Citrobacter spp.

Citrobacter spp. are Gram-negative, motile, rod-shaped bacteria from the Enterobacteriaceae family.

Citrobacter spp. are of increasing importance as a cause of nosocomial infections. The species Citrobacter freundii, Citrobacter werkmanii and Citrobacter braakii are of particular clinical importance.

The pathogen can cause the following diseases, among others:

  • Intra-abdominal (located within the abdominal cavity) infections

  • Urinary tract infections

  • Respiratory infections

  • Wound infections

  • Neonatal sepsis

Citrobacter spp. are common in almost all habitats such as soil and water and are also found in the gastrointestinal tract as part of the normal intestinal flora of humans.

Relevance of pathogen in transmission in endoscopy

  • Gastroenterology: Low

  • Pulmonology: Low

  • Ear, nose, and throat: Not relevant

  • Urology: Low

Relevance for endoscope surveillance

  • High concern organism

Transmission route

Transmission occurs mainly through direct or indirect contact with contaminated persons or objects.

Resistance to antibiotics

Citrobacter spp. belongs to the multi-resistant Gram-negative bacteria (MRGN) and shows resistance especially to beta-lactam antibiotics such as 3rd generation cephalosporins and carbapenems. Citrobacter spp. belongs to the ESBL (extended spectrum beta-lactamase) producing bacteria.

Sources and further readings

  1. Gries O, Ly T: Infektologie – Kompendium humanpathogener Infektionskrankheiten und Erreger, Springer-Verlag Berlin Heidelberg 2019.

  2. Hygienemaßnahmen bei Infektionen oder Besiedlung mit multiresistenten gramnegativen Stäbchen. Kommission für Krankenhaushygiene und Infektionsprävention (KRINKO) beim Robert Koch-Institut (RKI). Bundesgesundheitsbl 10/2012.

  3. Kim B.N. et al. Resistance to extended-spectrum cephalosporins and mortality in patients with Citrobacter freundii bacteremia, Infection, 2003. 31(4): p. 202–7.

  4. Citrobacter, Elsevier/ScienceDirect, Accessed on 07.20.2021.