Antimicrobial Resistance and Drug Efflux Pumps in Bacteroides

Abstract

Bacteroides spp. constitute an important part of the commensal intestinal microbiota, but some species such as Bacteroides fragilis are associated with human infections. There is an increasing occurrence of acquired antimicrobial resistance including multidrug resistance in Bacteroides spp., which, together with the limited availability of anti-anaerobe antimicrobials, raises a concern for effective therapy of Bacteroides infections. This chapter provides a current overview on antimicrobial susceptibility and resistance mechanisms of Bacteroides with detailed descriptions of the known drug effl ux pumps, which contribute to both intrinsic and acquired resistance. Keywords Bacteroides • Antimicrobial resistance • Multidrug resistance • Effl ux • RND pumps 20.1 Introduction In terms of bacterial classifi cation and taxonomy, the genus Bacteroides is composed of >40 species. It includes the Bacteroides fragilis group comprising the most fre-quent clinically isolated species from human biological samples [ 1 ]. Bacteria of this genus are anaerobic, bile-resistant, non-spore forming, Gram-negative rods. They are part of the indigenous microbiota of the human and animal gastrointestinal tracts but can be found in other locations such as the mouth, the upper respiratory tract, and urogenital tract. The Bacteroides spp. of the fragilis group are the predominant microorganisms isolated by culture methods from feces. Metagenomic sequencing has confi rmed that Bacteroides is a predominant genus of the gastrointestinal tract microbiota [ 2 ].