• Epidemiology is the study of the prevalence and causes of health-related conditions or occurrences in specific groups and using this knowledge to prevent or treat health issues. Epidemiology of Burkholderia gladioli is the study of how this bacterium affects the health of humans and plants in different settings and conditions.
• According to the web search results, aerobic, gram-negative, rod-shaped Burkholderia gladioli can harm people and plants. Additionally, it may coexist in harmony with fungi and plants. And can be discovered in numerous animals, water, soil, and the rhizosphere. It was formerly known as Pseudomonas marginata. Burkholderia gladioli synthesize several inhibitory substances: gladiolin, bongkrek acid, enacyloxin, and toxoflavin. Those chemicals can engage in hostile interactions with other bacteria in their environment of growth.
• Burkholderia gladioli is divided into several pathovars based on their host range and pathogenicity. A pathovar is a bacterial species subdivision distinguished by its ability to infect a specific plant or animal host. The four pathovars of Burkholderia gladioli are Gladiolus rot caused by B. gladioli pv. Gladioli, onion bulb rot by B. g. pv. alliicola, soft rot in mushrooms by B. g. pv. agaricicola, and cocovenenans by B. g. pv. cocovenenans: spoils coconut pulp and produces the respiratory toxin bongkrek acid.
• The epidemiology of Burkholderia gladioli infection in humans needs to be better understood, as it is a rare and opportunistic pathogen that mainly affects immunocompromised individuals, such as organ transplant recipients, cystic fibrosis patients, chronic granulomatous disease patients, or The symptoms of Burkholderia gladioli infection in humans can include pneumonia, bacteremia, endocarditis, osteomyelitis, peritonitis, urinary tract infections, skin, and soft tissue infections, corneal inflammation, and lymphadenitis. The mortality rate of Burkholderia gladioli infection in humans is high, especially if not diagnosed and treated promptly.
• The epidemiology of Burkholderia gladioli infection in plants is better documented, as it is a common plant pathogen that can cause significant crop losses. It has been reported to infect onions, gladiolus, iris, rice, coconut, mushrooms, corn, soybean, sunflower, and other plants.
• The symptoms of Burkholderia gladioli infection in plants can include brown lesions on leaves, water-soaked leaves, wilting, and rot of roots, stems, and petals. The transmission of Burkholderia gladioli infection in plants can occur through contaminated soil, water, seeds, bulbs, corms, or insects.
• The prevention and control of Burkholderia gladioli infection in humans and plants depend on several factors, such as the source of infection, the host susceptibility, the environmental conditions, and the availability of effective treatment.

• Kingdom: Bacteria
• Phylum: Proteobacteria
• Class: Betaproteobacteria
• Order: Burkholderiales
• Family: Burkholderiaceae
• Genus: Burkholderia
• Species: Burkholderia gladioli

Burkholderia gladioli, like other bacteria, is a unicellular microorganism. It has a typical bacterial cell structure with several key components:

• Cell Wall: The cell wall of Burkholderia gladioli is composed of peptidoglycan, a complex mesh-like framework that gives the cell its structural integrity. The cell wall’s makeup and structure can vary among different strains.
• Cell Membrane (Plasma Membrane): This lipid bilayer encloses the cytoplasm and separates the interior of the cell from its external environment. It is crucial in various cellular processes, including nutrient transport and energy production.
• Cytoplasm: The cytoplasm is the gel-like substance within the cell membrane where various cellular processes occur. It contains the bacterial chromosome (DNA), ribosomes, enzymes, and other cellular components.
• Flagella: Some strains of Burkholderia gladioli possess flagella, which are whip-like appendages that enable the bacterium to move. Flagella are used for bacterial motility.
• Pili/Fimbriae: These are hair-like projections on the bacterial cell surface that influence adherence to surfaces and interactions with other cells.
• Capsule: Some strains of Burkholderia gladioli may produce a slimy capsule surrounding the cell. This capsule can contribute to bacterial virulence and protect the bacterium from the host’s immune system.

Antigenic types are different forms of a microorganism that have distinct antigens on their surface. Antigens are molecule-based immunostimulatory agents from the host. Different antigenic types of the same microorganism may have different virulence, pathogenicity, or susceptibility to drugs or vaccines.

Burkholderia gladioli is divided into several pathovars based on their host range and pathogenicity. A pathovar is a bacterial species subdivision distinguished by its ability to infect a specific plant or animal host. The four pathovars of Burkholderia gladioli are:

• Gladiolus rot is brought on by B. gladioli pv. gladioli.
• Onion bulb rot is brought on by B. g. pv. alliicola.
• In mushrooms, B. g. pv. agaricicola induces soft rot.

• B. g. pv. cocovenenans:

The pathovars of Burkholderia gladioli may have different antigenic types, but not much information is available on this topic. One study reported that B. g. pv. cocovenenans has two serotypes, A and B, based on the agglutination reaction with specific antisera. Another study suggested that B. g. pv. agaricicola has three serotypes, I, II, and III, based on the immunoblotting analysis with polyclonal antibodies. However, these studies used different methods and criteria to define the serotypes so that they may differ.

