多重耐药铜绿假单胞菌中Ⅰ型整合子新结构的发现及其与耐药的相关性

Discovery of new structure of class 1 integron in MDR Pseudomonas aeruginosa and its association with drugresistance

摘要:

摘要:【目的】研究临床多重耐药铜绿假单胞菌中Ⅰ型整合子的结构特征，探讨整合子与细菌多重耐药之间的相关性。【方法】收集临床样品中的铜绿假单胞菌，从中挑选多重耐药菌。采用聚合酶链式反应扩增Ⅰ型整合子可变区，应用酶切方法和DNA测序技术分析整合子基因结构，并采用SPSS19.0软件分析整合子与耐药表型间的相关性。【结果】多重耐药铜绿假单胞菌中Ⅰ型整合子的检出率为27.3%。Ⅰ型整合子基因盒排列形式共有3种(1500 bp、2300 bp和4000 bp)，其中2种在其他细菌中也有发现。基因盒所编码的耐药基因有氨基糖苷类抗生素抗性基因(aadA、aadB、aac (6')Ⅱ和aadA13)、β-内酰胺类抗生素抗性基因(blaCARB8和oxa10)和氯霉素外排泵基因(cmlA8)，耐药表型相关性分析表明整合子与氨基糖苷类抗生素抗性密切相关。【结论】在多重耐药铜绿假单胞菌临床分离株中发现了3种不同Ⅰ型整合子结构，这3种结构中均含有氨基糖苷类抗生素耐药基因，其中aadB-aac(6')Ⅱ-blaCARB8结构最为流行。

Abstract:

Abstract:［Objective］ To investigate the characteristics of classⅠintegrons among clinical multidrug-resistant Pseudomonas aeruginosa isolates，and to analyze the association between class Ⅰ integrons and multidrug resistance.［Methods］Pseudomonas aeruginosa strains were isolated from clinical samples，and the multidrug-resistant ones were picked out from these isolates．PCR assays were used to detect the variable regions of class Ⅰ integrons，and the resulting products were then digested with restriction enzyme Sau 3AⅠand sequenced． SPSS19. 0 software was used for statistical analysis.［Results］ Class Ⅰ integrons were detected in 27.3% of the clinical multidrug-resistant Pseudomonas aeruginosa isolates．Amplification of variable regions of class Ⅰ integrons revealed three different gene cassette arrays (1500，2300 and 4000 bp)，two of them were also found in other bacteria．These gene cassette arrays encoded aminoglycoside-modifying enzymes (aadA，aadB，aac(6')Ⅱ and aadA13)，β-lactamases (blaCARB8 and oxa10) and chloromycetin efflux pump (cmlA8). Analysis results suggested closely relationship between class Ⅰ integrons and aminoglycoside resistance.［Conclusion］We revealed three different gene cassette arrays in the clinical isolates of the multidrug-resistant Pseudomonas aeruginosa，and gene cassette array aadB-aac(6')Ⅱ-blaCARB8 was the most prevalent．The three gene cassette arrays all contained the aminoglycoside-resistant genes.