Staphylococcal

Question 1

Gram positive Cocci

Answer 1

Staphylococci
Streptococci
Enterococci

Question 2

Staphylococcai

Answer 2

arranged in
grape like clusters, non capsulated, non motile
and non spore forming..

Question 3

Staph. aureus couaglase test

Answer 3

Positive

Question 4

Staph. epidermids and Staph. saprophyticus couaglase test

Answer 4

Negative

Question 5

Staphylococcai catalase test

Answer 5

Positive

Question 6

Sterptococcai catalase test ?

Answer 6

Negative

Question 7

Enterococcai catalase test

Answer 7

Negative

Question 8

Culture of staphylococcai

Answer 8

Facultative anaerobes
Grows on nutrient media : yellow golden colines
blood agar: Produce complete hemolysis
fermintat mannitol :yellow golden color

Question 9

DNAase test for staph aureus

Answer 9

Positive

Question 10

Staph. aureus can produce disease through

Answer 10

both
invasion by its cell components (antigenic structure), and by the production of extracellular enzymes and toxins.

Question 11

What kind of antigenic structure have endotoxin like activity and produce septic shock?

Answer 11

Peptidoglycan

Question 12

What part of antigenic structure function in antiphagocytic and anticomplement

Answer 12

Protein A

Question 13

cause Staphylococci to become more
resistant to phagocytosis.

Answer 13

Coagulase

Question 14

Most infections caused by Staph. aureus are
localized due to

Answer 14

coagulase production.

Question 15

limits the accessibility of antibiotics to the
infection site

Answer 15

Coagulase

Question 16

yielding
aggregation of the bacteria and promoting
their attachment to blood clots.

Answer 16

Clumping factor

Question 17

Causes shock in: - tampon-using menstruating women - individuals with wound infections - patients with nasal packing used to stop bleeding from
the nose. The toxin is produced locally in the vagina, nose, or other
infected site, then enters the bloodstream, causing
toxemia.

Answer 17

Toxic shock syndrome toxin

Question 18

In which type of toxin Blood cultures typically do not grow Staph. aureus.

Answer 18

Toxic shock syndrome toxin

Question 19

causes food poisoning with prominent
vomiting (caused by cytokines which stimulate
the enteric nervous system to activate the
vomiting center in the brain) and watery
diarrhea.
• is heat-resistant and not
inactivated by brief cooking.
• It is resistant to stomach acid and enzymes.

Answer 19

Enterotoxin

Question 20

Toxin seen in staphylococcal scalded skin
syndrome (peeling of the skin).

Answer 20

Exfoliative toxins

Question 21

toxins that kill leucocytes and
cause necrosis of tissues.

Answer 21

Leukocidins

Question 22

produced by recently isolated
community- associated CA-MRSA and is
associated with severe necrotizing pneumonia in
children.

Answer 22

Panton- Valentin leukocidin (PVL)(Pore-forming
toxin)

Question 23

superantigens

Answer 23

1- Toxic shock syndrome toxin (TSST – 1)

2- Enterotoxins

3-Exfoliative toxins

Question 24

Pyogenic diseases
Superficial examples of staph aureus

Answer 24

carbuncle, boils, impetigo,stye. wound infection and abscess formation.

Question 25

most comon organism that causes pneumonia

Answer 25

Staph aureus

Question 26

main cause of acute endocarditis in interavenous drug users(IVDUs) with high mortality rate.

Answer 26

Staph aureus

Question 27

common organisms that are involved in HAIs e.g. surgical site infections and pneumonia

Answer 27

Staph aureus

Question 28

Bacteremia

Answer 28

Organisim found in blood

Question 29

Septicemia

Answer 29

Organisms + toxin

Question 30

Toxinemia

Answer 30

Only toxin in blood

Question 31

Staph aureus is manifested by an abrupt onset of high fever, vomiting, diarrhea, myalgias, macular & sun burn-like rash that goes on to desquamate, and hypotension with cardiac and renal failure in the most severe cases. leading to *widespread capillary leakage* characterized by **fever **desquamative skin rash **hypotension ending in **shock with multisystem organ failures

Answer 31

Toxic shock syndrome

Question 32

Staph aureus superficial layers of the epidermis slough in response to the presence of exfoliative toxin.

Answer 32

Scalded skin syndrome

Question 33

Laboratory diagnosis of Staphylococcus aureus infections:

Answer 33

Specimen Direct gram stained smear Culture Biochemical reaction Phage typing

Question 34

To determine the source of infection in : • Epidemiological tracing of outbreaks in hospitals. Samples from wounds, nose and nail bed of doctors, nurses and from fomites are tested. • Outbreaks of food poisoning, the organism isolated from food, vomitus, stool, and from nose and nail bed of food handlers.

Answer 34

Phage typing

Question 35

The drug of choice for these Staphylococci aureus who are "methicillin"- resistant (MRSA).

Answer 35

Vancomycin

Question 36

causes urinary tract infections, particularly in sexually active young women.

