Actinomyces

• What type of bacteria are Actinomyces?

  Ubiquitous bacteria found abundantly in soil and microbiota of humans and animals
• Where are Actinomyces commonly found in the human body?

  Gingiva, colon, and vagina
• What disease is caused by Actinomyces organisms?

  Actinomycosis
• What is actinomycosis?

  A chronic suppurative bacterial infection caused by Actinomyces species
• Which species primarily causes actinomycosis?

  Actinomyces israelii
• How do Actinomyces cause disease?

  By invading the system through wounds
• In which patients do Actinomyces infections have a greater impact?

  Immunocompromised patients
• Why is actinomycosis usually difficult to diagnose?

  It causes indolent and slowly progressive infection
• What complicates the identification of Actinomyces infections?

  The need for complicated procedures to obtain tissue samples
• What is the taxonomy of Actinomyces?

  • KINGDOM: Bacteria
  • PHYLUM: Actinomycetota
  • CLASS: Actinomycetia
  • ORDER: Actinomycetales
  • FAMILY: Actinomycetaceae
  • GENERA: Actinomyces
  • SPECIES: A. israelii
• What is the shape and size of Actinomyces bacteria?

  Gram positive rods, 0.4–1.0 µm in size
• How do Actinomyces appear under a microscope?

  They form long, thin, branching hyphae resembling fungal mycelia

  
• What type of oxygen environment do Actinomyces prefer?

  Anaerobic to microaerophilic
• Are Actinomyces motile or non-motile?

  Non motile
• Do Actinomyces form spores?

  No, they are non spore forming
• Are Actinomyces acid-fast?

  No, they are non acid fast
• What is the epidemiology of actinomycosis?

  It has a worldwide distribution and usually affects middle-aged individuals
• How does the prevalence of actinomycosis differ between genders?

  It is two to four times more common in males than in females
• What is the most common area affected by actinomycosis?

  The cervicofacial area, representing 60% of cases
• What typically precedes cervicofacial actinomycosis?

  Dental or oral procedures, or poor dental care
• What is the second most common presentation of actinomycosis?

  Abdominal involvement, constituting 20% of cases
• What is the third most common presentation of actinomycosis?

  Thoracic actinomycosis
• How has antibiotic therapy affected the prognosis of actinomycosis?

  It has significantly improved the prognosis
• What happens to morbidity and mortality with appropriate identification and treatment of actinomycosis?

  They significantly decrease
• What are the risk factors for actinomycosis?

  • Male
  • Age 20-60
  • Diabetes
  • Poor oral hygiene
  • Dental procedures
  • Use of immunosuppressive therapy
  • HIV/AIDS
  • Malignancy
• What is the pathophysiology of actinomycosis?

  It involves a complex interplay between the bacterium, host immune response, and local tissue environment
• How does the site of invasion affect disease manifestation in actinomycosis?

  It depends on the site of invasion as the organism is part of human flora
• When do Actinomyces bacteria typically enter deeper tissues?

  Following disruption of mucosal barriers due to trauma, surgery, or underlying conditions
• What do Actinomyces form once inside tissues?

  Characteristic sulphur granules
• What are sulphur granules composed of?

  Tangled masses of bacterial filaments surrounded by inflammatory cells, necrotic debris, and fibrous tissue
• What role do sulphur granules play in actinomycosis?

  They serve as the focus for abscess formation and chronic inflammation
• What does the presence of sulphur granules trigger?

  A persistent immune reaction aimed at containing and eliminating the infection
• What can inflammation and abscess formation lead to in actinomycosis?

  Tissue destruction and fibrosis, resulting in sinus tracts and fistulas
• Can actinomycosis lead to systemic complications?

  Yes, especially in immunocompromised individuals or untreated infections
• What distant organs can be affected by disseminated actinomycosis?

  Brain, lungs, or bones
• What accounts for more than half of reported cases of actinomycosis?

  Cervicofacial actinomycosis
• What is the origin of cervicofacial actinomycosis?

  It is endogenous in origin, often following dental caries or procedures
• How does thoracic actinomycosis typically begin?

  It commences in the lung, likely from aspiration of Actinomyces from the mouth
• What complications can arise from thoracic actinomycosis?

  Sinuses on the chest wall and erosion of ribs and spine
• What is primary endobronchial actinomycosis?

  An uncommon complication of an inhaled foreign body