: 1.68, P = 0.03); urinary catheterization (OR: 1.88, P = 0.001); and previous beta-lactam antibiotic therapy (OR: 2.81, P < 0.001).


CONCLUSIONS
Inappropriate empirical therapy was the strongest independent factor that we could modify to improve mortality in E. coli bacteraemia and was more frequent in cases caused by fluoroquinolone-resistant or ESBL-producing strains. Nosocomial acquisition, urinary catheterization and previous therapy with a fluoroquinolone or beta-lactam were predictive factors for infection with an antibiotic-resistant strain.
Ortega
M
M
Emergency Department, Hospital Clínic, IDIBAPS, University of Barcelona, Barcelona, Spain.
Marco
F
F
Soriano
A
A
Almela
M
M
Martínez
J A
JA
Muñoz
A
A
Mensa
J
J
D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D016470:Bacteremia / Q000382:microbiology* / Q000401:mortality; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000401:mortality; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012769:Shock / Q000150:complications; D001618:beta-Lactamases / Q000096:biosynthesis; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D047090:beta-Lactams; D001618:beta-Lactamases