Molecular serotyping and antibiotic resistance of Listeria monocytogenes isolates from Liaoning Province,2021-2022
Objective To analyze the molecular serotyping and drug resistance of foodborne Listeria monocytogenes(LM)isolates from the food monitoring network of Liaoning Province,and to provide a reference for identifying and tracing the outbreaks of foodborne diseases.Methods The Listeria monocytogenes isolates were identified,biochemical typing was conducted by VITEK biochemical identification and PCR amplification techniques were applied for molecular serotyping of 67 strains of Listeria monocytogenes detected from 2 797 food samples collected from 15 monitoring sites across the province during 2021-2022.Verification was performed according to the instructions of the serodiagnosis manual.The sensitivity of the strains to ampicillin,penicillin,meropenem,cotrimoxazole,and erythromycin was determined by broth dilution method.Results In food from Liaoning Province,the molecular serotypes of Listeria monocytogenes carried were identified as 1/2a(3a),1/2b(3b,7),1/2c(3c),and 4b(4d,4e),with the predominant serotypes being 1/2a accounting for 62.7％(42/67),and 1/2b accounting for 28.4％(19/67).Among them,the 4b strain was isolated in 3 strains,representing 4.5％.The dominant strains of Listeria monocytogenes in 2021 and 2022 in Liaoning Province were 1/2a(3a)and 1/2b(3b,7),with the most diverse types carried by meat and meat products.Double resistance to cotrimoxazole and erythromycin accounted for 11.9％(8/67),while resistance to only one cotrimoxazole accounted for 9.0％(6/67).Conclusions The presence of pathogenic serotypes 1/2a(3a),1/2b(3b,7),1/2c(3c),and 4b(4d,4e)in food in Liaoning Province and the emergence of strains with one or more drug resistances indicate the existence of food safety issues caused by Listeria monocytogenes,posing a potential risk of listeriosis.There is a need to optimize source tracing methods and strengthen the confirmation of Listeria monocytogenes outbreaks.
NETL
NSTL
万方数据
