Burkholderia cepacia complex: Difference between revisions

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<br> 8 [http://www.cff.org/aboutcf/ “About CF.” Cystic Fibrosis Foundation.]  
<br> 8 [http://www.cff.org/aboutcf/ “About CF.” Cystic Fibrosis Foundation.]  
<br> 9 [http://emedicine.medscape.com/article/237122-overview#a0199 Cunha, B.A. “Burkholderia.” Medscape.]
<br> 9 [http://emedicine.medscape.com/article/237122-overview#a0199 Cunha, B.A. “Burkholderia.” Medscape.]
<br> 10 [http://jmm.sgmjournals.org/content/45/6/395.short Govan, J.R.W., Hughes, J.E., Vandamme, P. “<i>Burkholderia cepacia</i>: medical, taxonomic and ecological issues.” Journal of Medical Microbiology.]
<br> 11 [http://www.ncbi.nlm.nih.gov/pubmed/19074648 Callaghan, M., McClean, S. “Burkholderia cepacia complex: epithelial cell-pathogen confrontations and potential for therapeutic intervention." Journal of Microbiology.
<br> 12 [http://www.nature.com.ezproxy.lib.ou.edu/nrmicro/journal/v3/n2/full/nrmicro1085.html Mahenthiralingam, E., Urban, T.A., Goldberg, J.B. “The multifarious, multireplicon <i>Burkholderia cepacia</i> complex.” Nature.] 
<br> 13 [http://crd.sagepub.com/content/3/3/161.full.pdf Elborn, J.S. “Practical Management of Cystic Fibrosis.” Chronic Respiratory Disease.]





Revision as of 20:49, 27 July 2014

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University of Oklahoma Study Abroad Microbiology in Arezzo, Italy[1]
Image of Burkholderia cepacia. [www.cdc.gov]


Etiology/Bacteriology

Taxonomy

| Domain = Bacteria | Phylum = Proteobacteria | Class = Betaproteobacteria | Order = Burkholderiales | Family = Burkholderiaceae | Genus = Burkholderia | species = B. cepacia, B. multivorans, B. cenocepacia, B. vietnamiensis, B. stabilis, B. ambifaria, B. dolosa, B. anthina, B. pyrrocinia

Description

Burkholderia cepacia complex is a group of Gram-negative, non-spore forming bacilli composed of approximately 17 closely-related species which are grouped into nine genomovars. This is often referred to as the Burkholderia cepacia complex (BCC) [1][12]. It was originally recognized by W. H. Burkholder in the 1950s for the distinct stench it caused in onion bulbs, known as "sour skin" disease for its vinegar-like odor [1][12]. B. cepacia has emerged as a human respiratory opportunistic pathogen in individuals with weakened immune systems or chronic lung disease, espeically cystic fibrosis (CS) patients, within the past 30 years and has therefore recieved increased attention from the scientific community. BCC potentially causes abscesses and bacteremia, but this condition is highly uncommon in patients without CS [3]. Pulmonary colonization of B. cepacia can cause accelerated decline in lung funtions and cause “cepacia syndrome,” which is a progressive pneumonic illness that is fatal and essentially untreatable [2].


The organisms possess a remarkably large genetic make up with a total DNA content of more than 7 megabases and up to 3 megabase-sized replicons [1]. BCC was formerly classified as a Pseudomonas, but was transferred to the <Burkholderia genus in 1992 on the basis of phenotypic characteristics, 16S rRNA sequences, DNA-DNA homology values, and cellular lipid and fatty acid composition [12]. It poses little medical risk to healthy individuals, but weakened immune systems or chronic lung diseases, such as cystic fibrosis, may have increased susceptibility. BCC often causes infections in hospitalized patients as well [5]. Various traits distinguish BCC from other CF pathogens, such as its inherent resistance to many antibiotics, high transmissibility, and association with greater virulence. Because of these factors, management of B. cepacia complex patients is difficult [2].


Ecological Role

BCC bacteria exist throughout the environment. These bacteria can act as a powerful pesticide, capable of eliminating many soil-borne plant pathogens. In contrast, there is potential for the B. cepacia complex to act as a biofertiliser for rice that is cultivated in low fertile, low acidic soils [2]. Though initially discovered as a plant pathogen and capable of acting as a pesticide, these bacteria generally interact with plants in an ecologically beneficial manner. Additionally, their metabolic capacity and substantial genetic diversity allow them to degrade significant pollutants such as trichloroethylene [12]. Scientists are utilizing the diverse metabolic properties of BCC to create an assitive agent for bioremediation of contaminated environmental sites [2]. Currently, it is not possible to determine strains of B. cepacia that can be safely used in agriculture without potentially harming humans, which causes discourse between the scientific and agricultural communities [2].

