Sec 29 Bacterial Disease Flashcards
Sites of colonisation in carriers of Staphylococcus aureus
Anterior nares Throat Axillae, perineum Hands Involved skin in individuals with atopic dermatitis
Sites of colonisation in neonates of Staphylococcus aureus
Skin
Umbilicus
Circumcision site
Conjunctivae
Primary pyoderma of skin
Impetigo
Bullous impetigo
Erythema
Botryomycosis
Primary pyoderma of hair follicles
Superficial folliculitis (follicular or Bockhart impetigo)
Folliculitis (sycosis barbae)
Furuncle (boil)
Carbuncle
Secondary pyoderma
Impetiginization of dermatoses such as atopic dermatitis, herpes simplex (superinfection)
Pyodermas associated with systemic disease Job syndrome
Chédiak–Higashi syndrome
Chronic granulomatous disease
First line topical therapy for Impetigo
Mupirocin BID
Retapamulin BID
Fusidic acid BID (not available in United States)
First line systemic therapy for Impetigo
Dicloxacillin 250–500 mg PO qid for 5–7 days
Amoxicillin plus clavulanic acid 25 mg/kg tid
Cephalexin 250–500 mg qid
Second line systemic therapy for Impetigo (if with penicillin allergy)
Azithromycin 500 mg × 1, then 250 mg daily for 4 days
Clindamycin 15 mg/kg/day TID
Erythromycin 250–500 mg PO qid for 5–7 days
Bacterial folliculitis
Staphylococcus aureus folliculitis
Periporitis staphylogenes
Superficial (follicular or Bockhart impetigo)
Deep (sycosis) [may progress to furuncle (boil) or carbuncle]
Pseudomonas aeruginosa folliculitis (“hot tub” folliculitis)
Gram-negative folliculitis (occurs at the site of acne vulgaris, usually the face, with long-term antibiotic therapy)
Syphilitic folliculitis (secondary; acneiform)
First line topical treatment for Streptococcal Pyoderma
Mupirocin BID
First line systemic treatment for Streptococcal Pyoderma
Penicillin V 250–500 mg PO qid for 5–7 days
Dicloxacillin 250–500 mg qid for 5–7 days
Second line topical treatment for Streptococcal Pyoderma
Retapamulin BID
Second line systemic treatment for Streptococcal Pyoderma
Azithromycin 500 mg × 1 then 250 mg daily for 4 days
Clindamycin 15 mg/kg/day tid
Erythromycin 250–500 mg PO qid for 5–7 days
Toxins: Staphylococcus aureus
Exfoliatin type A - Epidermolytic - Bullous impetigo, SSSS
Exfoliatin type B - Epidermolytic - SSSS, Bullous impetigo
TSS toxin 1 - Superantigen - TSS (menstrual > nonmenstrual), food poisoning
Staphylococcal enterotoxins A–C - Superantigen - TSS (nonmenstrual > menstrual), food poisoning
Toxin: Streptococcus pyogenes
Streptococcal pyrogenic exotoxins A, C - Superantigen - TSS (nonmenstrual), scarlet fever
Major Criteria: Staphylococcal Toxic Shock Syndrome
Fever - Temperature >38.9°C (102°F)
Rash - Diffuse macular erythroderma
Desquamation - 1–2 week after onset of illness, particularly on palms/soles
Hypotension - Systolic blood pressure <95 mm
Hg for adults, or less than 5th percentile by age for children <16 years of age, or orthostatic syncope
MCC: Erysipelas
Group A Streptococcus
MCC: Cellulitis
S. aureus
Group A Streptococcus
MCC: Facial/periorbital cellulitis in children
S. aureus
Group A Streptococcus
MCC: Perianal cellulitis in children
Group A Streptococcus
MCC: Cellulitis secondary to bacteremia
Pseudomonas aeruginosa
MCC: Cellulitis associated with water exposure
E. rhusiopathiae (erysipeloid)
DOC: Erysipelas, simple outpatient
Penicillin V
Intramuscular procaine penicillin
Amoxicillin
Vancomycin
DOC: Erysipelas, severe hospitalized
Ampicillin/sulbactam
Ticarcillin/clavulanate
Piperacillin/tazobactam
Imipenem/cilastatin, meropenem
DOC: Cellulitis, simple outpatient
