|Blood agar plate culture of C. violaceum. Image from the CDC.|
Chromobacterium violaceum is a Gram-negative, facultative anaerobic, non-sporing coccobacillus. It is motile with the help of a single flagellum which is located at the pole of the coccobacillus. Usually, there are one or two more lateral flagella as well.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). Some strains of the bacteria which do not produce this pigment have also been reported. It has the ability to break down tarballs.
An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present.
A coccobacillus is a type of bacterium with a shape intermediate between cocci and bacilli. Coccobacilli, then, are very short rods which may be mistaken for cocci.
A flagellum is a lash-like appendage that protrudes from the cell body of certain bacteria and eukaryotic cells termed as flagellates. A flagellate can have one or several flagella. The primary function of a flagellum is that of locomotion, but it also often functions as a sensory organelle, being sensitive to chemicals and temperatures outside the cell. The similar structure in the archaea functions in the same way but is structurally different and has been termed the archaellum.
C. violaceum ferments glucose, trehalose, N-acetylglucosamine and gluconate but not L-arabinose, D-galactose, or D-maltose. It is positive for catalase and oxidase reactions.Bacterial isolates in many cases can show high level resistance to a range of antibiotics.
Glucose (also called dextrose) is a simple sugar with the molecular formula C6H12O6. Glucose is the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight. There it is used to make cellulose in cell walls, which is the most abundant carbohydrate. In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is partially stored as a polymer, in plants mainly as starch and amylopectin and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form of glucose is D-glucose, while L-glucose is produced synthetically in comparably small amounts and is of lesser importance.
Trehalose is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it as a source of energy, and to survive freezing and lack of water.
Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group.
C. violaceum rarely infects humans, but when it does it causes skin lesions, sepsis, and liver abscesses that may be fatal.The first reported case of Chromobacterium violaceum infection in humans in literature is from Malaysia in 1927. Only 150 cases have been reported in literature since then. To date, cases have been reported from Argentina, Australia, Brazil, Cuba, India, Japan, Nigeria, Singapore, Sri Lanka, Taiwan, United States and Vietnam. The commonest mode of entry of the bacteria into the body is through the injured skin coming in contact with soil or water containing the bacteria. The disease usually starts as a limited infection of the skin at the point of entry of the bacteria, which progresses to necrotizing metastatic lesions, then multiple abscesses of the liver, lung, spleen, skin, lymph nodes or brain, leading to severe septicaemia, culminating in multiorgan failure which may be fatal. Other reported pathologies include chronic granulomatosis, osteomyelitis, cellulitis, diarrhoea, septic spondylitis, conjunctivitis, periorbital and ocular infection. Care must be taken because Burkholderia pseudomallei 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.
Sepsis is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Common signs and symptoms include fever, increased heart rate, increased breathing rate, and confusion. There may also be symptoms related to a specific infection, such as a cough with pneumonia, or painful urination with a kidney infection. In the very young, old, and people with a weakened immune system, there may be no symptoms of a specific infection and the body temperature may be low or normal, rather than high. Severe sepsis is sepsis causing poor organ function or insufficient blood flow. Insufficient blood flow may be evident by low blood pressure, high blood lactate, or low urine output. Septic shock is low blood pressure due to sepsis that does not improve after fluid replacement.
A liver abscess is a pus-filled mass inside the liver. Common causes are abdominal conditions such as appendicitis or diverticulitis due to haematogenous spread through the portal vein.
Burkholderia pseudomallei is a Gram-negative, bipolar, aerobic, motile rod-shaped bacterium. It is a soil-dwelling bacterium endemic in tropical and subtropical regions worldwide, particularly in Thailand and northern Australia. It infects humans and animals and causes the disease melioidosis. It is also capable of infecting plants.
C. violaceum produces a number of natural antibiotics:
Aztreonam, sold under the brand name Azactam among others, is an antibiotic used primarily to treat infections caused by gram-negative bacteria such as Pseudomonas aeruginosa. This may include bone infections, endometritis, intra abdominal infections, pneumonia, urinary tract infections, and sepsis. It is given by injection into a vein or muscle or breathed in as a mist.
Pseudomonas aeruginosa is a common encapsulated, Gram-negative, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, P. aeruginosa is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes.
It has been described as a cause of infection in gibbons.
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,ciprofloxacin, amikacin, and co-trimoxazole. Other antibiotics that appear to be effective in vitro include chloramphenicol and tetracycline. For theoretical reasons, infection would not be expected to respond to penicillins, cephalosporins, or aztreonam, although carbapenems like meropenem or imipenem may possibly work. Though the bacteria is reported to be resistant to first generation cephalosporins, susceptibility to the newer cephalosporins is variable.
Pefloxacin is a quinolone antibiotic used to treat bacterial infections. Pefloxacin has not been approved for use in the United States.
Ciprofloxacin is an antibiotic used to treat a number of bacterial infections. This includes bone and joint infections, intra abdominal infections, certain type of infectious diarrhea, respiratory tract infections, skin infections, typhoid fever, and urinary tract infections, among others. For some infections it is used in addition to other antibiotics. It can be taken by mouth, in eye drops, or intravenously.
Amikacin is an antibiotic used for a number of bacterial infections. This includes joint infections, intra-abdominal infections, meningitis, pneumonia, sepsis, and urinary tract infections. It is also used for the treatment of multidrug-resistant tuberculosis. It is used either by injection into a vein or muscle.
