Chapter 19 - Microbial Disease of the Skin and Wounds Flashcards
*Folliculitis
pathogen
Staphylococcus
- gram pos bacteria
- facultative anaerobes
- cocci typically arranged in clusters
- tolerant of salt + desiccation
*Folliculitis
signs + symptoms
- infection of the hair follicle
- aka pimple
- called a STY when it occurs at the eyelid base
- spread of infection into surrounding tissues can produce furuncles
- carbuncles occur when multiple furuncles grow together
*2 common types of Staphylococcus found on skin
1 Staphylococcus EPIDERMIS
2 Staphylococcus AUREUS
*-differ by beta-lactamase production + toxin production
which is more pathogenic? staph. epidermis or staph aureus?
Staphylococcus aureus is more pathogenic
*Staphylococcal Scalded Skin Syndrome [SSSS]
pathogen
some Staph.AUREUS strains
- [SSSS]
* epidemiology + transmission
- -disease occurs PRIMARILY IN INFANTS
- transmits by person-to-person spread of bacteria
[SSSS]
pathogenesis
- no scarring bc dermis is unaffected
- death is rare but may occur due to secondary infections
- [SSSS]
* diagnosis + treatment
*D-characteristic sloughing of skin
T-administer antimicrobial drugs
P-widespread presence of S. aureus makes prevention difficult
*Impetigo/Pyoderma + Erysipelas
pathogen
- most caused by Staph. aureus
- some caused by Streptococcus pyogenes
*Impetigo/Pyoderma + Erysipelas
transmission + *epidemiology
-transmitted person-to-person contact or via fomites
- -Impetigo [mostly children]
- -Erysipelas [mostly elderly]
Impetigo/Pyoderma + Erysipelas
pathogenesis
- most caused by S. AUREUS
- some caused by Streptococcus pyogenes
Impetigo/Pyoderma + Erysipelas
virulence factors
Strep.pyogenes + Staph.aureus have similar virulence factors:
- -M protein
- -hyaluronic acid
- -pyogenic toxins
Necrotizing Fasciitis
pathogen
mostly caused by Strep. pyogenes
Necrotizing Fasciitis
*transmission
- -Step. pyogenes enters thru breaks in skin
- person-to-person
*Necrotizing Fasciitis
virulence factors
- -Exotoxin A + Streptolysin S are secreted
- various enzymes facilitate invasion of tissues (eating)
Necrotizing Fasciitis
diagnosis + treatment
D-early diagnosis is difficult bc symptoms are nonspecific
T-clindamycin + penicillin
*Acne
pathogen
commonly caused by Propionibacterium acnes
-grap pos, rod shaped diptheroids
Necrotizing Fasciitis
diagnosis + treatment
D-difficult to diagnose early bc symptoms are nonspecific
T-clindamycin + penicillin
*Pseudomonas Infection
pathogen
Pseudomonas aeruginosa
-found in soil, decaying matter, moist environments
*Pyocyanin
- -discoloration seen w pseudomonas infection
- -greenish pigment indicates massive infection
- indicator for diagnosis
*Pseudomonas Infection
pathogenesis
- infections can occur in BURN VICTIMS
- -grows under surface of burn
- p.aeruginosa kills cells, destroys tissue, + triggers shock
- typically do not occur in healthy individualts
- Pseudomonas Infection
* diagnosis + *treatment
- D-pyocyanin discoloration
* T-difficult to treat due to multidrug resistance of P.aeruginosa
Cutaneous Anthrax
treatment + prevention
T- antimicrobial drugs
P-control of disease in animals
*Gas Gangrene
pathogen
several Clostridium species
-C.perfringens [bacterial endospore]
Gas Gangrene
epidemiology/pathogenesis
- traumatic even must introduce endospores into dead tissue
- mortality rate exceeds 40%
*Gas Gangrene
virulence factors
C.perfringens secrete 11 toxins
forms endospores
Gas Gangrene
diagnosis + treatment + prevention
D-appearance:bubbling + blackening of infected skin
T-rapid treatment is crucial
- surgical removal of dead tissue
- administer ANTITOXIN + penicillin
P- proper cleaning of wounds
Poxvirus
pathogen
orthopoxvirus (variola virus)
-smallpox/variola
Poxvirus
signs + symptoms
- disease progress thru series of stages
- PUS FILLED SKIN LESIONS
Poxvirus
epidemiology/pathogenesis
increase in monkeypox (rare) cases over the past decade
spread by inhalation
Herpes
pathogen
herpesviruses 1 + 2
Herpes
signs + symptoms
- slow + spreading skin lesions
- recurrence of lesions is common