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101 Cards in this Set
- Front
- Back
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List some of the resident skin flora
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Coag-negative staph
Corynebacteria Propionibacteria Micrococci (fecal flora and staph aureus may appear transiently) |
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How does acne develop
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androgenic stimulation - excess sebaceous secretions -> blocked glands form pustule
secondary infection with Propionibacterium acnes |
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What is the treatment for acne?
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Doxycycline
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Which layer of the skin does impetigo involve?
What does it look like? |
Epidermis
Vesicles, evolving to crusts |
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What two organisms cause impetigo?
What is the treatment? |
Grp A Strep; staph aureus
Tx - fluclox, topical abx |
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True or false: folliculitis is defined by involvement of the subcutaneous tissue
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False - it does not reach this deep
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What bugs cause folliculitis?
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Pseudomonas and staph aureus
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What can folliculitis develop into?
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A furuncle, or carbuncle
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What causes furuncles and carbuncles?
What is the treatment? |
Staph aureus
Flucloxacillin |
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What is erysipelas?
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Superficial cellulitis with prominent lymphatic involvement
Erythematous, well-demarcated, peau d'orange |
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What is the MAIN cause of erysipelas? What is the treatment?
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Grp A strep; penicllin
Occasionally caused by grp B,C,G strep or staph aureus |
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Name three bacteria causing cellulitis
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Strep pyogenes (grp A)
staph aureus pasteurella multocida (cat/dog bites; oft w/ anaerobes) |
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What is the treatment for cellulitis?
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Benzylpen + fluclox, until results of culture are known
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What is Nikolsky sign?
What does it indicate and what bacteria causes it? |
Skin slides off when brushed lightly - indicates scaled skin syndrome - staph aureus producing exfoliative toxin
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Is scalded skin syndrome serious?
What is the treatment? |
Quite serious - 60% mortality in adults; not as bad in children
Flucloxacillin |
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Name three bugs you commonly find in an abscess
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Strep pyogenes, staph aureus, anaerobes
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How do you diagnose and treat an abscess?
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Dx - pus sample and gram stain
Tx - drainage and abx |
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What causes Type I necrotizing fasciitis?
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It is polymicrobial
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What causes Type II necrotizing fasciitis?
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Grp A strep
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What is Fournier's gangrene?
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Full thickness necrosis of the perineal skin, including penis, scrotum, abdominal wall
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What is the treatment of necrotizing fasciitis?
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Extensive surgical debridement and combo abx therapy -
- benzylpen - covers staph - clindamycin - covers anaerobes and shuts down toxin production - ciprofloxacin - broad spec cover |
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What causes gas gangrene?
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clostridium perfringens
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What causes infection in clean surgical wounds?
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Staph aureus and strep
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What causes infection in dirty surgical wounds?
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staph, strep, anaerobes, GNB, enterococci
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What bug classically infects burns?
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Pseudomonas
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Patient presents with erythema chronicum migrans; what is the dx and what is the treatment?
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Dx - Lyme disease
Tx - doxycycline and amoxicillin |
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Name the bacteria ass'd with meningitis in neonates
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LEG
listeria, e coli, grp B strep |
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Name a bacteria ass'd with meninngitis in the elderly and pregnant women
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Listeria
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Name two bacteria commonly ass'd with meningitis in healthy adults
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Strep pneumoniae
Neisseria meningitidis |
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What disease is caused by cocksackie A?
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Hand, foot and mouth - vesicles on said areas, usually in children; self-limiting
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Name 3 viral skin infections
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Herpes, HPV, cocksackie A
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Name four fungal skin infections
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candida
sporothrix (sporotrichosis) tinea (ringworm) malassezia (pityriasis) |
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What can candida cause in the skin?
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Diaper rash
Athletes foot Paronychia |
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What is used to treat candida skin infection
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fluconazole - oral
clotrimazole - topical |
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What three families of organisms cause ringworms
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Trichophyton
Epidermiphyton Microsporum |
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What is the treatment for tinea?
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clotrimazole - topical
terbinafine - good keratin penetration itraconazole - oral |
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What causes pityriasis versicolor?
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Malassezia furfur
- brown macules, chest/back |
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How do you treat pityriasis versicolor?
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oral - itraconazole, terbinafine
topical - clotrimazole |
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How do you treat sporotrichosis?
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Potassium iodide - oral
Amphotericin Itraconazole |
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What causes scabies?
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Sarcoptes scabeii
- a parasitic tick - burrows into epidermis, lays eggs - severe itching |
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Where is scabies classically seen (what part of body)?
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digital webs, axilla, perineum
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What is the treatment for scabies?
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Topical malathion, permethrin
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What setting are most antibiotics used in?
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50% human; 50% agricultural
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Name some factors contributing to antimicrobial resistance
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Increasing travel
Overcrowding of healthcare facilities Antibiotic use and misuse Elderly population OTC antibiotic use |
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What are the three types of resistance
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Clinical - wrong drug/dose
Intrinsic - always been present Acquired - gene transfer |
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What are plasmids containing resistance genes called?
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R plasmids
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What mechanism do plasmids increase their diversity by?
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Transposons
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Name some antibiotics for which resistance develops by inactivation
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beta-lactams
aminoglycosides |
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What setting are most antibiotics used in?
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50% human; 50% agricultural
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How does pseudomonas become resistant to gentamicin?
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altered permeability
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How does resistance to tetracylcines develop?
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Efflux pumps - drug actively pumped out of cell
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Name some factors contributing to antimicrobial resistance
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Increasing travel
Overcrowding of healthcare facilities Antibiotic use and misuse Elderly population OTC antibiotic use |
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Name some antibiotics for which resistance develops by altered binding targets
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altered PBP for strep penumoniae and MRSA
altered 30S subunit for streptomycin altered gyrase for quinolones altered 50S for macrolides |
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What are the three types of resistance
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Clinical - wrong drug/dose
Intrinsic - always been present Acquired - gene transfer |
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Metabolic bypass is a resistance mechanism for which antiobiotics?
