南京地区猪肉源中沙门氏菌分子分型及耐药性分析

沙门氏菌是造成我国食源性疾病的常见细菌之一，也是肉类消费过程中密切监测的重点对象。在2018年~2021年期间，共计采集了南京市545份猪肉源食品样本，利用选择性培养法分离得到44株沙门氏菌，采用血清学方法和分子生物学方法（MLST）对其进行分型鉴定，并分析其耐药性。结果表明，市售样本中共计检出44株沙门氏菌，平均检出率为8.07%，其中内脏样本检出率相对最高（检出率为30.49%）；血清型分析表明，检出的菌株中以鼠伤寒沙门氏菌（Salmonella typhimurium）、罗森氏沙门氏菌（Salmonella rissen）、德尔卑沙门氏菌（Salmonella derby）和伦敦沙门氏菌（Salmonella london）4种血清型沙门氏菌最为常见；基因分型表明，ST19型为猪肉源中优势沙门氏菌株，占比为20.45%；检出的沙门氏菌中，38株菌株对四环素具有明显耐药性，占全部检出菌株的86.36%，而对头孢他啶、头孢噻肟和头孢西丁的耐药不超过10%。此外，对检出的1株多重耐药性沙门氏菌耐药基因分析发现，共筛查出了包括7大类抗生素及与耐药相关的基因。该实验详细分析了南京市场猪肉源食品中沙门氏菌污染状况，也为后期沙门氏菌的综合防治提供了理论依据。

Analysis of the Strains and Drug Resistance of Salmonella spp. Isolated from Pork and Pork Products in Nanjing

Salmonella is a common bacterial pathogen causing foodborne diseases in China; therefore, it is crucial to closely monitor its presence in relation to meat consumption. From 2018 to 2021, a total of 545 pork and pork products in Nanjing were collected for this study. The selective culture method was utilized to isolate Salmonella, and the strains were identified via serological and molecular biological methods, such as multilocus sequence typing (MLST). Finally, the antibiotic susceptibility test was utilized to analyze the drug resistance of the isolated strains. The results show that a total of 44 Salmonella strains were identified in the samples available in the market, with an average detection rate of 8.07%. In particular, pig viscera exhibited the highest detection rate at 30.49%. Serotype analysis revealed the four most commonly isolated Salmonella species in the pork products: Salmonella typhimurium, Salmonella enterica serovar Rissen, Salmonella enterica subsp. enterica serovar Derby, and Salmonella enterica serovar London. Genotyping results further suggested that the ST19 was the dominant Salmonella strain in contaminated pork samples, accounting for nearly 20.45% of all isolated strains. Among the detected Salmonella, 38 strains exhibited obvious resistance to tetracycline, accounting for 86.36% of the total. Meanwhile, the resistance of all strains to ceftazidime, cefotaxime, and cefoxitin was <10%. Additionally, one multidrug resistant Salmonella strain was isolated. The presence of resistance-related genes and a total of seven categories of antibiotics associated were successfully identified. Collectively, this study provides detailed data analysis for Salmonella contamination in pork and pork products in Nanjing, Jiangsu, establishing a theoretical foundation for the comprehensive control of Salmonella in meat products.