Current epidemiology, genetic evolution and clinical impact of extendedspectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae

The worldwide spread of extended- spectrum beta-lactamase (ESBL)-producing bacteria, particularly Escherichia coli and Klebsiella pneumoniae, is a critical concern for the development of therapies against multidrug-resistant bacteria. Since the 2000s, detection rates of CTX-M types ESBL-producing E. coli in the community have been high, possibly contributing to their nosocomial detection. Various factors, such as environmental sources, food animals, and international travel, accelerate the global ESBL spread in the community. The dramatic dissemination of ESBLs in the community is associated with the relatively recent emergence of CTX-M-15-producing ST131 E. coli clones, which often carry many other antibiotic resistance genes (including quinolone). The usefulness of beta-lactam/beta-lactamase inhibitor, particularly, piperacillin/tazobactam, has been considered as a carbapenem-sparing regimen for ESBL infections, although the global trend of AmpC beta-lactamase-producing bacteria should be monitored carefully. Careful therapeutic selection and continued surveillance for the detection of multidrug-resistant bacteria are required.