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Volume 27, Number 6—June 2021

Increased Incidence of Antimicrobial-Resistant Nontyphoidal Salmonella Infections, United States, 2004–2016

Felicita MedallaComments to Author , Weidong Gu, Cindy R. Friedman, Michael Judd, Jason Folster, Patricia M. Griffin, and Robert M. Hoekstra
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Main Article

Table 3

Point estimates of the total number and changes in the total number of resistant nontyphoidal Salmonella infections extrapolated to the US population, by resistance category, United States, 2015–2016 versus 2004–2008 and 2010–2014*†

Resistance category Change in no. infections/year‡
No. infections/year†
vs. 2004–2008 2015–2016
vs. 2010–2014
2015–2016 2004–2008 2010–2014
Any clinically important resistance§ 222,000 159,000 166,000 63,000‡ 56,000
Multidrug resistance¶ 171,000 141,000 133,000 30,000 38,000
Amp-only§ 111,000 93,000 90,000 18,000 21,000
Cef/Amp§ 46,000 40,000 39,000 6,000 7,000
Cipro§ 65,000 27,000 38,000 38,000‡ 27,000‡

*Amp-only, resistant to ampicillin (MIC >32 µg/mL) but susceptible to ceftriaxone and ciprofloxacin; BHM, Bayesian hierarchical model; Cef/Amp, resistant to ceftriaxone (MIC >4 µg/mL) and ampicillin; Cipro, nonsusceptible to ciprofloxacin (MIC >0.12 µg/mL) but susceptible to ceftriaxone; CrI, credible interval.
†Point estimates extrapolated to the entire US population were calculated by multiplying mean estimates for culture-confirmed infections (derived using BHM) by the multiplier of 29 and the average total U.S. population for 2015–2016 (322 million). The multiplier of 29 is the mean estimate of the total number of infections for every culture-confirmed nontyphoidal Salmonella infection. The 95% CrIs were not derived. Extrapolated point estimates were rounded to the nearest thousand.
‡Model-derived mean estimates of changes in resistance incidence (Table 2) used to calculate extrapolated estimates are reported as significant if the 95% CrIs do not include 0; the extrapolated estimates corresponding to these BHM-derived estimates are shown in bold font. Although the 95% CrIs of extrapolated estimates were not derived, they can be assumed to include 0 if the 95% CrIs of BHM-derived estimates include 0.
§An overall category of clinically important resistance includes any of 3 resistance patterns (i.e., resistant to ceftriaxone, resistant to ampicillin, or nonsusceptible to ciprofloxacin). Amp-only, Cef/Amp, and Cipro are mutually exclusive categories of clinically important resistance. Isolates with any clinically important resistance might have resistance to other agents tested. Model estimates for overall clinically important resistance were derived separately and might differ from the sum of BHM estimates for the 3 mutually exclusive categories; thus, extrapolated estimates for the overall category might differ from the sum of mutually exclusive categories.
¶Resistant to >3 classes of antimicrobial agents.

Main Article

Page created: April 30, 2021
Page updated: May 18, 2021
Page reviewed: May 18, 2021
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