Sec 29 Bacterial Disease

Question 1

Sites of colonisation in carriers of Staphylococcus aureus

Answer 1

Anterior nares 
Throat
Axillae, perineum 
Hands
Involved skin in individuals with atopic dermatitis

Question 2

Sites of colonisation in neonates of Staphylococcus aureus

Answer 2

Skin
Umbilicus
Circumcision site
Conjunctivae

Question 3

Primary pyoderma of skin

Answer 3

Impetigo
Bullous impetigo
Erythema
Botryomycosis

Question 4

Primary pyoderma of hair follicles

Answer 4

Superficial folliculitis (follicular or Bockhart impetigo)
Folliculitis (sycosis barbae)
Furuncle (boil)
Carbuncle

Question 5

Secondary pyoderma

Answer 5

Impetiginization of dermatoses such as atopic dermatitis, herpes simplex (superinfection)
Pyodermas associated with systemic disease Job syndrome
Chédiak–Higashi syndrome
Chronic granulomatous disease

Question 6

First line topical therapy for Impetigo

Answer 6

Mupirocin BID
Retapamulin BID
Fusidic acid BID (not available in United States)

Question 7

First line systemic therapy for Impetigo

Answer 7

Dicloxacillin 250–500 mg PO qid for 5–7 days
Amoxicillin plus clavulanic acid 25 mg/kg tid
Cephalexin 250–500 mg qid

Question 8

Second line systemic therapy for Impetigo (if with penicillin allergy)

Answer 8

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

Question 9

Bacterial folliculitis

Answer 9

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)

Question 10

First line topical treatment for Streptococcal Pyoderma

Answer 10

Mupirocin BID

Question 11

First line systemic treatment for Streptococcal Pyoderma

Answer 11

Penicillin V 250–500 mg PO qid for 5–7 days

Dicloxacillin 250–500 mg qid for 5–7 days

Question 12

Second line topical treatment for Streptococcal Pyoderma

Answer 12

Retapamulin BID

Question 13

Second line systemic treatment for Streptococcal Pyoderma

Answer 13

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

Question 14

Toxins: Staphylococcus aureus

Answer 14

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

Question 15

Toxin: Streptococcus pyogenes

Answer 15

Streptococcal pyrogenic exotoxins A, C - Superantigen - TSS (nonmenstrual), scarlet fever

Question 16

Major Criteria: Staphylococcal Toxic Shock Syndrome

Answer 16

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

Question 17

MCC: Erysipelas

Answer 17

Group A Streptococcus

Question 18

MCC: Cellulitis

Answer 18

S. aureus

Group A Streptococcus

Question 19

MCC: Facial/periorbital cellulitis in children

Answer 19

S. aureus

Group A Streptococcus

Question 20

MCC: Perianal cellulitis in children

Answer 20

Group A Streptococcus

Question 21

MCC: Cellulitis secondary to bacteremia

Answer 21

Pseudomonas aeruginosa

Question 22

MCC: Cellulitis associated with water exposure

Answer 22

E. rhusiopathiae (erysipeloid)

Question 23

DOC: Erysipelas, simple outpatient

Answer 23

Penicillin V
Intramuscular procaine penicillin
Amoxicillin
Vancomycin

Question 24

DOC: Erysipelas, severe hospitalized

Answer 24

Ampicillin/sulbactam
Ticarcillin/clavulanate
Piperacillin/tazobactam
Imipenem/cilastatin, meropenem

Question 25

DOC: Cellulitis, simple outpatient

Answer 25

Cephalexin | Dicloxacillin

Question 26

DOC: Cellulitis, severe hospitalized

Answer 26

``` Ampicillin/sulbactam Cefazolin Piperacillin/tazobactam Ticarcillin/clavulanate Imipenem/cilastatin, meropenem ```

Question 27

Invasive infections caused by Group A Streptococcus

Answer 27

``` Acute lymphangitis Erysipelas Cellulitis Streptococcal gangrene Bacteremia, septicemia ```

