Bacterial Infections in Macular Rash

Question 1

Streptococcus Pyogenes

Answer 1

Bacterial Infections in Macular Rash
• Gr+ cocci, pairs or *chains
• nonmotile
• most facultative anaerobes
• catalase -
• B Hemolytic
• Bacitracin Sensitive 
• Penicillin G sensitive
DISEASE (for this lecture)
• *Scarlet fever
- *Streptococcal TSS 
• *Rheumatic fever
VIRULENCE
- *hyaluronic acid capsule
• *M protein in CW
• *streptolysin S & O
• *streptokinase
• *hyaluronidase 
• *DNases A-D
- *SpeB= exotoxin B (superantigen!)

Question 2

Treponema Pallidum

Answer 2

Bacterial Infections in Macular Rash
• Gr-, spiral or corkscrew shaped
• human reservoir
• microaerophilic to anaerobic
• extremely labile
• disinfectants, heat, drying
• no fomite transmission
- transmission sex, kiss, touch, congenital
DISEASE
- 1 syphilis
- *highly infectious, hard, painless chancre
- 2 syphilis
• *macular rash skin, mucus membranes over entire body incl. palms, soles (latter is impt. clue to diagnosis)
• *highly infectious
• **condyloma lata
- 3 (late) syphilis
- *gummatous
• granulomatous lesions that coalesce in the skin, bone, and mucous membranes
- *cardiovascular
• involves the ascending thoracic aorta, resulting in a dilated aorta and aortic valve regurgitation
- neurosyphilis
• most common
• ranges from meningitis to general paresis (progressive dementia) and tabes dorsalis (locomotor ataxia)presentation
VIRULENCE
– bundles of flagella (axial filaments–>very motile)

Question 3

Cornyebacterium minutissimum

Answer 3

Bacterial Infections in Macular Rash
• Gr+ filamentous bacillus
• normal microbiota skin
• *erythrasma (chronic infix of intertriginous ares)
• nonmotile, unencapsulated
• aerobe to facultative anaerobe
• catalase +
• non-acid-fast
DISEASE
- causes *Erythrasma
   • superficial skin infection
   • well-defined scaly, red to reddish brown patches inguinal, intergluteal, interdigital etc. 
DIAGNOSIS
• Wood lamp
   – *coral-red fluorescence
   • coproporphyrin III