Prior use of carbapenems may be a significant risk factor for extended-spectrum beta-lactamase-producing Escherichia coli or Klebsiella spp. in patients with bacteraemia.
BACKGROUND
The increasing prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae will probably trigger a rise in the use of carbapenems. The effect of these antibiotics on the risk of involvement of ESBL-producing organisms in serious infections is unclear.


METHODS
Retrospective analysis of 2172 episodes of healthcare-associated bacteraemia diagnosed during a 3 year period in a teaching hospital. Putative risk factors included demographics, co-morbidities, previous isolation of an ESBL-producing organism and exposure to antibiotics. Univariate and multivariate analysis of the association of risk factors with ESBL-producing organisms was performed in the entire series of bacteraemic episodes and in those due to Escherichia coli or Klebsiella spp.


RESULTS
In the entire series, prior isolation of an ESBL-producing organism [odds ratio (OR) 5.9 (3.02, 11.5)]; an ultimately/finally fatal co-morbidity [OR 2.8 (1.55, 4.95)]; renal transplantation [OR 4.3 (1.96, 9.63)]; a urinary source [OR 4.2 (2.22, 7.84)]; shock [OR 2.4 (1.35, 4.1)] and previous use of cephalosporins [OR 2.6 (1.54, 4.51)], carbapenems [OR 2.5 (1.24, 5.05)] and glycopeptides [OR 0.4 (0.13, 0.93)] were significantly associated with ESBL-producing E. coli or Klebsiella spp. by multivariate analysis. Prior isolation of an ESBL-producing organism, an ultimately/finally fatal co-morbidity, renal transplantation, and previous use of cephalosporins and carbapenems were also significant in the analysis restricted to episodes due to E. coli or Klebsiella spp.


CONCLUSIONS
In patients with healthcare-associated bacteraemia, prior use of carbapenems may be only second to cephalosporins as the most significant antibiotic exposure associated with the involvement of ESBL-producing organisms.
Martínez
José A
JA
Department of Infectious Diseases, Hospital Clínic, IDIBAPS-University of Barcelona, Barcelona, Spain. jamarti@clinic.ub.es
Aguilar
Josefa
J
Almela
Manel
M
Marco
Francesc
F
Soriano
Alex
A
López
Fina
F
Balasso
Valentina
V
Pozo
Laura
L
Mensa
Josep
J
D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000209:etiology / Q000382:microbiology*; D015780:Carbapenems / Q000009:adverse effects* / Q000627:therapeutic use; D003428:Cross Infection / Q000382:microbiology; D004351:Drug Resistance; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000209:etiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007709:Klebsiella / Q000201:enzymology* / Q000302:isolation & purification; D007710:Klebsiella Infections / Q000209:etiology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D001618:beta-Lactamases / Q000096:biosynthesis*
D015780:Carbapenems; D001618:beta-Lactamases