Biofilm screening of <em>Listeria monocytogenes</em> from common MLST subtypes present in food production environments. — ASN Events

Biofilm screening of Listeria monocytogenes from common MLST subtypes present in food production environments. (#241)

Jessica Gray 1 , Scott Chandry 1 , Chawalit Kocharunchitt 2 , Mandeep Kaur 2 , John Bowman 2 , Ed Fox 1
  1. CSIRO, Werribee, VIC, Australia
  2. University of Tasmania, Hobart, Tasmania

Listeria monocytogenes is a food borne pathogen capable of causing high hospitalisation and mortality rates. Populations of highest risk include the elderly, immunocompromised, pregnant women and neonates. In addition, L. monocytogenes is frequently identified as the causative agent responsible for microbial food recalls. Due to its ubiquitous nature, L. monocytogenes is a difficult microorganism to prevent from entering and colonising food production environments (FPEs). Some strains, known as persisters, may colonise the FPE and remain despite regular cleaning and sanitising regimes. These persistent strains act as a repetitive source of cross contamination and have been shown to persist over a substantial number of years. Factors influencing the persistence and survival of L. monocytogenes in FPEs are not well characterised; however, are postulated to be influenced by a number of genetic and environmental elements. One factor of significant influence is the bacterium’s ability to adhere to surfaces and form biofilms. Biofilms are structures containing microbial cells attached to each other and/or a surface housed in an extracellular polymeric substance. Biofilms offer a number of advantages to bacterial species in FPEs such as: multiple species in various metabolic states; increased protection from disinfectants, desiccation and other environmental elements; removal of toxic metabolites; transfer of nutrients; and the opportunity to acquire new genetic traits through horizontal gene transfer. Previous studies have tried to associate a particular serotype or pulsotype to increased biofilm formation; however, differing results have been reported. This study utilised 52 isolates from various MLST subtypes commonly identified in FPEs to assess attachment and biofilm formation over 96 h under conditions reflective of the FPE. The results indicated attachment and biofilm formation may be strain specific, with no individual MLST subtype demonstrating increased ability to attach or form biofilms. This information will help to further understand how L. monocytogenes survives in FPEs with further research required to identify potential strain specific differences.

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