摘要
目的研究株蜡样芽胞杆菌SCY分离株的毒力和耐药性。方法使用选择性培养基从银川市某餐厅鱼肉菜肴中培养分离获得蜡样芽胞杆菌SCY分离株,经23S rRNA基因PCR测序鉴定后,通过二代全基因组测序技术分析SCY分离株的基因组特征,进而分别采用免疫组化技术和药敏纸片实验研究SCY分离株的毒性和耐药性。结果SCY分离株的基因组大小为5.82 Mb,编码基因个数为5767,编码区总长度占全基因组的85.50%。SCY分离株基因组中共含有11个基因岛、16个CRISPR和5个前噬菌体;其中,SCY编码基因分别在PHI和VFDB毒力因子数据库中注释到了14个和62个毒力基因(Identiy>80,Evalue<0.05),在CARD耐药数据库中注释到了215个耐药基因(Best Hit evalue<0.05)。小鼠肠道组织切片免疫组化结果表明,炎性因子IL-1β、CASP1和Nlrp3的表达水平发生差异显著性上调。22种细菌抗生素药敏纸片试验结果显示,SCY分离株对氯霉素、克林霉素等高度敏感,对四环素、头孢唑啉、头孢哌酮、氨苄青霉素表现为中介,对青霉素、苯唑西林、哌拉西林、杆菌肽、头孢他啶等10种抗生素表现为耐药,SCY分离株多重耐药情况较为严重。结论本研究发现的SCY分离株属于肠毒株,携带多种肠毒素毒力基因,且具有典型的多重耐药特征。研究结果为揭示蜡样芽胞杆菌分离株的致病机制提供参考依据。
Objective The aim of this study was to investigate the virulence and resistance of Bacillus cereus SCY isolates.Methods B.cereus was isolated from fish dishes in a restaurant in Yinchuan using a selective medium and was named the SCY strain.After identification using PCR sequencing of the 23S rRNA gene,the genetic characteristics were analyzed by adopting second-generation whole genome sequencing technology.Next,the toxicity and drug resistance of the SCY isolate were studied using mouse studies and drug-sensitive paper experiments,respectively.Results The genome size of the SCY isolate was 5.82 Mb,the number of coding genes was 5767,and the total length of the coding region accounted for 85.50%of the whole genome.The genome of the SCY isolates contained 11 gene islands,16 CRISPR,and five prephages;among them,14 and 62 virulence genes were annotated in the PHI and VFDB virulence factor databases(Identity>80,Evalue<0.05),respectively,and 215 resistance genes were annotated in the CARD resistance databases for SCY-encoded genes(Best Hit evalue<0.05).The immunohistochemical results of the mouse intestinal tissue sections showed that the expression levels of the inflammatory factors IL-1β,CASP1,and Nlrp3 were differentially and significantly upregulated.The results of 22 bacteria antibiotic sensitivity paper tests showed that the SCY isolate was highly sensitive to chloramphenicol and clindamycin,showed an intermediary to tetracycline,cephalexin,and ampicillin,and showed resistance to 10 antibiotics,including penicillin,benzocillin,piperacillin,bacitracin,and cephalexin,and its multidrug resistance was more serious.Conclusion SCY isolates are enterotoxigenic strains,yet they carry multiple enterotoxin virulence genes and have typical multiple drug resistance characteristics.These findings provide clues for revealing the pathogenic mechanism of B.cereus isolates.
作者
秦希曦
李文
张雯
岳楠
马红梅
曾瑾
马臣杰
QIN Xixi;LI Wen;ZHANG Wen;YUE Nan;MA Hongmei;ZENG Jin;MA Chenjie(School of Life Sciences,Ningxia University,Ningxia Yinchuan 750021,China;Ningxia Hui Institute of Veterinary Drug and Feed Supervision,Ningxia Yinchuan 750001,China)
出处
《中国食品卫生杂志》
CSCD
北大核心
2023年第8期1183-1191,共9页
Chinese Journal of Food Hygiene
基金
宁夏自然科学基金项目(2021AAC03049、2022AAC02019)
2022年大学生创新创业训练计划(S202210749062)
关键词
蜡样芽胞杆菌
分离株
毒性
毒力基因
耐药性
Bacillus cereus
isolate
toxicity
virulence gene
drug resistance
作者简介
秦希曦,女,在读本科生,研究方向为生物科学,E-mail:2331496004@qq.com;共同通信作者:马臣杰,男,高级实验师,研究方向为食品微生物,E-mail:biom0707@163.com;共同通信作者:曾瑾,女,教授,研究方向为肠道微生物,Email:zengjinnxu@163.com
