铜绿假单胞菌β-内酰胺酶及其相关耐药基因的检测分析

Investigation of β-lactamases and β-lactamase-related resistant genes in multidrug-resistant Pseudomonas aeruginosa

目的了解医院临床分离的多药耐药铜绿假单胞菌β-内酰胺酶产生情况,以及β-内酰胺类相关耐药基因的存在状况。方法采用K-B法测定临床分离铜绿假单胞菌对17种抗菌药物的敏感性,筛选出135株多药耐药菌株;采用改良三维试验检测各种β-内酰胺酶;采用聚合酶链反应检测β-内酰胺酶编码基因及oprD2基因。结果135株多药耐药铜绿假单胞菌所产β-内酰胺酶按检出率依次为AmpC酶占36.3%,ESBLs+AmpC酶占14.8%,金属β-内酰胺酶占13.3%,ESBLs+AmpC酶变异子占11.9%,AmpC酶变异子占5.2%,ESBLs占4.4%;β-内酰胺酶编码基因的检出率CTX-M-1群为45.9%、TEM为25.9%、CARB为12.6%、DHA为10.4%、IMP为3.7%,未检出SHV、OXA-10群、PER、GES、VEB和VIM基因;oprD2基因的缺失率为69.6%。结论多药耐药铜绿假单胞菌β-内酰胺酶以AmpC酶为主,β-内酰胺类对抗菌药物的耐药主要与CTX-M-1群、TEM、CARB、DHA、IMP型耐药基因有关,对碳青霉烯类抗菌药物耐药主要与oprD2基因缺失有关。

OBJECTIVE To investigate β-lactamase and resistant genes in multidrug-resistant Pseudomonas aeruginosa isolated from clinical specimens.METHODS The antibiotic susceptibility of 17 different antibiotics of P.aeruginosa was tested by K-B method,and 135 multidrug-resistant strains were screened.The three-dimensional method was taken to differentiate the various β-lactamases.Resistant genes of β-lactamases and oprD2 genes were detected by polymerase chain reaction（PCR）.RESULTS Among the 135 strains of multidrug-resistant P.aeruginosa,the detection rate of AmpC beta-lactamases was highest（36.3%）,the second was ESBLs plus AmpC β-lactamases（14.8%）,the third was metallo-beta-lactamases（MBL）（13.3%）,ESBLs plus AmpC variants accounted for 11.9%,AmpC variants accounted for 5.2%,ESBLs accounted for 4.4%;the detection rates of β-lactamase gene CTX-M-1 group,TEM,CARB,DHA and IMP were 45.9%,25.9%,12.6%,10.4%,and 3.7%,respectively,and none of the 135 strains possessing the genes of SHV,OXA-10 group,PER,GES,VEB,and VIM were detected;the loss rate of oprD2 gene was 69.6%.CONCLUSION The main β-lactamases are AmpC beta-lactamases,the resistance toβ-lactamases antibiotics is related to the resistant genes of CTX-M-1 group,TEM,CARB,DHA and IMP,and the resistance to carbapenem is related to the loss of oprD2 gene.