Biofilm Formation Ability of ESBL/pAmpC-Producing Escherichia coli Isolated from the Broiler Production Pyramid

Escherichia coli able to produce extended spectrum beta-lactamases (ESBLs) and plasmid-mediated AmpC beta-lactamases (pAmpCs) represents a serious threat to public health, since these genes confer resistance to critically important antimicrobials (i.e., third generation cephalosporins) and can be transferred to non-resistant bacteria via plasmids. E. coli are known to be able to form a biofilm, which represents a favorable environment for the exchange of resistance determinants. Here, we assessed the ability of 102 ESBL/pAmpC-producing E. coli isolated from the broiler production pyramid to form a biofilm and to identify genetic factors involved in biofilm formation. All but one of the ESBL/pAmpC-producing E. coli were able to form a biofilm, and this represents a great concern to public health. E. coli belonging to phylogroups D, E, and F, as well as strains harboring the bla(CTX-M-type) gene, seem to be associated with an increased biofilm capability (p < 0.05). Furthermore, virulence genes involved in adherence and invasion (i.e., csgBAC, csgDEFG, matABCDEF, and sfaX) seem to enhance biofilm formation in E. coli. Efforts should be made to reduce the presence of ESBL/pAmpC- and biofilm-producing E. coli in the broiler production pyramid and, therefore, the risk of dissemination of resistant bacteria and genes.

Automated summary

Escherichia coli that produce ESBLs and pAmpCs pose a serious threat to public health as these genes confer resistance to critically important antibiotics and can be transferred to non-resistant bacteria through plasmids. In this study, 102 ESBL/pAmpC-producing E. coli isolated from broiler production were found to have the ability to form biofilms, with certain genetic factors and virulence genes associated with increased biofilm capability. Efforts should be made to reduce the presence of ESBL/pAmpC-producing E. coli and biofilms in the broiler production pyramid to minimize the risk of dissemination of resistant bacteria and genes.