Abstract
Objective: The aim of this study was to explore the occurrence and molecular characterization of extended-spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamase (pAmpC) and carbapenemases among ESBL-producing multidrug resistant (MDR) Escherichia coli from dogs and cats in the United States.Methods: Of 2443 E.coli isolated from dogs and cats collected between August 2009 and January 2013, 68 isolates were confirmed as ESBL-producing MDR ones. PCR and sequencing were performed to identify β-lactamases and plasmid-mediated quinolone resistance (PMQR) genes, and shed light on the virulence gene profiles, phylogenetic groups and ST types.Results: Phylogenic group D and B2 accounted for 69.1% of the isolates. 50 (73.5%) isolates carried CTX-M ESBL gene, and the most predominant specific CTX-M subtype identified was blaCTX−M−15 (n = 33), followed by blaCTX−M−1 (n = 32), blaCTX−M−123 (n = 27), blaCTX−M−9 (n = 19) and blaCTX−M−14 (n = 19), and blaCTX−M−123 was firstly reported in E. coli isolates in the United States alone or in association. Other β-lactamase genes blaTEM, blaSHV, blaOXA−48, and blaCMY−2 were detected in 41.2, 29.4, 19.1, and 17.6% of 68 ESBL-producing MDR isolates, respectively. The blaTEM and blaSHV genes were classfied as ESBLs with the exception of the blaTEM−1 gene. Additionally, 42.6% (29/68) of isolates co-expressed blaCTX−M−15 and PMQR gene aac(6′)-Ib-c. The overall occurrence of virulence genes ranged from 11.8 (ireA) to 88.2% (malX), and most of virulence genes were less frequent among CTX-M-producing isolates than non-CTX-M isolates with the exception of malX and iutA. The 68 isolates analyzed were assigned to 31 STs with six being novel. Three pandemic clonal lineages ST131 (n = 10), ST648 (n = 9), and ST405 (n = 9) accounted for more than 41% of the investigated isolates, and ST648 and ST405 of phylogenetic D were firstly reported in E. coli from dogs and cats in the United States.Conclusion: blaCTX−M−123 of ESBLs and carbapenemase blaOXA−48 were firstly reported in ESBL-producing MDR E.coli from dogs and cats in the United States, and ST131, ST648, and ST405 were the predominant clonal groups.
Highlights
Extraintestinal pathogenic strains of Escherichia coli (ExPEC) are the most important dogs and cats bacterial pathogens associated with extraintestinal infections (Beutin, 1999)
The high prevalence of blaCTX−M strongly suggests a significant role for E. coli isolates from companion animals as ESBL gene reservoirs, which poses an additional risk to humans
Our results showed that majority (58.3%) of CMY-2-producing isolates belonged to phylogenetic group D, consistent with a previous study in E. coli from human in Australia (Sidjabat et al, 2014)
Summary
Extraintestinal pathogenic strains of Escherichia coli (ExPEC) are the most important dogs and cats bacterial pathogens associated with extraintestinal infections (Beutin, 1999). Extended-spectrum β-lactamase (ESBL)-producing ExPEC are isolated worldwide with increasing frequency from human and animal clinical isolates (Pitout, 2012). ESBL-producing isolates are often cross-resistant to fluoroquinolones and other antimicrobial agents, expressed multidrug resistance (MDR). This combination of properties can significantly affect the course and outcomes of infections. Β-lactamase genes commonly located on mobile genetic elements, such as plasmids, transposons, or integrons, and the resistance plasmids can be transferred between bacterial isolates by conjugation mechanism. Transmission of βlactamase genes between companion animals and owner has become a subject of active discussion as companion animals could be potential sources of ESBL-producing E. coli isolates causing community-acquired infections (Schmiedel et al, 2014)
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
