The ABC Transporter AnrAB Contributes to the Innate Resistance ofListeria monocytogenesto Nisin, Bacitracin, and Various β-Lactam Antibiotics

Abstract

ABSTRACTAmarinertransposon bank was used to identify loci that contribute to the innate resistance ofListeria monocytogenesto the lantibiotic nisin. In addition to highlighting the importance of a number of loci previously associated with nisin resistance (mprF,virRS, andtelA), a nisin-sensitive phenotype was associated with the disruption ofanrB(lmo2115), a gene encoding the permease component of an ABC transporter. The contribution ofanrBto nisin resistance was confirmed by the creation of nonpolar deletion mutants. The loss of this putative multidrug resistance transporter also greatly enhanced sensitivity to bacitracin, gallidermin, and a selection of β-lactam antibiotics. A comparison of the relative antimicrobial sensitivities of a number of mutants established the ΔanrBstrain as being one of the most bacitracin-sensitiveL. monocytogenesstrains identified to date.