Answer 36

Staph. saprophyticus:

Question 37

Number one organism causing community-acquired urinary tract infections in young women ?

Answer 37

1E.coli 2 Staph. saprophyticus:

Question 38

A major cause of sepsis in neonates

Answer 38

Staph. epidermidis

Question 39

can enter the bloodstream (bacteremia) and organ abcesses infections, especially at the site of IV catheters, prosthetic implants

Answer 39

Staph. epidermidis

Question 40

Staph. epidermidis Are found especially at site of iv cathaters and prosthetic implants (prosthetic heart valves, vascular grafts, and prosthetic joints) due to the production of

Answer 40

glycocalyx (SLIME OR BIOFILM).

Question 41

Coagulase –ve and non hemolytic on blood agar

Answer 41

S.epidermidis S.saprophyticus

Question 42

Novobiocin sensitivity test of staph epidermis result

Answer 42

Sensitive

Question 43

Novobiocin sensitivity test of staph sarpophyticus result

Answer 43

Resistance

Question 44

Mannitol fermentation and DNAase test for Coagulase negative Staphylococci: Staph epidermis and staph sarpophyticus

Answer 44

Negative

Question 45

How are Staphylococci clinically classified? They are classified according to: a)Exotoxin production b)Exopigment production c)Coagulase production d)Catalase production

Answer 45

Coagulase production

Question 46

If the bacterial pathogen with this morphology is coagulase positive, what surface protein binds the Fc portion of IgG, thereby preventing effective opsonization?

Answer 46

Protein A

Question 47

A 20-year-old woman with a history of IV drug use presents at the emergency department with rapid onset lethargy, fever, and a heart murmur. Blood cultures were collected for analysis, and golden colonies grew from blood specimens. The Gram stain of the cells from the colonies resembled that shown. What is the most likely etiology and infection?

Answer 47

acute endocarditis caused by Staphylococcus aureus .

Question 48

You're in the clinical laboratory looking at a Gram stain when the laboratory technician comes up to you and says, "I think your patient has Staph epi [short for Staphylococcus epidermidis] bac-teremia." Which one of the following sets of results did the tech find with the organism recovered from the blood culture? (A) Gram-positive cocci in chains, catalase-positive, coagulase-positive (B) Gram-positive COCCi in chains, catalase-negative, coagulase-negative © Gram-positive cocci in clusters, catalase-positive, coagulase-negative (D) Gram-positive cocci in clusters, catalase-negative, coagulase-positive (E) Gram-positive diplococci, catalase-negative, coagulase-positive

Answer 48

© Gram-positive cocci in clusters, catalase-positive, coagulase-negative

Question 49

Superantigen production by Staphylococcus aureus is involved in the pathogenesis of which one of the following diseases? (A) Impetigo (B) Osteomyelitis (C) Scalded skin syndrome (D) Septicemia E-Toxic shock syndrome

Answer 49

E-Toxic shock syndrome

Question 50

Which one of the following is the virulence factor produced by Staphylococcus aureus that prevents the activation of complement and thereby reduces opsonization by C3b? (A) Catalase (B) Coagulase (C) Endotoxin (D) Protein A (E) Teichoic acid

Answer 50

Protein A

Question 51

The main reason why methicillin-resistant Staphylococcus aureus (MRSA) strains are resistant to methicillin and nafcillin is: (A) they produce B-lactamase that degrades the antibiotics. (B) they have altered penicillin-binding proteins that have reduced binding of the antibiotics. (C) they have mutant porin proteins that prevent the antibiotics from entering the bacteria. (D) they have plasmid-encoded export proteins that remove the drug from the bacteria.

Answer 51

B) they have altered penicillin-binding proteins that have reduced binding of the antibiotics.

Question 52

A pore-forming exotoxin produced by Staphylococcus aureus that kills cells and is important in the severe, rapidly spreading necrotizing lesions caused by MRSA strains is: (A) coagulase. (B) enterotoxin. (C) exfoliatin. (D P-V leukocidin.

Answer 52

leukocidin

Question 53

Of the following antibiotics, which one is the most appropriate to treat a severe necrotizing skin infection caused by an MRSA strain of Staphylococcus aureus? (A) Amoxicillin (B) Ceftriaxone (C) Ciprofloxacin (D) Gentamicin (E) Vancomycin

Answer 53

Vancomycin

Question 54

The Jones family of four had a delicious picnic lunch last Sunday. It was a warm day, and the food sat in the sun for several hours. Alas, 3 hours later, everyone came down with vomiting and non-bloody diarrhea. In the emergency room, it was found that Mrs. Jones, who prepared the food, had a paronychia on her thumb. Which one of the following is the most likely causative organism? (A) Enterococcus faecalis (B) Staphylococcus aureus (C) Staphylococcus epidermidis (D) Streptococcus agalactiae (E) Streptococcus pyogenes

Answer 54

B) Staphylococcus aureus