Effects of insertional inactivation of novel gene PA0058 on the aminoglycoside resistance in Pseudomonas aeruginosa

Abstract:

[Objective] Pseudomonas aeruginosa is a typical opportunistic pathogen which often causes serious and persistent infections in hospitals. As antibiotics have been used extensively and constantly, P. aeruginosa developing higher multi-drug resistance. Hence, investigating the mechanisms of antibiotic resistance in P. aeruginosa has significant clinical value. [Methods] A clinical isolated strain PA68 was adopted to construct a Mu transposon insertion mutant library. One mutant strain named M122 with abnormally high streptomycin resistance was isolated from the library. Southern blotting confirmed that the insertions had occurred as single event. DNA microarray was used to analyze the genomic expression in M122. [Results] Gene cloning and sequencing indicated that the alteration of M122 phenotype was due to the insertional activation of a novel gene PA0058. Mutation of PA0058 gene resulted in a higher resistance to several kinds of aminoglycoside antibiotics. After transforming a plasmid containing gene PA0058 into M122, the resistance phenotype restored partially. To exclude the strain specific, gene PA0058 was knocked-out in P. aeruginosia PAK. The results indicated that the mutation of gene PA0058 causes multiple gene expression change in P. aeruginosa, especially the significantly up-regulated antioxidant enzyme genes. [Conclusion] This is the first time the gene PA0058 was identified and reported to be involved in upward aminoglycoside resistance in P. aeruginosa.

Key words:Pseudomonas aeruginosa, Mu transposition, PA0058, Aminoglycoside resistance