2011—2021年福建省即食食品中单增李斯特菌的监测及菌株特征分析

Monitoring of Listeria monocytogenes in ready-to-eat foods and characterization of isolates in Fujian Province from 2011 to 2021

目的了解2011—2021年福建省即食食品中单增李斯特菌(Listeria monocytogenes,Lm)污染状况、毒力基因、耐药及分子分型特征。方法参照GB 4789.30检测Lm;采用PCR方法对Lm的13种毒力基因进行检测及开展血清学、MLST分型;应用微量肉汤稀释法,选择15种抗生素进行药敏试验。结果2011—2021年共采集8166份即食食品,Lm总检出率为1.25%,以寿司、中式凉拌菜及熟肉制品检出率较高,分别为6.26%、5.60%、1.87%;毒力基因plcB、llsX、ptsA的检出率分别为55.42%、16.87%、22.89%,prfA等其余10个毒力基因检出率均为100%;83株Lm对头孢西丁的耐药率为100%,苯唑西林为15.66%、四环素为13.25%;寿司、中式凉拌菜、熟肉制品中检出多重耐药株,多重耐药率达13.25%;83株Lm分4种血清型,1/2a、1/2b为优势血清型;83株Lm MLST分型得到16种序列型(ST),ST87为优势型,其次是ST8,ST101。结论2011—2021年福建省即食食品存在不同程度的单增李斯特菌污染,寿司、中式凉拌菜、熟肉制品为主要污染食品;分离株耐药情况不容乐观、具有潜在的致病性、感染风险,相关部门应加强对上述高风险类别食品的监测。

This study was aimed at understanding the contamination status,virulence genes,drug resistance and molecular typing characteristics of Listeria monocytogenes(Lm)in ready-to-eat foods in Fujian Province from 2011 to 2021.Refer to GB 4789.30 detection Lm.PCR was used to detect 13 Lm virulence genes,and to perform serological and MLST typing.The micro broth dilution method was used to select 15 antibiotics for susceptibility testing.From 2011 to 2021,8166 ready-to-eat food samples were collected,in which the total detection rate was 1.25%for Lm.Higher detection rates were found in sushi,Chinese coleslaw,and ready-to-eat meats,at 6.26%,5.60%,and 1.87%,respectively.The detection rates of the virulence genes plcB,llsX and ptsA were 55.42%,16.87%and 22.89%,respectively,and the detection rates of the remaining ten virulence genes,including prfA,were 100%.The resistance rate of 83 Lm strains was 100%to cefoxitin,followed by 15.66%to oxacillin and 13.25%to tetracycline.Multidrug-resistant strains were detected in sushi,Chinese coleslaw and ready-to-eat meats,with a multi-drug resistance rate of 13.25%.The 83 Lm strains were divided into four serogroups,among which 1/2a and 1/2b were dominant.The 83 Lm MLST strains were typed into 16 sequence types(ST),among which ST87 was dominant,and was followed by ST8 and ST101.From 2011 to 2021,different degrees of Lm contamination were observed in ready-to-eat foods in Fujian Province.Sushi,Chinese coleslaw and ready-to-eat meats were the main contaminated foods.The drug resistance of isolates was concerning,thus suggesting potential pathogenicity and infection risk.Relevant departments should strengthen monitoring of the above high-risk food categories.