Bacteriophage predation promotes serovar diversification in L isteria monocytogenes

• Published in: Molecular microbiology Vol. 97; no. 1; pp. 33 - 46
• Main Authors: Eugster, Marcel R., Morax, Laurent S., Hüls, Vanessa J., Huwiler, Simona G., Leclercq, Alexandre, Lecuit, Marc, Loessner, Martin J.
• Format: Journal Article
• Language: English
• Published: Wiley 01.07.2015
• Subjects: Acetylglucosamine; Bacteriology; Bacteriophages; Cell Wall; Genetic Complementation Test; Genetic Variation; Glycosylation; Life Sciences; Listeria monocytogenes; Microbiology and Parasitology; Molecular Sequence Data; Nucleoside Diphosphate Sugars; Phenotype; Point Mutation; Rhamnose; Serogroup; Serotyping; Teichoic Acids; Thymine Nucleotides
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/mmi.13009

Summary L isteria monocytogenes is a bacterial pathogen classified into distinct serovars ( SV s) based on somatic and flagellar antigens. To correlate phenotype with genetic variation, we analyzed the wall teichoic acid ( WTA ) glycosylation genes of SV 1/2, 3 and 7 strains, which differ in decoration of the ribitol‐phosphate backbone with N ‐acetylglucosamine ( GlcNAc ) and/or rhamnose. Inactivation of lmo1080 or the dTDP ‐ l ‐rhamnose biosynthesis genes rml ACBD ( lmo1081–1084 ) resulted in loss of rhamnose, whereas disruption of lmo1079 led to GlcNAc deficiency. We found that all SV 3 and 7 strains actually originate from a SV 1/2 background, as a result of small mutations in WTA rhamnosylation and/or G lc NA cylation genes. Genetic complementation of different SV 3 and 7 isolates using intact alleles fully restored a characteristic SV 1/2 WTA carbohydrate pattern, including antisera reactions and phage adsorption. Intriguingly, phage‐resistant L . monocytogenes   EGD e ( SV 1/2a) isolates featured the same glycosylation gene mutations and were serotyped as SV 3 or 7 respectively. Again, genetic complementation restored both carbohydrate antigens and phage susceptibility. Taken together, our data demonstrate that L . monocytogenes   SV 3 and 7 originate from point mutations in glycosylation genes, and we show that phage predation represents a major driving force for serovar diversification and evolution of L . monocytogenes .