16. bacterial skin diseases Flashcards
the ______ is the first line of protection for the skin, so it is in danger to many infections
skin
________ species are normal microbiota of the skin (_____ epidermis and ______ hominis are the most prevalent)
staphylococcus
gram ______ staphylococcus spp. and streptococcus spp. are responsible for many of the most common skin infections.
positive
__________ is quite contagious. it is spread through skin to skin contact, and from the nose to then hands and then to other individuals. many people are chronic nasal carriers of this bacteria
staphylococcus aureus
what are the 5 staphylococcal virulence factors?
- hemolysins: which are cytotoxic to many cells such as skin cells and RBCs
- Coagulase: a plasma clotting protein that is involved in abscess formation
- Leukocidins: kill WBCs and contribute to the formation of pus
- Protein A: an anti-phagocytosis factor
- Toxic shock syndrome toxin01 (TSST-1): causes toxic shock syndrome
Staph. aureus is often associated with _______, skin infection that are purulent. the bacteria invade the hair follicles and cause folluclitis leading to deeper infection in the skin tissue called boil, abscess or furuncle.
pyoderma
a large lesion progressing from a boil is called
carbuncle
sweat, skin injuries, ingrown hairs, tight clothing, irritation from shaving, and skin irritation conditions cal all contribute to _________. avoidance of tight clothing and skin irritation can prevent infection.
folliculitis
this is a superficial infection caused by S. aureus that is mostly seen in young children. bacterial exotoxins first produce erythema and then sever peeling of the skin, as might occur after scaling.
Staphylococcal scaled skin syndrome (SSSS)
this skin infection causes the formation of vesicles, pustules, and possibly bullae, often around then nose or mouth. bullae could become encrusted sores, the crust is yellowish with exudate draining from the base of the lesion. especially common in young children and is contagious.
impetigo
what are is the causative agents of impetigo?
S. aureus alone, Streptococcus pyogenes alone or a combination of both
what is the causative agent of all cellulitis, erysipelas, and erythema nosodum?
Streptococcus pyogenes
this is an infection of the dermis or hypodermic, which present as a painful reddened area in the skin
cellulitis
this is a condition that present as a large, intensely inflamed patch of skin involving the dermis (often on the legs or face). the infection can be suppurative, which results in a bullous form of erysipelas.
erysipelas
this condition is characterized by inflammation of the subcutaneous layer of the skin. the condition may lead to red nodules on the skin, most frequently on the shins
erythema nodosum
this condition, also known as flesh-eating bacterial syndrome is a rare but potentially life threatening condition caused by the spreading of streptococcal infections. it occurs when the fascia, a think layer of connective tissue between the skin and the muscle, becomes infected with Streptococcus pyogenes.
necrotizing fasciitis
in necrotizing fasciitis, S. pyogenes invasins virulence factors infiltrate and destroy host tissues and prevent _________ migration to the site of infection
neutrophil
__________, a gram negative, aerobic bacillus is a common cause of opportunistic infection of wounds and burns. it can also cause hot tub rash, a condition cahracterized by folliculitis that frequently afflicts users of pools and hot tubs
Pseudomonas aeruginosa
P. aeruginosa is also the cause of _______, an infection of the ear that causes itching, redness and discomfort and can progress to fever, pain and swelling
otitis externa/swimmers ear