辽宁省市售禽肉中沙门氏菌的污染状况及其MLST分型与耐药性分析

Contamination status, multilocus sequence typing, and drug resistance of Salmonella in poultry meat in Liaoning Province

摘要:

【背景】沙门氏菌(Salmonella)是重要的人畜共患病原菌，可通过禽类及其产品传播给人类，对人类健康造成威胁。了解市售禽肉中沙门氏菌病原学特征及耐药情况，对公共卫生具有重要意义。【目的】了解2022年辽宁省市售禽肉中沙门氏菌的污染状况、血清型分布、药物敏感性及分子流行特征情况，探讨不同血清型与多位点序列分型(multilocus sequence typing,MLST)、耐药性之间的关系。【方法】依据GB 4789.4—2016《食品安全国家标准食品微生物学检验沙门氏菌检验》检验方法对收集的样品进行检测及生化实验鉴定，采用玻片凝集法进行血清学实验，用微量肉汤法对菌株进行药物敏感性试验，使用BioNumerics 7.6软件对药敏结果、MLST分型结果进行分析。【结果】53株沙门氏菌包含11种血清型，以肠炎沙门氏菌(Salmonella enteritidis)为主。药物敏感性分析中，沙门氏菌对萘啶酸(nalidixic acid,NAL)的耐药率最高，为92.5%(49/53)，共发现有25种多重耐药谱，总耐药率为66.0%(35/53)，在耐药基因分析中，四环素类耐药基因tetC携带率最高为45.3%(24/53)。根据7种管家基因的序列沙门氏菌被分为10个ST型别和1个未分型型别。【结论】辽宁省市售禽肉沙门氏菌的污染率较为严重，血清型多样化，整体耐药水平较高，多重耐药情况严重，应加强对禽类规范化养殖。

Abstract:

[Background] Salmonella is a major group of zoonosis pathogens that can be transmitted to humans through poultry and its products, posing a threat to human health. It is important for public health to understand the pathogenic characteristics and drug resistance of Salmonella in poultry meat. [Objective] To investigate the contamination status, serotype distribution, drug sensitivity, and molecular epidemic characteristics of Salmonella in poultry meat sold in Liaoning Province in 2022, and to explore the relationship between different serotypes, multilocus sequence typing (MLST) results, and drug resistance. [Methods] The collected samples were tested according to the method in the National Standard for Food Safety: Microbiology Inspection of Salmonella (GB 4789.4—2016), and the strains were identified by biochemical tests. The slide agglutination method was used for the serological test, and the micro-broth method was employed to examine the drug sensitivity of the strains. BioNumerics 7.6 was used to analyze the results of drug sensitivity tests and MLST. [Results] The 53 Salmonella strains belonged to 11 serotypes, mainly S. enteritidis. The resistance rate of Salmonella to nalidixic acid (NAL) was the highest, 92.5% (49/53). A total of 25 multiple drug resistance spectra were identified, and the total resistance rate was 66.0% (35/53). Among the drug resistance genes, the tetracycline resistance gene tetC showed the highest carrying rate of 45.3% (24/53). The strains of Salmonella were classified into 10 sequence types (STs) and 1 unclassified type according to the sequences of 7 housekeeping genes. [Conclusion] The Salmonella in poultry meat sold in Liaoning Province demonstrates serious contamination, with diverse serotypes, high overall drug resistance, and serious multidrug resistance. Efforts should be doubled for the standardization of poultry breeding.