The key difference between Burkholderia mallei and Pseudomallei is that Burkholderia mallei is a non-motile, coccobacillus-shaped bacterium which rarely infects human while, Pseudomallei is a motile, rod-shaped bacterium which predominantly infects human.
Burkholderia mallei and Pseudomallei are proteobacteria that belong to the genus Burkholderia. They are closely related bacterial species that still possess quite distinct genomes. B. mallei and Pseudomallei have conserved genomic regions. B. mallei mainly infect animals such as horses, donkeys, and mules. It is an obligate mammalian pathogen. Pseudomallei is an opportunistic pathogen. It is an environmental organism. Moreover, it has no requirement to pass through an animal host to replicate. Pseudomallei mainly infects humans.
CONTENTS
1. Overview and Key Difference
2. What is Burkholderia Mallei
3. What is Pseudomallei
4. Similarities Between Burkholderia Mallei and Pseudomallei
5. Side by Side Comparison – Burkholderia Mallei vs Pseudomallei in Tabular Form
6. Summary
What is Burkholderia Mallei?
Burkholderia mallei is a gram-negative, bipolar, aerobic, non-motile, coccobacillary-shaped bacterium which rarely infects human. The size of the bacterium is approximately 1.5–3.0 μm in length and 0.5 – 1.0 μm in diameter with rounded ends. These bacteria cause a disease known as glanders. Glanders is a contagious infectious disease that occurs primarily in horses, mules, and donkeys. Glanders spreads to humans by direct contact with infected animals. This bacterium is evolved from Pseudomallei, which is a closely related bacterial species, by selective reduction and deletions from Pseudomallei genome. B. mallei was first isolated in 1882 from the infected liver and spleen of a horse.
Figure 01: B. mallei
The genome of B. mallei was sequenced by the institute of genomic research in the United States. The genome size of this bacterium is smaller than Pseudomallei. It has a chromosome of 3.5M bp and a plasmid of 2.5 Mbp. This microorganism can be destroyed by heat and ultraviolet light.
Antibiotics like streptomycin, amikacin, tetracycline, doxycycline, carbapenems, ceftazidime, clavulanicacid, piperacillin, chloramphenicol, and sulfathiazole are also effective against this bacterium. But it is resistant to antibiotics, including aminoglycosides, polymyxins, and beta-lactams. No vaccine is currently available to provide protection against B. mallei infection.
What is Pseudomallei?
Pseudomallei is a gram-negative, bipolar, aerobic, motile, rod-shaped bacterium that mainly infects human. The size of the bacterium is 2–5 μm in length and 0.4–0.8 μm in diameter, and it is capable of self-propulsion using flagella. It is also known as Burkholderia pseudomallei or Pseudomonas pseudomallei. It is a soil-dwelling bacterium. These bacteria are endemic in tropical and subtropical regions worldwide. These bacteria cause a disease known as melioidosis. It is also capable of infecting plants.
Figure 02: Pseudomallei
The genome size of the Pseudomallei is approximately 7.2 Mbp with one large and one small chromosome. This bacterium possesses genes for the fusogenic type VI secretion system that is required for the cell to cell spread in mammalian hosts. It also has genes for producing a toxin called lethal factor 1. These bacteria are susceptible to antibiotics such as ceftazidime, chloramphenicol, doxycycline, and co-trimoxazole. Moreover, they are resistant to antibiotics like gentamicin and colistin. No vaccine has been currently identified for this bacterium.
What are the Similarities Between Burkholderia Mallei and Pseudomallei?
- Burkholderia Mallei and Pseudomallei are proteobacteria.
- Both belong to the genus: Burkholderia.
- They are both gram-negative.
- They both can infect animals.
- They cause infectious diseases.
- Both have two chromosomes in their genomes.
What is the Difference Between Burkholderia Mallei and Pseudomallei?
Burkholderia mallei is a non-motile, coccobacillary shaped bacterium which rarely infects human. On the other hand, Pseudomallei is a motile, rod-shaped bacterium which mainly infects human. Thus, this is the key difference between Burkholderia Mallei and Pseudomallei. Moreover, Burkholderia mallei is an obligate mammalian pathogen. Pseudomallei is a soil-dwelling opportunistic pathogen.
The below infographic presents the differences between Burkholderia Mallei and Pseudomallei in tabular form.
Summary – Burkholderia Mallei vs Pseudomallei
Burkholderia mallei and Pseudomallei are two proteobacteria that cause glanders and melioidosis, respectively. Although they are rare in western countries, both microorganisms have recently gained much attention because of their unique potential as bioterrorism agents. Burkholderia mallei is a non-motile and coccobacillary shaped bacterium. Pseudomallei is a motile and rod-shaped bacterium. Burkholderia mallei rarely infect human. Pseudomallei predominantly infects human. Thus, this is the summary of the difference between Burkholderia Mallei and Pseudomallei.
Reference:
1. J, Gilad. “Burkholderia Mallei and BurkholderiaPseudomallei: the Causative Micro-Organisms of Glanders and Melioidosis.” Recent Patents on Anti-Infective Drug Discovery, U.S. National Library of Medicine, Available here.
2. “Melioidosis.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 26 Jan. 2012, Available here.
Image Courtesy:
1. “Burkholderia mallei” By Dr. Todd Parker, Audra Marsh – This media comes from the Centers for Disease Control and Prevention's Public Health Image Library (PHIL), with identification number #12270 (Public Domain) via Commons Wikimedia
2. “Burkholderia pseudomallei, illness, melioidosis, categorized, acute, localized, infection” (CC0) via Pixino