117 Questions
What is the primary habitat of Burkholderia pseudomallei?
Soil and water
What is the case fatality rate of melioidosis in some tropical countries?
~35-75%
What is the longest recorded period between exposure and clinical presentation of melioidosis?
~62 years
Which phylum does the Pseudomonadaceae family belong to?
Proteobacteria
What is the main difference between Burkholderia pseudomallei and Burkholderia mallei?
Geographic distribution and habitat
What is the term used to describe the delayed presentation of melioidosis?
The Vietnam time-bomb
What is the primary mechanism of immune evasion by Pseudomonas aeruginosa?
Capsule formation
Which of the following is NOT a characteristic of Pseudomonadaceae?
Fermentative metabolism
What is the name of the disease caused by Burkholderia pseudomallei?
Melioidosis
What is the primary function of pyocyanin in Pseudomonas aeruginosa?
Impairing ciliary function
What is the minimum duration of environmental survival of Burkholderia pseudomallei?
14 years
Which genus is closely related to Pseudomonas?
Burkholderia
What is the risk factor that increases the severity of melioidosis?
Diabetes, renal failure, and HIV
What is the primary site of infection for Pseudomonas aeruginosa in humans?
Lungs
What is the function of elastase in Pseudomonas aeruginosa?
Breaking down proteins
Which of the following is a common feature of opportunistic pathogens?
Ability to cause disease in immunocompromised individuals
What is the percentage of faecal carriage rates in vegetarians?
15-25%
Which of the following can Pseudomonas aeruginosa multiply in?
Nutritionally poor environments
What is the primary source of infection for Pseudomonas fluorescens?
Rare cases of cold storage
Which of the following is a non-pathogenic species of Pseudomonas?
Pseudomonas putida
What is the primary target of infection for Burkholderia cepacia?
CF lung infections
Which of the following is a rare cause of endotoxic shock?
Pseudomonas putida
What is the primary disease caused by Burkholderia mallei?
Glanders in horses
What is the primary use of API 20NE assimilation tests?
To identify Pseudomonas aeruginosa
Which of the following genera is associated with glanders?
Burkholderia
What is a unique characteristic of glanders?
Low infectious dose
Which animal species are commonly affected by glanders?
Horses and donkeys
What is a common symptom of glanders?
Cutaneous ulceration
Where was glanders eradicated in 1906?
China
What is a suspected reason for an outbreak of glanders in a Chinese village in 1942-3?
Japanese biowarfare
What has led to an increase in bacteraemia caused by Pseudomonas aeruginosa and related pseudomonads over the last 30 years?
Features of P. aeruginosa and related pseudomonads
What is a common occupation of people who are at risk of contracting glanders?
All of the above
What is the primary mechanism of pathogenesis in Pseudomonas aeruginosa?
Multifactorial
What is the role of pyocyanin in Pseudomonas aeruginosa?
Stimulates an inflammatory response
Where can Pseudomonas aeruginosa be found in hospital environments?
All of the above
What is the function of elastase in Pseudomonas aeruginosa?
Damages tissue
Which of the following is an opportunistic pathogen related to Pseudomonas aeruginosa?
Burkholderia cepacia
What is the effect of the capsule on Pseudomonas aeruginosa?
Evasion of immune cells
Pseudomonas aeruginosa is a strictly anaerobic bacterium.
False
The Pseudomonadaceae family belongs to the Phylum Firmicutes.
False
Burkholderia is a genus that is not part of the Pseudomonadaceae family.
False
Pyocyanin is a siderophore that inhibits protein synthesis.
False
Pseudomonas aeruginosa has a single mechanism of pathogenesis.
False
Xanthomonas is not a genus within the Pseudomonadaceae family.
False
Pseudomonas aeruginosa is a non-opportunistic pathogen.
False
The genus Stenotrophomonas is not part of the Pseudomonadaceae family.
False
Pseudomonas aeruginosa can cause opportunistic infections in humans.
True
Burkholderia pseudomallei is primarily found in soil and water in North America.
False
Melioidosis has a low case fatality rate in some tropical countries.
False
Burkholderia pseudomallei can survive in the environment for up to 10 years.
