Abstract
Escherichia coli is not only a commensal organism in humans and animals, but also a causative agent of diarrhea and extraintestinal infections. Information about the relationship between population structure, virulence gene profiles, and fluoroquinolone resistance of E. coli in dogs and cats in China is limited. A total of 174 pathogenic and commensal E. coli isolates were evaluated in terms of phylogenetic group, virulence gene profile, sequence types (STs), and fluoroquinolone susceptibility. A total of 46.6% of isolates belonged to phylogenetic group B2. Isolates displayed high resistance to tetracycline (82.2%), amoxicillin/clavulanic acid (73.6%), gentamicin (62.1%), and enrofloxacin (60.9%). fimH (81.6%) was the most prevalent virulence gene, and 83.9% of isolates contained one or more investigated virulence genes. The majority of the investigated virulence genes were more prevalent in fluoroquinolone-susceptible isolates and pathogenic isolates. Multilocus sequence typing (MLST) showed that E. coli isolates analyzed were assigned to 65 STs. Among of them, pathogenic-resistant and pathogenic-susceptible isolates had 44 and 10 STs, respectively, while there were 8 and 3 STs in the commensal resistant and susceptible isolates, respectively. Phylogenetic group B2 was the dominant group, accounting for 46.6% of the isolates. Pathogenic isolates and fluoroquinolone-susceptible isolates possessed more virulence genes. Pathogenic isolates and fluoroquinolone-resistant isolates exhibited high population diversity, and pandemic clone ST131 appeared in 9.8% of isolates.
Highlights
Escherichia coli is a commensal organism in humans and animals, and a causative agent of diarrhea and extraintestinal infections
Among the 174 E. coli isolates surveyed, 60.9% of isolates (n = 106, including 17 SDR and 89 MDR) were resistant to enrofloxacin, 21.3% of isolates (n = 37) remained susceptible to fluoroquinolones but expressed resistance to other antibacterial agents, and only 31 (17.8%) isolates were fully susceptible to the antibacterial agents tested
Our study revealed high resistance to tetracycline, ampicillin, amoxicillin/clavulanic acid, trimethoprimsulfamethoxazole, gentamicin, and enrofloxacin, and showed a similar pattern found in another study among E. coli isolates from companion animals in China [20]
Summary
Escherichia coli is a commensal organism in humans and animals, and a causative agent of diarrhea and extraintestinal infections. Methodology: A total of 174 pathogenic and commensal E. coli isolates were evaluated in terms of phylogenetic group, virulence gene profile, sequence types (STs), and fluoroquinolone susceptibility. The majority of the investigated virulence genes were more prevalent in fluoroquinolone-susceptible isolates and pathogenic isolates. Pathogenic isolates and fluoroquinolone-resistant isolates exhibited high population diversity, and pandemic clone ST131 appeared in 9.8% of isolates. E. coli isolates can be classified into commensal, intestinal pathogenic, and extraintestinal pathogenic E. coli (ExPEC) groups, based on different virulence genes [2]. Previous data suggested that fluoroquinolone-resistant ExPEC isolates harbored fewer virulence genes than did fluoroquinolone-susceptible isolates from humans [10,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
