RESUMEN
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.
RESUMEN
Background: Enterococcus spp. belongs to a group of pathogens which are responsible for serious infections. This study aims at highlighting the raw milk microbiological contamination and at providing data for prevalence and antimicrobial resistance of Enterococcus spp. isolated from raw cow's milk marketed (without any pasteurization) by street traders. Methods: During the period of May 2015 through April 2016, 150 cow's raw milk samples were collected from street traders in Meknes city. They were examined for the identification of Enterococcus spp. using biochemical tests and 16S rRNA gene sequencing. The antimicrobial susceptibility of the isolates was determined. Results: The results showed that 11.3% (17/150) of samples were positive for the presence of Enterococcus spp., of which 64.7% were identified as Enterococcus faecalis, 17.6% as Enterococcus faecium, 11.8% as Enterococcus durans and 5.9% as Enterococcus hirae. The antimicrobial susceptibility showed that all Enterococcus spp. were resistant to ampicillin. The species E. faecalis, E. faecium, E. durans and E. hirae were resistant to streptomycin, with percentages of 52.9% (9/17), 11.8% (2/17), 11.8% (2/17), and 5.9% (1/17) respectively. All isolated strains of E. faecalis and E. faecium were resistant to tetracycline. The multiple antibiotic resistance index was elevated in the majority of Enterococcus spp., reaching values higher than 0.5, indicating a risk for public health. Conclusion: This study shows that the raw milk consumed by the population is contaminated with strains of Enterococcus resistant to antibiotics used in breeding for prophylactic purposes. This requires raising the awareness of those involved in the production and marketing of milk, so as to take measures to apply good hygienic practices and rationalize the use of zootechnical antibiotics.