Cephalexin
Dicloxacillin
DOC: Cellulitis, severe hospitalized
Ampicillin/sulbactam Cefazolin Piperacillin/tazobactam Ticarcillin/clavulanate Imipenem/cilastatin, meropenem
Invasive infections caused by Group A Streptococcus
Acute lymphangitis Erysipelas Cellulitis Streptococcal gangrene Bacteremia, septicemia
Toxin-associated Syndromes caused by Group A Streptococcus
Scarlet fever
Streptococcal toxic-shock-like syndrome
Streptococcal gangrene
Streptococci, Staphylococcus aureus Predisposing: Surgery or drainage sinus Fever: minimal Pain: prominent Anesthesia: absent Crepitus: absent Course: slow
Progressive Bacterial Synergistic Gangrene
Mixture of organisms: Bacteroides, peptostreptococci, or Escherichia coli Predisposing: Diabetes Fever: moderate Pain: prominent Anesthesia: absent Crepitus: may occur Course: rapid
Synergistic Necrotizing Cellulitis
Group A streptococci Predisposing: Diabetes or abdominal surgery Fever: high Pain: prominent Anesthesia: may occur Crepitus: absent Course: very rapid
Streptococcal Gangrene
Clostridium perfringens Predisposing: Trauma Fever: moderate to high Pain: prominent Anesthesia: absent Crepitus: present Course: extremely rapid
Clostridial Myonecrosis (gas gangrene)
Rhizopus, Mucor, Absidia, Pseudomonas aeruginosa
Predisposing: Diabetes, corticosteroid use, immunosuppression, burn
Fever: Low in fungal, high in pseudomonal
Pain: prominent
Anesthesia: may occur
Crepitus: absent
Course: rapid
Necrotizing Infections in Immunosuppression
Exogenous cutaneous TB
Primary inoculation tuberculosis
Tuberculosis verrucosa cutis
Endogenous cutaneous TB, high immune status
Lupus vulgaris
Scrofuloderma
Endogenous cutaneous TB, low immune status
Acute miliary tuberculosis
Orificial tuberculosis
Metastatic tuberculous abscess (tuberculous gumma
Cutaneous TB due to BCG
Normal primary complex-like reaction
Perforating regional adenitis
Postvaccination lupus vulgaris
Tuberculids: conditions in which Mycobacterium tuberculosis/bovis appears to play a significant role
Lichen scrofulosorum
Papulonecrotic tuberculid
Facultative tuberculids: conditions in which M. tuberculosis/bovis may be one of several pathogenic factors
Nodular vasculitis/erythema induratum of Bazin
Erythema nodosum
Nontuberculids: conditions formerly designated as tuberculids; there is no relationship to tuberculosis
Lupus miliaris disseminatus faciei
Rosacea-like tuberculid
Lichenoid tuberculid
Lump with draining sinuses
Site: Cervicofacial, thorax, abdomen, pelvic
Source: Endogenous flora
Common with grains (Filamentous bacteria)
Stain: Gram-positive
Actinomycosis
Actinomyces israelii
Sporotrichoid, cellulitis Site: Extremities (upper > lower) Source: Environment Rare with grains (Filamentous bacteria) Stain: Gram-positive; Weak acid-fast bacillus
Nocardiosis
Nocardia brasiliensis, Nocardia asteroides
Lump with draining sinuses
Site: Feet, back, extremities
Source: Environment
Always with grains (Filamentous bacteria)
Stain: Gram-positive; Weak acid-fast bacillus
Actinomycetoma
(Nocardia brasiliensis, Actinomadura
madurae, Actinomadura pelletieri, Streptomyces
somaliensis)
Lump with draining sinuses Site: Feet mainly Source: Environment Always with grains (Hyphae) Stain: Periodic acid-Schiff, Grocott
Eumycetoma
Madurella mycetomatis, Magnaporthe grisea, Pseudallescheria boydii
Lump with draining sinuses Site: Hand, head, feet Source: Environment Always with grains (Cocci) Stain: Gram-positive
Botryomycosis
(Staphylococcus aureus, Escherichia coli, Pseudomonas
aeruginosa)
