摘要
目的研究铜绿假单胞菌对喹诺酮类药物的耐药机制。方法对环丙沙星耐药的铜绿假单胞菌变异株采用诺氟沙星、亚胺培南,头孢唑啉、氟氯西林、左氧氟沙星、环丙沙星等抗生素进行药敏实验;采用PCR扩增20株变异株的DNA拓扑异构酶Ⅱ和Ⅳ的gyrA、gyrB、parC、parE基因片段并测序,研究基因突变与耐药之间的关系。结果 20株铜绿假单胞菌环丙沙星耐药变异株对诺氟沙星100%耐药,对氟氯西林57%耐药,对亚胺培南55%耐药,对左氧氟沙星48%耐药,对头孢唑啉36%耐药。20株变异株中,17株发生基因突变,包括gyrA基因QRDR区域发生突变15株,其中12株突变发生于编码83位氨基酸密码子,突变形式为Thr→Ile(ACC→ATC);5株突变发生于编码87位氨基酸密码子,突变形式为Asp→Asn或Gly(GAC→AAC或GGC);3株在83位和87位氨基酸密码子发生双点突变。gyrB基因QRDR区域发生突变3株;其中2株突变发生于编码470位氨基酸密码子,突变形式为Glu→Asp(GAG→GAT);1株突变发生于编码361位氨基酸密码子,突变形式为Phe→Try(TTC→ACG)。parC基因QRDR区域发生突变13株,其中11株突变发生于编码80位氨基酸密码子,突变形式为Ser→Leu(TCG→TTG);4株突变发生于编码84位氨基酸密码子,突变形式为Glu→Lys(GAG→AAG);2株在80位和84位氨基酸密码子发生双点突变。parE基因QRDR区域发生突变4株,其中1株突变发生于编码420位氨基酸密码子,突变形式为Asp→Asn(GAC→AAC);3株突变发生于编码425位氨基酸密码子,突变形式为Ala→Val(GCG→ACG)。结论铜绿假单胞菌对喹诺酮类药物耐药机制主要DNA拓扑异构酶Ⅱ和Ⅳ的QRDR区域发生突变,需要引起高度重视,并进行针对性预防和治疗。
Objective To study the mechanism of quinolone resistance of Pseudomonas aeruginosa. Methods P.aeruginosastrains resistant to ciprofloxacin,norfloxacin,imipenem,cefazolin,flucloxacillin,levofloxacin,and ciprofloxacin were used in antibiotic susceptibility testing.PCR was used to amplify DNA topoisomeraseⅡandⅣfrom 20 mutant strains and gyrA,gyrB,parC,and parE gene fragments were sequenced to study the relationship between gene mutation and resistance. Results Ciprofloxacin-resistant mutants had 100% resistance to norfloxacin,57% to flucloxacillin,55% resistance to imipenem,48% resistance to levofloxacin,and 36% resistance to cefazolin.Of the 20 mutant strains,17 had gene mutations,including 15 with a mutation in the QRDR of the gyrA gene.Of these 15 strains,12had a mutation at codon 83 in the form of Thr→Ile（ACC → ATC）.Five strains had a mutation at codon 87 in the form of Asp→Asn or Gly（GAC→ AAC or GGC）.Three strains had a double point mutation at codons 83 and 87.Three strains had a mutation in the QRDR of the gyrB gene.Of these 3strains,2had a mutation at codon 470 in the form of Glu → Asp（GAG → GAT）.One strain had a mutation to codon 361 in the form of Phe→ Try（TTC → ACG）.Thirteen strains had a mutation in the QRDR of the parC gene.Of these 13 strains,11had a mutation at codon 80 in the form of Ser→ Leu（TCG → TTG）.Four strains had a mutation at codon 84 in the form of Glu→ Lys（GAG → AAG）.Two strains had a double point mutation at codons 80 and 84.Four strains had a mutation in the QRDR of the parE gene.Of these 4strains,1had a mutation at codon 420 in the form of Asp→ Asn（GAC → AAC）.Three 3strains had a mutation at codon 425 in the form of Ala→ Val（GCG → ACG）. Conclusion The mechanism for quinolone resistance of P.aeruginosais mainly attributed to mutations in the QRDR of DNA topoisomeraseⅡ andⅣ.Increased attention to these mutations is required and targeted prevention and treatment is needed.
出处
《中国病原生物学杂志》
CSCD
北大核心
2014年第11期1036-1040,共5页
Journal of Pathogen Biology
