Respi MedMicroLec

• Streptococcal Respiratory Diseases (Causative Agents)

  Group A streptococci (S. pyogenes)
• Group A streptococci (S. pyogenes)


  GRAM +

  No. 1 cause of sore throat
• Presentation of Streptococcal Respiratory Diseases

  Pharyngitis

  Laryngitis 

  bronchitis

  • Can develop acute rheumatic fever and acute glomerulonephritis
• Virulence factors of Group A streptococci (S. pyogenes)

  M proteins - inhibit function of C3b complement protein which leads to decrease opsonization

  Hyaluronic acid capsule - resist phagocytosis

  Streptokinases - destroy clots in blood that lead into propagation in deeper tissues

  C5a peptidase - inhibits the action of C5a leading to decrease in chemotaxis of WBC

  Pyrogenic toxins- produces fever

  Streptolysin - destroy, RBC WBC and platelets
• Treatment and Prevention of Streptococcal Respiratory Diseases

  Oral antibiotic

  Cell wall synthesis inhibitors

  • Penicillin
  • Cephalosporins
• Diphtheria causative agent

  Corynebacterium diphtheriae
• Corynebacterium diphtheriae

  GRAM + (Chinese characters)
• Diphtheria


  Sore throat, localized pain, fever

  Presence of a pseudomembrane that can obstruct airways

  Can lead to apnea
• Virulence of Diphtheria

  Diphtheria toxin → Prevents polypeptide synthesis and causes cell death
• Treatment and Prevention of Diphtheria

  Tx: Antitoxin (early stages) & Oral Antibiotic

  Px: Vaccine (DTap)
• Rhinosinusitis causative agent

  Various

  commonly in Adult population
• Rhinosinusitis Presentation

  Damage to upper respiratory system and auditory tube

  Colds, ”runny/ stuffy nose”, facial pain, post nasal drip, cough, bad breath
• Rhinosinusitis Presentation

  Bacteria (yellow-green)

  Viral (whitish)
• Ear Infections

  affects Small aged-children population
• Ear Infections causative agents

  Streptococcus pneumoniae (commonly),

  H. influenzae,

  Bacteroides fragilis
• Ear Infections Presentation

  • Otitis media (middle ear [3 small bones])

  • Otitis Externa (external ear [pinna])
• Ear infection Pathogenesis

  Blockage of the eustachian (auditory) tube or the sinuses due to allergic swelling of the mucosa

  Leading to local accumulation of inflammatory bacterial products
• Ear infections Treatment and Prevention

  Antibiotics

  PX:

  Pneumococcal Vaccine

  HIB VACCINE
• Pneumococcal Pneumonia causative agent

  Streptococcus pneumoniae
• Pneumococcal Pneumonia


  Most common (adults)

  GRAM + cocci (Streptococcus pneumoniae)
• Streptococcus pneumoniae


  Lobar pneumonia (bacterial infection)
• Streptococcus pneumoniae presentation

  Inhalation → IgA destruction → colonization → Lung inflammation accompanied by fluid-filled alveoli and bronchiole

  Include fever, coryza, malaise, sore throat, excessive sweating

  Blood enters the lungs, causing rust-colored sputum (pathognomonic sign)
• Pneumococcal Pneumonia Virulence Factors:

  Adhesins, Pneumolysin, Capsule

  Lobes in the lungs may be affected

  • Unilobe or multilobed
• Pneumococcal Pneumonia treatment and prevention

  Tx: Penicillin

  Px: Vaccine

  PCV- Pneumococcal conjugate

  PPSV- polysaccharide
• Atypical Pneumonia causative agent

  Mycoplasma pneumoniae
• Atypical pneumoniae


  Most common (teenager & young adults)

  Acid fast
• Atypical Pneumonia presentation

  Colonize and kill epithelial cells → mucus buildup and colonization by other bacteria

  Fever, chills, congestion, cough, chest pain

  Blood enters the lungs, causing rust-colored sputum

  May also develop DIARRHEA!!
• Atypical Pneumonia Virulence Factors:

  adhesion protein, Does not have a cell wall!! (has cholesterol)
• Atypical Pneumonia treatment

  Erythromycin/Doxycycline
• Klebsiella Pneumonia causative agent

  Klebsiella pneumoniae
• Klebsiella pneumoniae

  G (-), bacilli
• Klebsiella Pneumonia

  pneumonia disease for Immunocompromised individuals
• Klebsiella Pneumonia


  currant jelly sputum

  Pneumonia symptoms with a thick, bloody sputum

  • Also can be found in GI tract
• Klebsiella Pneumonia Virulence Factors

  Capsule

  Encapsulated like pneumococcal
• Klebsiella Pneumonia Treatment and Prevention

  higher order Antimicrobials (not Peniccilin)
• OTHER DISEASES SIMILAR TO PNEUMOCOCCAL PNEUMONIA

  Causative Agents:

  • Hemophilus influenzae

  • Staphylococcus aureus

  • Yersinia pestis - bubonic plague

  • Chlamydophila psittaci - Ornithosis infection (bird)

  • Chlamydophila pnuemoniae
• Mycoplasma pneumoniae and Legionella pneumophila


  2 organism that may develop diarrhea
• Legionnaires’ Disease Causative Agents


  Legionella pneumophila
• Legionella pneumophila

  G (-), cocco bacilli
• Legionnaires’ Disease Presentation


  pneumonia-like symptoms with non-bloody diarrhea and confusion

  
  

  Epidemiology:

  Natural water habitat

  
  

  No human to human contact , but reservoir to human is seen