Gram Positive Cocci Staphylococcus

Question 1

Micrococcaceae family includes two genus namely: ____________ and _____________

Answer 1

Micrococcaceae family includes two genus namely: Staphylococcus and Micrococcus

Question 2

Staphylococcus
General Characteristics
 Staphylococci are catalase-____________, gram-___________ cocci.
 On stained smears, they exhibit spherical cells- ____to _______ um, that appear singly, in ________, and in ___________.
 The genus name, Staphylococcus is derived from the Greek term “staphale” meaning “___________________”

Answer 2

Staphylococcus
General Characteristics
 Staphylococci are catalase-producing, gram-positive cocci.
 On stained smears, they exhibit spherical cells- 0.5 to 1.5 um, that appear singly, in
pairs, and in clusters.
 The genus name, Staphylococcus is derived from the Greek term “staphale” meaning “bunch of grapes”

Question 3

Staphylococcus
General Characteristics
 They are ____________ and _____________-forming and aerobic or facultatively anaerobic except for ________________ which is an obligate anaerobe
 Colonies produced after 18 to __ hours of incubation are medium sized and appear _______-colored, white or rarely light gold, and “__________________”
 Some species are Beta-hemolytic
 They are responsible for several suppurative types of infections

Answer 3

Staphylococcus
General Characteristics
 They are nonmotile and non-spore-forming and aerobic or facultatively anaerobic except for S. saccharolyticus which is an obligate anaerobe
 Colonies produced after 18 to 24 hours of incubation are medium sized and appear
cream-colored, white or rarely light gold, and “buttery-looking”
 Some species are Beta-hemolytic
 They are responsible for several suppurative types of infections

Question 4

________________________

 It is the most clinically significant species of staphylococci.
 It is responsible for numerous infections ranging from relatively mild to life threatening

Answer 4

Staphylococcus aureus

 It is the most clinically significant species of staphylococci.
 It is responsible for numerous infections ranging from relatively mild to life threatening

Question 5

Staphylococcus aureus
Virulence Factors
o ________________- are heat-stable endotoxin that cause various symptoms, including diarrhea and vomiting
o _________________________________- causes nearly all cases of menstruating associated Toxic Shock Syndrome
o __________________- It is also known as epidermolytic toxin. It causes the epidermal layer of the skin to slough off and is known to cause staphylococcal __________________________.

Answer 5

Staphylococcus aureus
Virulence Factors
o Enterotoxins- are heat-stable endotoxin that cause various symptoms, including diarrhea and vomiting
o Toxic Shock Syndrome Toxin-1- causes nearly all cases of menstruating associated Toxic Shock Syndrome
o Exfoliative toxin- It is also known as epidermolytic toxin. It causes the epidermal layer of the skin to slough off and is known to cause staphylococcal Scalded Skin Syndrome.

Question 6

Staphylococcus aureus
Virulence Factors

o Cytolytic toxin
 Alpha hemolysins-in addition to lysing erythrocytes, it also damage____________ and _____________ and cause severe tissue damage
 Beta hemolysins- acts on the __________________ in the plasma membrane of erythrocytes

Answer 6

Staphylococcus aureus
Virulence Factors

o Cytolytic toxin
 Alpha hemolysins-in addition to lysing erythrocytes, it also damage platelets and macrophages and cause severe tissue damage
 Beta hemolysins- acts on the sphingomyelin in the plasma membrane of erythrocytes

Question 7

Staphylococcus aureus
Virulence Factors

o Enzymes
 ___________________- causes bacterial cells to agglutinate in plasma
 ________________- hydrolyzes hyaluronic acid present in the intracellular ground substance that makes up connective tissues, permitting the spread of bacteria during infection.
 ______________- acts on lipids present on the surface of the skin, particularly fats and oil secreted by the sebaceous glands
o ________________- It has the ability to bind the Fc portion of immunoglobulin IgG

Answer 7

Staphylococcus aureus
Virulence Factors

o Enzymes
 Staphylocoagulase- causes bacterial cells to agglutinate in plasma
 Hyaluronidase- hydrolyzes hyaluronic acid present in the intracellular ground substance that makes up connective tissues, permitting the spread of bacteria during infection.
 Lipases- acts on lipids present on the surface of the skin, particularly fats and oil secreted by the sebaceous glands
o Protein A- It has the ability to bind the Fc portion of immunoglobulin IgG

Question 8

Staphylococcus aureus

TRUE OR FALSE
 Epidemiology
o The primary reservoir for staphylococcus is the human naris, with colonization also occurring in the axillae, vagina, pharynx, and other skin surfaces.
o Transmission of S. aureus may occur by direct contact with unwashed, contaminated hands and by contact with inanimate objects

Answer 8

Staphylococcus aureus

TRUE
 Epidemiology
o The primary reservoir for staphylococcus is the human naris, with colonization also occurring in the axillae, vagina, pharynx, and other skin surfaces.
o Transmission of S. aureus may occur by direct contact with unwashed, contaminated hands and by contact with inanimate objects

Question 9

 Infections caused by Staphylococcus aureus

S. aureus infections can be _______________ or __________________.

Answer 9

 Infections caused by Staphylococcus aureus

S. aureus infections can be suppurative or toxin mediated.

Question 10

 Infections caused by Staphylococcus aureus

o Skin and Wound Infections- They are _______________ in nature. Typically, the abscess is filled with pus and surrounded by necrotic tissues and damaged leukocytes.
 ________________- is a relatively mild inflammation of a hair follicle or oil gland; the infected area is raised and red.
 _____________- It is an extension of folliculitis, are large, raised, superficial abscesses.
 ____________- occur when larger, more invasive lesions develop from multiple furuncles.
 ___________- causes staphylococcal pustules that are large and surrounded by a small zone of erythema

