Open Forum Infect DisOpen Forum Infect DisofidOpen Forum Infectious Diseases2328-8957Oxford University PressUS777823210.1093/ofid/ofaa439.906ofaa439.906Poster AbstractsAcademicSubjects/MED00290714. Increase in Multidrug-resistant Salmonella Serotype I 4,[5],12:i:- Infections Linked to Pork—United States, 2009–2018PlumbIan DMBBS, MSc1BrownAllison CPhD MPH2StokesErin KMPH3ChenJessicaPhD3TolarBethMS3SundararamanPreethiMPH1FolsterJasonPhD1CarletonHeatherPhD3FriedmanCindy RMD3 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, Atlanta, Georgia CDC, Atlanta, GA Centers for Disease Control and Prevention, Atlanta, Georgia10202031122020311220207Suppl 1IDWeek 2020 AbstractsS408S409© The Author 2020. Published by Oxford University Press on behalf of Infectious Diseases Society of America.2020This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.comAbstractBackground

Salmonella enterica I 4,[5],12:i:- is the 5th most common serotype causing clinical Salmonella infections in the United States. A strain with resistance to ampicillin, streptomycin, sulfamethoxazole, and tetracycline (ASSuT) has been linked to swine production in Europe and the United States. We reviewed U.S. surveillance data to describe clinical infections with antibiotic-resistant I 4,[5],12:i:-.

Methods

We reviewed data from CDC’s National Antimicrobial Resistance Monitoring System (NARMS) from 2009–2018 to describe trends. We analyzed whole-genome sequence data in PulseNet, the molecular surveillance network for foodborne illness in the United States, from 2015–2018 to distinguish between strains of I 4,[5],12:i:- using core-genome multilocus sequence typing, and identified antibiotic resistance determinants (ARDs). We reviewed data from the Foodborne Disease Outbreak Surveillance System to identify foods associated with outbreaks during 2009–2018.

Results

From 2009–2013 to 2014–2018, I 4,[5],12:i:- increased as a proportion of nontyphoidal Salmonella isolates in NARMS from 4.3% to 5.0% (P=0.006), while I 4,[5],12:i:- resistant to ASSuT increased from 1.1% to 2.6% (P< 0.001). Of the 3,056 sequenced I 4,[5],12:i:- isolates in PulseNet, 2,105 (69%) were in a clade within 0–108 alleles of each other (ASSuT clade). Within this clade, 77% of isolates had ARDs conferring resistance to ASSuT, compared with 3% outside the clade. Isolates in the clade were also more likely than those outside the clade to have ARDs conferring decreased susceptibility to ciprofloxacin (13.1% vs. 5.2%, P< 0.001) and resistance to ceftriaxone (5.4% vs. 2.3%, P< 0.001). Among I 4,[5],12:i:- outbreaks with a single food source, those related to the ASSuT clade were more often linked to pork (10/15 [67%] vs. 1/5 [20%], P=0.07).

Conclusion

The increase in I 4,[5],12:i:- infections during 2009–2018 was likely driven by a clade of which most members had resistance to ASSuT, and many had decreased susceptibility to antibiotics used for empiric treatment. The association of this strain with outbreaks linked to pork suggests that measures to decrease carriage of Salmonella and selection for this strain in swine could prevent clinical infections with multidrug resistant Salmonella I 4,[5],12:i-.

Disclosures

All Authors: No reported disclosures