Extended-spectrum β-lactamases (ESBLs) and/or AmpC enzymes combined with deficiency of porins OmpK35 and OmpK36 are important for the development of carbapenem-resistant Klebsiella pneumoniae. We characterized the cl...Extended-spectrum β-lactamases (ESBLs) and/or AmpC enzymes combined with deficiency of porins OmpK35 and OmpK36 are important for the development of carbapenem-resistant Klebsiella pneumoniae. We characterized the clinical K. pneumoniae human isolates and investigated the effect of meropenem induction on the ompK35 and ompK36 mutation to develop carbapenem resistance from six carbapenem-susceptible ESBL-producing K. pneumoniae strains. 163 clinical K. pneumoniae isolates were grouped mostly into the ESBL + AmpC (44.2%) and ESBL (42.9%) phenotypes. The resistance rate differed between cephalosporins (52.1% for cefepime - 97.5% for cefotaxime) and carbapenems (16% for meropenem - 28.2% for imipenem) (P blaTEM, blaSHV, blaCTX-M-3-like, and blaCTX-M-14-like of AmpA β-lactamase genes and blaDHA and blaCMY of AmpC β-lactamase genes. Compared to all 163 clinical isolates, the 56 carbapenem-resistant isolates carried less frequently of blaTEM, blaCTXM-14-like, and blaCTXM-3-like and more frequently of blaDHA-1 and blaCMY-2. The carbapenem-resistant isolates differed in prevalence against imipenem, ertapenem, and meropenem and lacked OmpK35 more frequently than OmpK36, but abnormal PCR amplicons were detected fewer in the Omp K35-deficient group than in the OmpK36-deficient group (32.5% vs. 68.4%, respectively). The carbapenem-resistant isolate mostly carried blaDHA (91.1%) and three isolates carried blaKPC-2. Following induction with meropenem insertion sequences in ompK36, not ompK36, were identified as IS5 for KP08, IS1 for KP15, and IS903 for KP16 isolates. OmpK36 deficiency increased resistance to ertapenem, but not imipenem and meropenem. Clinical isolates belonged mainly to ESBL + AmpC group and ESBL group with difference in resistance to cephalosporins and carbapenems, the bla genes. Carbapenem resistant isolates lacked OmpK35 expression, than the OmpK36 expression, Meropenem induction developed the carbapenem resistant isolates with insertion of different insertion sequences in ompK36, not ompK35.展开更多
目的探索鲍曼不动杆菌外膜孔道蛋白介导的耐药机制,研究碳青霉烯耐药相关性外膜蛋白(Car O)在舒巴坦耐药中的地位与作用。方法测定临床分离的鲍曼不动杆菌的最低抑菌浓度(MIC),用液质联用法测定菌体内舒巴坦浓度,并对外膜蛋白提取后进...目的探索鲍曼不动杆菌外膜孔道蛋白介导的耐药机制,研究碳青霉烯耐药相关性外膜蛋白(Car O)在舒巴坦耐药中的地位与作用。方法测定临床分离的鲍曼不动杆菌的最低抑菌浓度(MIC),用液质联用法测定菌体内舒巴坦浓度,并对外膜蛋白提取后进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE),测定Car O的表达情况,分析外膜蛋白与菌体内舒巴坦浓度间关系。结果舒巴坦对5株临床分离的鲍曼不动杆菌58C5、878-13、8F3、161-20、373-58的MIC分别为16,4,32,8,16μg·m L^(-1),相应外膜蛋白29 k Da条带的光密度值分别为1.00,2.02,0.33,1.80,0.85。29 k Da条带光密度值与胞内舒巴坦浓度存在显著相关性(P<0.01)。结论 Car O低表达可能是舒巴坦对鲍曼不动杆菌MIC值升高的机制之一。展开更多