Answer 10

 Infections caused by Staphylococcus aureus

o Skin and Wound Infections- They are suppurative in nature. Typically, the abscess is filled with pus and surrounded by necrotic tissues and damaged leukocytes.
 Folliculitis- is a relatively mild inflammation of a hair follicle or oil gland; the infected area is raised and red.
 Furuncles- It is an extension of folliculitis, are large, raised, superficial abscesses.
 Carbuncles- occur when larger, more invasive lesions develop from multiple furuncles.
 Bullous impetigo- causes staphylococcal pustules that are large and surrounded by a small zone of erythema

Question 11

 Infections caused by Staphylococcus aureus

o ________________________- It is a bullous exfoliative dermatitis that occurs primarily in newborns and previously healthy young children
o ________________________- It is a rare but potentially fatal, multisystem disease characterized by a sudden onset of fever, chills, vomiting, diarrhea, muscle aches, and rash, which can quickly progress to hypotension shock.

Answer 11

 Infections caused by Staphylococcus aureus

o Scalded Skin Syndrome- It is a bullous exfoliative dermatitis that occurs primarily in newborns and previously healthy young children
o Toxic Shock Syndrome- It is a rare but potentially fatal, multisystem disease characterized by a sudden onset of fever, chills, vomiting, diarrhea, muscle aches, and rash, which can quickly progress to hypotension shock.

Question 12

 Infections caused by Staphylococcus aureus

o __________________________-It is most commonly drug induced, but some cases have been linked to infections and vaccines
o ______________- Enterotoxin A and B have been associated with gastrointestinal disturbances.

Answer 12

 Infections caused by Staphylococcus aureus

o Toxic Epidermal Necrolysis-It is most commonly drug induced, but some cases have been linked to infections and vaccines
o Food Poisoning- Enterotoxin A and B have been associated with gastrointestinal disturbances.

Question 13

_________________________

 Infections caused by _______________ are predominantly hospital acquired.
o Predisposing Factors: Instrumentation procedures such as ____________________, medical implantation and immunosuppressive therapy
 It is a common cause of __________________________

Answer 13

Staphylococcus epidermidis

 Infections caused by S. epidermidis are predominantly hospital acquired.
o Predisposing Factors: Instrumentation procedures such as catheterization, medical implantation and immunosuppressive therapy
 It is a common cause of healthcare-acquired UTIs

Question 14

_____________________________

 It has been associated with UTIs in young women

Answer 14

Staphylococcus saprophyticus

 It has been associated with UTIs in young women

Question 15

_____________________________

 It can cause both community-associated and hospital acquired infections

Answer 15

Staphylococcus lugdunensis

 It can cause both community-associated and hospital acquired infections

Question 16

Other Coagulase-__________ Staphylococci: S. warneri, ___________, S. simulans, S. hominis, and ______________

Answer 16

Other Coagulase-Negative Staphylococci: S. warneri, S. capitis, S. simulans, S. hominis, and S. scheliferi

Question 17

_____________ Staph aureus is a proprietary selective and differential medium for isolation and identification of S. aureus.

Answer 17

CHROMagar Staph aureus is a proprietary selective and differential medium for isolation and identification of S. aureus.

Question 18

Cultural Characteristics

o _________________ colonies are usually small – to medium sized, nonhemolytic gray to white colonies
o _________________ forms slightly larger colonies with about 50% of the strains producing yellow pigment
o _________________ produces medium-sized colonies, with moderate or weak hemolysis and variable pigmentation

Answer 18

Cultural Characteristics

o S. epidermidis colonies are usually small – to medium sized, nonhemolytic gray to white colonies
o S. saprophyticus forms slightly larger colonies with about 50% of the strains producing yellow pigment
o S. haemolyticus produces medium-sized colonies, with moderate or weak hemolysis and variable pigmentation

Question 19

 Identification Methods

o Staphylococci have been traditionally differentiated from micrococci on the basis of ________________________ produced in ___ glucose medium.
 Staphylococci ferment _________ whereas micrococci fail to produce _____ under anaerobic conditions

Answer 19

 Identification Methods

o Staphylococci have been traditionally differentiated from micrococci on the basis of oxidation-fermentation (O/F) reactions produced in O/F glucose medium.
 Staphylococci ferment glucose whereas micrococci fail to produce acid under anaerobic conditions

Question 20

 Identification Methods

o A _______________________ can be used to rapidly differentiate staphylococci from micrococci.
 Most staphylococci are __________ whereas micrococci are ________
o S. aureus is often identified by the ____________,
 Clumping factor, formerly referred to as cell-bound coagulase, causes agglutination in human, rabbit, or pig plasma and is considered an important marker for S. aureus

Answer 20

 Identification Methods

o A modified oxidase test can be used to rapidly differentiate staphylococci from micrococci.
 Most staphylococci are negative whereas micrococci are positive
o S. aureus is often identified by the coagulase test,
 Clumping factor, formerly referred to as cell-bound coagulase, causes agglutination in human, rabbit, or pig plasma and is considered an important marker for S. aureus

Question 21

 Identification Methods

o Test for __________________ activity can be used to differentiate S. aureus (negative) from S. lugdunensis, S. intermedius and S. schleiferi (positive)

Answer 21

 Identification Methods

o Test for pyrrolidonyl arylamidase activity can be used to differentiate S. aureus (negative) from S. lugdunensis, S. intermedius and S. schleiferi (positive)