Chromobacterium violaceum is a Gram-negative

Gram-negative

Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

, facultative anaerobic, non-sporing coccobacillus

Coccobacillus

A coccobacillus is a type of rod-shaped bacteria. The word coccobacillus reflects an intermediate shape between coccus and bacillus . Coccobacilli rods are so short and wide that they resemble cocci. Haemophilus influenzae and Chlamydia trachomatis are coccobacilli...

. It is part of the normal flora of water and soil of tropical and sub-tropical regions of the world. It produces a natural antibiotic called violacein, which may be useful for the treatment of colon and other cancers. It grows readily on nutrient agar, producing distinctive smooth low convex colonies with a dark violet metallic sheen (due to violacein production). Its full genome was published in 2003. It has the ability to break down tarballs

Tarball (oil)

A tarball is a blob of petroleum which has been weathered after floating in the ocean. Tarballs are an aquatic pollutant in most environments, although they can occur naturally and as such are not always associated with oil spills....

.

Biochemistry

C. violaceum ferments glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

, trehalose

Trehalose

Trehalose, also known as mycose or tremalose, is a natural alpha-linked disaccharide formed by an α,α-1,1-glucoside bond between two α-glucose units. In 1832, H.A.L. Wiggers discovered trehalose in an ergot of rye, and in 1859 Marcellin Berthelot isolated it from trehala manna, a substance made...

, N-acetylglucosamine and gluconate but not L-arabinose

Arabinose

Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde functional group.For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde.For sugars, the D/L...

, D-galactose

Galactose

Galactose , sometimes abbreviated Gal, is a type of sugar that is less sweet than glucose. It is a C-4 epimer of glucose....

 or D-maltose

Maltose

Maltose , or malt sugar, is a disaccharide formed from two units of glucose joined with an αbond, formed from a condensation reaction. The isomer "isomaltose" has two glucose molecules linked through an α bond. Maltose is the second member of an important biochemical series of glucose chains....

. In many cases can show high level resistance to a range of antibiotics (Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 11, No. 9, September 2005).

Medical significance

C. violaceum rarely infects humans, but when it does it causes skin lesions, sepsis

Sepsis

Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

, and liver abscess

Liver abscess

A liver abscess is a pus-filled mass inside the liver. Common causes are abdominal infections such as appendicitis or diverticulitis due to haematogenous spread through the portal vein...

es that may be fatal. Care must be taken because Burkholderia pseudomallei

Burkholderia pseudomallei

Burkholderia pseudomallei is a Gram-negative, bipolar, aerobic, motile rod-shaped bacterium. It infects humans and animals and causes the disease melioidosis. It is also capable of infecting plants....

is commonly misidentified as C. violaceum by many common identification methods. The two are readily distinguished because B. pseudomallei produces large wrinkled colonies, whereas C. violaceum produces a distinctive violet pigment.

C. violaceum produces a number of natural antibiotics:

• Aztreonam
  Aztreonam
  Aztreonam is a synthetic monocyclic beta-lactam antibiotic , with the nucleus based on a simpler monobactam isolated from Chromobacterium violaceum. It was approved by the U.S. Food and Drug Administration in 1986...
  
   is a monobactam antibiotic that is active against gram-negative
  Gram-negative
  Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
  
   aerobic bacteria including Pseudomonas aeruginosa
  Pseudomonas aeruginosa
  Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many...
  
  . It is marketed as Azactam.
• Violacein is active against amoebae and trypanosomes;
• Aerocyanidine is active against Gram-positive
  Gram-positive
  Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
  
   organisms;
• Aerocavin is active against Gram-positive and Gram-negative
  Gram-negative
  Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
  
   organisms.

It has been described as a cause of infection in gibbons.

Treatment

Infection caused by C. violaceum is rare, therefore there are no clinical trials evaluating different treatments. Antibiotics that have been used to successfully treat C. violaceum include pefloxacin

Pefloxacin

Pefloxacin is a synthetic chemotherapeutic agent used to treat severe and life threatening bacterial infections. Pefloxacin is commonly referred to as a fluoroquinolone drug and is a member of the fluoroquinolone class of antibacterials. It is an analog of norfloxacin. It is a synthetic...

, ciprofloxacin

Ciprofloxacin

Ciprofloxacin is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class.It is a second-generation fluoroquinolone antibacterial. It kills bacteria by interfering with the enzymes that cause DNA to rewind after being copied, which stops synthesis of DNA and of...

, amikacin

Amikacin

Amikacin is an aminoglycoside antibiotic used to treat different types of bacterial infections. Amikacin works by binding to the bacterial 30S ribosomal subunit, causing misreading of mRNA and leaving the bacterium unable to synthesize proteins vital to its growth.-Administration:Amikacin may be...

, and co-trimoxazole

Co-trimoxazole

Trimethoprim/sulfamethoxazole or co-trimoxazole is a sulfonamide antibiotic combination of trimethoprim and sulfamethoxazole, in the ratio of 1 to 5, used in the treatment of a variety of bacterial infections.The name co-trimoxazole is the British Approved Name, and has been marketed worldwide...

. Other antibiotics that appear to be effective in vitro include chloramphenicol

Chloramphenicol

Chloramphenicol is a bacteriostatic antimicrobial that became available in 1949. It is considered a prototypical broad-spectrum antibiotic, alongside the tetracyclines, and as it is both cheap and easy to manufacture it is frequently found as a drug of choice in the third world.Chloramphenicol is...

 and tetracycline. For theoretical reasons, infection would not be expected to respond to penicillins, cephalosporins, or aztreonam

Aztreonam

Aztreonam is a synthetic monocyclic beta-lactam antibiotic , with the nucleus based on a simpler monobactam isolated from Chromobacterium violaceum. It was approved by the U.S. Food and Drug Administration in 1986...

, although carbapenem

Carbapenem

Carbapenems are a class of β-lactam antibiotics with a broad spectrum of antibacterial activity. They have a structure that renders them highly resistant to most β-lactamases...

s like meropenem

Meropenem

Meropenem is an ultra-broad spectrum injectable antibiotic used to treat a wide variety of infections, including meningitis and pneumonia. It is a beta-lactam and belongs to the subgroup of carbapenem, similar to imipenem and ertapenem. Meropenem was originally developed by Sumitomo Pharmaceuticals...

 or imipenem

Imipenem

Imipenem is an intravenous β-lactam antibiotic developed in 1980. It has an extremely broad spectrum of activity.Imipenem belongs to the subgroup of carbapenems. It is derived from a compound called thienamycin, which is produced by the bacterium Streptomyces cattleya...

 may possibly work.

Genome

The complete genome was sequenced and the results were published in 2003. C. violaceum type strain ATCC 12472 was found to have 4,751,080 base pairs with a G + C content of 64.83% and 4,431 ORF

Open reading frame

In molecular genetics, an open reading frame is a DNA sequence that does not contain a stop codon in a given reading frame.Normally, inserts which interrupt the reading frame of a subsequent region after the start codon cause frameshift mutation of the sequence and dislocate the sequences for stop...

s.