Characteristics of Listeria monocytogenes Strains Isolated from Milk and Humans and the Possibility of Milk-Borne Strains Transmission

Abstract

Listeria monocytogenes is the etiological factor of listeriosis. The main source of these organisms is food, including dairy products. The aim was to determine the multiple correlations between the drug susceptibility, virulence genes (VGs), and biofilm formation on silicone teat cups of milk-borne and human L. monocytogenes strains. The spread of L. monocytogenes via contaminated teat rubbers was assessed. The L. monocytogenes strains recovered from milk (18), human blood (10), and the reference strain ATCC®19111™ were used in the study. Penicillin resistance was the most prevalent resistance in the milk isolates (n = 8; 44.4%), whereas among clinical strains erythromycin resistance was predominating – (n = 6; 60%). The most frequent VGs among strains isolated from milk were hlyA (100%) and plcB (100%) whereas in strains isolated from blood – hlyA (100%) and prfA (90%). All tested VGs were present in 50% of blood isolates and 11% of milk-borne strains. The strains isolated from milk formed a significantly stronger biofilm. The strains with more numerous virulence genes were resistant to more antibiotics and formed a stronger biofilm. It was shown that contaminated teat cups might contribute to the transmission of L. monocytogenes in the herd. It seems reasonable to monitor the occurrence of L. monocytogenes biofilm in a dairy processing environment.

Molecular Detection of Listeria Species Isolated From Raw Milk with Special Reference to Virulence Determinants and Antimicrobial Resistance in Listeria monocytogenes

“…Because these biofilms are persistent for several months or even years, food can be contaminated repeatedly (Markkula et al, 2005). Our research confirms the findings of Skowron et al (2019), who showed that L. monocytogenes of milk origin frequently exhibit biofilm activity and possess a number of genes linked with virulence and antibiotic resistance. Additionally, L. monocytogenes only moderately or weakly produced biofilm on different surfaces in earlier investigations by Djordjevic et al (2002) and Harvey et al (2007).…”

“…The presence of the hlyA gene in all strains examined for our study's virulotyping analysis was consistent with research by Osman et al (2016), Şanlıbaba et al (2018), Owusu-Kwarteng et al (2018), El-Demerdash et al (2019 and Skowron et al (2019). Additionally, it was found that L. monocytogenes' ability to form biofilms is impacted by the presence of the hlyA virulence gene (Price et al, 2018), as this organism is better able to withstand ineffective disinfection during cleaning procedures, which results in the continued presence of L. monocytogenes in the final product.…”

Progress in research on the safety of silicone rubber products in food processing

“…After exposing the silver‐plated SR surface to L. monocytogenes for 12 h, no live bacteria were detected, demonstrating their bactericidal properties (Jiang et al., 2004). L. monocytogenes was found in the silicone teat cup, which may be caused by insufficient pasteurization or cross‐contamination (Skowron et al., 2019). Furthermore, L. monocytogenes contaminate food on a regular basis, pose a significant risk to public health, and their control is a significant barrier in the food production chain (Galié et al., 2018).…”

Characterization and Preliminary Application of Phage Isolated From Listeria monocytogenes

“…The diseases caused by LM are predominantly treated with drugs, such as penicillin, fluoroquinolones, cephalosporins, and vancomycin ( 12 ). LM carried the plcb and iap genes, which make the bacterium highly resistant to drugs, such as penicillin and erythromycin ( 13 ). L. monocytogenes can cross the intestinal barrier by the active invasion of host cells, which is mainly triggered by internalins InlA and InlB.…”