Citrobacter koseri

Citrobacter koseri is a Gram-negative, facultative anaerobic, flagellated, rod-shaped bacteria that is commonly found in the environment and the human intestinal tract. It is a member of the Enterobacteriaceae family and is named after the American bacteriologist, Bernhard W. Koser.

Characteristics

Citrobacter koseri is a motile bacterium, possessing peritrichous flagella. It is capable of fermenting lactose within 48 hours, producing colonies that are moist, smooth, and cream-colored. The bacterium is also capable of producing indole and hydrogen sulfide.

Pathogenicity

While Citrobacter koseri is a normal inhabitant of the human gut, it can cause opportunistic infections in immunocompromised individuals. These infections can include urinary tract infections, respiratory tract infections, sepsis, and meningitis. In particular, Citrobacter koseri is known to cause neonatal meningitis, leading to brain abscesses and significant mortality.

Treatment

Treatment of Citrobacter koseri infections typically involves the use of antibiotics. However, the bacterium has shown resistance to several commonly used antibiotics, including ampicillin and first-generation cephalosporins. Therefore, treatment often involves the use of third-generation cephalosporins, aminoglycosides, or quinolones.

Epidemiology

Citrobacter koseri is found worldwide and can be isolated from a variety of environmental sources, including soil, water, and food. It is also a common inhabitant of the human gut, particularly in infants. However, it is not a common cause of disease, with infections typically occurring in immunocompromised individuals.

See also

• Citrobacter
• Enterobacteriaceae
• Opportunistic infection