Citrobacter freundii

Citrobacter freundii

Citrobacter freundii

Citrobacter Freundii

Citrobacter freundii and Citrobacter koseri can cause urinary tract infections, and are found in wound, respiratory, meningitis, and sepsis. They can cause healthcare-associated infections, especially in pediatric and immunocompromised patients [41] . Third-generation cephalosporins are the choice of treatment for meningitis. Citrobacter spp. are intrinsically resistant to ampicillin. C. freundii is intrinsically resistant to ampicillin-sulbactam and cephalosporins. They can resemble Salmonella on agar media due to production of H2S by both genera. They are also citrate positive, however, only Citrobacter is positive for ONPG.

Alimentary System and the Peritoneum, Omentum, Mesentery, and Peritoneal Cavity1

Citrobacter freundii Enteritis.

Bacteremia and septicemia associated with Citrobacter freundii have been reported to cause mucohemorrhagic diarrhea in dogs with hemorrhagic lesions in the small intestine and colon. It is believed to be a condition of puppies and immunocompromised dogs. Being bacteremic and/or septicemic, many organs and tissues are affected besides the gut. The condition is more common in human beings as a nosocomial infection with a high mortality rate. In human beings the route of infection is through the urinary tract, gallbladder, GI tract, or cutaneous wounds. Citrobacter infections should be considered potentially zoonotic.

Infections caused by Citrobacter freundii bacteria is treated using antibiotics. The usual antibiotics of choice are cephalosporins, fluoroquinolones, and carbapenems. The doctor will determine the right antibiotic of choice. Basically, the health care professional will take into consideration the vulnerability of the bacteria to antibiotics as well as the site of the infection. (9, 10)

Citrobacter freundii treatment using antibiotics is modified because some strain of citrobacter freundii developed resistance to a certain number of antibiotics. To hasten the healing process, supportive treatment is given to the patient along with tested and proven effective antibiotic of choice.

During the course of treatment, it is important to be open to your health care provider. If you have any allergy to antibiotics, you should inform your physician right away to prevent adverse reactions.

Antibiotics offer a quick relief from the symptoms that are currently bothering you. Even so, you should continue taking the antibiotics until your doctor tells you to stop. This is to prevent recurring infection. If you are experiencing any side effects, you should inform your doctor right away.

This is to avoid another infection and prevent worsening of your condition. If you are suffering from severe Citrobacter freundii infection, the antibiotic is given to you via intravenous route every eight hours until you no longer have fever. This typically lasts for three days. After that, you can take oral antibiotics.

On the other hand, if you are suffering from mild Citrobacter freundii infection, you will be required to take oral antibiotics for two weeks or until the infection subsides. (4, 5, 7)


Citrobacter freundii infection has a moderate prognosis. It is important to treat the infection right away. Neglected cases of Citrobacter freundii infection could lead to severely poor prognosis. If the infection is left untreated, the patient could die.

If you are suffering from urinary tract infection secondary to Citrobacter freundii infection, the prognosis is good. However, the prognosis is moderate to poor in patients with peritonitis (inflammation of the lining of the abdomen). In the case of people with meningitis caused by Citrobacter freundii infection, the prognosis is poor. In fact, the death rate ranges from 25% to 50%.

What causes Citrobacter Freundii? – Related Questions

How did Citrobacter get?

Citrobacter are found in a variety of environmental sources, including soil and water, and in the human intestines. They are rarely the primary source of illness, though some strains can cause infections of the urinary tract, sepsis, and infant meningitis.

Where is Citrobacter Freundii normally found?

Citrobacter freundii is isolated from human and animal feces, as well as from extraintestinal specimens. It is also commonly found in soil water and food.

How can you prevent Citrobacter?

Since several nosocomial outbreaks of Citrobacter infections have been reported and the sources of the organisms have been found to be the gastrointestinal tracts or hands of hospital staff members, infection control measures to prevent person-to-person transmission, such as hand washing, are the most important

Is Citrobacter Freundii antibiotic resistance?

freundii isolates were considered to be multidrug resistant based on having resistance to three or more antibiotics of different classes. This is the first reported study of antibiotic resistance profiles of C. freundii collected from environmental waters in the United States.

What antibiotics treat Citrobacter?

Various types of antibiotics, including amino- glycosides carbapenems, cephalosporins, chloramphenicol and quinolones, are used for the treatment of C. koseri infections. Treatment options can be monotherapy, with agents potentially active against Citrobacter spp. or combination therapy [8].

Does Citrobacter Freundii reduce sulfur?

Citrobacter is facultative anaerobic bacteria, and they are associated with Enterobacteriaceae family. Sulfide production is wide spread among Enterobacteriaceae. They mentioned that this strain of Citrobacter is able to reduce sulfate to sulfide. The isolation of bacteria belongs to C.

What causes Citrobacter Freundii UTI?

A frail immune system makes the body more vulnerable and predisposed to C. freundii, thus triggering UTI or intestinal infection or meningitis. Hospitalized patients, especially those who have been hospitalized for a prolonged period of time, are more vulnerable to C. freundii infections.

Is Citrobacter Freundii normal flora?

C. freundii is a common component of the gut microbiome of healthy humans. While most strains are beneficial, there are significant phenotypic variations among strains, even those that share >99% of their genome. Some rare strains of C.

What is Citrobacter Freundii sensitive to?

Abstract. An examination of 99 field and reference strains of Citrobacter freundii showed 79% of them to be resistant to cephaloridine and sensitive to carbenicillin, while 96% of 45 field and reference strains of Citrobacter koseri examined were sensitive to cephaloridine and resistant to carbenicillin.

Can Citrobacter cause diarrhea?

