bacterial infections of the skin

Question 1

Sulphur granules in Pus

Answer 1

Actinomycosis

foot note: bacterium
called Nocardia also has a similar appearance.

Question 2

Actinomycosis causative agent: most common

Answer 2

Actinomyces israelii.

Question 3

Features of actinomyces

Answer 3

normal inhabitants of the mouth, gastrointestinal tract, and female genital tract

Question 4

Condition required for actinomyces to cause infection

Answer 4

1. break in the skin or mucosa.
2. require the presence of other accompanying bacteria in order to cause disease.

Question 5

Characteristic features of the disease

Answer 5

1. formation of an abscess and draining sinus tracts
2. The draining pus contains yellow granules called sulphur granules.
   (These are named from the colour of the granules, not their content.)

Question 6

Actinomycetoma

Answer 6

chronic infection of the skin and subcutaneous
tissue, usually involving the foot

Question 7

Treatment for actinomycosis

Answer 7

Penicillin: high doses

Goal: create unfavourable aerobic
conditions for the growth of Actinomyces species

Question 8

Alternative antibiotics include

Answer 8

tetracyclines, erythromycin, and clindamycin.

Question 9

Skin diseases caused by staphylococcus

Answer 9

1. Impetigo Contagiosa
2. Carbuncle
3. Psychosis Barbe
4. SSSS— Ritter’s Disease ( newborn); Toxic Epidermal Necrolysis (TEN) ( adults)
5. Toxic shock syndrome ( in IUCD users)
6. Ecthyma
7. Furuncle

Question 10

Erysipelas is caused by

Answer 10

Beta hemolytic streptococci

Foot note: acute inflammation of lymphatics of skin

Question 11

What is ecthyma?

Answer 11

1. a deep form of impetigo
2. crusted sores beneath which ulcers form.
3. deeper erosions
   of the skin into the dermis.

Question 12

the bacteria responsible for ecthyma?

Answer 12

Streptococcus pyogenes and Staphylococcus aureus

Question 13

Ecthyma most often affects which area?

Answer 13

buttocks, thighs, legs, ankle and feet

Question 14

Characteristics of ecthyma lesion

Answer 14

Blister/ Pustule— hard Crust— can be removed— indurated ulcer revealed— oozing with pus—- scar: yes

Question 15

What is the treatment for ecthyma?

Answer 15

1. Soak crusted areas
2. Topical antiseptics or antibiotics: fusidic acid or >mupirocin
   or
3. topical antiseptic–povidone iodine, superoxidised solution, antibacterial Manuka honey or hydrogen peroxide cream
4. antibiotic of choice is a penicillin, usually dicloxacillin or flucloxacillin: for extensive

Question 16

What is impetigo?

Answer 16

highly contagious bacterial skin infection characterised by pustules and honey-coloured crusted
erosions.

Question 17

Impetigo causative organism

Answer 17

Staphylococcus aureus and Streptococcus pyogenes (Group A beta – haemolytic streptococci (GABHS)).

Question 18

Classification of impetigo

Answer 18

non-bullous
(also known as ‘school sores’) and bullous impetigo.

Question 19

Non-bullous impetigo Caused by

Answer 19

either Staphylococcus aureus, Streptococcus pyogenes, or both bacteria conjointly.

Question 20

Bullous impetigo caused by

Answer 20

Staphylococcus aureus which produces exfoliative toxins (exfoliatins A and B).