Resistance of Listeria monocytogenes biofilms to disinfectants 326

Abstract

Purkrtová S., Turoňová H., Pilchová T., Demnerová K., Pazlarová J. (2010): Resistance of Listeria monocytogenes biofilms to disinfectants. Czech J. Food Sci., 28: 326-332.We studied the optimal conditions for the biofilm development by Listeria monocytogenes on a model system represented by microtiter plates, and also for determined some effective disinfectant agents. Listeria monocytogenes ATCC 13932 and an industrial isolate of Listeria monocytogenes Lm-24 were compared as to their abilities to form biofilms. The starting concentration of the cells leading to the most reproducible results was 0.5 McFarland. The temperatures tested ranged between 8°C to 37°C, the optimal values to form biofilm in buffered peptone water (BPW) with 0.05% glucose were 25°C and 30°C. Under comparable conditions the persistent strain L. monocytogenes Lm-24 constituted more massive biofilm than did the reference strain. The following disinfectants were applied: Savo, Merades Alco, benzalalkonium chloride. A persistent industry in isolate Listeria monocytogenes Lm-24 was used as the model organism for these tests. Benzalalkonium chloride treatment was found to be the most efficient way to damage the biofilm. One minute treatment with 500 mg/l was lethal for the biofilm cells, and that with 125 mg/l for planctonic cells. Savo suppresed the viability of the biofilm cells only by about 20% on average while being lethal for planctonic cells. Merades Alco exhibited only a weak effect on both the biofilm and planctonic cells.

Efficacy of chemical agents and power ultrasound on biofilms formed by Asaia spp. - spoilage bacteria in beverage industries

“…When the biofilm was treated with both the E-agent and PUS, the reduction amounted to 2.1 log CFU/cm 2 for A. lannensis 1 and 1.9 log CFU/cm 2 for A. lannensis 2 after 5 min, and to 3.0 log CFU/cm 2 for A. lannensis 1 and 2.9 log CFU/cm 2 for A. lannensis 2 after 7 min of action. The low efficacy of the E-agent complies with the results of Purkrtová et al (2010) on the efficacy of a similar product on Listeria monocytogenes biofilms, which concluded that the number of biofilm viable cells was not significantly reduced even after 30 min of exposure.…”

The Expression of Superoxide Dismutase (SOD) and a Putative ABC Transporter Permease Is Inversely Correlated during Biofilm Formation in Listeria monocytogenes 4b G

“…Biofilms are structured communities of microorganisms adhering to a surface, and may be encapsulated within a self-produced protective and adhesive matrix of extracellular polymeric substances (EPS) [4] . Bacteria in biofilms are more resistant to various environmental stresses such as desiccation, UV light, antimicrobials, and sanitizers [5] , [6] . Therefore, biofilms that are difficult to eliminate completely impose major challenges to the food industry.…”

Antimicrobial factors effects on biofilm formation in Staphylococcus aureus

“…In previous experiments, it was found that direct staining of biofilm with crystal violet after the treatment with disinfectants is not optimal because the cells surface is damaged. The dead cells bind crystal violet more readily (Purkrtová et al 2010).…”