Bacteria B. pseudomallei with bipolar Gram staining showing safety-pin appearance<unk>  is caused by a Gram-negative, motile, saprophytic bacterium named Burkholderia pseudomallei. The bacterium can also be an opportunistic, facultative intracellular pathogen. It is also aerobic and oxidase test positive. A vacuole at the centre of the bacterium makes it resemble a “safety pin” when Gram stained. The bacteria emit a strong soil smell after 24 to 48 hours of growth in culture. B. pseudomallei produces a glycocalyx polysaccharide capsule that makes it resistant to many types of antibiotics. It is generally resistant to gentamicin and colistin, but sensitive to amoxicillin/clavulanic acid (co-amoxiclav). B. pseudomallei is a biosafety level 3 pathogen, which requires specialized laboratory handling. In animals, another similar organism named Burkholderia mallei is the causative agent of the disease glanders. B. pseudomallei can be differentiated from another closely related, but less pathogenic species, B. thailandensis, by its ability to assimilate arabinose. B. pseudomallei is highly adaptable to various host environments ranging from inside mycorrhizal fungi spores to amoebae. Its adaptability may give it a survival advantage in the human body. The genome of B. pseudomallei consists of two replicons: chromosome 1 encodes housekeeping functions of the bacteria such as cell wall synthesis, mobility, and metabolism; chromosome 2 encodes functions that allow the bacteria to adapt to various environments. Horizontal gene transfer among bacteria has resulted in highly variable genomes in B. pseudomallei. Australia has been suggested as the early reservoir for B. pseudomallei because of the high genetic variability of the bacteria found in this region. Bacteria isolated from Africa and Central and South America seem to have a common ancestor that lived in the 17th to 19th centuries. B. mallei is a clone of B. pseudomallei that has lost substantial portions of its genome as it adapted to live exclusively in mammals. Transmission B. pseudomallei is normally found in soil and surface water, and is most abundant at soil depths of 10 cm to 90 cm. It has been found in soils, ponds, streams, pools, stagnant water, and paddy rice fields. It can survive in nutrient-poor conditions such as distilled water, desert soil, and nutrient-depleted soil for more than 16 years. It can also survive in antiseptic and detergent solutions, acidic environments (pH 4.5 for 70 days), and environments at temperatures ranging from 24 to 32 °C (72 to 89.6 °F). The bacteria do not survive in the presence of ultraviolet light. Bacteria can enter the body through wounds, inhalation, and ingestion of polluted water. Person-to-person transmission is extremely rare.<unk>  is a recognised disease in animals including cats, dogs, goats, sheep, and horses. Cattle, water buffalo, and crocodiles are considered to be relatively resistant to<unk>  despite their constant exposure to infected water and soil. Birds are also resistant to<unk> . Transmission from animals to humans is rare. Inadequate chlorination of water supply had been associated with B. pseudomallei outbreak in Northern and Western Australia. The bacteria have also been found in an unchlorinated water supply in rural Thailand. Irrigation fluid contaminated with B pseudomallei is associated with nosocomial wound infection in hospitals. Based on the whole genome sequencing of the bacteria, humans may play a role in moving B. pseudomallei from place to place. In October 2021, the US Centers for Disease Control and Prevention confirmed an outbreak in the United States, which was traced back to an aromatherapy spray produced in India.
Melioidosis
Sarcoidosis
Tuberculosis
Gamasoidosis
Amyloidosis
Miliary tuberculosis
Chronic pulmonary aspergillosis
Extrapulmonary tuberculosis