Interaction and inactivation of Listeria and Lactobacillus cells in single and mixed species biofilms exposed to different disinfectants

Abstract

Listeria spp. are ubiquitously found in both the natural and the food processing environment, of which Listeria monocytogenes is of an important health risk. Here, we report on the formation of single and mixed species biofilms of L. monocytogenes/Listeria innocua and Lactobacillus plantarum strains in 24‐well polystyrene microtiter plates and on the inactivation of 24‐hr and 72‐hr biofilms using quaternary ammonium compound‐, tertiary alkyl amine‐, and chlorine‐based disinfectants. Fluorescent in situ hybridization (FISH) and LIVE/DEAD BacLight staining were applied for 72‐hr L. innocua–L. plantarum mixed biofilms in the LabTek system for the species identification and the reaction of biofilm cells to disinfectants, respectively. L. monocytogenes/L. innocua were more resistant to disinfectants in 72‐hr than in 24‐hr biofilms, whereas L. plantarum strains did not show any significant differences between 72‐hr and 24‐hr biofilms. Furthermore, L. innocua when grown with L. plantarum was more resistant to all disinfection treatments, indicating a protective effect from lactobacilli in the mixed species biofilm. The biofilm formation and reaction to disinfectants, microscopically verified using fluorescence in situ hybridization and LIVE/DEAD staining, showed that L. innocua and L. plantarum form a dense mixed biofilm and also suggested the shielding effect of L. plantarum on L. innocua in the mixed species biofilm.

A Novel Cryptic Clostridial Peptide That Kills Bacteria by a Cell Membrane Permeabilization Mechanism

“…The fluorescence from both live and dead bacteria was viewed simultaneously with a Nikon blue excitation B-2A (long-pass emission) filter. Additionally, the biofilm of A. baumannii CARB KPD 205 was prepared in an experimental system according to methods described by Kocot and Olszewska ( 65 ). Briefly, 1 mL of A. baumannii in the exponential phase of growth was placed in the LabTek chamber slide system (Thermo Fisher Scientific).…”

Listeria monocytogenes in food businesses: From persistence strategies to intervention/prevention strategies—A review

“…A 4‐day‐old biofilm is already mature, indicating that even when the EPS matrix is fully developed, longer residence times can still attribute to enhanced resistance. Kocot and Olszewska (2019) confirmed the enhanced resistance in more mature biofilms (72‐h biofilms) compared to more immature/younger biofilms (24‐h biofilms), but this is not always the case (Ibusquiza et al., 2011; Pang et al., 2019; Somers & Wong, 2004). The influence of age could depend on additional factors, as in the study of Pang et al.…”

“…Although it is shown that the age of the biofilm might also have a significant influence on its resistance toward disinfection, many studies use immature/young biofilms (maximum 72 h) to investigate the disinfectant resistance/tolerance (Fagerlund, Heir, et al, 2020;Haubert et al, 2019;Kocot & Olszewska, 2019;Pan et al, 2006;. Ibusquiza et al (2011) noticed that 11-day-old L. monocytogenes biofilms had an enhanced biofilm disinfectant resistance in comparison to 4-dayold biofilms and planktonic cells.…”

“…The influence of age could depend on additional factors, as in the study of only an influence of age on the disinfectant tolerance was visible in diluted tryptic soy broth and not when using salmon broth (Table 2). The overall higher tolerance in mature biofilms might be attributed to the spatial arrangement, formation of a three-dimensional structure with a thick EPS matrix, and the shielding of dead cells protecting the underlying cells from adverse environmental conditions (Ibusquiza et al, 2011;Kocot & Olszewska, 2019). Due to the possibility that mature biofilms are less susceptible to disinfectants and the fact that biofilms have sufficient time to reach maturation in between C&D cycles when establishing the C&D procedure, in-house testing must take mature biofilms into account.…”

Lactobacillus plantarum in Dual-Species Biofilms With Listeria monocytogenes Enhanced the Anti-Listeria Activity of a Commercial Disinfectant Based on Hydrogen Peroxide and Peracetic Acid

“…Van der Veen and Abee (2011) reported that the mixed species biofilms of L. monocytogenes and L. plantarum showed enhanced resistance to BAC and peracetic acid. Kocot and Olszewska (2019) reported an increased resistance to quaternary ammonium compounds (QACs)-based, tertiary alkyl amine-based, and chlorine-based disinfectants. These differences may be explained by specific biofilm forming conditions since these authors incubated the biofilms at 37°C.…”