Question 28

Toxin-associated Syndromes caused by Group A Streptococcus

Answer 28

Scarlet fever Streptococcal toxic-shock-like syndrome Streptococcal gangrene

Question 29

``` Streptococci, Staphylococcus aureus Predisposing: Surgery or drainage sinus Fever: minimal Pain: prominent Anesthesia: absent Crepitus: absent Course: slow ```

Answer 29

Progressive Bacterial Synergistic Gangrene

Question 30

``` Mixture of organisms: Bacteroides, peptostreptococci, or Escherichia coli Predisposing: Diabetes Fever: moderate Pain: prominent Anesthesia: absent Crepitus: may occur Course: rapid ```

Answer 30

Synergistic Necrotizing Cellulitis

Question 31

``` Group A streptococci Predisposing: Diabetes or abdominal surgery Fever: high Pain: prominent Anesthesia: may occur Crepitus: absent Course: very rapid ```

Answer 31

Streptococcal Gangrene

Question 32

``` Clostridium perfringens Predisposing: Trauma Fever: moderate to high Pain: prominent Anesthesia: absent Crepitus: present Course: extremely rapid ```

Answer 32

Clostridial Myonecrosis (gas gangrene)

Question 33

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

Answer 33

Necrotizing Infections in Immunosuppression

Question 34

Exogenous cutaneous TB

Answer 34

Primary inoculation tuberculosis | Tuberculosis verrucosa cutis

Question 35

Endogenous cutaneous TB, high immune status

Answer 35

Lupus vulgaris | Scrofuloderma

Question 36

Endogenous cutaneous TB, low immune status

Answer 36

Acute miliary tuberculosis Orificial tuberculosis Metastatic tuberculous abscess (tuberculous gumma

Question 37

Cutaneous TB due to BCG

Answer 37

Normal primary complex-like reaction Perforating regional adenitis Postvaccination lupus vulgaris

Question 38

Tuberculids: conditions in which Mycobacterium tuberculosis/bovis appears to play a significant role

Answer 38

Lichen scrofulosorum | Papulonecrotic tuberculid

Question 39

Facultative tuberculids: conditions in which M. tuberculosis/bovis may be one of several pathogenic factors

Answer 39

Nodular vasculitis/erythema induratum of Bazin | Erythema nodosum

Question 40

Nontuberculids: conditions formerly designated as tuberculids; there is no relationship to tuberculosis

Answer 40

Lupus miliaris disseminatus faciei Rosacea-like tuberculid Lichenoid tuberculid

Question 41

Lump with draining sinuses Site: Cervicofacial, thorax, abdomen, pelvic Source: Endogenous flora Common with grains (Filamentous bacteria) Stain: Gram-positive

Answer 41

Actinomycosis | Actinomyces israelii

Question 42

``` Sporotrichoid, cellulitis Site: Extremities (upper > lower) Source: Environment Rare with grains (Filamentous bacteria) Stain: Gram-positive; Weak acid-fast bacillus ```

Answer 42

Nocardiosis | Nocardia brasiliensis, Nocardia asteroides

Question 43

Lump with draining sinuses Site: Feet, back, extremities Source: Environment Always with grains (Filamentous bacteria) Stain: Gram-positive; Weak acid-fast bacillus

Answer 43

Actinomycetoma (Nocardia brasiliensis, Actinomadura madurae, Actinomadura pelletieri, Streptomyces somaliensis)

Question 44

``` Lump with draining sinuses Site: Feet mainly Source: Environment Always with grains (Hyphae) Stain: Periodic acid-Schiff, Grocott ```

Answer 44

Eumycetoma | Madurella mycetomatis, Magnaporthe grisea, Pseudallescheria boydii

Question 45

``` Lump with draining sinuses Site: Hand, head, feet Source: Environment Always with grains (Cocci) Stain: Gram-positive ```

Answer 45

Botryomycosis (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa)