The gram-negative bacillus Burkholderia pseudomallei is a saprophyte and the cause of melioidosis. Natural infection is most commonly reported in northeast Thailand and northern Australia but also occurs in other parts of Asia, South America, and the Caribbean. Melioidosis develops after bacterial inoculation or inhalation, often in relation to occupational exposure in areas where the disease is endemic. Clinical infection has a peak incidence between the fourth and fifth decades; with diabetes mellitus, excess alcohol consumption, chronic renal failure, and chronic lung disease acting as independent risk factors. Most affected adults ( approximately 80%) in northeast Thailand, northern Australia, and Malaysia have >/=1 underlying diseases. Symptoms of melioidosis may be exhibited many years after exposure, commonly in association with an alteration in immune status. Manifestations of disease are extremely broad ranging and form a spectrum from rapidly life-threatening sepsis to chronic low-grade infection. A common clinical picture is that of sepsis associated with bacterial dissemination to distant sites, frequently causing concomitant pneumonia and liver and splenic abscesses. Infection may also occur in bone, joints, skin, soft tissue, or the prostate. The clinical symptoms of melioidosis mimic those of many other diseases; thus, differentiating between melioidosis and other acute and chronic bacterial infections, including tuberculosis, is often impossible. Confirmation of the diagnosis relies on good practices for specimen collection, laboratory culture, and isolation of B. pseudomallei. The overall mortality rate of infected persons is 50% in northeast Thailand (35% in children) and 19% in Australia.
An outbreak of Burkholderia cepacia septicaemia occurred in our neonatal unit over a 9-week period in 2001, affecting 23 babies and two died. A second outbreak lasting 8 days occurred a year later, affecting five babies.
Matched MeSH terms: Burkholderia Infections/prevention & control
Burkholderia cepacia is an opportunistic human pathogen associated with lung infections. Secretory proteins of B. cepacia are known to be involved in virulence and may mediate important host-pathogen interactions. In the present study, secretory proteins isolated from B. cepacia culture supernatant were separated using two-dimensional gel electrophoresis, followed by Western blot analysis to identify the immunogenic proteins. Mice antibodies raised to B. cepacia inactivated whole bacteria, outer membrane protein and culture filtrate antigen detected 74, 104 and 32 immunogenic proteins, respectively. Eighteen of these immunogenic proteins which reacted with all three antibodies were identified and might be potential molecules as a diagnostic marker or a putative candidate vaccine against B. cepacia infections.
Matched MeSH terms: Burkholderia Infections/prevention & control
The genus Burkholderia consists of diverse species which includes both "friends" and "foes." Some of the "friendly" Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei, and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis (CF) patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei, and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines.