Gram Negative Resistance

Question 1

Which Enterobacterales should be considered at moderate to high risk for
clinically significant ampC production due to an inducible AmpC gene?

Answer 1

Enterobacter cloacae complex
Klebsiella aerogenes
Citrobacter freundii

Question 2

Which Enterobacterales should be considered at low risk for
clinically significant ampC production due to an inducible ampC gene?

Answer 2

Serratia marcescens
Morganella morgannii
Providencia spp.

Question 3

How should Enterobacterales at low risk for clinically significant ampC production be treated?

Answer 3

According to antimicrobial susceptibility testing results (IDSA AMR Guidance 2023)

Question 4

What other Gram-negative organisms that carry inducible chromosomal ampC genes have treatment decisions that depend on bacterial burden and source control?

Answer 4

Hafnia alvei
Citrobacter youngae
Yersinia enterocolitica

If low burden with source control, treat according to antimicrobial susceptibility testing.
If high burden without source control, consider cefepime or a carbapenem.