7. Diseases of the skin, soft tissue and wounds

• outer thick layer of keratinized dead cells
• sebaceous glands
• endogenous organisms
• lysozyme

dermatophytes - species of fungi

reservoir - humans, animals, soil

transmission - direct contact with reservoir or fomites

• grow only in the dead, keratinized outer layer
• cannot grow internally
• grow best in moist areas

wood's light - fungi flouresce at UV wavelength of the light

skin scrapings are looked at under the microscope - morphology

very poor - inhabit outer layer where there is no blood supply

• topical ointment
• systemic treatment - griseofulvin

• elimination of excess skin moisture
• powders
• anti-fungal ointments

staphylococcus aureus

reservoir - humans

transmission - direct contact or fomites

• main carriage is in the nose
• causes noscomial infections
• penicillin-resistant strains

• boil or pimple
• impetigo - lesions
• sty
• abcesses, cellulitis

• laboratory - morphology, gram staining reaction, ability to produce coagulase
• antibiotic sensitivity testing

immune response is not good - infections too superficial to get into blood and stimulate response

• drainage of large lesions
• antibiotic taken orally or intravenously
• antibacterial ointment

• good hygiene
• elimination of carriers among hospital personnel by treating with antibiotic ointment
• - disinfection of hospital surfaces
• there is no vaccine

herpes simplex virus type I

• humans
• direct contact - usually kissing

no protective immune response

• generally not treated - resolve on their own
• acyclovir may be used

• usually secondary - avoid triggering factors
• avoid kissing people with cold sores - only transmissible from the sore

• clostridium perfringes - gas gangrene
• bacteroides species - perirectal abcesses
• streptococcus pyogenes - flesh-eating bacteria
• staphylococcus aureus and peptostreptococcus species - necrotizing fasciitis
• pseudomonas aeruginosa - burn infections and severe eye infections

• invasiveness
• infect tissue that has become anaerobic through loss of blood supply from injury, surgical wounds, or diseases that result in poor circulation
• multiply and produce enzymes that destroy the tissue and becomes anaerobic - spreads rapidly

signs, culture and identification of organisms isolated

• antibiotics of peripheral area
• amputation or excision of infected tissue
• oxygenation of tissue with hydrogen peroxide

mycobacterium leprae

• humans
• not known for certain - incubation period is long

tuberculoid form - less severe, scaling/ discoloration of the skin, more common

lepromatous form - more severe, disfigurement, less common

depends on immune response

• obligate intracellular parasite - destroys cells it multiplies in
• destroys nerves - leads to lack of feeling

• appearance of lesions and lack of feeling in lesions
• laboratory diagnosis

CMI because intracellular

multidrug therapy with dapsone

• dapsone treatment of exposed genetically susceptible persons
• treatment of patients helps prevent spread to others