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Burkholderia cepacia Complex and Other Burkholderia Species


Acknowledgment

Substantial material from Jane L. Burns’ chapter in the previous edition has been used.

The genus Burkholderia was proposed in 1992 for 7 species that previously were included in Pseudomonas homology group II. All are animal or plant pathogens and are considered opportunistic pathogens in healthy humans. Burkholderia spp. are nutritionally diverse water and soil organisms that are catalase producing and non-glucose fermenting. Species can be distinguished on the basis of phenotype and biochemical characteristics (including carbohydrate fermentation patterns and production of indophenol oxidase) and can be confirmed using molecular tests such as recA based PCR tests.

Infections associated with Burkholderia spp. are shown in Table 156.1 . Burkholderia cepacia complex has been associated with severe pulmonary infections in patients with cystic fibrosis (CF) and with fatal bloodstream infection (BSI) in patients with chronic granulomatous disease (CGD). Burkholderia pseudomallei is the cause of melioidosis, an endemic disease in Southeast Asia and northern Australia, and Burkholderia mallei is the organism that causes glanders, an equine infection seen in Asia and Africa that can be transmitted to humans. Burkholderia gladioli has been isolated from patients with CF, from immunocompromised people, and from high-risk neonates. Other Burkholderia spp. can cause sporadic infections or nosocomial outbreaks in immunocompromised people but have not been associated with specific syndromes.

TABLE 156.1
Infections Caused by Burkholderia Species
Organism Underlying Condition Disease Caused Site or Type of Infection
Burkholderia cepacia complex Cystic fibrosis
Chronic granulomatous disease
Immunocompromised state		 Pneumonia and others Lungs
Lungs and pleura
Lymph nodes
Skin and soft tissue
Bloodstream
Septicemia
Burkholderia pseudomallei Immunocompromised state
Diabetes mellitus
Renal insufficiency		 Melioidosis Septicemia
Lungs
Skin and soft tissue
Bone
Burkholderia mallei Glanders Septicemia
Skin
Peritoneum
Lymph nodes
Burkholderia thailandensis Post Trauma Wound infection and others Soft tissue infection
Bone
Pneumonia
Septicemia
Burkholderia gladioli Cystic fibrosis
Chronic granulomatous disease		 Pneumonia and others Lungs
Lungs and pleura
Lymph nodes
Skin and soft tissue
Bloodstream
Septicemia

Burkholderia Cepacia Complex

B. cepacia is recognized as a complex of 23 named species, and some of which can be distinguished phenotypically and others require genotypic identification ( Box 156.1 ). B. cepacia complex is primarily a group of nosocomial pathogens and multiple outbreaks of B. cepacia complex infections associated with contamination of intravenous solutions, drugs, and equipment have been described. Because B. cepacia complex is able to grow in many commonly used disinfectants, such outbreaks are frequently associated with contaminated cleaning solutions. Endemic B. cepacia complex infections in a large pediatric hospital were associated with contamination of ultrasound gel. B. cepacia complex BSI has also been reported in children with cancer as well as post transplantation. Patients with CF , and CGD , appear to be susceptible specifically to infection by B. cepacia complex; such infections can be fatal.

BOX 156.1
Named Burkholderia (B.) Species Within Burkholderia cepacia Complex

  • B. ambifaria

  • B. anthina

  • B. arboris

  • B. catarinensis

  • B. cenocepacia

  • B. cepacia

  • B. contaminans

  • B. diffusa

  • B. dolosa

  • B. lata

  • B. latens

  • B. metallica

  • B. multivorans

  • B. paludis

  • B. pseudomultivorans

  • B. puraquae

  • B. pyrrocinia

  • B. seminalis

  • B. stabilis

  • B. stagnalis sp. nov.

  • B. territorii sp. nov.

  • B. ubonensis

  • B. vietnamiensis

Virulence and Pathogenesis

Despite the virulence of B. cepacia complex in certain subpopulations of patients, specific mechanisms of pathogenesis have been difficult to elucidate, and they may depend on the underlying disease process. , Intracellular growth within professional phagocytes and epithelial cells and the proinflammatory activity of B. cenocepacia lipopolysaccharide likely contribute to pathogenesis. In vitro studies have identified potential pathways involved in virulence and establishment of infection including iron acquisition, exopolysaccharide production, quorum sensing and biofilm formation, , adherence, and motility. These findings are supported by studies examining B. cenocepacia gene expression during growth in CF-affected sputum.

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