This article may be confusing or unclear to readers. In particular, it confuses the complex (which is described by text) with the species (which is described by the infobox).(October 2023) |
Burkholderia cepacia complex | |
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Scientific classification | |
Domain: | |
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Species complex: | B. cepacia complex |
Burkholderia cepacia complex (BCC) is a species complex consisting of Burkholderia cepacia and at least 20 different biochemically similar species of Gram-negative bacteria. They are catalase-producing and lactose-nonfermenting. [1] Members of BCC are opportunistic human pathogens that most often cause pneumonia in immunocompromised individuals with underlying lung disease (such as cystic fibrosis or chronic granulomatous disease). [2] Patients with sickle-cell haemoglobinopathies are also at risk. The species complex also attacks young onion and tobacco plants, and displays a remarkable ability to digest oil.
Burkholderia cepacia | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Pseudomonadota |
Class: | Betaproteobacteria |
Order: | Burkholderiales |
Family: | Burkholderiaceae |
Genus: | Burkholderia |
Species: | B. cepacia |
Binomial name | |
Burkholderia cepacia (Palleroni and Holmes 1981) Yabuuchi et al. 1993 | |
Type strain | |
* ATCC 25416 [3] [lower-alpha 1] | |
Synonyms | |
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The group includes B. cepacia, B. multivorans , B. cenocepacia , B. vietnamiensis , B. stabilis , B. ambifaria , B. dolosa , B. anthina , B. pyrrocinia and B. ubonensis , among other species. [1]
BCC is resistant to a number of common disinfectants, specifically povidone-iodine, triclosan, chlorohexidine, cetylpyridinium chloride, and quaternary ammoniums such as benzalkonium chloride. Concentrations used as preservatives in water-based pharmaceutical products are often not enough to kill BCC or even stop it from proliferating. [5] Even higher-concentration versions of these biocides intended for disinfection, such as povidone-iodine solution for wound dressing and benzonium chloride wipes, may harbor live BCC if not sterilized using another method. [6] [7]
Burkholderia cepacia is also found in marine environments (marine sponges) and some strains of Burkholderia cepacia can tolerate high salinity. [8] S.I. Paul et al. (2021) [8] isolated and biochemically characterized salt tolerant strains of Burkholderia cepacia from marine sponges of Saint Martin's Island of the Bay of Bengal, Bangladesh. [8]
BCC organisms are typically found in water and soil and can survive for prolonged periods in moist environments. They show a relatively poor virulence. Virulence factors include adherence to plastic surfaces (including those of medical devices) and production of several enzymes such as elastase and gelatinase. Also relevant might be their ability to survive attacks from neutrophils. [9]
Person-to-person spread has been documented; as a result, many hospitals, clinics, and camps have enacted strict isolation precautions for those infected with BCC. Infected individuals are often treated in a separate area from uninfected patients to limit spread, since BCC infection can lead to a rapid decline in lung function and result in death. [10]
Diagnosis of BCC involves culturing the bacteria from clinical specimens, such as sputum or blood. BCC organisms are naturally resistant to many common antibiotics, including aminoglycosides and polymyxin B. [11] and this fact is exploited in the identification of the organism. The organism is usually cultured in Burkholderia cepacia agar (BC agar), which contains crystal violet and bile salts to inhibit the growth of Gram-positive cocci, and ticarcillin and polymyxin B to inhibit the growth of other Gram-negative bacilli. It also contains phenol red pH indicator which turns pink when it reacts with alkaline byproducts generated by the bacteria when it grows.[ citation needed ]
Alternatively, oxidation-fermentation polymyxin-bacitracin-lactose (OFPBL) agar can be used. OFPBL contains polymyxin (which kills most Gram-negative bacteria, including Pseudomonas aeruginosa ) and bacitracin (which kills most Gram-positive bacteria and Neisseria species). [12] [13] It also contains lactose, and organisms such as BCC that do not ferment lactose turn the pH indicator yellow, which helps to distinguish it from other organisms that may grow on OFPBL agar, such as Candida species, Pseudomonas fluorescens , and Stenotrophomonas species.[ citation needed ]
