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
wounds infected with P. aeruginosa may produce a blue-green pus due to the pigments ______ and _______
pyocyanin and pyoverdine
this condition inflicts 80% of teenagers and young adults. higher incidence among adolescents is due to hormonal changes that can result in overproduction of sebum. it occurs when hair follicles become clogged by shed skin cells and sebum causing non-inflammatory lesions called comedones which take the form of whitehead and then blackhead pimples
acne vulgaris
the _____ color occurs when lipids in the clogged follicle become exposed to the air and then oxidize
black
often comedones lead to infection caused by ________ (gram positive, aero tolerant bacillus) found on the skin which consumes sebum
Cutibacterium acnes
_______ causes inflammatory lesions that may include papules, pustules, nodules or pseudocysts, depending on their size and severity
C. acnes
C. acnes and other gram _______ bacteria on the skin convert lipids secreted by oil glands to unsaturated fatty acids (some are volatile and have strong odour). this is why many deodorants contains antibacterial substances against gram _______ bacteria, to reduce the production of volatile fatty acids and body odour
positive
this us a zoonotic disease. it mainly affects animals such as sheep, goats, cattle and deer but can be transmitted to humans through contact with infected animals or animal products, such as wool or hides.
anthrax
what is the causative agent of anthrax?
Bacillus athracis
the majority of anthrax cases (_________________) occur when anthrax endospores enter the body through abrasions of the skin -> the formation of a nodule on the skin -> the cells die forming a black eschar (a mass of dead skin tissue). this can lead to bacteriemia and septicemia
cutaneous anthrax
B. anthracis forms a ________ that prevents the bacteria from being phagocytized
capsule
B. anthracis produces two exotoxins that cause edema and tissue damage. these are:
- enzymatic lethal toxin (LeTX)
- edema toxin (EdTX)
this is s type of non-cutaneous anthrax; ingested spores, infect first the digestive tract. the mortality rate can be up to 40%, even with treatment.
gastrointestinal anthrax
this is a type of non-cutaneous anthrax; when anthrax spores are inhaled, initially cause influenza-like symptoms, but mortality rates are approxiamtely 45% in treated individuals and 85% in those not treated.
pulmonary/inhahaltion anthrax
this is a type of non-cutaneous anthrax; this has been reported in Europe in iv drug users. it occurs when drugs are contaminated with B. anthracis. high a high mortality rate.
injection anthrax
true or false: there is a vaccine for athrax
true
true or false: there is a vaccine for athrax
true
this infection affects the PNS and skin cells leading to permanent damage and loss of appendages and other body parts. it is not highly contagious, person-to-person transmission only occurs by inhalation into nasal mucosa or prolonged and repeated contact with infected skin. deformed hands and feet and eroded bones, fingers and toes are seen with the disease
leprosy (Hanson’s disease)
what is the causative agent of leprosy
Mycobacterium leprae
M. leprae’s virulence factors are located on the capsule and cell wall enabling it to bind to and evade _____ cells resulting in progressive demyelination and destroying neutrons of the PNS
Scwann
true or false: the patent can sense environmental changes, and injury to the skin tissue results.
false
a group of non-tuberculosis mycobacteria known as rapidly growing mycobacterium (RGM) have been identified as the cause of ________. these are commonly found in water, soil and dust.
tattoo-associated skin infection
this mycobacterium has been reported in cases that have a range of skin lesions, including pink, red and purple papules, scaly papules, granulomatous papules, lichenoid papules and pustules
Mycobacterium chelonae
what is another mycobacterium associated with tattoo-asoocated skin infections?
Mycobacterium haemophilium
this is inflammation of the conjunctiva and is characterized by red, itchy eyes with a discharge of sticky fluid. it is very contagious but also very self limiting. in some cases, certain symptoms such as blurred vision, eye pain, and light sensititivyt can be associated with serious conditions and require medical conditions
bacterial conjunctivitis (pink-eye)
what are the most common causative agents of pink eye?
Haemiphilus influenzae, Moraxella catarrhalis, streptococcus penumoiae and staph aureus
this occurs in newborns whose mothers have certain sexually transmitted diseases where the bacteria are transmitted during the birth process,
neonatal conjunctivitis
___________ is caused by Neisseria gonorrhea, the organism of gonorrhea. inflammation of the cornea in the newborn can lead to blindness
gonococcal ophthalmia
__________ (inclusion conjunctivitis) is due to infection with Chlamydia trachomatis, the organism that causeschlamydia. symptoms include red eyes, pus in the eye and swollen eyelids
chalmydial ophthalmia
this is an infection of the cornea. contact users are particularly at risk for such an infection. symptoms include eye pain and redness, blurred vision, sensitivity to light, excessive tearing and eye discharge
bacteria keratitis
what is the causative agent of bacterial keratitis?
staph aureus and/or psuedomonas aeruginosa
