Serratia marcescens

Serratia marcescens

  • anaerobic GNR, family Enterobacter
  • associated with hospital-onset infections
  • intrinsically resistant to ampicillin, amoxicillin, ampisulbactam, amoxiclav,, narrow-spectrum cephalosporins, cefuroxime,/ macrolides, tetracytclines, nitrofurantin and colistin
  • potential to harbor MDR mechanisms (AmpC or ESBL and carbapenemases)


  • uncomplicated infection – FQ, TMP SMZ, zosyn, ceph3 or ceph4, carbapenems
  • risk of AmpC-mediated resistance during therapy
    • likely with CNS infections, infections in sequestered sites that require prolonged antibiotic therapy, retained infected material
    • do not use ceph3 even if susceptible
    • in CNS infections – favor carbapenem or cefepime
    • other sequestered sites  FQ and TMP-SMZ
  • high level expression of AmpC beta-lactamase or ESBL – carbapenem

Duration of therapy 

  • depends on site of infection and clinical response
  • repeat culture/susceptibility testing and adjust Rx accordingly



Uptodate.  Serratia marcescens. Accessed 03/15/2016.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s