The ecology of extended-spectrum β-lactamases (ESBLs) in the developed world

Abstract

Background: Since the initial appearance in the 1980s, Enterobacteriaceae producing extended-spectrum β-lactamase (ESBL) have increased in prevalence and emerged as a major antimicrobial-resistant pathogen. The source of these antimicrobial-resistant bacteria in the developed world is an area of active investigation.

Methods: A standard internet search was conducted with a focus on the epidemiology and potential sources of ESBL-producing Enterobacteriaceae in the developed world.

Results: The last decade has witnessed several major changes in the epidemiology of these bacteria: replacement of TEM and SHV-type ESBLs by CTX-M-family ESBLs, emergence of Escherichia coli ST131 as a prevalent vehicle of ESBL, and spread of ESBL-producing E. coli in the community. The most studied potential sources of ESBL-producing Enterobacteriaceae in humans in the community include food and companion animals, the environment and person-to-person transmission, though definitive links are yet to be established. Evidence is emerging that international travel may serve as a major source of introduction of ESBL-producing Enterobacteriaceae into the developed world.

Conclusions: ESBL-producing Enterobacteriaceae has become a major multidrug-resistant pathogen in the last two decades, especially in the community settings. The multifactorial nature of its expansion poses a major challenge in the efforts to control them.

Keywords: Extended-spectrum beta-lactamase; epidemiology; source.

Figure 1.

Estimated rates of ESBL producers among E. coli clinical isolates. Most of the data were adopted from ‘Antimicrobial resistance: global report on surveillance 2014’ published by the World Health Organization (http://www.who.int/drugresistance/documents/surveillancereport/en/). Grey indicates countries with insufficient data

Figure 2.

Conceptual scheme of the ecology of ESBL-producing Enterobacteriacae in the developed world