Three strains of class I integrons with novel cassette arrays in Pseudomonas aeruginosa isolates

Objectives To investigate the mechanism of integron mediated resistance and multidrug-resistance in P.aeruginosa.Methods The variable region of integron was amplified by integron PCR.Restriction fragment length polymorphism(RFLP)and DNA sequencing were used to investigate the resistance genes in the variable region of integron.Results Of the 98 strains 35(35.7%)were the variable region positive,and size of the amplicons ranged from 1.0 kb to 4.0 kb.A total of 6 different cassette arrays were detected,including genes coding resistance to aminoglycosides,β-lactam compounds and sulfanilamides.Of the 5 cassette arrays 3 were novel,including aadA6-orfD,aadB-blaP1 and aadB-aac6-Ⅱ-blaCARB-8,and the Genbank numbers were DQ 091179,DQ 141316 and DQ 288251 respectively.Conclusions Integron mediates the resistance and multidrug resistance in P.aeruginosa.The majority of the genes located in integrons are those coding resistance to aminoglycosides.Three strains of class I integron with novel cassette arrays are reported.