AUTHOR=Liu Xiaoqiang , Thungrat Kamoltip , Boothe Dawn M. 

TITLE=Occurrence of OXA-48 Carbapenemase and Other β-Lactamase Genes in ESBL-Producing Multidrug Resistant Escherichia coli from Dogs and Cats in the United States, 2009–2013

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01057

DOI=10.3389/fmicb.2016.01057

ISSN=1664-302X

ABSTRACT=<p><bold>Objective:</bold> 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) <italic>Escherichia coli</italic> from dogs and cats in the United States.</p><p><bold>Methods:</bold> Of 2443 <italic>E</italic>.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.</p><p><bold>Results:</bold> 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 <italic>bla</italic><sub>CTX−M−15</sub> (<italic>n</italic> = 33), followed by <italic>bla</italic><sub>CTX−M−1</sub> (<italic>n</italic> = 32), <italic>bla</italic><sub>CTX−M−123</sub> (<italic>n</italic> = 27), <italic>bla</italic><sub>CTX−M−9</sub> (<italic>n</italic> = 19) and <italic>bla</italic><sub>CTX−M−14</sub> (<italic>n</italic> = 19), and <italic>bla</italic><sub>CTX−M−123</sub> was firstly reported in <italic>E. coli</italic> isolates in the United States alone or in association. Other β-lactamase genes <italic>bla</italic><sub>TEM</sub>, <italic>bla</italic><sub>SHV</sub>, <italic>bla</italic><sub>OXA−48</sub>, and <italic>bla</italic><sub>CMY−2</sub> were detected in 41.2, 29.4, 19.1, and 17.6% of 68 ESBL-producing MDR isolates, respectively. The <italic>bla</italic><sub>TEM</sub> and <italic>bla</italic><sub>SHV</sub> genes were classfied as ESBLs with the exception of the <italic>bla</italic><sub>TEM−1</sub> gene. Additionally, 42.6% (29/68) of isolates co-expressed <italic>bla</italic><sub>CTX−M−15</sub> and PMQR gene <italic>aac(6</italic>′<italic>)-Ib-c</italic>. The overall occurrence of virulence genes ranged from 11.8 (<italic>ireA</italic>) to 88.2% (<italic>malX</italic>), and most of virulence genes were less frequent among CTX-M-producing isolates than non-CTX-M isolates with the exception of <italic>malX</italic> and <italic>iutA</italic>. The 68 isolates analyzed were assigned to 31 STs with six being novel. Three pandemic clonal lineages ST131 (<italic>n</italic> = 10), ST648 (<italic>n</italic> = 9), and ST405 (<italic>n</italic> = 9) accounted for more than 41% of the investigated isolates, and ST648 and ST405 of phylogenetic D were firstly reported in <italic>E. coli</italic> from dogs and cats in the United States.</p><p><bold>Conclusion:</bold><italic>bla</italic><sub>CTX−M−123</sub> of ESBLs and carbapenemase <italic>bla</italic><sub>OXA−48</sub> were firstly reported in ESBL-producing MDR <italic>E</italic>.coli from dogs and cats in the United States, and ST131, ST648, and ST405 were the predominant clonal groups.</p>