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 ORFs.
Beta-lactamases are enzymes produced by bacteria that provide multi-resistance to β-lactam antibiotics such as penicillins, cephalosporins, cephamycins, and carbapenems (ertapenem), although carbapenems are relatively resistant to beta-lactamase. Beta-lactamase provides antibiotic resistance by breaking the antibiotics' structure. These antibiotics all have a common element in their molecular structure: a four-atom ring known as a β-lactam. Through hydrolysis, the lactamase enzyme breaks the β-lactam ring open, deactivating the molecule's antibacterial properties.
Typhoid fever, also known simply as typhoid, is a bacterial infection due to Salmonella typhi that causes symptoms. Symptoms may vary from mild to severe and usually begin six to thirty days after exposure. Often there is a gradual onset of a high fever over several days; weakness, abdominal pain, constipation, headaches, and mild vomiting also commonly occur. Some people develop a skin rash with rose colored spots. In severe cases there may be confusion. Without treatment, symptoms may last weeks or months. Diarrhea is uncommon. Other people may carry the bacterium without being affected; however, they are still able to spread the disease to others. Typhoid fever is a type of enteric fever, along with paratyphoid fever.
Melioidosis is an infectious disease caused by a Gram-negative bacterium, Burkholderia pseudomallei, found in soil and water. It is of public health importance in endemic areas, particularly in northeast Thailand, Vietnam, and northern Australia. It exists in acute and chronic forms. Signs and symptoms may include pain in chest, bones, or joints; cough; skin infections, lung nodules, and pneumonia.
Acinetobacter is a genus of Gram-negative bacteria belonging to the wider class of Gammaproteobacteria. Acinetobacter species are oxidase-negative, exhibit twitching motility, and occur in pairs under magnification.
The cephalosporins are a class of β-lactam antibiotics originally derived from the fungus Acremonium, which was previously known as "Cephalosporium".
Tonsillitis is inflammation of the tonsils, typically of rapid onset. It is a type of pharyngitis. Symptoms may include sore throat, fever, enlargement of the tonsils, trouble swallowing, and large lymph nodes around the neck. Complications include peritonsillar abscess.
Streptococcus suis is a peanut-shaped, Gram-positive bacterium, and an important pathogen of pigs. Endemic in nearly all countries with an extensive pig industry, S. suis is also a zoonotic disease, capable of transmission to humans from pigs.
Lung abscess is a type of liquefactive necrosis of the lung tissue and formation of cavities containing necrotic debris or fluid caused by microbial infection.
Carbapenems are a class of highly effective antibiotic agents commonly used for the treatment of severe or high-risk bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins, carbapenems are members of the beta lactam class of antibiotics, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams.
Bartonellosis is an infectious disease produced by bacteria of the genus Bartonella. Bartonella species cause diseases such as Carrión´s disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders.
Pyomyositis, also known as tropical pyomyositis or myositis tropicans, is a bacterial infection of the skeletal muscles which results in a pus-filled abscess. Pyomyositis is most common in tropical areas but can also occur in temperate zones.
Burkholderia mallei is a Gram-negative, bipolar, aerobic bacterium, a human and animal pathogen of genus Burkholderia causing glanders; the Latin name of this disease (malleus) gave its name to the species causing it. It is closely related to B. pseudomallei, and by multilocus sequence typing it is a subspecies of B. pseudomallei.B. mallei evolved from B. pseudomallei by selective reduction and deletions from the B. pseudomallei genome. Unlike B. pseudomallei and other genus members, B. mallei is nonmotile; its shape is coccobacillary measuring some 1.5–3.0 μm in length and 0.5–1.0 μm in diameter with rounded ends.
Bacteroides fragilis is an obligately anaerobic, Gram-negative, rod-shaped bacterium. It is part of the normal microbiota of the human colon and is generally commensal, but can cause infection if displaced into the bloodstream or surrounding tissue following surgery, disease, or trauma.
Cefotiam is a parenteral second-generation cephalosporin antibiotic. It has broad-spectrum activity against Gram-positive and Gram-negative bacteria. As a beta-lactam, its bactericidal activity results from the inhibition of cell wall synthesis via affinity for penicillin-binding proteins.
Arcanobacterium haemolyticum, formerly known as Corynebacterium hæmolyticum, is a species of bacteria classified as a gram-positive bacillus. It is catalase-negative, aerobic, beta-hemolytic, and not motile. It has been known to cause head and neck infections, pharyngitis, and sinusitis.
Burkholderia thailandensis is a nonfermenting motile, Gram-negative bacillus that occurs naturally in soil. It is closely related to Burkholderia pseudomallei, but unlike B. pseudomallei, it only rarely causes disease in humans or animals. The lethal inoculum is approximately 1000 times higher than for B. pseudomallei. It is usually distinguished from B. pseudomallei by its ability to assimilate arabinose. Other differences between these species include lipopolysaccharide composition, colony morphology, and differences in metabolism.
Bartonella bacilliformis is a proteobacterium, Gram negative aerobic, pleomorphic, flagellated, motile, coccobacillary, 2–3 μm long, 0.2–0.5 μm wide, and a facultative intracellular bacterium.
Ashdown's medium is a selective culture medium for the isolation and characterisation of Burkholderia pseudomallei.
Gram-negative bacterial infection refers to a disease caused by gram-negative bacteria. One example is E. coli.