Comparison of the intensity of biofilm formation by Listeria monocytogenes using classical culture-based method and digital droplet PCR

Abstract

Listeria monocytogenes is a Gram-positive bacterium, commonly found in food, water or sewage. This microorganism is capable of forming biofilm on different surfaces such as steel, glass, polypropylene etc. Recently an increase in cases of listeriosis has been noted, making L. monocytogenes the important health threat. Therefore, there is a need for rapid and sensitive detection of this pathogen. This study aimed to compare the number of L. monocytogenes cells recovered from the biofilm (prepared on steel and polypropylene) using the detection and amplification of the hlyA gene (droplet digital PCR, ddPCR) and the classical culture method. The research material consisted of 96 L. monocytogenes strains. A total of 58 isolates were obtained from clinical samples and 38 isolates derived from the municipal sewage treatment plant. Additionally, the reference strain ATCC ® 19111 ™ (WDCM00020) was used. The Pearson correlation coefficient for the results obtained by the classical culture-based method and ddPCR was 0.864 and 0.725, for biofilms produced on AISI 304 stainless steel surface and the polypropylene surface, respectively. Correlations were statistically significant (p ≤ 0.001), indicating that the ddPCR technique is an effective tool for the assessment of bacteria number in the biofilm.

Occurrence of Multidrug-Resistant Listeria monocytogenes in Environmental Waters: A Menace of Environmental and Public Health Concern

“…The biofilm formation by Lm in tap water was demonstrated as reported in a previous study by Gião and Keevil (2014). Also, a previous study posited that the capability of Lm isolates for biofilm formation could be attributed to the level of expression of the prfA and agr genes (Gandra et al, 2019;Grudlewska-Buda et al, 2020). In addition, Lm ability for biofilm formation is known to enhance its persistence in the environment and also contribute to higher antimicrobial resistance (Pan et al, 2006;Grudlewska-Buda et al, 2020;Bjergbaek et al, 2021).…”

“…Also, a previous study posited that the capability of Lm isolates for biofilm formation could be attributed to the level of expression of the prfA and agr genes (Gandra et al, 2019;Grudlewska-Buda et al, 2020). In addition, Lm ability for biofilm formation is known to enhance its persistence in the environment and also contribute to higher antimicrobial resistance (Pan et al, 2006;Grudlewska-Buda et al, 2020;Bjergbaek et al, 2021). Although, Herbert-Guillou et al (2001 put forward that biofilm is usually formed wherever there is water in the environment.…”

Anti-Biofilm Activity of Cell Free Supernatants of Selected Lactic Acid Bacteria against Listeria monocytogenes Isolated from Avocado and Cucumber Fruits, and from an Avocado Processing Plant

“…The presence of L. monocytogenes biofilms on food-contact surfaces present a consistent source of contamination and thus a food safety risk [ 7 ]). The biofilm formed on these hydrophilic and hydrophobic surfaces promotes persistence of L. monocytogenes in different environments, including food-processing environments [ 9 ]. L. monocytogenes biofilms adhere to various surfaces including polytetrafluoroethylene (PTFE) used in conveyor belts; polyester used as a floor sealer; stainless steel used for the majority of the equipment, polystyrene as a material for the drains; rubber used in joints; wood and also glass [ 10 , 11 ].…”

Research progress on detection techniques for point-of-care testing of foodborne pathogens

“…dPCR does not require the establishment of a standard curve and concentration comparison by Ct value (the number of cycles that PCR fluorescence signal goes through when it reaches a set threshold) and is considered an absolute quantitative method ( Grudlewska-Buda et al, 2020 ; Lei et al, 2021 ; Plante et al, 2021 ). Droplet digital PCR (ddPCR) is a new method that disperses a single target DNA molecule into multiple separated droplets, detects each droplet one by one after PCR amplification, and accurately quantifies DNA copy number ( Lei et al, 2020b ; Iwu et al, 2020 ).…”