泛耐药鲍曼不动杆菌PBP1A、CarO及β-内酰胺酶的编码基因分析  

PBP1A, CarO and β-lactamase genes detection in a pandrug-resistant Acinetobacter baumannii

作　　者：翁幸鐾[1] 糜祖煌[2] 

机构地区：[1]宁波市第一医院检验科,315010 [2]无锡新区虎马生物信息工作室无锡市克隆遗传技术研究所生物信息学室

出　　处：《中华临床感染病杂志》2012年第4期215-220,共6页Chinese Journal of Clinical Infectious Diseases

摘　　要：目的了解一株泛耐药鲍曼不动杆菌（js01株）可能存在的β-内酰胺类药物耐药机制。方法对自2011年12月宁波市第一医院住院患者的痰样本js01株分离，用gyrA和parC基因PCR扩增、测序和BLASTn比对确认菌种。用PCR法分析33种β-内酰胺酶基因（13种A类酶基因、10种B类酶基因、2种C类酶基因、8种D类酶基因）和插入序列与β-内酰胺酶编码基因连锁检测以及CarO膜孔蛋白编码基因。再用分段PCR法扩增PBP1A编码基因，双向测序后拼接成全长序列。结果js01株检出β-内酰胺酶TEM-1、ADC-30、OXA-23和OXA-66编码基因。插入序列与β-内酰胺酶编码基因连锁检测显示ISabal-ADC-30和ISabal—OXA-23为阳性。js01株carO基因序列与鲍曼不动杆菌敏感株（SDF）相比存在有义突变，氨基酸序列一致率为76．0％（189／249），存在3个氨基酸缺失。is01株PBP1A编码基因序列与SDF株相比存在有义突变，氨基酸序列的一致率为99．6％（848／851），存在3个氨基酸变异，但js01株PBP1A蛋白分子立体结构比SDF株丢失2个螺旋结构。结论本株鲍曼不动杆菌对β-内酰胺类药物耐药主要与该菌株管家基因（PBP1A、CarO编码基因）突变与可移动遗传元件介异的β-内酰胺酶编码基因有关。Objective To investigate resistant mechanisms of a pandrug-resistant Acinetobacter baumannii （js01） to β-1actams. Methods Strain js01 isolated from sputum sample of an inpatient from Ningbo First Municipal Hospital in December 2011 was confirmed by PCR amplifying and sequencing of gyrA and parC, and aligning with BLASTn. Thirty-three kinds of β-1actamase genes （ 13 kinds of class A, 10 kinds of class B, 2 kinds of class C, 8 kinds of class D） , linkage detection of insertion sequences and β-1actamase genes, as well as outer membrane porin gene carO were analyzed by PCR. Genes encoding PBP1A were divided into three fragments, PCR amplified and bidirectional sequenced, and ligated to the full-length gene. Results Four kinds of β-1actamase genes were positive in is01 ： TEM-1, ADC-30, OXA- 23 and OXA-66. Linkage detection of insertion sequences and β-1actamase genes showed that ISabal-ADC- 30 and ISabal-OXA-23 were positive. When compared with sensitive strain （SDF） of Acinetobacter baumannii, sense mutations were found in carO gene of is01, and identity of amino acid sequence of carO gene between js01 and SDF was 76.0% （189/249） , and differences owed to loss of 3 amino acids. Sense mutations were also found in genes encoding PBP1A of js01, and identity of amino acid sequence of genes encoding PBP1A between js01 and SDF was 99.6% （848/851）, and differences owed to variations of 3 amino acids. However, compared with three-dimensional structure of PBP1A of SDF, PBP1A of is01 lost 2 helixes. Conclusion In strain is01, mutations of housekeeping genes （genes encoding PBPIA and CarO） , and genes producing β-1actamase mediated by mobile genetic elements, may play a key role in resistance to β-1actams.

关 键 词：鲍氏不动杆菌 Β-内酰胺类 基因 膜孔蛋白 CarO 青霉素结合蛋白 PBP1A 抗药性 

分 类 号：R446.5[医药卫生—诊断学]