Skin Infections

Question 0

What are the microbial strategies to bypass skin defense ?

Answer 0

A) parenteral route
1- Break in skin ( cute and biting arthropods )
B) infecting hair follicles or sebaceous glands
( staphylococcus aureus which bind to accessory oranges and causes ( boils and abscesses )

Question 1

What are the skin defense?

Answer 1

1)Stratified squamous epithelium-
Tight junction b/t cell 
Keratinization for water proofing 
2) normal flora :-
Breaks down oils to fatty acids 
3) lysozyme:- degrades peptidoglycan

Question 2

Etiology of staphylococcus aureus ?

Answer 2

Gram positive ( staphylococcus)
Resistant to b- lactams ( penicillin)
Produce many toxin and tissue damaging enzymes
Causes Boils***

Question 3

What causes Boils ( دمله) ?

Answer 3

Staphylococcus aureus
Gram positive
R to b-lactams ( pencillininc)
Produce many toxic and tissue damage enzymes

Question 4

How does Boil ( staphylococcus aureus) transmitted and what kind of mode ?

Answer 4

Reservoir ( person or animal colonized with staphylococcus aureus, some chronically carry staphylococcus aureus in their nasal mucous)
Mode of transmission is contact mode ( direct or through fomites contact )

Question 5

High solute called named as (—)? Which kills most of the bacteria expect staphylococcus aureus

Answer 5

Facultative Halophile

Question 6

How does ( staphylococcus aureus) boil enter ? Attach ? Avoid ? Damage and exit ?

Answer 6

1-Enter- direct contact infected person or self inoculate (Nose reservoir )
2-Attach- to hair follicles
3-avoid- by Leukocidins ; coagulase ( white blood cells)
4- damage- inflammatory response
5- exist - By Rupture release pus

Question 7

What is the signs and clinical symptoms of Boil ( staphylococcus aureus) ?

Answer 7

1- progressing edema at the site of infection ( coagulase form a blood clot ) 
2- pain 
3-redness 
4-localized fever 
Inflammatory response (2-3-4)
5-pus 
6- hard core

Question 8

How you treat boil ( staphylococcus aureus) ?

Answer 8

Treatment choses are ( cloxacillin or Flucloxacillin )
You might use b-lactams that are not susceptible to B-lactamase
Used for MSSA ( methicillin-susceptible staphylococcus aureus not degraded by B-lactamase

Question 9

Ampicillin binds to PBP ( penicillin-binding- protein ) which results on deactivate of PBP
What is PBP ?

Answer 9

Cell wall synthetase enzymes

Question 10

How you prevent Boil ( staphylococcus aureus) ?

Answer 10

1-By treating chronic nasal carriers with antibiotics creams
2- good personal hygiene ( showers , washing hands)

Aureus mean =gold

Question 11

Streptococcus pyogenes characters ?

Answer 11

• gram +
• Fermentation metabolism ( takes place on lack of Oxygen)
• B- hemolytic on blood agar
• group A protein on surface
• produces many tissues-damaging enzymes

Causes Cellulitis *****

Question 12

What causes Cellulitis For immunocompent individual ( mean healthy person) ?

Answer 12

( most commonly staphylococcus aureus and group A strep ( streptococcus pyogenes )

Question 13

What are these Predisposing Factors that causes Cellulitis ?

Answer 13

Diabetes
Immunodeficiency
Varicella
Impaired peripheral circulation
Lymphadenectomy following tumor excision , such as mastectomy
Postvenectomy status following vein stripping
Chronic steroids uses

Question 14

How does Cellulitis ( streptococcus pyogenes) transmitted and what kind of mode ?

Answer 14

• reservoir ( symptomatic or asymptotic individuals ) :-( colonization with Staphylococcus aureus or streptococcus pyogenes is common )
• mode via contact mode ( direct or fomites contact)

Question 15

What are the sign and clinical features of Cellulitis ? Uncomplicated

Answer 15

• Uncomplicated ( infection of the dermis and subcutaneous tissue resulting in ( Redness , edema, pain and local fever

Question 16

What are the signs and clinical features of Cellulitis the potential complications?

Answer 16

1- potential complications:-

• May become a very serious illness by uncontrolled spread contiguous or VIA the Lymphatic or Circulatory system
• deep and rapidly spreading infection may develop into life -threatening emergencies

Question 17

How does Cellulitis may be Diagnosed ? For Non- complicated

Answer 17

Normally specimen collection and lab tests are not done because non complicated Cellulitis in immunocompent individuals is Consistently caused by Strep and Staph and Is Treatable

Question 18

How may Cellulitis diagnosed ? For immunocompent and complicated Cellulitis-

Answer 18

1) Specimen : Aspirate of Infected site

2) Test : Culture & Gram stain

Question 19

How does Cellulitis treated?

Answer 19

Penicillinase -resistant synthetic Penicillin ( Diclixacillin ) or 1St generation Cephalosporins ( Cephazolin )
These antibiotics Will treat both Group A Streptococcu and MSSA (Methcillin-susceptible staphylococcus aureus)

** if allergic, Erythromycin is used as an alternative **

Question 20

How does Cellulitis can be prevented?

Answer 20

1- educate pt regarding proper skin hygiene
2- wash , treat and cover cuts and skin abrasion
** patients with recurrent streptococcal Cellulitis may used Penicillin G Or Erythromycin
3- Support Stocking

Question 21

Etiology of Pseudomonas aeruginosa ? very Common pathogens

Answer 21

Gram -
Monopolar Flagellum
Often Drug R
Resistant to Disinfectants

Question 22

What are the Site of infection that Caused by Pseudomonas aeruginosa? Common Pathogens

Answer 22

1- Epidermis
2- Burns
3- Lungs ( purple Pus )
4- Nosocomial ( hospital ) UTIs ( urinary tract infections)

Question 23

Etiology of Clostridium perfringens ? Uncommon Pathogens

Answer 23

-1-gram + , endospore -forming rod shape
2-obligate anaerobic ( they can grow with or without Oxygen)
( infect puncture wounds ,, wounds with poor blood supply)
- 3 Causes Gas Gangrene

Question 24

What pathogen Causes Gas gangrene ?

Answer 24

Clostridium perfringens

The Gas Gangrene ( is a potentially deadly form of tissue death )