Genes involved in attachment of Listeria monocytogenes to abiotic surfaces
thesisposted on 05.02.2014, 13:25 by Sarah Marie Glenn
This study investigated genes involved in attachment of Listeria monocytogenes to abiotic surfaces. L. monocytogenes has previously been shown to attach to a variety of different abiotic surfaces, including polystyrene, stainless steel and glass. Consequently biofilm formation is a significant problem in food processing industries. An existing attachment assay was modified to allow screening of transposon mutants for a deficiency in attachment of bacteria to wells of a microtitre plate. Using this assay, three mutants were identified that had previously been shown to have reduced attachment to stainless steel and glass. The location of insertion of the transposon into each of the mutants M113, B380 and M237 was mapped to the genes lmo1226, lmo0401 and lmo0501, respectively. Deletion mutants were made in these genes and the gene lmo0402 to better clarify the role of these genes in attachment. The gene lmo1226 was identified as a drug exporter of the RND superfamily, responsible for the streptomycin resistance exhibited by L. monocytogenes strain 10403s. Lmo1226 is also involved in attachment, virulence, and growth of L. monocytogenes in sodium chloride. The genes lmo0401 and lmo0501 were identified as an α-mannosidase and a BglG transcriptional antiterminator respectively, and were identified to be involved in attachment alongside another transcriptional antiterminator (lmo0402). The transcriptional antiterminators were shown to be involved with transcription of the Bgl operon which encodes genes required for phosphoenolpyruvate phosphate transferase systems in L. monocytogenes. The results from these experiments have helped to elucidate the processes involved in L. monocytogenes attachment to surfaces, and have identified targets for future antimicrobials against this bacterium.