AUTHOR=Tran Tam , Checkley Sylvia , Caffrey Niamh , Mainali Chunu , Gow Sheryl , Agunos Agnes , Liljebjelke Karen 

TITLE=Genetic Characterization of AmpC and Extended-Spectrum Beta-Lactamase Phenotypes in Escherichia coli and Salmonella From Alberta Broiler Chickens

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.622195

DOI=10.3389/fcimb.2021.622195

ISSN=2235-2988

ABSTRACT=<p>Horizontal gene transfer is an important mechanism which facilitates bacterial populations in overcoming antimicrobial treatment. In this study, a total of 120 <italic>Escherichia coli</italic> and 62 <italic>Salmonella enterica</italic> subsp. <italic>enterica</italic> isolates were isolated from broiler chicken farms in Alberta. Fourteen serovars were identified among <italic>Salmonella</italic> isolates. Thirty one percent of <italic>E. coli</italic> isolates (37/120) were multiclass drug resistant (resistant to ≥ 3 drug classes), while only about 16% of <italic>Salmonella</italic> isolates (10/62) were multiclass drug resistant. Among those, eight <italic>E. coli</italic> isolates had an AmpC-type phenotype, and one <italic>Salmonella</italic> isolate had an extended-spectrum beta-lactamase (ESBL)-type beta-lactamase phenotype. We identified both AmpC-type (<italic>bla</italic><sub>CMY-2</sub>) and ESBL-type (<italic>bla</italic><sub>TEM</sub>) genes in both <italic>E. coli</italic> and <italic>Salmonella</italic> isolates. Plasmids from eight of nine <italic>E. coli</italic> and <italic>Salmonella</italic> isolates were transferred to recipient strain <italic>E. coli</italic> J53 through conjugation. Transferable plasmids in the eight <italic>E. coli</italic> and <italic>Salmonella</italic> isolates were also transferred into a lab-made sodium azide-resistant <italic>Salmonella</italic> recipient through conjugation. The class 1 integrase gene, <italic>int1</italic>, was detected on plasmids from two <italic>E. coli</italic> isolates. Further investigation of class 1 integron cassette regions revealed the presence of an <italic>aadA</italic> gene encoding streptomycin 3’’-adenylyltransferase, an <italic>aadA1a</italic>/<italic>aadA2</italic> gene encoding aminoglycoside 3’’-O-adenyltransferase, and a putative adenylyltransferase gene. This study provides some insight into potential horizontal gene transfer events of antimicrobial resistance genes between <italic>E. coli</italic> and <italic>Salmonella</italic> in broiler chicken production.</p>