Burkholderia cepacia complex
Encyclopedia
Burkholderia cepacia complex (BCC), or simply Burkholderia cepacia is a group of catalase
-producing, non-lactose
-fermenting
Gram-negative
bacteria
composed of at least seventeen different species, including B. cepacia, B. multivorans
, B. cenocepacia
, B. vietnamiensis
, B. stabilis
, B. ambifaria
, B. dolosa
, B. anthina
, and B. pyrrocinia
. B. cepacia is an important human pathogen which most often causes pneumonia
in immunocompromised individuals with underlying lung disease (such as cystic fibrosis
or chronic granulomatous disease
).
function and result in death.
the bacteria from clinical specimens such as sputum
or blood. BCC organisms are naturally resistant to many common antibiotics including aminoglycosides and polymyxin B
. and this fact is exploited in the identification of the organism.
Oxidation-fermentation polymyxin-bacitracin-lactose (OFPBL) agar contains polymyxin
(which kills most gram-negative bacteria, including Pseudomonas aeruginosa
) and bacitracin
(which kills most gram-positive bacteria and Neisseria
species). It also contains lactose
, and organisms such as BCC that 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
, Stenotrophomonas
species, and Proteus
species.
(a common topical antiseptic). Recently, a 0.2% chlorhexidine mouthwash was also recalled, after it was found to be contaminated with B. cepacia.
, doxycycline
, piperacillin
, meropenem
, chloramphenicol
and co-trimoxazole
(trimethoprim/sulfamethoxazole). Although co-trimoxazole has been generally considered the drug of choice for Burkholderia cepacia infections ceftazidime
, doxycycline
, 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. In April 2007 Researchers from the Schulich School of Medicine & Dentistry at The University of Western Ontario, working with a group from Edinburgh, announced they had discovered a way to kill the organism.
pathogen
in the 1950s. In the 1980s, it was first recognized in individuals with cystic fibrosis
, and outbreaks were associated with a 35% death rate. Burkholderia cepacia has a large genome
, containing twice the amount of genetic material as E. coli
.
Catalase
Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it catalyzes the decomposition of hydrogen peroxide to water and oxygen...
-producing, non-lactose
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
-fermenting
Fermentation (biochemistry)
Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...
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...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
composed of at least seventeen different species, including B. cepacia, B. multivorans
Burkholderia multivorans
Burkholderia multivorans is a species in Phylum proteobacteria. It is known to cause human disease, such as colonisation of the lung in cystic fibrosis....
, B. cenocepacia
Burkholderia cenocepacia
Burkholderia cenocepacia is a species of Gram-negative bacteria that is common in the environment and may cause disease in plants. It is an opportunistic pathogen and human infections are common in patients with cystic fibrosis and chronic granulomatous disease, and are often fatal...
, B. vietnamiensis
Burkholderia vietnamiensis
Burkholderia vietnamiensis is a species of proteobacteria. It can be found as an opportunistic pathogen in patients with cystic fibrosis or other immunocompromising illnesses. It differs from most Burkholderia species in that it is often susceptible to aminoglycosides, but not polymyxin B [1]. ...
, B. stabilis
Burkholderia stabilis
Burkholderia stabilis is a species of proteobacteria....
, B. ambifaria
Burkholderia ambifaria
Burkholderia ambifaria is a species of proteobacteria....
, B. dolosa
Burkholderia dolosa
Burkholderia dolosa is a species of proteobacteria. It is a member of the Burkholderia cepacia complex. This particular strain is highly drug resistant and found primarily in immunocompromised patients...
, B. anthina
Burkholderia anthina
Burkholderia anthina is a species of proteobacteria....
, and B. pyrrocinia
Burkholderia pyrrocinia
Burkholderia pyrrocinia is a Gram-negative soil bacterium....
. B. cepacia is an important human pathogen which most often causes pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
in immunocompromised individuals with underlying lung disease (such as cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
or chronic granulomatous disease
Chronic granulomatous disease
Chronic granulomatous disease is a diverse group of hereditary diseases in which certain cells of the immune system have difficulty forming the reactive oxygen compounds used to kill certain ingested pathogens...
).
Pathogenesis
BCC organisms are typically found in water and soil and can survive for prolonged periods in moist environments. 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 noninfected patients to limit spread, since BCC infection can lead to a rapid decline in lungLung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
function and result in death.
Diagnosis
Diagnosis of BCC involves culturingMicrobiological culture
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...
the bacteria from clinical specimens such as sputum
Sputum
Sputum is mucus that is coughed up from the lower airways. It is usually used for microbiological investigations of respiratory infections....
or blood. BCC organisms are naturally resistant to many common antibiotics including aminoglycosides and polymyxin B
Polymyxin B
Polymyxin B is an antibiotic primarily used for resistant gram-negative infections. It is derived from the bacterium Bacillus polymyxa. Polymyxin B is a mixture of two closely related compounds, polymyxin B1 and polymyxin B2. It has a bactericidal action against almost all gram-negative bacilli...
. and this fact is exploited in the identification of the organism.
