Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
56 Cards in this Set
- Front
- Back
|
Define colonisation |
The presence of bacteria on the skin, a mucous membrane or a wound without any symptoms or signs of infection |
|
|
Describe the microbiology of normal skin - permanent residents |
Staphylococci Corynebacteria (diptheroids) Propionibacteria (acne) Acinetobacter |
|
|
What bacterium can be described as a temporary resident on normal skin? |
S. aureus |
|
|
What comprises the transient flora of skin? |
Coliforms Pseudomonas |
|
|
What effect does damaged skin have on colonisation? |
Makes skin prone to colonisation with more pathogenic bacteria |
|
|
Give three examples of pathogenic bacteria that colonise damaged skin |
S. aureus Streptococci Pseudomonas |
|
|
What must happen for colonisation to become infection? |
Breaching of the normal skin barrier |
|
|
What are the two main pathogens of skin/soft tissue? |
Staph. aureus Strep. pyogenes |
|
|
Give examples of pathogens affecting the skin/soft tissue - Bacterial |
Haemolytic streptococci Pseudomonas Coliforms Anaerobes |
|
|
Give examples of pathogens affecting the skin/soft tissue - Viral |
Herpes (HSV, VZV) |
|
|
Give examples of pathogens affecting the skin/soft tissue - Fungal |
Ringworm (Tinea) |
|
|
Describe the skin/soft tissue infections caused by S. aureus |
Pustular lesions Impetigo Cellulitis Infected wounds Cannula infections Toxin-mediated (scalded skin syndrome) |
|
|
Describe the skin/soft tissue infections caused by S. pyogenes |
Impetigo Erysipelas Cellulitis Necrotising fasciitis Toxin-mediated (scarlet fever) |
|
|
Describe a carbuncle |
A cluster of boils draining pus onto the skin |
|
|
How are carbuncles treated? |
Draining of pus and antibiotic therapy |
|
|
Describe cellulitis |
Infection of the upper layers of skin Erythrema, swelling, painful Often turns white on pressure Can cause blisters/ulcers |
|
|
Describe erysipelas |
Infection of the upper skin and lymphatics that causes a skin rash on the face/limbs |
|
|
How is erysipelas different from cellulitis? |
More superficial More raised/demarcated |
|
|
Describe impetigo |
Yellow, crusting lesions present on the skin Often heals w/o scarring Often a mix of S. aureus/S. pyogenes Very contagious |
|
|
Describe scalded skin syndrome |
Due to S. aureus infection (often at distant site) releasing scalded skin syndrome toxin Layers of skin split, can slough off easily |
|
|
Describe Herpes Simplex - Whitlow |
An abscess in the soft tissue near fingernails/toenails V. painful |
|
|
Describe Shingles (VZV) |
Reactivation of dormant Varicella Zozter Virus Characterised by painful skin rash w/ blisters in a localised area |
|
|
Describe Thrush |
Infection w/ Candida Itching, burning, white discharge |
|
|
Describe Tinea Pedis (Dermatophyte) |
Athletes Foot Fungal infection causing itching, redness and scaling |
|
|
Describe Anthrax |
Infection caused by bacillus anthracis Skin form presents as a small blister w/ surrounding swelling that develops into an ulcer w/ black centre Relatively painless |
|
|
Describe necrotising fasciitis |
Infection resulting in soft tissue death Sudden onset and rapid spread Red/purple skin, fever, vomiting SEVERE PAIN |
|
|
What is the surgical treatment for necrotising fasciitis? |
Debridement, cutting away of soft tissue |
|
|
Describe a central line infection |
Infection of inserted central line Can give rise to soft tissue infection Can be v. serious |
|
|
What is the antibiotic therapy for S. aureus? |
Flucloxacillin Co-amoxiclav |
|
|
Define MRSA |
Methicillin Resistant Staph Aureus |
|
|
What is the antibiotic therapy for S. pyogenes? |
Penicillins Flucloxacillin |
|
|
What antibiotics are available for treating MRSA/resistant S. pyogenes? |
Erythromycin Clindamycin Cefuroxime Vancomycin |
|
|
By what mechanism does resistance arise in MRSA? |
PBP2 is the main target site for penicillins in S. aureus MRSA has a mutated PBP2a Cross-resistant to all Beta-lactams Usually resistant to macrolides |
|
|
What proportion of hospital-acquired skin/soft tissue infections are caused by MRSA? |
1-2% |
|
|
Define disinfectant |
Chemical w/ ability to destroy or inactivate potentially pathogenic micro-organisms |
|
|
Define antiseptic |
Disinfectant that can be applied to skin or mucous membranes |
|
|
Define topical antibiotic |
Natural/synthetic drug w/ antimicrobial activity applied directly to the skin |
|
|
What are the advantages of topical antibiotics? |
High conc at site of infection Can use agents too toxic for systemic use Cheap Combination preparations w/ steroids available |
|
|
What are the disadvantages of topical antibiotics? |
May not penetrate to site of infection Can get systemic absorption Resistance |
|
|
Where are topical antibiotics most commonly used? |
Skin Mucous membranes Mouth Eyes Nose Skin Vagina |
|
|
What topical antibiotics are used around the mouth? - What are they treating? |
Nystatin (candida) |
|
|
What topical antibiotics are used around the eyes? - What are they treating? |
Chloramphenicol/Tetracycline (conjunctivitis) |
|
|
What topical antibiotics are used around the nose? - What are they treating? |
Mupirocin (S. aureus/MRSA) |
|
|
What topical antibiotics are used on the skin? - What are they treating? |
Fucidin (impetigo) Aciclovir (cold sores) Azoles (fungal infections) |
|
|
What topical antibiotics are used around the vagina? - What are they treating? |
Azoles (thrush) |
|
|
Describe septic arthritis |
Acute bacterial infection of a joint, often metastatic |
|
|
What are the principle pathogens for SA? |
S. aureus S. pyogenes Pneumococcus |
|
|
What are the clinical features of SA? |
Pain, inflammation Joint effusion Restricted movement Pyrexia Systemic sepsis |
|
|
How is SA diagnosed? |
Mc&C on Joint aspirate Blood culture |
|
|
What is the treatment for SA? |
High dose of i.v. antibiotics >2wks Followed by 4wks oral antibiotics |
|
|
Define osteomyelitis |
Acute/chronic infection of bone, usually metastatic spread |
|
|
What are the principle pathogens for osteomyelitis? |
S. aureus Streptococci M. tuberculosis |
|
|
What are the clinical features of osteomyelitis? |
Pain, swelling, fever Systemic sepssis Deformity, collapse (vertebra), fracture |
|
|
How is osteomyelitis diagnosed? |
X-ray, bone scan, MRI Blood cultures Bone biopsy |
|
|
What is the treatment for osteomyelitis - Acute |
High dose i.v. antibiotics >6wks +/- surgical drainage |
|
|
What is the treatment for osteomyelitis - Chronic |
Formation of sequestrum (dead bone w/i tissue) Months of antibiotics + surgery Often relapses |
