[Bacteraemia due to Escherichia coli producing extended-spectrum beta-lactamases (ESBL): clinical relevance and today's insights].

Antibiotic resistance is an old problem with new face as the rate of infections due to multidrug resistant bacteria is higher everyday and the number of new antibiotics to overwhelm the problem is becoming smaller. E. coli is the most frequent agent causing nosocomial or community-acquired bacteraemia being in our country 10% of them extended-spectrum beta-lactamases (ESBL) producing E. coli isolates. Nowadays the number of community- acquired or health-related infections caused by these ESBL producing E. coli is increasing. CTX-M has also become the most frequent ESBL compared to other enzymes. The role of these enzymes as a virulence factor increasing mortality in patients with bacteraemia due to E. coli is not well defined. The relevance of ESBL-E. coli seems to be related with the higher frequency of inadequate treatment and therefore the importance of identifying factors or features that might predict that the patient's infection is due to one of these isolates. In terms of prevention and control of infection measures, the role of patient's isolation is not clear but a proper prescription of antibiotics and antibiotic control policies are probably important to reduce the problem.