MICP BAC INFECTIONS

• Macules


  Flat lesions characterized by change in color of the affected skin

  
• Papules


  Raised lesions, solid in consistency of less than 5 mm in diameter
• Plaques


  Flat with elevated surface (plateau-like) with more than 5 mm in diameter
• Nodules


  Rounded raised lesions more than 5 mm in diameter
• Urticaria


  Ring-like papules or plaques with pinkish color (Wheals or hives)
• Vesicles


  Fluid-filled lesions less than 5 mm in diameter
• Pustules


  Exudate-filled lesions
• Purpura


  Skin lesions due to bleeding into the skin

  
• Petechiae


  Purpura less than 3 mm diameter
• Ecchymosis


  Purpura more than 3 mm diameter
• Ulcers


  Crater-like lesions that involve deeper layers of the epidermis and dermis
• Eschar


  Necrotic ulcer covered with blackened scab
• Pathogenic bacteria possess characteristics that enable them to circumvent the body's defenses and exploit its resources, resulting in infection
• Bacterial infections can spread by direct contact, ingestion, or inhalation
• Staphylococcus aureus


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

  Direct contact with a person having purulent lesions, hands of healthcare workers, fomites (bed linens and contaminated clothing)

  
• Clinical findings of Staphylococcus aureus infections

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

  
• Staphylococcal Scalded Skin Syndrome

  Sudden onset of perioral erythema that covers the whole body within two days, caused by exfoliative toxin

  
• Laboratory diagnosis of Staphylococcus aureus

  Gram stain showing gram-positive cocci, culture showing gray to golden yellow colonies

  
• Treatment and prevention of Staphylococcus aureus infections

  Oxacillin, incision and drainage, standard precautions for minor infections, contact precautions for major infections or MRSA
• Staphylococcus epidermidis


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

  
• Streptococcus pyogenes


  Gram-positive cocci that belong to group A beta-hemolytic, M protein is a major virulence factor, produces enzymes and toxins responsible for pathogenesis
• Transmission of Streptococcus pyogenes


  Direct contact with an infected person, fomites
• Clinical manifestations of Streptococcus pyogenes infections

  • Erysipelas (St. Anthony's Fire)
  • Cellulitis
  • Necrotizing Fasciitis

  
• Necrotizing Fasciitis


  Involves deep subcutaneous tissue, starts as cellulitis and progresses to bullous and gangrenous lesions, can lead to multi-organ failure and death
• Complications of Streptococcus pyogenes infections

  • Acute glomerulonephritis
  • Rheumatic fever
• Laboratory diagnosis of Streptococcus pyogenes

  Gram stain showing gram-positive cocci, positive beta hemolysis in blood agar, bacitracin test for antibiotic susceptibility
• Treatment and prevention of Streptococcus pyogenes infections

  Penicillin as drug of choice, alternative is erythromycin or cephalosporin, drainage and debridement of infected tissues, standard precautions for minor infections, contact or droplet precautions for major infections
• Pseudomonas aeruginosa


  Gram-negative bacillus, an opportunistic pathogen, common cause of nosocomial infections, resistant to most antibiotics, produces water-soluble pigments and virulence factors like adhesins, toxins, and enzymes
• Transmission of Pseudomonas aeruginosa


  Colonization of previously injured skin

  
• Clinical findings of Pseudomonas aeruginosa infections

  • Colonization of burn wounds with blue-green pus and sweet grape-like odor
  • Folliculitis
  • Secondary infection to acne and nail infection
  • Osteochondritis
  • Ocular keratitis in contact lens wearers, endocarditis and osteomyelitis in IV drug users
  • External otitis (swimmer's ear)
  • Respiratory failure in cystic fibrosis patients
  • Sepsis in extensive skin burns

  
• Laboratory diagnosis of Pseudomonas aeruginosa

  Gram stain, culture showing colonies with green pigmentation and sweet grape-like odor

  
• Treatment and prevention of Pseudomonas aeruginosa infections

  Preventing contamination of sterile hospital equipment and instruments, preventing cross-contamination, drug of choice is cephalosporins (cefepime)
• Clostridium perfringens


  Gram-positive rod-shaped bacilli that are anaerobic and rarely produce endospores, produces toxins like alpha, beta, iota, and epsilon, associated with soil and water contaminated with feces
• Transmission of Clostridium perfringens

  Colonization of the skin following physical trauma or surgery

  
• Laboratory diagnosis of Clostridium perfringens

  Microscopic detection of gram-positive bacilli in pairs, culture growth under anaerobic conditions
• Clinical findings of Clostridium perfringens infections

  • Cellulitis, suppurative myositis, myonecrosis or gas gangrene
  • Shock, renal failure, and death within two days of onset
• Treatment and prevention of Clostridium perfringens infections

  Surgical wound debridement, high-dose penicillin therapy, use of standard precautions
• Bacteria are generally associated with many types of ocular infections, and if left untreated, can harm the structures of the eye, resulting in blindness and visual impairment

  
• Types of bacterial eye infections

  • Conjunctivitis
  • Keratitis
  • Keratoconjunctivitis