Coagulase Negative Staphylococci

Question 1

What species are the coagulase negative Staph?

Answer 1

S. epidermidis
S. haemolyticus
S. saprophyticus
S. lugdunensis
S. hominis

Question 2

General Features of: Staphylococcus epidermidis

Answer 2

Gram +
Habitat- normal skin flora
Grape like structure
Facultative anaerobic

Question 3

Biochemical Properties of S. Epidermidis

Answer 3

Catalase +
Coagulase - (negative)
Novobiocin sensitive
Urease +

Question 4

Pathogenesis of S. Epidermidis

Answer 4

Affect prosthetic joints
Infecting catheters (nosocomial)

Formation of Biofilm (Teichoic acid)- protects from antibiotics)

Opportunistic pathogen- found on skin and can infect open wounds and go into the blood when pricked

Question 5

Clinical Features of S. Epidermidis

Answer 5

Urinary Tract Infection (UTI)- related to catheter infection

Endocarditis in artificial heart valve

Bacteremia and Sepsis
Related to foreign bodies (usually in hospital environment, nosocomial)- e.g. from IV cannula or catheter

Question 6

Diagnosis of S. epidermidis

Answer 6

No (gamma) Hemolysis on Blood agar or Chocolate agar
White pigments on culture medium
Contaminating hemocultures
(since it is found on the skin flora) Susceptibility test is essential- often multi-resistant

Question 7

Treatment of S. epidermidis:

Answer 7

Vancomycin

Question 8

General Features of S. saprophyticus

Answer 8

Gram +
Habitat- normal skin flora (mainly genitals)
Facultative anaerobe

Question 9

Biochemical Properties of S. saprophyticus

Answer 9

Catalase +
Coagulase - (negative)
Novobiocin resistant
Urease +

Question 10

Pathogenesis of S. saprophyticus

Answer 10

Affect sexually active young women

Question 11

Clinical Features of S. saprophyticus

Answer 11

Urinary Tract Infection (UTI)

i.e., acute cystitis (bladder infection) 2nd most common after E. coli

Question 12

Diagnosis of S. saprophyticus

Answer 12

No (Gamma) Hemolysis on Blood agar or Chocolate agar

White pigments on culture medium

Question 13

Treatment of S. saprophyticus

Answer 13

Ciprofloxacin (2nd generation Fluoroquinolones)

Question 14

Common structures about S. Haemolyticus:

Answer 14

Part of normal skin flora (axillae)
Opportunistic pathogen- wound infection, endocarditis, bacteremia and sepsis
Strong Beta-hemolytic activity
facultatively anaerobic

Question 15

Common structures about S. lugdunensis

Answer 15

Opportunistic pathogen- can cause aggressive endocarditis (special type)
Can also be commonly involved in other cardiovascular infections.

Question 16

Common structures about S. hominis

Answer 16

Part of normal skin flora (contribute to body odor)

Opportunistic pathogen (especially in immunocompromised, like all staphylococci) 
No (gamma) hemolytic activity

facultative anaerobe