Four novel resistance integron gene-cassette occurrences in bacterial isolates from zhenjiang, china.

Integrons, which are widely distributed among bacteria and are strongly associated with resistance, are specialized genetic elements that are capable of capturing, integrating, and mobilizing gene cassette. In this work, we investigated classes 1, 2, and 3 integrons associated integrases genes in 365 bacteria isolates, amplified and analyzed the structure of class 1 integron, detected 8 resistant gene cassettes [dfr17, aadA5, aadA1, aadA2, dhfrI, aadB, aac(6')-II, and pse-I], and found four novel gene-cassette arrays. We also found that commensal bacteria in the common microenvironment had the same integron gene cassette, which provided direct evidence that integron was an important horizontal transmission element.