Influence of freezing stress on morphological alteration and biofilm formation by Listeria monocytogenes: relationship with cell surface hydrophobicity and membrane fluidity

• Published in: Archives of microbiology 2013-11, Vol.195 (10-11), p.705-715
• Main Authors: Miladi, Hanene, Ammar, Emna, Ben Slama, Rihab, Sakly, Nawfel, Bakhrouf, Amina
• Format: Article
• Language: English
• Subjects: Adhesives; Animals; Bacteria; Bacterial Adhesion; benzalkonium chloride; Benzalkonium Compounds - pharmacology; Biochemistry; biofilm; Biofilms; Biofilms - drug effects; Biomedical and Life Sciences; Biotechnology; Cell Biology; Cell Membrane - chemistry; Cell Membrane - metabolism; cold stress; Disinfection; Disinfection & disinfectants; Ecology; fatty acid composition; Fatty acids; Fatty Acids - metabolism; Food; Freezing; genes; Gram-positive bacteria; Hydrophobic and Hydrophilic Interactions; hydrophobicity; Life Sciences; Listeria; Listeria monocytogenes; Listeria monocytogenes - chemistry; Listeria monocytogenes - cytology; Listeria monocytogenes - drug effects; Listeria monocytogenes - physiology; Membrane Fluidity; Microbial Ecology; Microbiology; Morphology; Original Paper; pathogens; Salmon; Salmon - microbiology; Salmonidae; Sanitation; Slime; Stainless steel; starvation; Temperature
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-013-0921-7

The morphological changes and adhesive property of three Listeria monocytogenes strains submitted to freezing stress (−20 °C) were studied. The atomic force micrographs showed a reduction in the cell size and an evolution to coccoid shape. The phenotypic slime production of L. monocytogenes and the expression of the adhesive gene were investigated before and after 10 months of incubation in salmon at −20°. Our results showed that after ten months, stressed stains become more adherent and able to produce slime. In addition, we noted that this pathogen presents same physiological changes to adapt to starvation conditions. The cellular fatty acids composition of adhered and floating cells of three L. monocytogenes strains was taken into consideration. The stressed strains presented different chain lengths and therefore an increase in the hydrophobicity level. Moreover, we noted that the adhesive property of L. monocytogenes strains affects the Benzalkonium chloride bacterial sensitivity which increased after biofilm formation.