目的研究外膜蛋白CarO的表达、序列突变与鲍曼不动杆菌对亚胺培南敏感性的关系。方法收集鲍曼不动杆菌8株,E-test鉴定亚胺培南敏感性;用脉冲场凝胶电泳(PFGE)鉴定菌株同源性;PCR法检验CarO基因,并进行序列分析;Real time PCR法检验CarO ...目的研究外膜蛋白CarO的表达、序列突变与鲍曼不动杆菌对亚胺培南敏感性的关系。方法收集鲍曼不动杆菌8株,E-test鉴定亚胺培南敏感性;用脉冲场凝胶电泳(PFGE)鉴定菌株同源性;PCR法检验CarO基因,并进行序列分析;Real time PCR法检验CarO mRNA的表达;SDS电泳法比较CarO蛋白的表达。结果本实验发现4株耐药菌株CarO序列同源性高;所有菌株中均存在CarO基因,但亚胺培南敏感及耐药菌株基因序列相似性仅87%,敏感菌株与耐药菌株均有CarO mRNA基因表达,且两者表达水平差异无统计学意义;SDS电泳也发现其基因序列不同者CarO蛋白分子量不同。结论 CarO基因序列改变可能与鲍曼不动杆菌对亚胺培南敏感性的变化有关。展开更多
文摘Extended-spectrum β-lactamases (ESBLs) and/or AmpC enzymes combined with deficiency of porins OmpK35 and OmpK36 are important for the development of carbapenem-resistant Klebsiella pneumoniae. We characterized the clinical K. pneumoniae human isolates and investigated the effect of meropenem induction on the ompK35 and ompK36 mutation to develop carbapenem resistance from six carbapenem-susceptible ESBL-producing K. pneumoniae strains. 163 clinical K. pneumoniae isolates were grouped mostly into the ESBL + AmpC (44.2%) and ESBL (42.9%) phenotypes. The resistance rate differed between cephalosporins (52.1% for cefepime - 97.5% for cefotaxime) and carbapenems (16% for meropenem - 28.2% for imipenem) (P blaTEM, blaSHV, blaCTX-M-3-like, and blaCTX-M-14-like of AmpA β-lactamase genes and blaDHA and blaCMY of AmpC β-lactamase genes. Compared to all 163 clinical isolates, the 56 carbapenem-resistant isolates carried less frequently of blaTEM, blaCTXM-14-like, and blaCTXM-3-like and more frequently of blaDHA-1 and blaCMY-2. The carbapenem-resistant isolates differed in prevalence against imipenem, ertapenem, and meropenem and lacked OmpK35 more frequently than OmpK36, but abnormal PCR amplicons were detected fewer in the Omp K35-deficient group than in the OmpK36-deficient group (32.5% vs. 68.4%, respectively). The carbapenem-resistant isolate mostly carried blaDHA (91.1%) and three isolates carried blaKPC-2. Following induction with meropenem insertion sequences in ompK36, not ompK36, were identified as IS5 for KP08, IS1 for KP15, and IS903 for KP16 isolates. OmpK36 deficiency increased resistance to ertapenem, but not imipenem and meropenem. Clinical isolates belonged mainly to ESBL + AmpC group and ESBL group with difference in resistance to cephalosporins and carbapenems, the bla genes. Carbapenem resistant isolates lacked OmpK35 expression, than the OmpK36 expression, Meropenem induction developed the carbapenem resistant isolates with insertion of different insertion sequences in ompK36, not ompK35.
文摘目的探索鲍曼不动杆菌外膜孔道蛋白介导的耐药机制,研究碳青霉烯耐药相关性外膜蛋白(Car O)在舒巴坦耐药中的地位与作用。方法测定临床分离的鲍曼不动杆菌的最低抑菌浓度(MIC),用液质联用法测定菌体内舒巴坦浓度,并对外膜蛋白提取后进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE),测定Car O的表达情况,分析外膜蛋白与菌体内舒巴坦浓度间关系。结果舒巴坦对5株临床分离的鲍曼不动杆菌58C5、878-13、8F3、161-20、373-58的MIC分别为16,4,32,8,16μg·m L^(-1),相应外膜蛋白29 k Da条带的光密度值分别为1.00,2.02,0.33,1.80,0.85。29 k Da条带光密度值与胞内舒巴坦浓度存在显著相关性(P<0.01)。结论 Car O低表达可能是舒巴坦对鲍曼不动杆菌MIC值升高的机制之一。
