Abstract
Background
Antimicrobial resistance (AMR) in foodborne pathogens of animal origin, including nontyphoidal Salmonella (NTS), is a public health concern. Pennsylvania conducts integrated surveillance for AMR in NTS from human and animal sources in collaboration with the FDA and CDC National Antimicrobial Resistant Monitoring System (NARMS).
Methods
We reviewed pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility (SST) and whole-genome sequencing (WGS) data for isolates from animal and food sources, including 96 NTS from 2,520 meat samples (poultry, ground beef and pork chops) purchased during 2015–2017 from randomly selected retail outlets in Pennsylvania. SST to 15 antimicrobial agents was done on 109 NTS clinical isolates that had similar PFGE patterns to meat isolates. SST and WGS were used to characterize all isolates from meat and two clinical isolates from 2017.
Results
28 (29.2%) and 17 (17.7%) NTS isolated from meat sources were resistant to ≥3 and ≥5 antibiotics classes, respectively. Resistance to ceftriaxone rose from 12% (3/25) in 2015 to 27% (10/37) in 2016 and resistance to amoxicillin/clavulanate also increased. Plasmid-mediated bla CMY-2 β-lactam resistance genes that hydrolyze extended-spectrum cephalosporins (ESC) increased from 12% in 2015 (3/25) to 18.9% (7/37) in 2016. Four blaCTX-M-65 genes that confer resistance to extended-spectrum β-lactamases (ESBLs) were identified in 2016 (n = 3) and 2017. Of the 109 clinical isolates, 25.7% demonstrated resistance to ≥3 and 11% to ≥5 antibiotics classes, respectively. No clinical isolates were resistant to ceftriaxone in 2015, 12.5% (6/48) and 24.3% (9/37) were resistant in 2016 and 2017, respectively. Resistance to amoxicillin/clavulanate was demonstrated in 8.3% (4/48) of isolates in 2016 (figure). Two clinical isolates carried blaCTX-M-65 ESB Ls genes and were resistant to eight antimicrobial agents (ACSSuTCxNalCot. Phenotype).
Conclusion
NTS (≥25%) from animal and human sources were multidrug-resistant and harbored CMY-2 and CTX-M-65 genes. Dissemination of genes that confer resistance to ESBLs and ESCs in NTS undermines recommended treatment for severe infections and underscores the need for One-Health surveillance and antimicrobial stewardship efforts.
Disclosures
All authors: No reported disclosures.