Incidence and risk factors of recurrent bacteraemia due to Escherichia coli

Abstract number: P1087

Villar J., Rodriguez Aranda A., Sanz F., Otero J.R., Chaves F.

Objectives:E. coli recurrent bacteraemia (RB), defined as relapse or reinfection, is a relevant but not well known clinical process. The aim of this study was to determine the frequency of RB and risk factors for relapse (isolates with the same pulsed-field gel electrophoresis pattern [PFGE]) or reinfection (different PFGE) after a first episode of E. coli bacteraemia.

Methods: This is a retrospective study conducted in a tertiary Hospital. RB was defined as a new episode of bacteraemia after at least 1 month since a prior episode sucessfully treated. Patients with RB during 2001–2005 were included. The control group included 41 patients with a single episode of bacteraemia and a year of follow-up. A systematic review of clinical data was performed. Blood isolates were analysed by PFGE and the phylogenetic background studied. We compared demographic, clinical and microbiological variables between relapse or reinfection and control group.

Results: 945 patients had E. coli bacteraemia, 32 (3.4%) had RB. We studied blood isolates from 28 patients (4 excluded) with 58 clinical episodes. According to PFGE analysis, 13 patients (46.4%) suffered relapse and 15 (53.6%) reinfection. Relapse occurred earlier than reinfection (median, 56 versus 67 days, p = 0.02), and it was caused by strains more resistant to antibiotics. In the comparison with no RB, multivariate analysis showed that patients with relapse were more likely to be younger than 60 years (OR:17.5; p = 0.05), admitted in the nefrology unit (OR:246.9; p = 0.012), to have received antibiotics previously (OR:15.6; p = 0.045) and to be infected with ciprofloxacin resistant strains (OR: 97.0; p = 0.008). On the other hand, patients with reinfection were associated with prior hospital admissions (OR: 21.6; p = 0.027), being admitted in haematology/oncology units (OR: 19.8; p = 0.037), having a central intravascular catheters (OR:60.9; p = 0.008), and having a biliary/gastrointestinal source of infection (OR: 20.9; p = 0.039). The distribution of phylogenetic groups in relapses was: group B1 38.5%, D 30.8%, B2 23.1%, and A 7.7% and in reinfections was: group B1 33.3%, B2 25.9%, D 18.5%, and A 22.2%.

Conclusions: We have determined the frequency of recurrent Escherichia coli bacteraemia in our hospital and delineated some risk factors for relapse and reinfection. Appropriate management for the prevention of further recurrences may need more research on treatment strategies and virulence factors of E. coli strains

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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