Open Forum Infect DisOpen Forum Infect DisofidOpen Forum Infectious Diseases2328-8957Oxford University PressUS777646210.1093/ofid/ofaa439.442ofaa439.442Poster AbstractsAcademicSubjects/MED00290132. Emergence and Spread of Multidrug-resistant salmonella Serotype Infantis Infections in the United States, 2003–2018MedallaFelicitaMD, MS1PayneDaniel CPhD, MSPH2SundararamanPreethiMPH1BirhaneMeseretMPH, MAS1ClassonAndrewMPH1CaidiHayatPhD1FolsterJasonPhD1FriedmanCindy RMD2WatkinsLouise FrancoisMD, MPH3 Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, Atlanta, Georgia Centers for Disease Control and Prevention, Atlanta, Georgia Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia10202031122020311220207Suppl 1IDWeek 2020 AbstractsS196S196© 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

Infantis re-emerged as a leading Salmonella serotype when a multidrug-resistant (MDR) strain with a rare extended spectrum β-lactamase (ESBL) blaCTX-M-65 gene emerged among returned travelers from Peru in 2012 and then spread domestically. This strain has been isolated from chickens at slaughter and retail, and humans in outbreaks traced to chicken. We reviewed national surveillance data to determine incidence trends and antibiotic resistance among Infantis infections.

Methods

We reviewed data from 2003–2018 from the Foodborne Diseases Active Surveillance Network to determine the incidence and epidemiology of infections in 10 sites under surveillance; PulseNet to determine pulsed-field gel electrophoresis (PFGE) patterns; and National Antimicrobial Resistance Monitoring System (NARMS) to determine antimicrobial susceptibility testing (AST) results and resistance genes of isolates identified by whole genome sequencing (WGS). We defined MDR Infantis as having ceftriaxone resistance by AST and either the blaCTX-M-65 gene or one of 18 PFGE patterns linked to that gene by WGS.

Results

The 2,154 patients with Infantis infection had a median age of 36 years and 57% were female; 86% had isolates from stool, 9% from urine, and 3% from blood. Only 10% reported foreign travel and 27% were hospitalized. The incidence of infections began increasing in 2010 and by 2017–2018 was 2-fold higher than the average during 2003–2009. During 2003–2018, 856 (88%) of 970 NARMS isolates had PFGE or WGS data; 48 isolates were MDR Infantis, and in addition to ceftriaxone and ampicillin resistance (by definition), all 48 were resistant to 3 or more antibiotic classes, 94% had decreased susceptibility to ciprofloxacin, and 67% were resistant to cotrimoxazole. During 2012–2016, 2% of isolates were MDR Infantis; this increased to 17% during 2017–2018 (Figure).

Conclusion

During the past decade, the incidence of Infantis infections markedly increased. This was likely driven by the emergence of an ESBL-producing strain that was initially associated with travel, and is now mostly domestically acquired and associated with consuming chicken. MDR Infantis now accounts for 1 in 5 Infantis infections. Public health strategies to reduce Salmonella contamination of chicken could help prevent these infections.

Disclosures

All Authors: No reported disclosures