Distribution, diversity and persistence of Listeria monocytogenes in swine slaughterhouses and their association with food and human listeriosis strains

Abstract

Listeria monocytogenes is the etiological agent of listeriosis, a major foodborne disease and an important public health concern. Contamination of meat with L. monocytogenes occurs frequently at the slaughterhouse. Our aims were; 1) to investigate the distribution of L. monocytogenes in the processing areas of four swine slaughterhouses; 2) to describe the diversity of L. monocytogenes strains by pulsed-field gel electrophoresis; 3) to identify persistent L. monocytogenes strains and describe their distribution; 4) to investigate the associations between persistence of strains and their following characteristics: detection in food isolates, detection in human clinical isolates, and the presence of benzalkonium chloride (BAC) resistance genes. Various operation areas within the four swine slaughterhouses were sampled on four occasions. A total of 2496 samples were analyzed, and L. monocytogenes was successfully isolated from 243 samples. The proportion of positive samples ranged from 32 to 58% in each slaughterhouse and from 24 to 68% in each operation area. Fifty-eight different pulsotypes were identified and eight pulsotypes, present in samples collected during 4 visits, were considered persistent. The persistent pulsotypes were significantly more likely to be detected in food (P < 0.01, exact χ 2) and human clinical cases (P < 0.01, exact χ 2), respectively. Among pulsotypes harboring the BAC bcrABC resistance cassette or the emrE multidrug transporter gene, 42.8% were persistent compared to 4.5% for pulsotypes without these resistance genes (P < 0.01, exact χ 2). Our study highlights the importance of persistent L. monocytogenes strains in the environmental contamination of slaughterhouses, which may lead to repeated contamination of meat products. It also

Application of Whole Genome Sequencing to Aid in Deciphering the Persistence Potential of Listeria monocytogenes in Food Production Environments

“…Many studies reported the presence of L. monocytogenes resistant to QACs in different food processing facilities [ 65 , 124 , 194 , 195 ]. Several have also linked QAC resistance to persistence of L. monocytogenes in food production environments [ 65 , 195 , 196 , 197 ].…”

“…Many studies reported the presence of L. monocytogenes resistant to QACs in different food processing facilities [ 65 , 124 , 194 , 195 ]. Several have also linked QAC resistance to persistence of L. monocytogenes in food production environments [ 65 , 195 , 196 , 197 ]. BC resistance in L. monocytogenes is considered low-level and is unlikely to lead to resistance to the concentrations of these compounds usually applied in the food industry (generally 200–1000 mg L −1 ) [ 70 , 194 ].…”

Potential Application of Essential Oils for Mitigation of Listeria monocytogenes in Meat and Poultry Products

“…monocytogenes is frequently isolated in various food products. This pathogen results in listeriosis, which remarkably affects pregnant women, newborns, and individuals with immunodeficiency (10,11). Due to the ability of this microorganism to growth at low temperatures (2-4 • C), there is a particular concern about the presence of L. monocytogenes in meat and poultry products (12,13).…”

Counteracting Bacterial Motility: A Promising Strategy to Narrow Listeria monocytogenes Biofilm in Food Processing Industry

“…Four biofilm-forming strains of L. monocytogenes were used in the present study, LM 2A51, LM C97, LM 3C15, and LM 3C24. These strains were isolated from the floor of different areas in the pork slaughterhouses after sanitation procedures ( Table 1 ) and belong to the serotypes 1/2a, 1/2a, 1/2a, and 1/2b, respectively, and they were characterized by Pulsed Field Gel Electrophoresis (PFGE) and are referred to the following PFGE types LS4, LS19, LS21, and LS16, respectively, in Cherifi et al (2020) . Five coagulase-negative staphylococci (CNS) of bovine origin were used to generate cell-free supernatants with an anti-biofilm activity ( Goetz et al, 2017 ).…”