Pseudomonas + relate opportunistic pathogens

• What is the focus of the study on Pseudomonadaceae and related opportunistic pathogens?

  To introduce the bacterial group, focusing on Pseudomonas aeruginosa and Burkholderia genus
• What is the clinical significance of Pseudomonadaceae?

  It includes important opportunistic pathogens affecting immunocompromised individuals
• What should students be familiar with regarding Pseudomonadaceae?

  Phylogeny, nature, and key members of the group
• Why is Pseudomonas aeruginosa considered an epitome of an opportunistic pathogen?

  It exploits failing host defenses to initiate infections
• What are the faecal carriage rates of Pseudomonas aeruginosa?

  Between 15-25%, higher in vegetarians
• In what types of environments can Pseudomonas aeruginosa multiply?

  In nutritionally poor environments
• What are some examples of substances that Pseudomonas aeruginosa can grow in?

  Aviation fuel, distilled water, photographic chemicals, cosmetics, plasticisers
• What type of bacteria are Pseudomonadaceae?

  Gram-negative bacilli
• What are the characteristics of Pseudomonadaceae?

  They are aerobic, non-fermentative, and have polar flagella
• What are the common and uncommon human pathogens in the Pseudomonadaceae family?

  Common human pathogens:

  • Pseudomonas
  • Burkholderia

  
  

  Uncommon human pathogens:

  • Sphingomonas
  • Ralstonia
  • Stenotrophomonas
• What disease is caused by Pseudomonas aeruginosa?

  It is a model opportunistic pathogen affecting immunosuppressed individuals, cystic fibrosis patients, and burn patients
• What is the role of Pseudomonas fluorescens and Pseudomonas putida in human health?

  They are poor pathogens but can cause rare cases of endotoxic shock from contaminated blood products
• What opportunistic infection is associated with Burkholderia cepacia?

  It causes opportunistic infections in cystic fibrosis lung infections
• What disease does Burkholderia mallei cause?

  Glanders in horses, rarely in humans
• What is the main difference between Burkholderia mallei and Burkholderia pseudomallei?

  Their geographic distribution and habitat
• How does Pseudomonas aeruginosa initiate infections?

  By exploiting failing host defenses
• What types of infections can Pseudomonas aeruginosa cause in humans?

  Endocarditis, respiratory infections, bacteraemia, central nervous system infections, ear infections, eye infections, bone and joint infections, urinary tract infections, skin and soft tissue infections, and gastrointestinal infections
• What are the routes of spread for Pseudomonas aeruginosa?

  • Ubiquitous in the environment: soil, water, domestic, and hospital settings
  • Spread via person-to-person contact, fomite spread, and exposure to environmental sources
• What disease does Ralstonia solanacearum cause?

  Wilt disease of many cultivated plants
• What is the role of Pseudomonas syringae in plant pathology?

  It causes chlorosis and necrotic lesions on leaves and cankers in woody plants
• What is Burkholderia pseudomallei known for?

  Causing melioidosis in humans and farm animals
• What is the significance of Burkholderia pseudomallei's long-term environmental survival?

  It can survive in soil and water for over a year
• What is the "Vietnam time bomb" in relation to melioidosis?

  It refers to patients with latent melioidosis who may be symptom-free for decades
• What are the symptoms of glanders caused by Burkholderia mallei?

  Ulceration and cutaneous lesions, pulmonary abscesses, and septicaemia
• Why is Burkholderia mallei considered a potential biological weapon?

  It has a low infectious dose, is easy to produce, and has high mortality rates
• What is the occurrence of Burkholderia cepacia?

  It occurs commonly as a resistant saprophyte in soil and water worldwide
• What impact does Burkholderia cepacia have on human health?

  It can cause rapidly fatal necrotizing pneumonia and bacteraemia in cystic fibrosis and chronic granulomatous disease patients
• What are the key virulence factors of Pseudomonas aeruginosa and their functions?

  • Fimbriae & adhesins: attachment to host cells, biofilm formation
  • Neuraminidase: modifies host receptors for attachment
  • Polysaccharide capsule: protects against immune systems and antibiotics
  • Endotoxin: may cause septic shock
  • Exotoxin A: inhibits host cell protein synthesis
  • Elastase, protease, haemolysins: break down host cell fibers
  • Pyocyanin: generates tissue-damaging radicals
  • Exopolysaccharides: facilitates biofilm formation
• What is the primary habitat of Burkholderia pseudomallei?

  Found in soil, water, rice paddies
• What is the significance of the outbreak caused by Burkholderia pseudomallei in a Paris zoo?

  It caused major outbreaks and serious damage to zoo populations and equestrian clubs
• What is the mortality rate associated with pulmonary and septicaemia infections caused by Burkholderia mallei?

  High mortality rate, even when treated
• What historical events are associated with Burkholderia mallei?

  It affected Russian military horses in WW1 and caused an outbreak in a Chinese village in 1942
• What is the role of Burkholderia cepacia in the environment?

  It acts as a soil saprophyte and can cause soft rot of onions
• In which patients is Burkholderia cepacia particularly dangerous?

  In cystic fibrosis and chronic granulomatous disease patients

  
• What type of pneumonia can Burkholderia cepacia cause?

  Rapidly fatal necrotizing pneumonia