Fenotipik ve genotipik yöntemlerle Bolu'da satılan kıyma ve tavuk etinde lısterıa türlerinin varlığının ve bazı patojenik özelliklerinin belirlenmesi

Listeria and particularly Listeria monocytogenes is an important pathogen that can cause listeriosis with flu-like symptoms in healthy people, and severe complications including bacteremia, meningitis, encephalitis, and endocarditis in immunocompromised people such as children, pregnant women and the elderly. They have been frequently isolated from foods such as meat and meat products. In the present study, a total of 124 food samples composed of ground beef and chicken meat were examined for the presence of Listeria spp. Out of the 124 samples, 101 (81.5%) were positive for Listeria spp. Overall, out of all samples, 44 (35.5%) isolates were phenotypically identified as L. innocua; the remaining isolates were L. monocytogenes (26.6%), L. seeligeri (15.3%), L. grayi (12.9%), L. welshimeri (8.9%), L. ivanovii subsp. londoniensis (3.2%) and L. ivanovii subsp. ivanovii (0.8%). The phenotypically identified L. monocytogenes strains were also confirmed by hlyA virulence gene amplification. The prevalence of Listeria spp. was 96.8% in ground beef and 66.1% in chicken meat. L. innocua was the most common species in this study that was most frequently isolated in ground beef. All 33 L. monocytogenes strains were examined for the virulence genes such as hlyA, inlB and actA, and serovars. All 33 (100%) L. monocytogenes strains were positive for hlyA gene. Out of the 33 L. monocytogenes strains, 29 (87.9%) and 16 (48.5%) strains harbored inlB and actA virulence genes, respectively. Nineteen strains (57.6%) belonged to serovar "1/2a, 3a" and 14 (42.4%) belonged to serovar "1/2c, 3c". In our study, the antimicrobial susceptibility of the 128 Listeria spp. isolated from ground beef and chicken meat to commonly used antimicrobial agents was examined. Most Listeria strains with a rate of 90.6% were resistant to penicillin, 79.7% to ceftriaxone and 71.1% to ampicillin. A multidrug resistance was observed in 112 (87.5%) of the strains to at least three or more antimicrobial agents. Prevalence and antimicrobial resistance of Listeria spp. in ground beef and chicken meat samples were determined in the present study. In addition, virulence characteristics and serovars of the 33 L. monocytogenes strains obtained from this research were reported. The results of this study indicated that consumption of inadequately cooked ground beef and chicken meat, and products made from raw meat may develop a potential risk of human listeriosis.