Citrobacter freundii is classically considered as an indigenous intestinal species that is sporadically associated with diarrhea.

Where does Citrobacter Koseri come from?

Citrobacter koseri (formerly Citrobacterdiversus) is a motile gram-negative bacillus usually arising from urinary and gastrointestinal tracts.

Is Citrobacter and anaerobic?

Citrobacter freundii (C. freundii) is a motile, facultative anaerobe, non-sporing gram-negative bacilli colonize in the gastrointestinal tract of humans and other animals. It is also found in water, soil, and food.

Is Citrobacter a Freundii bacilli?

The Citrobacter species, including Citrobacter freundii, are aerobic gram-negative bacilli.

Does ciprofloxacin treat Citrobacter Freundii?

Ciprofloxacin is the antibiotic treatment option for systemic infection or meningitis caused by Citrobacter kosery. Ciprofloxacin has been used to treat neonatal pneumonia, meningitis, and septicemia and was effective in all cases.

Is K pneumoniae gram negative?

General Information. Klebsiella [kleb−see−ell−uh] is a type of Gram-negative bacteria that can cause different types of healthcare-associated infections, including pneumonia, bloodstream infections, wound or surgical site infections, and meningitis.

Does Citrobacter cause UTI?

UTIs caused by Citrobacter species have been described in 5 to 12% of bacterial urine isolates in adults. [3,4,5] We report here the emergence of Citrobacter as an increasingly common urinary pathogen in hospitalized patients.

What is the treatment for Citrobacter Koseri?

koseri mandates antimicrobial therapy based on the sensitivity of the pathogen microorganism. Various types of antibiotics, including aminoglycosides carbapenems, cephalosporins, chloramphenicol and quinolones, are used for the treatment of C. koseri infections.

Is Citrobacter a lactose fermenter?

Citrobacter spp. are late lactose fermenters and they grow on MacConkey Agar. Its cultivation is 24 hours, aerobic atmosphere is at 37°C and approximately 20% of clinical isolates are lactose negative.

What does Citrobacter Diversus cause?

Citrobacter koseri, formerly known as Citrobacter diversus, is a gram-negative bacillus that causes mostly meningitis and brain abscess in neonates and infants.

Is Citrobacter Mr positive?

They ferment glucose and other carbohydrates with the production of acid and gas. They are oxidase negative, catalase and methyl red positive, Voges-Proskauer negative, and do not decarboxylate lysine. Taxonomically, the genus Citrobacter is most closely related to Salmonella and Escherichia.

Can Citrobacter Freundii cause pneumonia?

Citrobacter koseri, formerly known as Citrobacter diversus, is a facultative anaerobe and motile, gram-negative bacillus of the family Enterobacteriaceae. Citrobacter spp. have been implicated in a wide array of disease processes, including urinary tract infections, pneumonia, and bacteremia.

Citrobacter freundii characteristics

Citrobacter freundii bacteria have a long rod shape with a typical length of 1–5 μm. A majority of C. freundii cells generally have a few flagella used for locomotion, but some do not and are therefore non-motile.

C. freundii contains two membranes – inner and outer – since it’s a gram-negative bacteria. It is capable of growing on glycerol as its only carbon and energy source, by fermenting carbon in the absence of oxygen.

Citrobacter freundii

Citrobacter freundii (Photo Credit : public domain/ Wikimedia Commons)

These bacteria are often found in soil, water, food and the intestines of animals and humans. It’s interesting to note that these bacteria were previously identified as contaminants or colonizers with low virulence.

Citrobacter freundii often cause a number of opportunistic infections, also known as OIs, which are infections that are more severe and more frequently observed in individuals with weakened immune systems. This means that the bacteria does not generally cause ailments in healthy individuals. As mentioned above, it causes opportunistic infections, meaning that it looks for an ‘opportunity’ to infect a person, which they find in people with previously weakened immunity.

Citrobacter freundii

Citrobacter freundii

General information

the following information is not yet verified
Family: Enterobacteriaceae

C.freundii complex
C. freundii, C. braakii, C. gilleni, C. murlinae, C. sedlakii, C. werkmanii, C. youngae
C. koseri (C. diversus)
C. amalonaticus
C. farmeri

Natural habitats
Isolated from soil, water, food, feces, urine of humans and animals.
They are commensals of the intestine.

The natural habitat of some Citrobacter species is unknown.

Clinical significance
Citrobacter species cause a wide variety of nosocomial infections, including infections of the respiratory- and urinary tract, blood, wounds, bone, meninges and other normally sterile tissues.

Especially patients which are hospitalized for more than 72 hours and immunocompromised patients are at risk for an infection caused by Citrobacter.

In many cases the infection arises from the gastrointestinal or genitourinary tract.

Gram stain

the following information is not yet verified
Gram negative straight rods,

found singly or in pairs.

Usually not encapsulated

Culture characteristics

  • the following information is not yet verified

Facultative anaerobic

Colonies are 2-4 mm, smooth, low convex, moist, translucent or opaque, and gray with a shiny surface.
Mucoid or rough forms may occur.

McConkey growth, lactose fermenter

BBAØ growth

Mucoid or rough strains may occur occasionally.

Colonies which slowly ferment lactose can resemble Salmonella colonies on enteric media.


  • Gram-negative
  • bacilli
  • medium-bacilli
  • growth both-aerobic-and-anaerobic
  • catalase-positive
  • oxidase-negative
  • indole-negative
  • urease-negative
  • motility
  • vancomycin-resistant
  • colistine-susceptible


James Versalovic et al.(2011) Manual of Clinical Microbiology 10th Edition

Другие статьи:

Похожие статьи:

Популярное на сайте:

Leave a Reply