Distribution and Sequencing of Class 1 Integrons Carrying qac Gene Cassettes in Environment Sample

The distribution and characterization of the class 1intergrons (int1) and qac (quaternary ammonium compounds) gene cassettes in environments were investigated in order to clarify its potential risk on the spread of antibiotic resistance genes. The study showed that there are 10% of environment bacteria which have benzalkonium chloride resistant, 96 strains were selected among all the benzalkonium chloride resistant bacteria in environment, class 1intergrons (intI1) and integrated gene cassettes were examined with specific primers by PCR. It was found that among 96 strains, 74 strains (77.1%) were positive for class 1 gene cassettes, 9 strains (9.4%) were positive for the class 1 integron-integrase gene, intI1. By sequencing those positive strains´ PCR products, 4 strains carried integron intI1 with qac gene cassettes, suggesting that about 45% of intI1-positive cells from environmental samples carry a qac gene cassette. In total, there are about 4.2% which carrying class 1 integron containing qac gene cassettes in the environmental bacteria, Integrons carrying qac gene cassettes are enormous potential reservoir of antibiotic-resistant bacteria in environments. From the observations in the present study, it is evident that integrons carrying qac gene cassettes are prevalent among environment samples, showing definite influence on the development of antibiotic resistance.