Extended-spectrum β-lactamase producing Escherichia coli: changing epidemiology and clinical impact

Purpose of review This review discusses the recent findings (July 2008-January 2010) on extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, mainly focussed on the epidemiology and clinical impact of infections owing to this pathogen. Recent findings CTX-M-producing E. coli, mainly the CTX-M-15 producers, has emerged and disseminated worldwide as an important cause of both nosocomial and community-onset infections. The clonal spread of the ST131 epidemic E. coli strain is linked not only to the CTX-M-15 pandemia but also to other ESBLs types. The most commonly reported risk factors for community-onset ESBL-producing E. coli infections are contact with healthcare centres, recent use of antimicrobial agents, and presence of comorbidities. But infections owing to ESBL-producing E. coli in patients without obvious risk factors can occur, probably related to the increase of healthy carriers colonized with this pathogen. The main significant predictor of mortality caused by ESBL-producing E. coli is inadequate initial antimicrobial therapy. Alternatives of treatment of severe ESBL-producing E. coli infections included carbapenems, amikacin, tigecycline, and beta-lactam/beta-lactamase inhibitor combinations; with some of them enough clinical evidence is lacking (tigecycline, beta-lactam/beta-lactamase inhibitor combinations). For urinary tract infections, fosfomycin and nitrofurantoin could be useful. Summary The worldwide emergence of multiresistant ESBL-producing E. coli raises key therapeutic problems; interventions addressed to their quick detection and early appropriate antibiotic treatment and prevention are urgently needed.