Cell Shape and Antibiotic Resistance Are Maintained by the Activity of Multiple FtsW and RodA Enzymes in Listeria monocytogenes

Abstract

Rod-shaped bacteria have two modes of peptidoglycan synthesis: lateral synthesis and synthesis at the cell division site. These two processes are controlled by two macromolecular protein complexes, the elongasome and divisome. Recently, it has been shown that the Bacillus subtilis RodA protein, which forms part of the elongasome, has peptidoglycan glycosyltransferase activity. The cell division-specific RodA homolog FtsW fulfils a similar role at the divisome. The human pathogen Listeria monocytogenes carries genes that encode up to six FtsW/RodA homologs; however, their functions have not yet been investigated. Analysis of deletion and depletion strains led to the identification of the essential cell division-specific FtsW protein, FtsW1. Interestingly, L. monocytogenes carries a gene that encodes a second FtsW protein, FtsW2, which can compensate for the lack of FtsW1, when expressed from an inducible promoter. L. monocytogenes also possesses three RodA homologs, RodA1, RodA2, and RodA3, and their combined absence is lethal. Cells of a rodA1 rodA3 double mutant are shorter and have increased antibiotic and lysozyme sensitivity, probably due to a weakened cell wall. Results from promoter activity assays revealed that expression of rodA3 and ftsW2 is induced in the presence of antibiotics targeting penicillin binding proteins. Consistent with this, a rodA3 mutant was more susceptible to the β-lactam antibiotic cefuroxime. Interestingly, overexpression of RodA3 also led to increased cefuroxime sensitivity. Our study highlights that L. monocytogenes genes encode a multitude of functional FtsW and RodA enzymes to produce its rigid cell wall and that their expression needs to be tightly regulated to maintain growth, cell division, and antibiotic resistance. IMPORTANCE The human pathogen Listeria monocytogenes is usually treated with high doses of β-lactam antibiotics, often combined with gentamicin. However, these antibiotics only act bacteriostatically on L. monocytogenes, and the immune system is needed to clear the infection. Therefore, individuals with a compromised immune system are at risk to develop a severe form of Listeria infection, which can be fatal in up to 30% of cases. The development of new strategies to treat Listeria infections is necessary. Here we show that the expression of some of the FtsW and RodA enzymes of L. monocytogenes is induced by the presence of β-lactam antibiotics, and the combined absence of these enzymes makes bacteria more susceptible to this class of antibiotics. The development of antimicrobial agents that inhibit the activity or production of FtsW and RodA enzymes might therefore help to improve the treatment of Listeria infections and thereby lead to a reduction in mortality.

Non-essentiality of canonical cell division genes in the planctomycete Planctopirus limnophila

“…FtsW is essential in most organisms containing a single copy of this gene. Depletion of FtsW in rod-shaped bacteria leads to a block in cell division and formation of elongated cells [59][60][61] . In the polyploid spherical cyanobacterium Synechocystis sp.…”

Bactericidal Activity of Usnic Acid-Chitosan Nanoparticles against Persister Cells of Biofilm-Forming Pathogenic Bacteria

“…The elongation of L. monocytogenes cells by UA-CS NPs in the present study might be due to the inhibition of cell division. The genome of L. monocytogenes contains the lmo1071 gene that encodes the FtSW protein, which is responsible for cell division; when the gene is mutated cells become elongated [79]. Hence, in the presence of UA-CS NPs, the elongation of cells might be due to the inhibition of cell division.…”

Building peptidoglycan inside eukaryotic cells: A view from symbiotic and pathogenic bacteria

“…I am particularly intrigued with this idea of environment sensing. A recent study revealed that the genome of the intracellular pathogen Listeria monocytogenes encodes three RodA (RodA1, RodA2, RodA3) and two FtsW (FtsW1, FtsW2) paralogs (Rismondo, Halbedel, & Grundling, ). Deficiencies in some of these proteins result in changes in shape and antibiotic resistance, therefore displaying capacity for a functional interchange in the laboratory medium.…”