Drug-susceptibility, biofilm-forming ability and biofilm survival on stainless steel of Listeria spp. strains isolated from cheese

Krzysztof Skowron; Natalia Wiktorczyk; Katarzyna Grudlewska; Joanna Kwiecińska-Piróg; Ewa Wałecka-Zacharska; Zbigniew Paluszak; Eugenia Gospodarek-Komkowska

doi:10.1016/j.ijfoodmicro.2019.02.021

Drug-susceptibility, biofilm-forming ability and biofilm survival on stainless steel of Listeria spp. strains isolated from cheese

Int J Food Microbiol. 2019 May 2:296:75-82. doi: 10.1016/j.ijfoodmicro.2019.02.021. Epub 2019 Mar 1.

Authors

Krzysztof Skowron¹, Natalia Wiktorczyk², Katarzyna Grudlewska², Joanna Kwiecińska-Piróg², Ewa Wałecka-Zacharska³, Zbigniew Paluszak⁴, Eugenia Gospodarek-Komkowska²

Affiliations

¹ Department of Microbiology, Nicolaus Copernicus University in Toruń, L. Rydygier Collegium Medicum in Bydgoszcz, 9 M. Skłodowska-Curie St., 85-094 Bydgoszcz, Poland. Electronic address: skowron238@wp.pl.
² Department of Microbiology, Nicolaus Copernicus University in Toruń, L. Rydygier Collegium Medicum in Bydgoszcz, 9 M. Skłodowska-Curie St., 85-094 Bydgoszcz, Poland.
³ Department of Food Hygiene and Consumer Health, Wrocław University of Environmental and Life Sciences, 31 C.K. Norwid St., 50-375 Wrocław, Poland.
⁴ Department of Microbiology and Food Technology, UTP University of Science and Technology, 6 Bernardyńska St., 85-029 Bydgoszcz, Poland.

PMID: 30851643
DOI: 10.1016/j.ijfoodmicro.2019.02.021

Abstract

The aim of the study was to analyze the contamination of mold cheese (Brie, Camembert, Gorgonzola, Munster and Roquefort) with Listeria spp. and assessment of culturable cells number recovered from the biofilm formed on the surface of stainless steel by obtained strains. Identified isolates (MALDI TOF MS technique) were subjected to susceptibility testing (disk-diffusion method) and their genetic similarity (PFGE method), ability to form biofilm (quantitative method), biofilm dry weight, and biofilm survival on stainless steel were evaluated. Out of 250 samples of cheese 26 (10.4%) were Listeria spp. positive, including 15 isolates (6.0% of samples) of L. monocytogenes, 7 isolates of L. innocua (2.8% of samples) and 4 isolates of L. welshimeri species (1.6% of samples). Of the 26 isolates tested, 22 strains were genetically different. It was shown that L. innocua and L. welshimeri strains were sensitive to all antibiotics tested, while two (16.7%) L. monocytogenes strains were resistant to penicillin and one (8.3%) to erythromycin. L. monocytogenes formed biofilm most intensively on stainless steel, while L. welshimeri the least effectively. The median of bacteria number recovered from the biofilm for L. monocytogenes was 6.81 log CFU × cm^-2, for L. innocua - 5.63 log CFU × cm^-2, and for L. welshimeri - 4.93 log CFU × cm^-2. The survival in the biofilm of Listeria spp. strains decreased along with the increase in a storage temperature of steel coupons. The longest survival time was reported at 4 °C, i.e. 47.58-124.41 days, with an elimination rate of 0.06-0.13 log CFU × day^-1. Collectively, L. monocytogenes is the most prevalent species of Listeria genus in the mold cheese. The ability of L. monocytogenes strains to form biofilm on stainless steel and survive in the food processing environment increases chance of the secondary contamination of food posing risk to the consumer health.

Keywords: Antibiotic resistance; Biofilm; Biofilm biomass; Cheese; Listeria spp.; Stainless steel; Temperature.

MeSH terms

Anti-Bacterial Agents / pharmacology*
Biofilms / growth & development*
Cheese / microbiology*
Disk Diffusion Antimicrobial Tests
Food Contamination / analysis
Food Handling
Food Microbiology
Listeria monocytogenes / drug effects*
Listeria monocytogenes / genetics
Listeria monocytogenes / growth & development*
Listeria monocytogenes / isolation & purification
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Stainless Steel*

Substances

Anti-Bacterial Agents
Stainless Steel