Chlamydia, rickettsia, miscellaneous gram negatives

• What are the two main genera that were once included in the Chlamydiaceae family?

  Chlamydia and Chlamydophila
• What is the primary focus of the study material regarding Chlamydia and Rickettsia?

  To cover their impact and aetiology
• What is the significance of Chlamydia trachomatis in public health?

  It is the most common preventable cause of blindness
• What are the two types of chlamydial morphologies mentioned?

  Elementary bodies (EB) and Reticular bodies (RB)
• What is the role of elementary bodies (EB) in Chlamydia?

  They are the infectious form and metabolically inactive
• How do reticular bodies (RB) differ from elementary bodies (EB)?

  RBs are metabolically active and can divide by binary fission
• What is the size range of elementary bodies (EB)?

  Approximately 0.2 to 0.3 microns in diameter
• What is the size range of reticular bodies (RB)?

  Approximately 0.5 to 2 microns in diameter
• What is the primary habitat of Chlamydia species?

  They inhabit epithelial cells and macrophages
• What is the significance of the study by Liechti et al., 2014 regarding Chlamydia trachomatis?

  It revealed the existence of peptidoglycan in Chlamydia trachomatis
• What is the primary energy source for Chlamydia species?

  They are energy parasites and must obtain ATP from host cells
• What is the global impact of Chlamydia trachomatis in terms of blindness?

  Responsible for blindness or visual impairment of about 1.9 million people
• What does the SAFE strategy stand for in relation to trachoma?

  Surgery, Antibiotics, Facial cleanliness, and Environmental improvement
• What are the types of trachoma caused by Chlamydia trachomatis?

  Types A, B, and C
• How is inclusion conjunctivitis transmitted in infants?

  It can develop when the infant is in the birth canal
• What are the symptoms of genital chlamydiasis in men?

  Urethritis, mild burning, and white discharge from the penis
• What are the complications associated with genital chlamydiasis in women?

  Infertility, ectopic pregnancy, and postpartum fever
• What is psittacosis and how is it transmitted?

  It is a disease isolated from avian species, especially cockatiels and parakeets
• What are the general features of Rickettsia?

  They are obligate intracellular pathogens and small coccoids or rods
• What is the primary vector for Rickettsia prowazekii transmission?

  Pediculus humanus corporis (body louse)
• What are the symptoms of typhus caused by Rickettsia prowazekii?

  High fever, chills, headache, and may lead to coma
• How does typhus differ from typhoid in terms of transmission?

  Typhus is transmitted by insect vectors, while typhoid is transmitted by food consumption
• What is the incubation period for Legionnaire's disease?

  2 to 10 days
• What is the primary mode of transmission for Legionella pneumophila?

  Inhalation of contaminated aerosols
• What is the role of amoeba in the environment of Legionella species?

  Amoeba serve as an intracellular parasite that protects Legionella against chlorine and heat
• What are the key characteristics of Bordetella pertussis?

  It is an aerobic Gram-negative coccobacillus specific to humans
• What is the primary disease caused by Bordetella pertussis?

  Whooping cough (Pertussis)
• What is the incubation period for whooping cough?

  5 to 10 days
• What are the stages of whooping cough and their symptoms?

  Catarrhal stage: rhinorrhea and mild cough; Paroxysmal stage: forceful coughing and whoop
• What are the complications associated with whooping cough?

  Pneumonia, otitis media, and asthma
• What are the clinical diseases associated with gram-negative obligate anaerobes?

  Periodontal infections, abscesses, and intra-abdominal infections
• Which bacterium is associated with 80% of intra-abdominal infections?

  Bacteroides fragilis
• What is acute necrotizing gingivitis caused by?

  A mixed bacterial infection that includes anaerobes
• What are the general features of Chlamydiaceae?

  • Non-motile, obligate intracellular coccoid bacilli
  • Inhabit epithelial cells/macrophages
  • Small enough to pass through 0.45 micron filters
  • Energy parasites that lack ATP-generating ability
• What are the general features of Rickettsia?

  • Obligate intracellular pathogens
  • Small coccoids or rods (0.3 by 1-2 microns)
  • Fastidious, requiring embryonic eggs or tissue culture cells
  • Multiply by binary fission only in infected cells
• What are the key facts about Legionella pneumophila?

  • Non-spore forming Gram-negative rods
  • Aerobic and motile via a single polar flagellum
  • Nutritionally fastidious in artificial media
  • Most common transmission is inhalation of contaminated aerosols
• What are the stages of whooping cough caused by Bordetella pertussis?

  1. Catarrhal stage: rhinorrhea and mild cough
  2. Paroxysmal stage: forceful coughing and whoop
  3. Complications: pneumonia, otitis media, asthma
• What are the clinical diseases associated with gram-negative obligate anaerobes?

  • Periodontal infections
  • Abscesses
  • Intra-abdominal infections
  • Gynaecological infections
• What is the chain of causation for Legionella infection?

  1. Environmental reservoir
  2. Multiplication (stagnation, temperature, nutrients)
  3. Dissemination by aerosol generation
  4. Inhalation into lungs by susceptible host