Surveillance of antimicrobial resistance and detection of ESBL and PMQR genes in pet-associated Salmonella in Beibei District, Chongqing

Abstract:

[Background] Salmonella is a common zoonotic pathogen. With the increasing number of pet owners, the threat of Salmonella in pet intestines to public health is gradually emerging, but there are few reports on the epidemiology and antimicrobial resistance of pet-associated Salmonella.[Objective] To investigate the epidemiology, antimicrobial susceptibility to commonly used antimicrobials and the prevalence of extended-spectrum β-lactamases (ESBL) gene and plasmid-mediated quinolone resistance (PMQR) genes of Salmonella isolated from pets in Beibei District, Chongqing. [Methods] Salmonella was isolated and identified by pre-enrichment, selective enrichment, selective plate screening and amplifying invA gene through PCR. Then, the antimicrobial susceptibility of the isolates to 28 antimicrobials was determined, and 10 ESBL genes and 10 PMQR genes were detected. [Results] A total of 41 Salmonella strains were isolated, the isolation rate was 3.95%. The resistance rates of these strains to sulfamethoxazole, ampicillin, tetracycline, doxycycline were more than 50%, 82.92% of them were multi-drug resistant, and all of isolates were completely sensitive to amikacin, ofloxacin, enoxacin and gatifloxacin. 85.37% of the isolates carried ESBL gene and the bla_TEM gene was the most popular. 46.34% of the isolates had PMQR genes and qnrS was the most popular one. 48.57% of ESBL positive strains carried at least one PMQR gene. [Conclusion] The above results demonstrated that pet-associated Salmonella in Beibei District were resistant to a variety of antimicrobials, and the drug resistance may be mediated by drug-resistant plasmids.