False
Diabetes is a risk factor that decreases the severity of melioidosis.
False
Pulmonary disease is a rare manifestation of melioidosis.
False
Burkholderia pseudomallei is primarily found in animals in Southeast Asia.
False
The longest recorded period between exposure and clinical presentation of melioidosis is 20 years.
False
Pseudomonas syringae is a model opportunistic pathogen.
False
Burkholderia cepacia is a poor pathogen that can grow at 4°C.
False
Xanthamonas is a genus that can cause infections in humans.
False
Rastonia is a genus that can cause infections in humans.
True
Pseudomonas aeruginosa can multiply in nutritionally rich environments only.
False
Faecal carriage rates of Pseudomonas aeruginosa are higher in non-vegetarians.
False
Pseudomonas fluorescens is a model opportunistic pathogen.
False
API 20NE assimilation tests are used to detect Pseudomonas aeruginosa in aviation fuel.
False
Pseudomonas aeruginosa is a primary pathogen of plants.
False
Ralstonia solanacearum is a pathogen of animals.
False
Burkholderia is a genus that can cause infections in both humans and animals.
True
Xanthomonas is a genus that can cause infections in humans.
False
Pseudomonas aeruginosa is commonly found in soil and water.
True
Pseudomonas marginalis is a pathogen of humans.
False
The Pseudomonadaceae family includes only the genus Pseudomonas.
False
Pseudomonas syringae is a pathogen of animals.
False
Burkholderia mallei is a biological weapon.
True
Glanders can be eradicated from a region in a short period of time.
True
Pulmonary abscesses are a symptom of glanders.
True
Pseudomonas aeruginosa is not an opportunistic pathogen.
False
Burkholderia mallei causes melioidosis.
False
Xanthamonas is a genus within the Pseudomonadaceae family.
True
Pseudomonas aeruginosa can multiply in urine.
True
Glanders has been eradicated globally.
False
Pseudomonas aeruginosa is a strictly anaerobic bacterium.
False
Burkholderia pseudomallei is primarily found in soil and water in North America.
False
Melioidosis has a low case fatality rate in some tropical countries.
False
Pyocyanin is a siderophore that inhibits protein synthesis.
False
Pseudomonas aeruginosa has a single mechanism of pathogenesis.
False
The Pseudomonadaceae family belongs to the Phylum Firmicutes.
False
Burkholderia is a genus that is part of the Pseudomonadaceae family.
True
Pseudomonas aeruginosa can cause opportunistic infections in humans.
True
Burkholderia pseudomallei can survive in the environment for up to 14 years.
True
Glanders is a disease that primarily affects humans.
False
Burkholderia mallei is the causative agent of melioidosis.
False
Pseudomonas aeruginosa is a strictly anaerobic bacterium.
False
Xanthomonas is not a genus within the Pseudomonadaceae family.
False
Burkholderia is a genus that is part of the Pseudomonadaceae family.
True
Pseudomonas aeruginosa can only cause pneumonia in humans.
False
Glanders has been eradicated in all parts of the world.
False
Burkholderia pseudomallei is primarily found in soil and water in North America.
False
The Pseudomonadaceae family belongs to the Phylum Actinobacteria.
False
Pseudomonas aeruginosa is a facultative anaerobe.
False
The genus Rastonia is not part of the Pseudomonadaceae family.
False
Pyocyanin is a siderophore that stimulates an inflammatory response.
True
Pseudomonas aeruginosa has a single mechanism of pathogenesis.
False
The genus Zyomonas is not part of the Pseudomonadaceae family.
False
Burkholderia cepacia is a non-pathogenic species of Burkholderia.
False
Pseudomonas aeruginosa is a non-opportunistic pathogen.
False
Pseudomonas aeruginosa has a single mechanism of pathogenesis.
False
Pyocyanin is a siderophore that inhibits protein synthesis.
False
Burkholderia is a genus that is not part of the Pseudomonadaceae family.
False
Pseudomonas aeruginosa is a non-opportunistic pathogen.
False
Xanthomonas is not a genus within the Pseudomonadaceae family.
False
Pseudomonas aeruginosa is a strictly anaerobic bacterium.
