BACTERIAL INFECTIONS

• Types of Skin Lesions

  • Macules
  • Papules
  • Plaques
  • Nodules
  • Urticaria
  • Vesicles
  • Pustules
  • Purpura
  • Ulcers
  • 10. Eschar

  
• Pathogenic bacteria possess characteristics that enable them to circumvent the body's defenses and exploit its resources, resulting in infection
• Bacterial infections spread by a variety of mechanisms: direct contact, ingestion, inhalation
• Staphylococcus aureus


  Gram-positive cocci usually arranged in pairs, short chains, or in grape-like clusters, found in the skin and the nasopharynx, produces enzymes and toxins that contribute to its virulence and pathogenicity
• Staphylococcus aureus


  • - Produces enzymes and toxins
  • Responsible for its invasiveness and pathogenicity
• Clinical Findings of Staphylococcus aureus

  • Folliculitis
  • Furuncle
  • Carbuncle
  • Sty or hordeolum
  • Impetigo
  • Staphylococcal Scalded Skin Syndrome (Ritter's Disease)

  
• Staphylococcal Scalded Skin Syndrome (Ritter's Disease)


  • Sudden onset of perioral erythema that covers the whole body within two days
  • Nikolsky sign - displacement of the skin when slight pressure is applied over the skin
  • Exfoliative toxin is responsible for the manifestation
  • 7-10 days - antibodies against exfoliative toxin are produced and enabling the skin to become intact again, only the outer layer of the epidermis is affected hence there will be no scarring

  
• Laboratory Diagnosis for Staphylococcus aureus

  • Microscopic examination: Gram-stained (gram-positive cocci)
  • Culture: gray to golden yellow colonies

  
• Treatment and Prevention for Staphylococcus aureus

  • Oxacillin - the only penicillin-derived antibiotics that has remained active against S. aureus
  • Incision and drainage
• Patient Care for Staphylococcus aureus infections

  • Standard Precautions for skin, burn, and wound infections if they are minor

  2. Contact Precaution if major, SSSS (Staphylococcus scalded skin syndrome)

  3. Standard Precautions for infections caused by methicillin-resistant S. aureus (MRSA)

  4. Contact Precautions if wounds cannot be contained by dressings
• Staphylococcus epidermidis


  Gram-positive bacteria and it is a part of the skin's normal flora, frequently linked to "stitch abscess", UTI, and endocarditis, it causes infections in people who utilize prosthetic equipment

  
• Streptococcus pyogenes


  Gram-positive cocci, belong to group A beta-hemolytic (cause complete hemolysis of blood), M protein is the major virulence factor (anti-phagocytic), produces enzymes and toxins responsible for pathogenesis of infection
• Clinical Manifestations of Streptococcus pyogenes

  • Erysipelas (St. Anthony's Fire)
  • Cellulitis
  • Necrotizing Fasciitis
• Complications of Streptococcus pyogenes

  • Acute glomerulonephritis
  • Rheumatic fever

  
• Laboratory Diagnosis for Streptococcus pyogenes

  • Microscopy - gram stain of infected tissue will show gram-positive cocci
  • Culture - positive beta hemolysis in blood agar
  • Bacitracin test - antibiotic susceptibility test
• Diseases of the Upper Respiratory Tract

  • Common Cold
  • Tonsillopharyngitis
  • Croup
  • Influenza
  • Diphtheria

  
• Diseases of the Lower Respiratory Tract

  • Chronic Bronchitis
  • Pneumonia
  • Pertussis
  • Tuberculosis

  
• Tonsillopharyngitis


  Inflammation of the pharynx and tonsils
• Tonsillopharyngitis


  • Seasonal occurrence
  • Children: 5-10 years
  • Adults: 18-20 years
• Causative agent of Tonsillopharyngitis

  Streptococcus pyogenes
• Mode of transmission for Tonsillopharyngitis


  Direct contact with large droplets or respiratory secretions

  
• Clinical manifestations of Tonsillopharyngitis

  • Sudden onset of fever
  • Sore throat
  • Headache
  • Nausea
  • Malaise
  • Pain
  • Tonsillopharyngeal erythema
• Laboratory diagnosis of Tonsillopharyngitis


  Culture of specimen obtained by swab of the posterior pharyngeal-tonsillar regions
• Treatment and prevention of Tonsillopharyngitis

  • Penicillin
  • Erythromycin
  • Clindamycin

  
• Diphtheria


  Serious infection caused by a bacteria that make toxin (poison)
• Diphtheria


  • Can lead to difficulty breathing, heart failure, paralysis, and even death
• Causative agent of Diphtheria

  Corynebacterium diphtheria
• Incubation period of Diphtheria

  2 - 5 days
• Period of communicability for Diphtheria

  Up to 3 weeks following onset of manifestations
• Clinical findings of Diphtheria

  • Inflammation of respiratory tract
  • Sore throat
  • Fever
  • Thick, gray, adherent pseudomembrane over the tonsils & throat
  • Extension of the membrane into the larynx and trachea causing airway obstruction

  
• Clinical findings of Diphtheria (continued)

  • Obstruction may cause suffocation relieved by intubation or tracheostomy
  • Do not attempt to remove the membrane because it is tightly adherent to the underlying tissue à massive bleeding
  • Arrhythmia
  • Nerve weakness or paralysis
  • "Bull neck" appearance = massive enlargement of cervical lymph nodes
• Laboratory diagnosis of Diphtheria

  • Swab from the nose, throat or other suspected lesions
  • Gram stain
  • Culture = definitive diagnosis
• Treatment for Diphtheria


  • Penicillin G
  • Erythromycin
  • Diphtheria antitoxin = to neutralize the exotoxin
• Prevention of Diphtheria


  • Vaccine
  • Diphtheria-Pertussis-Tetanus (DPT)
  • Given: 2 - 4 - 6 months
  • Isolate infected patients

  
• Chronic Bronchitis


  • A chronic inflammatory condition involving the bronchi
  • A recurrent bacterial infection
• Causative agent of Chronic Bronchitis

  Streptococcus pneumonia = most common
• Mode of transmission for Chronic Bronchitis

  • Droplets
  • Direct contact
• Pneumonia


  Infection involving the lung parenchyma

  
• Types of Pneumonia


  • Typical pneumonia: Lobar pneumonia, Interstitial pneumonia, Bronchopneumonia
  • Atypical pneumonia: "walking pneumonia"
• Causative agents of Pneumonia

  • Streptococcus pneumoniae
  • Staphyloccocus aureus
  • Klebsiella pneumoniae
  • Escherichia coli