Persistent Listeria monocytogenes Isolates from a Poultry-Processing Facility Form More Biofilm but Do Not Have a Greater Resistance to Disinfectants than Sporadic Strains

Abstract

Some strains of Listeria monocytogenes can persist in food-processing environments, increasing the likelihood of the contamination of foodstuffs. To identify traits that contribute to bacterial persistence, a selection of persistent and sporadic L. monocytogenes isolates from a poultry-processing facility was investigated for biofilm-forming ability (crystal violet assay). The susceptibility of sessile cells to treatments (five minutes) with sodium hypochlorite having 10% active chlorine (SHY: 10,000 ppm, 25,000 ppm, and 50,000 ppm) and benzalkonium chloride (BZK: 2500 ppm, 10,000 ppm, and 25,000 ppm) was also studied. All isolates exhibited biofilm formation on polystyrene. Persistent strains showed larger (p < 0.001) biofilm formation (OD580 = 0.301 ± 0.097) than sporadic strains (OD580 = 0.188 ± 0.082). A greater susceptibility to disinfectants was observed for biofilms of persistent strains than for those of sporadic strains. The application of SHY reduced biofilms only for persistent strains. BZK increased OD580 in persistent strains (2500 ppm) and in sporadic strains (all concentrations). These results indicate that the use of BZK at the concentrations tested could represent a public health risk. Findings in this work suggest a link between persistence and biofilm formation, but do not support a relationship between persistence and the resistance of sessile cells to disinfectants.

Genomic insights into persistence of Listeria species in the food processing environment

“…Exposure to disinfectants imposes a continual stress on bacterial species colonizing FPEs, as these are central to hygiene efforts and food safety. Previous studies have suggested that disinfectant resistance may be a feature of strains encountered, or persisting, in FPEs; this is thought to contribute to the dominance of ST121 and ST204 clonally related strains (Schmitz-Esser et al 2015;Fox et al 2016); however, a positive association with persistence of specific strains in FPEs varies (Kastbjerg and Gram 2009;Fox et al 2011a;Rodr ıguez-Campos et al 2019). A variety of disinfectant resistance markers have been identified in Listeria species, typically comprising efflux pump systems; these include the bcrABC cassette, emrC, emrE, qacA, qacC, qacH and qacED1 determinants.…”

Lytic Capacity Survey of Commercial Listeria Phage Against Listeria spp. with Varied Genotypic and Phenotypic Characteristics

“…Control of persistent L. monocytogenes strains has been extensively studied (Holah et al, 2002;Romanova et al, 2002;Lundén et al, 2003;Leong et al, 2016;Rodríguez-Campos et al, 2019;Ochiai et al, 2020). A previous study by Vongkamjan et al (2013) b Point estimates of the ratio of odds of having a score (0, 1, 2) when the effect is compared with the odds of having a score of 3. differences in 50 persistent L. monocytogenes strains to 28 different Listeria phages isolated from food processing and dairy production facilities.…”

“…Listeria spp. may persist owing to varying biofilm-forming capacity conferring increased resistance to environmental stressors and commonly utilized cleaning and sanitation protocols compared with planktonic isolates (Lou and Yousef, 1996;Lundén et al, 2003;Soni and Nannapaneni, 2010;Fagerlund et al, 2017;Sadekuzzaman et al, 2017;Rodríguez-Campos et al, 2019). Bacteriophage are a promising biocontrol strategy against biofilms and have potential to overcome some of the challenges associated with Listeria control (Moye et al, 2018).…”

Listeria monocytogenes Biofilms in the Food Industry: Is the Current Hygiene Program Sufficient to Combat the Persistence of the Pathogen?

“…Biofilms of L. monocytogenes on food contact surfaces have been identified as an important pathway for pathogenic persistence and subsequent product contamination [ 10 , 11 , 12 ]. To this effect, in-depth study of the nature, formation, detection, and elimination of biofilms on surfaces is of great importance due to their impact as a risk factor on outbreaks of foodborne diseases that affect public health [ 13 , 14 ].…”