Oxidation-fermentation polymyxin-bacitracin-lactose (OFPBL) agar contains polymyxin
Polymyxin
Polymyxins are antibiotics, with a general structure consisting of a cyclicpeptide with a long hydrophobic tail. They disrupt the structure of thebacterial cell membrane by interacting with its phospholipids...
(which kills most gram-negative 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...
) and bacitracin
Bacitracin
Bacitracin is a mixture of related cyclic polypeptides produced by organisms of the licheniformis group of Bacillus subtilis var Tracy, isolation of which was first reported in 1945....
(which kills most gram-positive bacteria and Neisseria
Neisseria
The Neisseria is a large genus of commensal bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens. N. meningitidis and N. gonorrhoeae often cause asymptomatic infections, a commensal-like behavior...
species). It also contains lactose
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
, and organisms such as BCC that ferment lactose turn the pH indicator yellow, which helps to distinguish it from other organisms that may grow on OFPBL agar, such as Candida
Candida (genus)
Candida is a genus of yeasts. Many species are harmless commensals or endosymbionts of animal hosts including humans, but other species, or harmless species in the wrong location, can cause disease. Candida albicans can cause infections in humans and other animals, especially in immunocompromised...
species, Pseudomonas fluorescens
Pseudomonas fluorescens
Pseudomonas fluorescens is a common Gram-negative, rod-shaped bacterium. It belongs to the Pseudomonas genus; 16S rRNA analysis has placed P. fluorescens in the P. fluorescens group within the genus, to which it lends its name....
, Stenotrophomonas
Stenotrophomonas
Stenotrophomonas is a genus of Gram-negative bacteria. With species ranging from common soil organisms to opportunistic human pathogens , the molecular taxonomy of the genus is still somewhat unclear....
species, and Proteus
Proteus
In Greek mythology, Proteus is an early sea-god, one of several deities whom Homer calls the "Old Man of the Sea", whose name suggests the "first" , as protogonos is the "primordial" or the "firstborn". He became the son of Poseidon in the Olympian theogony In Greek mythology, Proteus (Πρωτεύς)...
species.
Infection control
The bacteria is so hardy that it has been found to persist in betadineBetadine
Povidone-iodine is a stable chemical complex of polyvinylpyrrolidone and elemental iodine. It contains from 9.0% to 12.0% available iodine, calculated on a dry basis....
(a common topical antiseptic). Recently, a 0.2% chlorhexidine mouthwash was also recalled, after it was found to be contaminated with B. cepacia.
Treatment
Treatment typically includes multiple antibiotics and may include ceftazidimeCeftazidime
Ceftazidime is a third-generation cephalosporin antibiotic. Like other third-generation cephalosporins, it has broad spectrum activity against Gram-positive and Gram-negative bacteria. Unlike most third-generation agents, it is active against Pseudomonas aeruginosa, however it has weaker activity...
, doxycycline
Doxycycline
Doxycycline INN is a member of the tetracycline antibiotics group, and is commonly used to treat a variety of infections. Doxycycline is a semisynthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin...
, piperacillin
Piperacillin
Piperacillin is an extended spectrum beta-lactam antibiotic of the ureidopenicillin class.It is normally used together with a beta-lactamase inhibitor such as tazobactam. The combination drug piperacillin/tazobactam is commercially available as e.g. Tazocin, Zosyn, Brodactam, Piptaz and as Trezora...
, 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...
, 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 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...
(trimethoprim/sulfamethoxazole). Although co-trimoxazole has been generally considered the drug of choice for Burkholderia cepacia infections ceftazidime
Ceftazidime
Ceftazidime is a third-generation cephalosporin antibiotic. Like other third-generation cephalosporins, it has broad spectrum activity against Gram-positive and Gram-negative bacteria. Unlike most third-generation agents, it is active against Pseudomonas aeruginosa, however it has weaker activity...
, doxycycline
Doxycycline
Doxycycline INN is a member of the tetracycline antibiotics group, and is commonly used to treat a variety of infections. Doxycycline is a semisynthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin...
, piperacillin
Piperacillin
Piperacillin is an extended spectrum beta-lactam antibiotic of the ureidopenicillin class.It is normally used together with a beta-lactamase inhibitor such as tazobactam. The combination drug piperacillin/tazobactam is commercially available as e.g. Tazocin, Zosyn, Brodactam, Piptaz and as Trezora...
and 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...
are considered to be viable alternative options in cases where co-trimoxazole cannot be administered because of hypersensitivity reactions, intolerance or resistance. In April 2007 Researchers from the Schulich School of Medicine & Dentistry at The University of Western Ontario, working with a group from Edinburgh, announced they had discovered a way to kill the organism.
History
B.cepacia was discovered by Walter Burkholder in 1949 as the culprit of onion skin rot, and first described as a humanHuman
Humans are the only living species in the Homo genus...
pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
in the 1950s. In the 1980s, it was first recognized in individuals with cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
, and outbreaks were associated with a 35% death rate. Burkholderia cepacia has a large genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
, containing twice the amount of genetic material as E. coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
.
See also
- Contamination controlContamination controlContamination control is the generic term for all activities aiming to control the existence, growth and proliferation of contamination in certain areas...
- Burkholderia Cepacia Infection