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Sulfonamides, trimethoprim - altered folate synthesis pathways
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What are plasmids containing resistance genes called?
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R plasmids
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How does strep pneumoniae become resistant to penicillin?
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altered PBP (production of beta-lactamase has NEVER been seen)
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What mechanism do plasmids increase their diversity by?
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Transposons
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Is cross-resistance in seen in penicillin-resistant strep pneumoniae?
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Some - macrolides, tetracyclines
NOT to vancomycin yet |
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Name some antibiotics for which resistance develops by inactivation
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beta-lactams
aminoglycosides |
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What is the recommended treatment for pneumoococcal meningitis?
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Cefotaxime + vancomycin until sensitivities are available
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How does pseudomonas become resistant to gentamicin?
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altered permeability
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True or false: higher doses of penicillin are often sufficient to overcome penicillin resistance in strep pneumoniae
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True
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How does resistance to tetracylcines develop?
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Efflux pumps - drug actively pumped out of cell
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Besides appropriate prescribing, what other strategy is effective for reducing penicillin-resistant strep pneumoniae?
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Vaccination against commonly resistant strains
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Name some antibiotics for which resistance develops by altered binding targets
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altered PBP for strep penumoniae and MRSA
altered 30S subunit for streptomycin altered gyrase for quinolones altered 50S for macrolides |
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Metabolic bypass is a resistance mechanism for which antiobiotics?
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Sulfonamides, trimethoprim - altered folate synthesis pathways
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How does strep pneumoniae become resistant to penicillin?
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altered PBP (production of beta-lactamase has NEVER been seen)
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Is cross-resistance in seen in penicillin-resistant strep pneumoniae?
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Some - macrolides, tetracyclines
NOT to vancomycin yet |
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What is the recommended treatment for pneumoococcal meningitis?
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Cefotaxime + vancomycin until sensitivities are available
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True or false: higher doses of penicillin are often sufficient to overcome penicillin resistance in strep pneumoniae
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True
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Besides appropriate prescribing, what other strategy is effective for reducing penicillin-resistant strep pneumoniae?
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Vaccination against commonly resistant strains
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True or false: MRSA is susceptible to certain narrow-spectrum cephalosporins
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False: resistant to ALL beta-lactams
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What are some typical areas on the body which carry MRSA?
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Nose
Perineum Axilla Broken skin |
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True or false: MRSA particularly affects young females
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False; particularly old males
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True or false: healthcare-acquired MRSA is typically multiply resistant, while community-acquired is typically resistant to beta-lactams only
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True
healthcare acquired often resistant to quinolones, macrolide, aminoglycosides |
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What gene is responsible for MRSA resistance?
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MecA - altered PBP with low affinity for all beta-lactams
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Name some agents which would be appropriate for MRSA
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Vancomycin
Linezolid Daptomycin Tigecycline - combo therapy may be indicated |
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How is MRSA transitted?
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Hands, devices
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What are some risks for VRE infection?
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Recent major surgery
Immunosuppression Recent treatment with vanc or cephalosporins |
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What would you use to treat VRE?
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Linezolid
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Which type of bacteria are ass'd with ESBL production?
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Aerobic gram(-) eg.
enterobacter, e. coli, klebsiella |
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What does ESBL confer resistance to?
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Penicillins and cephalosporins
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Is ESBL easy to detect?
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It is not always obvious. It may be inducible only and require special techniques to demonstrate
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What treatment is useful for treatment of ESBL-producing bugs?
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Meropenem; aminoglycosides and quinolones may be as well
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How is multi-resistant TB defined?
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TB resistant to two or more 1st-line drugs
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What is XDR TB?
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TB resistant to rifampicin, isoniazid, fluoroquinolones, and one injectable preparation of aminoglycoside
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What are four common primary immunodeficiency disorders?
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XLA
SCID chronic granulomatous disease leukocyte adhesion deficiency |
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What protein is defective in XLA?
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cytoplasmic tyrosine kinase -- Bruton's TK (chr 21)
B cells fail to develop; occasionally neutropenic |
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Common infections in XLA?
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sinusitis, otitis media, brochiectasis
normal size spleen and lymph nodes absent/not enlarged |
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What treatment is typical for XLA?
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IVIG for life
antibiotics as req'd postural drainage |
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What cells are missing in SCID
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T cells fail to mature; B and NK cells also deficient; occ
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What protein is defective in SCID?
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Common gamma chain of IL-2 receptor (several cytokines receptors defective as a result)
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What is the commonest subtype of SCID?
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X-linked -- 60% of cases - B cells present in this (NK and T missing)
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How is SCID treated?
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BM transplant or gene therapy
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Which cells are defective in chronic granulomatous disease?
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Neutrophils (not deficient -- just defective)
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What molecular defect cause chronic granulomatous disease?
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NADPH oxidase - failed respiratory burst - defective cell killing
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What hallmark infections/symptoms are seen in CGD?
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lymphadenitis
skin abscesses pneumonia hepatosplenomegaly diarrhea |
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What treatments used in CGD?
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abx - septrin
anti-fungal - itraconazole IFN-gamma BM transplant steroids |
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What is the defect in leukocyte adhesion deficiency?
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Failed expression of CD18
- a beta-2 integrin on leukocytes - failure of cells to migrate to sites of infection - tx - bm transplant |
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List some acquired immunodeficient states
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HIV
malignancy (bm infiltration) malnutrition splenectomy steroids chemotherapy |
