Drug resistance detection of canine origin Escherichia coli in China and inhibition by genipin

Zoonotic transmission from pets to their owners is a major health problem. It is important to determine and control the drug resistance in pets to mitigate risks of human transmission. In this work, the current prevalence of multi-drug resistance (MDR) and resistance gene in Escherichia coli (E. coli) derived from dogs in nine cities across various regions of China initially evaluated using microfluidic dilution methods and polymerase chain reaction (PCR) technology. To control antibiotic resistance, genipin as natural product was used to combat MDR E. coli. Finally, the synergistic effect of genipin and norfloxacin on MDR E. coli was studied using time-kill curves to retard the resistance spread. A total of 126 E. coli strains were isolated from 154 collected fecal samples of dogs. Minimum inhibitory concentrations (MIC) results revealed that the highest detection rate of MDR E. coli appeared in Zhengzhou at 90.9 %, and the lowest in Shenyang at 10.0 %. The results of drug resistance gene testing indicated that the bla_TEM gene had the highest detection rate (99.2 %), then tetA and bla_CTX-M-1, whose detection rates all exceed 50 %. Furthermore, the MIC of genipin against MDR E. coli was found to be 4096 μg/mL, and genipin at ½ MIC demonstrated significant inhibition on MDR E. coli within 6 h. Finally, the combination of ¼ MIC genipin with ½ MIC norfloxacin showed partial synergistic inhibitory effect on MDR E. coli. Our findings suggest that although antibiotic resistance in canine origin E. coli varies across different regions of China, it remains concerning, and genipin shows potential as a treatment option for MDR E. coli infections.