Occurrence, antimicrobial resistance, serotyping and virulence genes of Listeria monocytogenes isolated from foods

Aziz Bouymajane; Fouzia Rhazi Filali; Said Oulghazi; Nada Lafkih; Abdelaziz Ed-Dra; Amal Aboulkacem; Abdallah El Allaoui; Bouchra Ouhmidou; Mohieddine Moumni

doi:10.1016/j.heliyon.2021.e06169

Occurrence, antimicrobial resistance, serotyping and virulence genes of Listeria monocytogenes isolated from foods

Heliyon. 2021 Feb 2;7(2):e06169. doi: 10.1016/j.heliyon.2021.e06169. eCollection 2021 Feb.

Authors

Aziz Bouymajane¹, Fouzia Rhazi Filali¹, Said Oulghazi², Nada Lafkih², Abdelaziz Ed-Dra¹, Amal Aboulkacem³, Abdallah El Allaoui¹, Bouchra Ouhmidou⁴, Mohieddine Moumni²

Affiliations

¹ Team of Microbiology and Health, Laboratory of Chemistry-Biology Applied to the Environment, Moulay Ismail University Faculty of Sciences, BP 11201 Zitoune Meknes, Morocco.
² Cellular Genomics and Molecular Techniques of Investigations, Moulay Ismail University Faculty of Sciences, BP 11201 Zitoune Meknes, Morocco.
³ Regional Laboratory of Epidemiological Diagnosis and Environmental Hygiene, Fez-Meknes, Morocco.
⁴ Laboratory of Bioactive Molecules, Structures and Functions, Faculty of Sciences and Technologies, Sidi Mohamed Ben Abdallah University, Fes, Morocco.

Abstract

Listeria monocytogenes is a pathogen contaminated food, it is the cause of listeriosis worldwide. The aims of this study were to investigate the occurrence, antimicrobial resistance, serotyping and virulence genes of L. monocytogenes isolated from foods in Meknes city of Morocco. From June 2017 to May 2018, 520 food samples were randomly collected from a traditional market and two overcrowded popular neighborhoods (Lahdim and Hamria) and subjected to the detection of L. monocytogenes. Then, the antimicrobial susceptibility of the isolated strains were evaluated using the standard disk diffusion method and the determination of serotypes and virulence genes was performed by PCR. The results showed the detection of L. monocytogenes in fifteen (2.9%) of 520 samples, including three (5.7%) isolates in traditional whey, raw minced meat and raw sausage, two (3.8%) in raw milk and one (1.9%) in smen (traditional butter), raw bovine meat, raw poultry meat and raw fish, while salads and rayeb (traditional coagulated milk) were not contaminated. Among the fifteen isolated L. monocytogenes, nine (60%) belonged to the serogroup (1/2a, 1/2c, 3a and 3c), two (13.3%) belonged to the serogroup (1/2b, 3b, 4b and 4d) and four (26.6%) do not belong to any studied serogroup. Furthermore, fifteen (100%) isolates showed the presence of actA gene, fourteen (93.3%) harbored hlyA, prfA and plcB genes, thirteen (86.7%) carried inlA and inlC genes and twelve (80%) showed inlJ gene. The antimicrobial susceptibility analysis showed that the isolated strains were more resistant to amoxicillin/clavulanic acid (67.0%), erythromycin (60.0%), sulphamethoxazole (40.0%), ampicillin and sulphamethoxazole/trimethoprim (33.0%) and tetracycline (20.0%). Furthermore, 66.7% (10/15) were multidrug-resistant. From this study, we can conclude that foods marketed in Meknes city were contaminated by multidrug-resistant strains of L. monocytogenes harboring virulence genes, which may cause a serious risk to public health.

Keywords: Foods; Listeria monocytogenes; Multidrug-resistance; Serotypes; Virulence genes.