Abstract:

【Objective】 The objective of this study is to detect plasmid-mediated quinolone resistance qnrD gene in clinical isolates of Escherichia coli from pet animals, analyze the sequence of this gene and study the transmission mechanism of qnrD gene. 【Method】 Susceptibility of positive strain to 15 antimicrobial agents was determined by micro-dilution method; PCR method was used for cloning qnrD gene, clone products and positive plasmid were used for transmission tests, and conjugation experiments were made. 【Results】One (GP2009-036) of the 164 specimens was detected containing qnrD gene, GP2009-036 showed high rate of resistance to 14 antimicrobial agents widely used in veterinary clinical medicine and showed multiple-resistance (14 drugs). PCR products connected with PMD19-T vector could be transformed into DH5α competent cells. The positive plasmid were transmitted into Escherichia coli J53 successfully by conjugation experiments and the positive plasmid could be extracted from GP2009-036 and transconjugants. 【Conclusion】 This qnrD positive strain of Escherichia coli showed high rate of resistance to antimicrobial agents widely used in veterinary clinical medicine, and the positive plasmid can transmit among pathogenic microorganism, and the mechanism of transmission indicates that qnrD gene may spread in pet animal veterinary clinic.

Key words: qnrD, Escherichia coli, plasmid-mediated, quinolone, resistance