Pathogenesis


Transmission

Susceptible persons can acquire B. cepacia organisms through person-to-person contact, contact with contaminated surfaces, and exposure to it in the enviroment (i.e. soil and water) [5]. Transmission from contaminated medicines, nasal spray, mouthwash, and sublingual probes have been recorded also[5]. B. cepacia complex is highly transmissible between cystic fibrosis patients and can be transferred from one CF patient to another in hospitals, health clinics, and social environments [2].


Infectious dose, incubation, and colonization


Epidemiology


Virulence Factors


Clinical Features


Diagnosis


Treatment

Clinical indicators of BCC infection vary. Cepacia syndrome is almost universally fatal, but aggressive treatment has yielded some success in specific cases [4]. BCC is often resistant to many common antibiotics, and treatment decisions are typically made on a case-by-case basis [5]. Because it is resistant to many antibiotics, effective therapies and treatments are not straightforward. Therefore, management efforts are primarily aimed at prevention of infection [6]. ADD MORE

Prevention


Host Immune Response



B. cepacia and cystic fibrosis

From: medscape.com Cystic fibrosis patient with B. cepacia infection [2]
Cystic fibrosis is a genetic, life-threatening disease that primarily affects the digestive system and the lungs (7). The major cause of morbidity and mortality in CF patients is chronic microbial colonization of major airways, which lead to exacerbations of pulmonary infection. Common CF pathogens are Staphylococcus aureus, Pseudomonas aeruginosa, and haemophilus influenzae. Reports of B. cepacia in CF patients appeared in the late 1970s and early 1980s. In 1984 the first thorough description of the clinical significance of its colonization and infection was published. CONTINUE THIS


References


1 Miller, S.C.M., LiPuma, J.J., Parke, J.L. “Culture-Based and Non-Growth-Dependent Detection of the Burkholderia cepacia Complex in Soil Environments.” Applied and Environmental Microbiology.
2 Jones, A.M., Dodd, M.E., Webb, A.K. “Burkholderia cepacia: current clinical issues, environmental controversies and ethical dilemmas.” European Respiratory Journal.
3 Hua, C.N.C., Tokeshi, J. “Emergence of Burkholderia cepacia in Honolulu: A Case of Nursing Home-acquired B. cepacia sepsis. Hawai’i Journal of Medicine and Public Health.
4 Gilchrist, F.J., Webb, A.K., Bright-Thomas, R.J., Jones, A.M. “Successful treatment of cepacia syndrome with a combination of intravenous cyclosporin, antibiotics and oral corticosteroids.” European Cystic Fibrosis Soceity.
5 Burkholderia cepacia in Healthcare Settings.” Centers for Disease Control and Prevention.
6 Coenye, T., Vandamme, P., Govan, J.R.W., LiPuma, J.J. “Taxonomy and Identification of the Burkholderia cepacia Complex.” Journal of Clinical Microbiology.
7 Chu, K.K., Davidson, D.J., Halsey, K., Chung, J.W., Speert, D.P. “Differential Persistence among Genomovars of the Burkholderia cepacia Complex ina Murine Model of Pulmonary Infection.” American Society for Microbiology.
8 “About CF.” Cystic Fibrosis Foundation.
9 Cunha, B.A. “Burkholderia.” Medscape.
10 Govan, J.R.W., Hughes, J.E., Vandamme, P. “Burkholderia cepacia: medical, taxonomic and ecological issues.” Journal of Medical Microbiology.
11 [http://www.ncbi.nlm.nih.gov/pubmed/19074648 Callaghan, M., McClean, S. “Burkholderia cepacia complex: epithelial cell-pathogen confrontations and potential for therapeutic intervention." Journal of Microbiology.
12 Mahenthiralingam, E., Urban, T.A., Goldberg, J.B. “The multifarious, multireplicon Burkholderia cepacia complex.” Nature.
13 Elborn, J.S. “Practical Management of Cystic Fibrosis.” Chronic Respiratory Disease.




Created by Paige Whitson
Student of Dr. Tyrrell Conway, University of Oklahoma