2011-2022年宁夏食源性金黄色葡萄球菌耐药状况与分子分型研究

Study on drug resistance and molecular typing of food-borne Staphylococcus aureus in Ningxia,2011-2022

目的了解宁夏地区食源性金黄色葡萄球菌产肠毒素基因、耐药基因携带情况,分子分型特征,耐药现状及耐药基因携带情况。方法收集2011-2022年宁夏食品安全风险监测项目中分离到的金黄色葡萄球菌,采用微量肉汤稀释法进行药敏试验,荧光PCR法检测肠毒素基因。用Smal内切酶对菌株进行脉冲场凝胶电泳(pulsed field gel eleetrophoresis,PFGE)分子分型。基于细菌全基因组测序技术,进行细菌多位点序列分型(multilocus sequence typing,MLST)和耐药基因筛查,并通过Resfinder数据库对耐药基因预测结果与耐药表型进行一致性分析。结果87株金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)检出率为10.34%(9/87),肠毒素基因(sea~see)菌株检出率为70.11%(61/87),其中有2株茵同时携带sec和sed基因。PFGE和MLST分型分别得到26种带型和23种ST型,优势型别明显。所有菌株除对替考拉宁和利福平表现为完全敏感以外,对其余药物都有不同程度耐药,其中对青霉素表现为完全耐药,即耐药率100.00%,对红霉素和克林霉素的耐药率也相对较高,分别达到60.92%(53/87)和45.98%(40/87)。对9类21种耐药基因进行分析,编码不同抗菌药物的耐药基因均有不同程度携带,其中编码青霉素酶的blaZ基因检出率较高81.61%(71/87),基因预测结果与耐药表型一致率为85.05%(74/87)。结论宁夏食源性金黄色葡萄球菌中已分离到MRSA,提示抗生素合理用药并加强监测,以减缓和控制MRSA的播散。

OBJECTIVE To investigate the molecular typing characteristics,drug resistance status and drug resistance gene carrying of food-borne Staphylococcus aureus in Ningxia.METHODS Staphylococcus aureus isolated from food safety risk monitoring project in Ningxia in the past ten years were collected,drug resistance was detected using microbroth dilution method,enterotoxins were detected by real-time PCR.The strains were genotyped by pulsed field gel electrophoresis(PFGE)using Smal endonuclease.Based on bacterial whole genome sequencing(WGS)technology,multilocus sequence typing(MLST)typing and drug resistance gene screening were performed,and the consistency between the prediction result of drug resistance genes and drug resistance phenotypes was analy zed by resfinder database.RESULTS Among the 87 strains of Staphylococus aureus,the detection rate of methicillin-resistant Staphylococcus aureus(MRSA)was 10.34%(9/87),and the detection rate of sea-see strains was 70.11%(61/87),among which two strains carried both see and sed genes.There were 26 band types and 23 ST types from PFGE and MLST,respectively,and the dominant type was obvious.All strains were completely resistant to penicillin except teicoplanin and rifampicin,and the resistance rate to penicillin was 100.00%.The resistance rates to.erythromycin and clindamycin were also relatively high,reaching 60.92%(53/87)and 45.98%(40/87).The 21 drug-resistant genes in 9 classes were analyzed,and the drug-resistant genes encoding different antibiotics were carried in different degrees.The detection rate of blaZ gene encoding penicillase was 81.61%(71/87),and the consistency rate of gene prediction result with drug-resistant phenotype was 85.05%(74/87).CONCLUSION MRSA has been isolated from food-borne Staphylococcus aureus in Ningxia,suggesting rational use of antibiotics and strengthening surveillance to slow down and control the spread of MRSA.