Burkholderia gladioli in humans is an opportunistic pathogen that is an essential agent for infections brought on by hospitals. Recently, it has emerged as a dangerous bacterium that can lead to severe lung infections in people with cystic fibrosis. though it is still an uncommon pathogen, its presence is associated with a poor prognosis.

The pathogenesis of Burkholderia gladioli in humans involves several steps:

• Invasion: The bacterium enters the human body through inhalation, ingestion, or contact with contaminated materials. Transfusions of blood or organs from infected donors can also spread it.
• Adhesion: The bacterium adheres to the epithelial cells of the respiratory tract, gastrointestinal tract, urinary tract, or skin using various surface structures such as pili, flagella, lipopolysaccharides, and adhesins.
• Colonization: The bacterium multiplies and forms biofilms on the mucosal surfaces or within the host’s tissues. Biofilms are communities of bacteria encased in an extracellular polymeric matrix that protects them from host defenses and antibiotics.
• Evasion: The bacterium evades the host immune system by various mechanisms such as resisting phagocytosis, producing a capsule, modifying surface antigens, secreting proteases and siderophores, and inducing apoptosis of immune cells.
• Damage: The bacterium damages the host tissues and organs by producing toxins, enzymes, and inflammatory mediators that cause necrosis, inflammation, edema, hemorrhage, and fibrosis

The host defenses of  Burkholderia gladioli in humans and plants may vary depending on the pathovar, the site of infection, and the host’s immune status. Some of the possible host defenses are:

• Physical barriers: The skin and mucous membranes of the respiratory, gastrointestinal, and urinary tracts act as physical barriers that prevent the entry or attachment of Burkholderia gladioli to the host cells.
• Chemical barriers: The acidic pH of the stomach, the lysozyme in saliva and tears, and the antimicrobial peptides in sweat and secretions act as chemical barriers that inhibit the growth or survival of Burkholderia gladioli in the host fluids.
• Innate immunity: Innate immune components include cells and molecules that recognize and respond to common microbial patterns without prior exposure. Some of the components of innate immunity that can defend against Burkholderia gladioli are:
• Phagocytes: Cells that engulf and destroy foreign particles using ROS and NO. Examples: neutrophils, macrophages, and dendritic cells.
• Natural Killer (NK) cells: Lymphocytes that kill infected or abnormal cells through apoptosis-inducing molecules and cytokines.
• Complement system: Protein cascade that coats or breaks microbial membranes and activates inflammation. Three pathways: classical, alternative, and lectin.

Adaptive Immunity against Burkholderia gladioli:

• B Cells: Produce antibodies to neutralize or tag Burkholderia gladioli. It can present antigens and regulate immune responses.
• T Cells: Recognize infected cells, killing or activating other immune cells; Includes helper (Th) & cytotoxic (Tc) cells.
• Immunoglobulins: Antibodies secreted by B cells. IgM for early response, IgG versatile, IgA in mucosal areas, IgE for allergies/parasites, IgD on B cells.
• Cytokines: Small proteins modulating immune responses. Interleukins (IL), interferons (IFN), TNF, chemokines, CSF. e.g., IL-1 and TNF-α are pro-inflammatory, IFN-γ boosts antiviral defense, IL-4/IL-10 dampens inflammation, and CSF promotes blood cell production.

Some of the clinical manifestations of Burkholderia gladioli infection in humans are:

• Pneumonia: This lung infection causes Inflammation and fluid buildup in the lungs’ air sacs. Symptoms include cough, fever, chest pain, and difficulty breathing.
• Bacteremia: This is a blood infection that occurs when bacteria multiply in the bloodstream. Symptoms include fever, chills, low blood pressure, and organ failure.
• Endocarditis: This is an infection of the heart’s inner lining or the heart valves. Symptoms include fever, heart murmur, fatigue, weight loss, and night sweats.
• Osteomyelitis: This is an infection of the bone or bone marrow. Symptoms include pain, swelling, redness, warmth in the affected area, fever, and loss of function.
• Peritonitis: This is an infection of the abdominal cavity’s lining. Symptoms include abdominal pain, tenderness, distension, nausea, vomiting, and fever.

These are some of the possible complications of Burkholderia gladioli infection in humans. However, not all infected individuals may develop these symptoms.

The diagnosis of Burkholderia gladioli infection can be made by using different methods, such as:

• Clinical exam: Symptoms and exposure history help suspect but not confirm.
• Microscopy: Stained samples checked for motile, oxidase-negative rods.
• Culture: Samples were grown on Burkholderia-selective medium, and the colonies’ appearance was noted.
• Molecular ID: DNA amplified, sequenced, and compared for accurate identification.

• Several general steps can help lower the risk of Burkholderia gladioli infection are:
• Avoiding contact with contaminated soil, water, plants, or animals
• Practicing good hygiene and sanitation
• Masks and protective gloves when handling potentially hazardous substances and infected materials.
• Disinfecting tools and equipment that may have been exposed to Burkholderia gladioli.
• Isolating infected individuals or plants from healthy ones
• Seeking medical attention if symptoms develop
• Using appropriate antibiotics or antifungals as a doctor or veterinarian prescribes.

Burkholderia gladioli sinonasal infection – PubMed (nih.gov)

Burkholderia gladioli – an overview | ScienceDirect Topics