False
Pseudomonas fluorescens is a model opportunistic pathogen.
False
Pseudomonas aeruginosa can multiply in nutritionally rich environments only.
False
Faecal carriage rates of Pseudomonas aeruginosa are between 5-10% in vegetarians.
False
Rastonia is a genus within the Pseudomonadaceae family.
True
Pseudomonas aeruginosa is a poor pathogen that can only grow at 4°C.
False
Burkholderia cepacia is a non-pathogenic species.
False
API 20NE assimilation tests are used to diagnose melioidosis.
False
Stenotrophomonas is not a genus that can cause infections in humans.
False
Study Notes
Pseudomonas Aeruginosa
- Can multiply in nutritionally poor environments, such as aviation fuel, distilled water, photographic chemicals, cosmetics, and plasticisers.
- Faecal carriage rates are between 15% and 25%, with higher rates in vegetarians.
Pseudomonas and Related Genera
- Many genera and species within the group, including Pseudomonas, Burkholderia, Xanthamonas, Rastonia, Zyomonas, Sphingomonas, and Stenotrophomonas.
- Aside from Pseudomonas, Burkholderia, Xanthamonas, Rastonia, Zyomonas, Sphingomonas, and Stenotrophomonas can also cause infections in humans.
Pseudomonas Aeruginosa Infections
- Opportunistic: exploits failings in host defences to initiate infection.
- Can cause infections in immunosuppressed individuals, cystic fibrosis patients, and burns patients.
Burkholderia Pseudomallei - Melioidosis
- Occurs as a saprophyte in parts of Southeast Asia, India, Africa, and North Australia.
- Found in soil, water, and rice paddies, with long-term environmental survival (up to 14 years).
- Causes severe infections in animals and humans in some tropical countries, with a 20% case fatality rate in Thailand.
Infections Caused by Pseudomonas and Related Genera
- Pseudomonas aeruginosa: opportunistic infections in humans, including immunosuppressed individuals, cystic fibrosis patients, and burns patients.
- Burkholderia cepacia: opportunistic infections in CF lung patients.
- Burkholderia mallei: causes glanders in horses and rarely in humans.
- Burkholderia pseudomallei: causes melioidosis in humans and farm animals in tropical countries.
Characteristics of Pseudomonadaceae
- Gram-negative.
- Polar flagella.
- Strictly aerobic (except for Zyomonas).
- Many genera and species within the group, including Pseudomonas, Burkholderia, Xanthamonas, Rastonia, Zyomonas, Sphingomonas, and Stenotrophomonas.
Pathogenesis of Pseudomonas Aeruginosa
- Multifactorial, with no single mechanism.
- Structural factors: adhesins, pili, EPS, LPS, capsule, and pyocyanin.
- Pyocyanin: impairs ciliary function, stimulates inflammatory response, and is a siderophore.
- Exotoxins: inhibit protein synthesis and cause tissue damage.
- Enzymes: elastase, protease, and haemolysins.
Survival of Pseudomonas Aeruginosa
- Can survive in hospital environments, including mops, sinks, toilets, dialysis equipment, respiratory tubing, and cut flowers.
Pseudomonadaceae and Opportunistic Pathogens
- The Pseudomonadaceae family includes diverse genera such as Pseudomonas, Burkholderia, Xanthamonas, Rastonia, Zyomonas, Sphingomonas, and Stenotrophomonas.
- These bacteria are Gram-negative, have polar flagella, and are strictly aerobic.
- Pseudomonas aeruginosa is an opportunistic pathogen that exploits weakened host defenses to initiate infection.
