Staphylococcus

Question 1

Staphylococci

Answer 1

Include the number of species of bacteria many of the species form part of the normal flora of human skin or mucous membranes and do not cause disease other species a pathogenic and cause disease in humans and animals through infection or toxin production the most common reason for food poisoning is due to staphylococcal toxins which accumulate in improperly stored food

Question 2

Main human pathogens

Answer 2

S aureus significant and human pathogens and disease ranges and severity from food poisoning and minor skin infections to life-threatening infections
S epidermidis may be associated with infections of implanted devices such as prostheses shunts and catheters specially in immunocompromised patients
S saprophyticus common cause of urinary tract infections

Question 3

Staphylococci morphology

Answer 3

Gram positive spherical bacteria archaea and grape-like clusters also a cure a single cells pears or tetrads
Easily cultured most types of bacteriological media and grow best at 37 degrees Celsius the colonies formed around smooth raised and classy different degrees of haemolysis may be observed for s aureus
Non motile non sporing

Question 4

Haemolysis

Answer 4

Removal of damaged red blood cells

Question 5

S aureus

Answer 5

Causes food poisoning and minor skin infections coagulase positive which converts fibrinogen to fibrin and cause blood to clot
Non sporing
Non motile
Turns golden yellow and blood agar

Question 6

S aureus antigenic structure

Answer 6

Capsule promotes adherence to cells of prosthetic devices prevents phagocytosis
Peptidoglycan acts as endotoxin chemotactant for neutrophils stimulate complement and coagulation
teichoic acid adherence to mucosal surface protein a reduce phagocytosis
Coagulase enzyme converts fibrinogen to fibrin resulting in blood clotting
Can disguise themselves as blood clot preventing phagocytosis

Question 7

S epidermidis

Answer 7

Infections of implanted devices catalase positive coagulase-negative

Question 8

S saprophyticus

Answer 8

Urinary tract infections catalase positive coagulase-negative

Question 9

Diseases caused by s aureus

Answer 9

Meningitis pimples toxic shock syndrome bacteremia pneumonia sepsis

Question 10

Violence factors and toxins

Answer 10

Important enzymes produced by staphylococcus aureus 
Coagulase 
Deoxyribonuclease 
Hyaluridonase
Staphylokinase
Lipase
B lactamase
Toxins produced by staphylococci
Exotoxins panton valentine leukocidin toxic shock syndrome enterotoxins

Question 11

Staphylococcus diagnosis

Answer 11

Microscopy culture catalase test coagulase test

Pus aspirate from trachea vomit feces blood spinal fluid

Question 12

Medicine in resistant staphylococcus aureus

Answer 12

Treated using antimicrobials of the glycopeptide type such as vancomycin and teichoplanin