调控基因hptRSA突变与甲氧西林耐药金黄色葡萄球菌对磷霉素耐药相关性研究
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摘要
目的了解磷霉素耐药的甲氧西林耐药金黄色葡萄球菌(MRSA)调控基因hptR、hptS及hptA的变异情况,探索此类基因变异与磷霉素耐药的相关性。方法收集2004-2014年复旦大学附属华山医院住院患者无菌体液分离得到的MRSA50株,采用琼脂稀释法测定磷霉素最低抑菌浓度;聚合酶链反应(PCR)及测序分析hptR、hptS、hptA及uhpT、glpT、fosB基因的变异情况。结果 50株MRSA中,磷霉素耐药34株。50株MRSA中广泛存在hptR、hptS、hptA基因变异,变异类型分别为3类、6类、5类,一些突变类型仅在磷霉素耐药株中出现。结论本次临床分离的磷霉素耐药MRSA菌株中hptR、hptS及hptA突变常见,且某些突变类型可能参与磷霉素耐药性形成。
Objective Previous studies indicate that hptRSA may influence fosfomycin susceptibility of Staphylococcus aureus by regulating the expression of fosfomycin transporter UhpT. The sequences of hptR, hptS and hptA genes were analyzed in fosfomycinresistant strains of methicillin-resistant Staphylococcus aureus(MRSA) to examine the correlation between mutation of these genes and fosfomycin resistance. Methods Fifty MRSA isolates were collected from blood and cerebrospinal fluid from inpatients in Huashan Hospital during the period from 2004 to 2014. The minimum inhibitory concentration of fosfomycin against these strains was determined by agar dilution method. Polymerase chain reaction and sequencing analysis were used to profile mutations of hptR,hptS, hptA, uhpT, glpT, and fosB genes. Results Of the 50 MRSA strains, 34 were resistant to fosfomycin. Each of the 50 strains harbors at least one mutation on the three genes. Overall, there were 3 types of hptR mutation, 6 types of hptS mutation, and 5 types of hptA mutation. Some mutation types were observed only in fosfomycin-resistant strains. Conclusions Mutation of hptR, hptS and hptA genes is prevalent in fosfomycin-resistant MRSA isolates. Some mutation types may contribute to fosfomycin resistance.
Objective Previous studies indicate that hptRSA may influence fosfomycin susceptibility of Staphylococcus aureus by regulating the expression of fosfomycin transporter UhpT. The sequences of hptR, hptS and hptA genes were analyzed in fosfomycinresistant strains of methicillin-resistant Staphylococcus aureus(MRSA) to examine the correlation between mutation of these genes and fosfomycin resistance. Methods Fifty MRSA isolates were collected from blood and cerebrospinal fluid from inpatients in Huashan Hospital during the period from 2004 to 2014. The minimum inhibitory concentration of fosfomycin against these strains was determined by agar dilution method. Polymerase chain reaction and sequencing analysis were used to profile mutations of hptR,hptS, hptA, uhpT, glpT, and fosB genes. Results Of the 50 MRSA strains, 34 were resistant to fosfomycin. Each of the 50 strains harbors at least one mutation on the three genes. Overall, there were 3 types of hptR mutation, 6 types of hptS mutation, and 5 types of hptA mutation. Some mutation types were observed only in fosfomycin-resistant strains. Conclusions Mutation of hptR, hptS and hptA genes is prevalent in fosfomycin-resistant MRSA isolates. Some mutation types may contribute to fosfomycin resistance.
引文
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[8]REED J M,OLSON S,BREES D F,et al.Coordinated regulation of transcription by CcpA and the Staphylococcus aureus two-component system HptRS[J].PLoS One,2018,13(12):e0207161.
[9]PARK J Y,KIM J W,MOON B Y,et al.Characterization of a novel two-component regulatory system,HptRS,the regulator for the hexose phosphate transport system in Staphylococcus aureus[J].Infect Immun,2015,83(4):1620-1628.
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[12]傅祝英杰,吴湜,郭燕,等.磷霉素耐药金黄色葡萄球菌临床分离株murA、glpT及uphT序列分析[J].中国感染与化疗杂志,2015,15(6):505-508.
[13]FU Z,MA Y,CHEN C,et al.Prevalence of fosfomycin resistance and mutations in murA,glpT,and uhpT in methicillinresistant Staphylococcus aureus strains isolated from blood and cerebrospinal fluid samples[J].Front Microbiol,2016,6:1544.
[14]YANG Y,SUN H,LIU X,et al.Regulatory mechanism of the three-component system HptRSA in glucose-6-phosphate uptake in Staphylococcus aureus[J].Med Microbiol Immunol,2016,205(3):241-253.
[2]汪复.实用抗感染治疗学[M].2版.北京:人民卫生出版社,2012:365.
[3]DEL RIO A,GARCIA-DE-LA-MARIA C,ENTENZA J M,et al.Fosfomycin plusβ-lactams as synergistic bactericidal combinations for experimental endocarditis due to methicillinresistant and glycopeptide-intermediate Staphylococcus aureus[J].Antimicrob Agents Chemother,2016,60(1):478-486.
[4]郭燕,朱德妹,胡付品,等.2010年中国CHINET葡萄球菌属细菌耐药性监测和分析[J].中国感染与化疗杂志,2013,13(2):86-92.
[5]CASTANEDA-GARCIA A,RODRIGUEZ-ROJAS A,GUELFO J R,et al.The glycerol-3-phosphate permease GlpT isthe only fosfomycin transporter in Pseudomonas aeruginosa[J].J Bacteriol,2009,191(22):6968-6974.
[6]FU Z,LIU Y,CHEN C,et al.Characterization of fosfomycin resistance Gene,fosB,in methicillin-resistant Staphylococcus aureus isolates[J].PLoS One,2016,11(5):e0154829.
[7]XU S,FU Z,ZHOU Y,et al.Mutations of the transporter proteins GlpT and UhpT confer fosfomycin resistance in Staphylococcus aureus[J].Front Microbiol,2017,8:914.
[8]REED J M,OLSON S,BREES D F,et al.Coordinated regulation of transcription by CcpA and the Staphylococcus aureus two-component system HptRS[J].PLoS One,2018,13(12):e0207161.
[9]PARK J Y,KIM J W,MOON B Y,et al.Characterization of a novel two-component regulatory system,HptRS,the regulator for the hexose phosphate transport system in Staphylococcus aureus[J].Infect Immun,2015,83(4):1620-1628.
[10]Clinical and Laboratory Standards Institute.Performance standards for antimicrobial susceptibility testing[S].2017,M100-S27.
[11]European Committee on Antimicrobial Susceptibility Testing.Clinical breakpoints and dosing of antibiotics[EB/OL].[2019-03-19].http://www.eucast.org/clinical_breakpoints/.
[12]傅祝英杰,吴湜,郭燕,等.磷霉素耐药金黄色葡萄球菌临床分离株murA、glpT及uphT序列分析[J].中国感染与化疗杂志,2015,15(6):505-508.
[13]FU Z,MA Y,CHEN C,et al.Prevalence of fosfomycin resistance and mutations in murA,glpT,and uhpT in methicillinresistant Staphylococcus aureus strains isolated from blood and cerebrospinal fluid samples[J].Front Microbiol,2016,6:1544.
[14]YANG Y,SUN H,LIU X,et al.Regulatory mechanism of the three-component system HptRSA in glucose-6-phosphate uptake in Staphylococcus aureus[J].Med Microbiol Immunol,2016,205(3):241-253.