DATA FOR THE PROPERTIES OF LISTERIA STRAINS

It seems that taxonomy of listeriae is in a fluid stage. Between beta- haemolytic property and virulence of these bacteria a strong relations hip has been demonstrated. These characters are coded by hlyA gene whi ch seems to belong to a monocistronic unit. Virulent Listeria strains possess specific surface antigens and can enter as well as multiply in host cells. Their exact human virulence is not known. Listeriae can g row from around 0 to 42-degrees-C and can survive either the effect of frost or of temperature of 48-degrees-C. They may form biofilm on dif ferent surfaces. Their growth kinetics, persistance and heat resistanc e can be influenced by many factors (type of growth environment, pH, a cidulants, salts, chemicals, antibiotics, plant substances, enzymes, h umidity, atmosphere, temperature, prior temperature-effects, microbial competition and the length of influences). Radiation sensitivity of L isteria is usual. Plasmid mediated antibiotic resistant mutant of List eria monocytogenes is verified.