摘要
目的探究2个来自非脱羧勒克菌的多药耐药(MDR)质粒p707804-CTXM和pP12375-CTXM的耐药机制。方法采用16S rDNA基因扩增初步鉴定菌种,得到测序数据后进行平均核苷酸一致性(ANI)比对最终核定菌种;全自动细菌鉴定及药敏分析系统检测细菌的MIC值;随后进行全基因组测序,获得细菌的全基因组序列,通过RAST、BLASTP/BLASTN、ResFinder和ISfinder等进行精细注释及比较基因组学分析确定耐药基因所在基因环境,阐明耐药移动元件的进化与传播历程。结果非脱羧勒克菌150707804和P12375分别携带质粒p707804-CTXM和pP12375-CTXM,均编码超广谱β-内酰胺酶(ESBL)。这两个质粒均只包含一个MDR区,p707804-CTXM含有β-内酰胺类、氨基糖苷类、氯霉素类、利福平类和磺胺类耐药基因,pP12375-CTXM含有除利福平类以外的上述所有耐药基因。p707804-CTXM的MDR区为新型转座子Tn6810,为Tn1696衍生物,由新型整合子In1684插入至Tn1696骨架而产生。blaCTX-M-3位于ISEcp1介导的转座元件Tn6502(ISEcp1-blaCTX-M-3-orf4 77)中;pP12375-CTXM的MDR区插入在orf531中,由Tn6322、ISKpn25、IS1R、In609、IS26和ΔISPa38构成,blaCTX-M-9由ISCR介导,位于In609的3’-CS下游。结论 p707804-CTXM和pP12375-CTXM均携带多种耐药基因,介导相应菌株的多药耐药。其中blaCTX-M由ISEcp1-blaCTX-M-orf477或ISCR介导并插入至整合子或转座子内。该研究中,p707804-CTXM是非脱羧勒克菌中携带blaCTX-M-3的首个测序质粒。
Objective To explore the drug resistance mechanisms of two multi-drug resistant(MDR) plasmids p707804-CTXM and pP12375-CTXM from Leclercia adecarboxylate.Methods Bacterial species were identified by 16 S rDNA gene amplification and finally confirmed by average nucleotide identity(ANI) alignment.The minimum inhibitory concentrations(MICs) of the antimicrobial agents were determined by VITEK 2 Compact System.Complete plasmids sequences were obtained by whole genome sequencing.The genetic environment of drug-resistant genes was determined via elaborate annotation and comparative genomics analysis so that the mechanism of drug resistance was clarified.Results L.adecarhoxylate 150707804 and P12375 carried p707804-CTXM and pP12375-CTXM,respectively,encoding extendedspectrum β-lactamases(ESBL).Both plasmids contained only one MDR region.p707804-CTXM contained genes conferring resistance to β-lactam,aminoglycoside,chloramphenicol,rifampicin and sulfanilamide,while pP12375-CTXM contained all the above resistance genes other than rifampicin.The MDR region of p707804-CTXM was a novel transposon Tn6810 derived from Tn1696,which was generated from the insertion of the new integron In 1684 into the backbone of Tn1696.The blaCTX-M-3 was mediated by ISEcp1 located in the transposition element Tn6502(ISEcp1-blaCTX-M-3-orf477).orf531 was interrupted by the insertion of the MDR region in pP12375-CTXM and composed of Tn6322,ISKpn25,IS1 R,In609,IS26 and ΔISPa38.blaCTX-M-9 was mediated by ISCR located downstream of 3’-CS of In609.Conclusion p707804-CTXM and pP12375-CTXM carry multiple drug-resistant genes,mediating multi-drug resistance of corresponding strains.blaCTX-M is mediated by ISEcp1-blaCTX-M-orf477 or ISCR and inserted into integrons or transposons.p707804-CTXM is the first fully sequenced blaCTX-M-3 carrying plasmid from L.adecarboxylate.
作者
陈方舟
蒋晓圆
罗新华
殷喆
王岩
周冬生
赵月峨
吴家红
CHEN Fang-zhou;JIANG Xiao-yuan;LUO Xin-hua;YIN Zhe;WANG Yan;ZHOU Dong-sheng;ZHAO Yue-e;WU Jia-hong(The Key and Characteristic Laboratory of Modern Pathogen Biology,Basic Medical College,Guizhou Medical University,Guiyang 550025,China;State Key Laboratory of Pathogen and Biosecurity,Institute of Microbiology and Epidemiology,Academy of Military Medical Sciences,Academy of Military Sciences,Beijing 100071,China)
出处
《军事医学》
CAS
2021年第4期256-261,271,共7页
Military Medical Sciences
基金
国家科技重大专项(2018ZX10733409)
国家重点实验室研究课题(SKLPBS1810)。