Treatment typically includes multiple antibiotics and may include ceftazidime, minocycline, piperacillin, meropenem, chloramphenicol, and trimethoprim/sulfamethoxazole(co-trimoxazole). [11] [14] Although co-trimoxazole has been generally considered the drug of choice for B. cepacia infections, ceftazidime, minocycline, piperacillin, and meropenem are considered to be viable alternative options in cases where co-trimoxazole cannot be administered because of hypersensitivity reactions, intolerance, or resistance. [15] Newer beta-lactam / beta-lactamase combinations like ceftazidime-avibactam or ceftolozane-tazobactam can also be effective. [14] BCC intrinsically resistant to colistin and usually resistant to aminoglycosides. [16]
In people with cystic fibrosis, evidence is insufficient about the effectiveness of long-term antibiotic treatment with continuous inhaled aztreonam lysine (AZLI) in terms of lung function or chest infections. [17]
B. cepacia was discovered by Walter Burkholder in 1949 as the cause of onion skin rot, and first described as a human pathogen in the 1950s. [18] It was first isolated in patients with cystic fibrosis (CF) in 1977, when it was known as Pseudomonas cepacia. [19] In the 1980s, outbreaks of B. cepacia in individuals with CF were associated with a 35% death rate. B. cepacia has a large genome, containing twice the amount of genetic material as E. coli .[ citation needed ]
Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that impairs the normal clearance of mucus from the lungs, which facilitates the colonization and infection of the lungs by bacteria, notably Staphylococcus aureus. CF is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. The hallmark feature of CF is the accumulation of thick mucus in different organs. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. Other signs and symptoms may include sinus infections, poor growth, fatty stool, clubbing of the fingers and toes, and infertility in most males. Different people may have different degrees of symptoms.
Melioidosis is an infectious disease caused by a gram-negative bacterium called Burkholderia pseudomallei. Most people exposed to B. pseudomallei experience no symptoms; however, those who do experience symptoms have signs and symptoms that range from mild, such as fever and skin changes, to severe with pneumonia, abscesses, and septic shock that could cause death. Approximately 10% of people with melioidosis develop symptoms that last longer than two months, termed "chronic melioidosis".
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 intravenous or intramuscular injection or by inhalation.
Colistin, also known as polymyxin E, is an antibiotic medication used as a last-resort treatment for multidrug-resistant Gram-negative infections including pneumonia. These may involve bacteria such as Pseudomonas aeruginosa, Klebsiella pneumoniae, or Acinetobacter. It comes in two forms: colistimethate sodium can be injected into a vein, injected into a muscle, or inhaled, and colistin sulfate is mainly applied to the skin or taken by mouth. Colistimethate sodium is a prodrug; it is produced by the reaction of colistin with formaldehyde and sodium bisulfite, which leads to the addition of a sulfomethyl group to the primary amines of colistin. Colistimethate sodium is less toxic than colistin when administered parenterally. In aqueous solutions, it undergoes hydrolysis to form a complex mixture of partially sulfomethylated derivatives, as well as colistin. Resistance to colistin began to appear as of 2015.
Burkholderia is a genus of Pseudomonadota whose pathogenic members include the Burkholderia cepacia complex, which attacks humans and Burkholderia mallei, responsible for glanders, a disease that occurs mostly in horses and related animals; Burkholderia pseudomallei, causative agent of melioidosis; and Burkholderia cepacia, an important pathogen of pulmonary infections in people with cystic fibrosis (CF). Burkholderia species is also found in marine environments. S.I. Paul et al. (2021) isolated and characterized Burkholderia cepacia from marine sponges of the Saint Martin's Island of the Bay of Bengal, Bangladesh.
Ceftazidime, sold under the brand name Fortaz among others, is a third-generation cephalosporin antibiotic useful for the treatment of a number of bacterial infections. Specifically it is used for joint infections, meningitis, pneumonia, sepsis, urinary tract infections, malignant otitis externa, Pseudomonas aeruginosa infection, and vibrio infection. It is given by injection into a vein, muscle, or eye.
