Car-R/Ceph-S的铜绿假单胞菌OprD基因突变分析

  目的  研究对碳青霉烯类耐药而对头孢菌素敏感（carbapenem-resistant but cephalosporin-susceptible ，Car-R/Ceph-S）的铜绿假单胞菌（Pseudomonas aeruginosa）中OprD基因的突变类型。  方法   对2021年1月至2021年3月昆明医科大学第一附属医院临床分离的10株对碳青霉烯类耐药而对头孢菌素敏感的铜绿假单胞菌进行分离培养；使用聚合酶链式反应（polymerase chain reaction，PCR）检测该表型铜绿假单胞菌中OprD基因的携带情况，并测序分析OprD基因的突变类型。  结果   10株菌株均显示出明显的OprD扩增条带，测序分析显示有以下突变类型，分别是移码突变2株、氨基酸替代突变8株、提前终止密码子2株、大片段缺失4株。  结论   对碳青霉烯类耐药而对头孢菌素敏感（Car-R/Ceph-S）的铜绿假单胞菌中OprD基因的突变类型呈多样化，点突变频率最高，还有大片段的缺失以及提前终止密码子。这些突变导致OprD结构发生改变，从而使得耐药现象的发生。

Mutation Analysis of OprD Gene in Pseudomonas Aeruginosa with Car-R/ Ceph-S

  Objective   To study the mutation types of OprD gene in Pseudomonas aeruginosa resistant to carbapenems but sensitive to cephalosporins （Car-R/Ceph-S）.   Methods  Ten strains of Pseudomonas aeruginosa which were resistant to carbapenems but sensitive to cephalosporins were isolated and cultured in the First Affiliated Hospital of Kunming Medical University from January 2021 to March 2021. Polymerase chain reaction （PCR） was used to detect the carrying status of OprD gene in Pseudomonas aeruginosa, and the mutation type of OprD gene was analyzed by sequencing.   Results   All the 10 strains showed obvious OprD bands and the sequencing analysis showed that there were 2 frameshift mutations, 8 amino acid substitutions, 2 early termination codons and 4 large fragment deletions.   Conclusion  The mutation types of OprD gene in carbapenem-resistant but cephalosporin-sensitive （Car-R/Ceph-S） strains of Pseudomonas aeruginosa are diversified with the highest frequency of point mutations, deletion of large segments and early termination of codons. These mutations lead to changes in the structure of OprD, resulting in the occurrence of drug resistance.