CH 19: Microbial Diseases of the Skin and Wounds

An infected hair follicle at the base of the eyelid is called a

Sty

What is the causative agent of cat scratch fever?

Bartonella henselae

Smallpox was the first human disease to be

Globally eradicated from nature

What type of virus causes measles?

Morbillivirus

A fungus that is classified as an anthropophilic dermatophyte

Is associated only with humans

What feature of Staphylococcus aureus differentiates it from other staphylococci?

production of coagulase

Which of the following is NOT a sign or symptom of a pseudomonas infection?

rash on the face and neck

How does a person acquire Rocky Mountain spotted fever (RMSF)?

tick bite

What is shingles?

reactivation of the chickenpox virus

How do people acquire leishmaniasis?

bite of an infected sand fly

What type of organism causes scabies?

arachnid

Functions of the skin

prevents water loss, regulates temperature, sensory phenomena, vitamin D formation, barrier against invaders

Two layes of skin

Dermis, epidermis

Normal microbiota

harmless, cannot be removed, grow in moist areas, waste products cause BO

Folliculitis

Often called a pimple, infection of a hair follicle. Called a sty at the base of the eyelid

Furuncles

Produced by spread of infection into surrounding tissues

Carbuncles

multiple furuncles grow together

Two species commonly found on skin

Staphylococcus epidermidis, staphylococcus aureus

Staphylococcus transmitted via

Direct contact or by fomites

S. Epidermidis

Lacks virulence factors and rarely causes disease

Staphylococcus aureus

colonizes the skin or mucous membranes of most people

Staphylococcal Scalded Skin Syndrome (SSSS)

Skin becomes red and wrinkled, forms blisters, outer epidermis peels off in sheets

Pathogensis of SSSS

no scarring, death is rare but cold happen die to secondary infections

Epidemiology of SSSS

Occurs primarily in infants, transmitted by spread of bacteria

Impetigo signs and symptoms

red patches form on face and limbs

Erysipelas signs and symptoms

infection spreads to lymph nodes

Impetigo and erysipelas pathogensesis

bacteria invade where skin is compromised

Impetigo and erysipelas epidemiology

transmitted via fomites, occurs mainly in children

Impetigo and erysipelas treatment

oral and topical antimicrobials, careful cleaning, penicillin. Prevented with proper hygiene and cleanliness

Necrotizing Fasciitis

Spreads, enters through breaks in skin, treated with clindamycin and penicilin

Acne

caused by Propionibacterium acnes, found on skin, begins in adolesence but can occur later in life, treatment using antimicrobial drugs, accutane and UV light

Cat scratch disease symptoms

fever, malaise, swelling at infection site

Cat scratch disease pathogenesis, epidemiology, treatment

transmitted by cat bites or scratches, blood sucking arthropods, diagnosed with serological testing, treated with antimicrobials

Pseudomonas

Blood infection causes fever, chills, shock, blue-green color skin

Pseudomonas Pathogenisis

infection occurs in burn victims, bacteria kills cells, tissues, triggers shock

Spotted fever rickettsiosis signs and symptoms

non-itchy spotted rash, organ failure

Rocky Mountain SPotted Fever pathogenesis, epidemiology

disease occurs from damage to blood vessels, transmitted via tick bite, diagnosed w/ serological testing, treated with antimicrobials

Cutaneosus anthrax

caused by an eschar (black, painless ulcer), treated with anitmicrobial drugs, prevention requires control of disease in animals

Gas gangrene signs and symptoms

death of muscle and connective tissue, presence of gas bubbles

Gas gangrene pathogenesis, epidemiology, diagnosis

traumatic event introduces ednosopores into dead tissue, 40% mortality rate, surgical removal and administration of antitoxin and anitmicrobials, cleaning of wounds

Poxviruses that cause human diseases

small pox, orf, cowpox, monkey pox

First hman disease to be eradicated

smallpox

Herpes signs and symptoms

spin lesions, reoccurence

Herpes epidemiology, diagnosis, treatment

spread between mucous membranes of mouth and genitals, can be fatal in infants, no cure but chemotherapeutic drugs help

Warts signs and symptoms

benign growths on skin or mucous membranes, can from on body surfaces. Most are harmless

Wart epidemiology and treatment

transmitted via contact and fomites, diagnosed by observation, can be removed