Pseudomonas aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, 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. P. aeruginosa is able to selectively inhibit various antibiotics from penetrating its outer membrane - and has high resistance to several antibiotics. According to the World Health Organization P. aeruginosa poses one of the greatest threats to humans in terms of antibiotic resistance.
Stenotrophomonas maltophilia is an aerobic, nonfermentative, Gram-negative bacterium. It is an uncommon bacterium and human infection is difficult to treat. Initially classified as Bacterium bookeri, then renamed Pseudomonas maltophilia, S. maltophilia was also grouped in the genus Xanthomonas before eventually becoming the type species of the genus Stenotrophomonas in 1993.
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 was reported in 2008 that there had been an expansion of the affected regions due to significant natural disasters, and it could be found in Southern China, Hong Kong, and countries in the Americas. B. pseudomallei, amongst other pathogens, has been found in monkeys imported into the United States from Asia for laboratory use, posing a risk that the pathogen could be introduced into the country.
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.
Burkholderia cenocepacia is a Gram-negative, rod-shaped bacterium that is commonly found in soil and water environments and may also be associated with plants and animals, particularly as a human pathogen. It is one of over 20 species in the Burkholderia cepacia complex (Bcc) and is notable due to its virulence factors and inherent antibiotic resistance that render it a prominent opportunistic pathogen responsible for life-threatening, nosocomial infections in immunocompromised patients, such as those with cystic fibrosis or chronic granulomatous disease. The quorum sensing systems CepIR and CciIR regulate the formation of biofilms and the expression of virulence factors such as siderophores and proteases. Burkholderia cenocepacia may also cause disease in plants, such as in onions and bananas. Additionally, some strains serve as plant growth-promoting rhizobacteria.
Burkholderia gladioli is a species of aerobic gram-negative rod-shaped bacteria that causes disease in both humans and plants. It can also live in symbiosis with plants and fungi and is found in soil, water, the rhizosphere, and in the microbiome of many animals. It was formerly known as Pseudomonas marginata.
Etest is a way of determining antimicrobial sensitivity by placing a strip impregnated with antimicrobials onto an agar plate. A strain of bacterium or fungus will not grow near a concentration of antibiotic or antifungal if it is sensitive. For some microbial and antimicrobial combinations, the results can be used to determine a minimum inhibitory concentration (MIC). Etest is a proprietary system manufactured by bioMérieux. It is a laboratory test used in healthcare settings to help guide physicians by indicating what concentration of antimicrobial could successfully be used to treat patients' infections.
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract.
Polypeptide antibiotics are a chemically diverse class of anti-infective and antitumor antibiotics containing non-protein polypeptide chains. Examples of this class include actinomycin, bacitracin, colistin, and polymyxin B. Actinomycin-D has found use in cancer chemotherapy. Most other polypeptide antibiotics are too toxic for systemic administration, but can safely be administered topically to the skin as an antiseptic for shallow cuts and abrasions.
Pseudomonas infection refers to a disease caused by one of the species of the genus Pseudomonas.
Walter Hagemeyer Burkholder was an American plant pathologist who helped establish the role of bacteria as plant pathogens. He was awarded a Ph.D. by Cornell University in 1917 and subsequently appointed as professor of plant pathology.
Pandoraea pulmonicola is a Gram-negative, non-spore-forming, motile bacterium with a single polar flagellum, of the genus Pandoraea. P. pulmonicola has been isolated from respiratory samples of patients with cystic fibrosis and other respiratory diseases. P. pulmonicola is a part of the Burkholderia cepacia complex, which is a group of bacteria commonly associated with infections in individuals with compromised immune systems.
Ornibactin is a siderophore, or small iron-binding compound secreted by bacteria to transport iron into the cell. Ornibactin is produced by Burkholderia cenocepacia under iron-deficient conditions. B. cenocepacia is known to opportunistically infect humans, specifically ones suffering from cystic fibrosis.
Diffusible signal factor (DSF) is found in several gram-negative bacteria and play a role in the formation of biofilms, motility, virulence, and antibiotic resistance. Xanthomonas campestris was the first bacteria known to have DSF. The synthesis of the DSF can be seen in rpfF and rpfB enzymes. An understanding of the DSF signaling mechanism could lead to further disease control.
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