Characteristics of P. aeruginosa
- Has a capsule that evades immune cells and antibiotics
- Produces pyocyanin, which impairs ciliary function, stimulates an inflammatory response, and is a siderophore
- Secrete exotoxins that inhibit protein synthesis and cause tissue damage
- Has adhesins, pili, EPS, and LPS, which contribute to its pathogenesis
- Causes a range of infections, including gastrointestinal, skin, and soft tissue infections, particularly in immunocompromised individuals
Environmental Significance of Pseudomonads
- Ubiquitous in the environment, found in soil, decaying organic matter, vegetation, and water
- Can multiply in nutritionally poor environments, such as distilled water and photographic chemicals
- Faecal carriage rates are between 15-25%
Pseudomonas syringae
- A plant pathogen that causes wilt diseases in many cultivated plants, including potatoes and tomatoes
- Causes chlorosis and necrotic legions on leaves
Burkholderia
- Burkholderia cepacia can cause opportunistic infections in cystic fibrosis patients
- Burkholderia mallei causes glanders in horses and rarely in humans
- Burkholderia pseudomallei causes melioidosis in humans and animals, particularly in Southeast Asia and tropical regions
Melioidosis
- Caused by Burkholderia pseudomallei, which survives for long periods in soil and water
- Causes severe infections in animals and humans, with a high case fatality rate
- Patients with latent melioidosis may be symptom-free for decades
- Can be a biological weapon due to its low infectious dose and high mortality rate
Pseudomonadaceae & Other Opportunistic Pathogens
- The Pseudomonadaceae family includes a diverse group of Gram-negative bacteria, with a focus on Pseudomonas aeruginosa.
Classification of Pseudomonadaceae
- Domain: Bacteria
- Phylum: Proteobacteria
- Class: Beta and Gamma
- Order: Burkholderiales and Pseudomonadales
- Family: Burkholderiaceae and Pseudomonadaceae
- Genus: Burkholderia and Pseudomonas
- Species: cepacia and aeruginosa
Characteristics of Pseudomonadaceae
- Gram-negative
- Polar flagella
- Strictly aerobic
- Many genera and species within the group, including:
- Pseudomonas
- Burkholderia
- Xanthamonas
- Rastonia
- Zyomonas
- Sphingomonas
- Stenotrophomonas
Pseudomonas aeruginosa
- Causes infections in humans, particularly in immunosuppressed individuals, cystic fibrosis patients, and burns patients
- Ubiquitous, can multiply in nutritionally poor environments
- Faecal carriage rates are between 15-25% (higher in vegetarians)
- Pathogenesis: No single mechanism – multifactorial
- Structurally, P. aeruginosa has:
- Adhesins / pili / EPS / LPS
- Capsule (evades immune cells & antibiotics)
- Pyocyanin: impairs ciliary function, stimulates inflammatory response, and is a siderophore
- Exotoxins: Inhibit protein synthesis, cause tissue damage
- Cytotoxin: Leukocyte damage, pulmonary injury
- Enzymes: Elastase, protease, haemolysins
Other Opportunistic Pathogens
- Burkholderia cepacia: Opportunistic infection in CF lung infections
- Burkholderia mallei: Glanders in horses, rarely in humans
- Burkholderia pseudomallei: Melioidosis in humans and farm animals, particularly in tropical countries
- Pseudomonas syringae: Plant pathogen, environmental significance
Pseudomonas syringae
- Plant pathogen, environmental significance
- Video: https://www.youtube.com/watch?v=pH-afIrfUbQ
Other Genera Causing Infections
- Burkholderia: Opportunistic infection in CF lung infections
- Xanthamonas: May cause infections in humans
- Rastonia: May cause infections in humans
- Zyomonas: May cause infections in humans
- Sphingomonas: May cause infections in humans
- Stenotrophomonas: May cause infections in humans
Burkholderia pseudomallei - Melioidosis
- Occurs as a saprophyte in parts of Southeast Asia, India, Africa, and North Australia
- Found in soil, water, rice paddies, with long-term environmental survival (14 years)
- Causes severe infections in animals and humans in tropical countries, with a high case fatality rate
- Infections:
- Pulmonary disease
- Cutaneous disease
- Abscess
- May be symptom-free for decades, with a longest period of 62 years between exposure and clinical presentation
Burkholderia mallei - Glanders
- Causes glanders in horses, rarely in humans
- Endemic in parts of Africa, Asia, and the Middle East
- Biological weapon, with low infectious dose, easy to produce, and high mortality rate
- Glanders symptoms:
- Cutaneous ulcer
- Ulceration and formation
- Pulmonary abscesses
- Septicaemia
Learn about the Pseudomonadaceae family, focusing on Pseudomonas aeruginosa, its clinical significance, and environmental impact of Pseudomonas syringae.
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