Addressing the challenge of extended-spectrum beta-lactamases.

During the last decade, community-acquired extended-spectrum beta-lactamase (ESBL)-producing bacteria, and in particular Escherichia coli producing ESBLs of the CTX-M-type, have spread worldwide. These organisms are most often isolated from the urinary tract, but have also been isolated from bacteria in the blood. Cephalosporin- and fluoroquinolone-containing treatments are the two most common risk factors identified in patients with ESBL...