Citrobacter freundii

Citrobacter freundii is a species of Gram-negative bacteria in the family Enterobacteriaceae. It is commonly found in the environment, including soil, water, and sewage, and is also present in the intestinal tracts of animals and humans. This bacterium is known for its ability to cause a variety of infections, particularly in immunocompromised individuals.

Characteristics

Citrobacter freundii is a facultative anaerobe, meaning it can grow in both the presence and absence of oxygen. It is motile due to the presence of peritrichous flagella. The bacterium is rod-shaped and measures approximately 1-5 micrometers in length. It is capable of fermenting lactose, producing gas and acid as byproducts.

Pathogenicity

Citrobacter freundii is an opportunistic pathogen. It can cause a range of infections, including urinary tract infections, respiratory tract infections, wound infections, and sepsis. In rare cases, it can also lead to meningitis and brain abscesses, particularly in neonates and individuals with compromised immune systems.

Antibiotic Resistance

Citrobacter freundii has been noted for its ability to acquire and disseminate antibiotic resistance genes. It is often resistant to multiple antibiotics, including beta-lactams, due to the production of beta-lactamase enzymes. This resistance complicates the treatment of infections caused by this bacterium.

Clinical Significance

In clinical settings, Citrobacter freundii is often isolated from patients with nosocomial infections. It is important for healthcare providers to identify this bacterium accurately and determine its antibiotic susceptibility to ensure effective treatment.

Laboratory Identification

Citrobacter freundii can be identified in the laboratory using a variety of biochemical tests. It is typically positive for the citrate test, urease test, and methyl red test. It also produces hydrogen sulfide on triple sugar iron agar.

Prevention and Control

Preventing infections caused by Citrobacter freundii involves standard infection control practices, including proper hand hygiene, sterilization of medical equipment, and appropriate use of antibiotics to prevent the development of resistance.

See Also

• Enterobacteriaceae
• Gram-negative bacteria
• Nosocomial infection
• Antibiotic resistance