Extended-spectrum beta-lactamases in ambulatory care: a clinical perspective.

Extended-spectrum beta-lactamase (ESBL)-producing organisms are emerging as a cause of infection in outpatients in many areas of the world. Most of these involve urinary tract infections caused by Escherichia coli harbouring CTX-M types of ESBLs. Risk-factors for such infections include older age and previous use of quinolones and cephalosporins. Oral alternatives for such infections are limited. These organisms may also cause some community-acquired life-threatening infections, such as bacteraemic urinary tract or intra-abdominal infections. Patients with these infections are at increased probability of receiving inappropriate empirical treatment. More studies addressing the risk-factors and therapeutic options for these infections are needed.