MIcro unit 2

Question 1

staphlyccocus are gram what and catalase what?

Answer 1

gram positive cocci and catalase positive

Question 2

streptococcus are gram what and catalase what?

Answer 2

gram positive cocci and catalase negative

Question 3

staph aureus infections

Answer 3

skin and soft tissue, scalded skin syndrome (ritter disease), toxic shock syndrome

Question 4

staph aureus colony morphology

Answer 4

beta hemolytic, round, creamy, yellowish white, round

Question 5

identification test for staph

Answer 5

1. staph latex, if pos its staph aureus
2. if neg, PYR– if pos staph lugunensis
3. if neg, novobiocin, if pos staph saprophyticus, if neg staph epidermis

Question 6

what species is gram positive cocci, catalase positive, bright yellow, staph latex= , and microdase positive?

Answer 6

Micrococcus species

Question 7

staph aureus growth requirements

Answer 7

enterotoxins, enzymes, protein A - binds IgG

Question 8

Staphylococcus saprophyticus infections

Answer 8

UTIS but is also normal in vaginal flora

Question 9

Staphylococcus saprophyticus growth factors

Answer 9

Adheres more effectively than other pathogens to the lining of
the urogenital tract

Question 10

Staphylococcus saprophyticus colony morpholgoy

Answer 10

bright white, opaque, round, non-
hemolytic
* Slide and tube coagulase: Negative
* Novobiocin resistant

Question 11

Staphylococcus lugdunensis infections

Answer 11

Can mimic S. aureus infection
* Endocarditis, septicemia, meningitis, skin and soft tissue
infection, urinary tract infection, septic shock

Question 12

Staphylococcus lugdunensis colony morphology

Answer 12

Colony morphology: white, opaque, round, sometimes beta-
hemolytic
* Slide coagulase – sometimes positive
* Tube coagulase - negative

Question 13

Staphylococcus lugdunensis growth requirements

Answer 13

biofilm production, bound coagulase

Question 14

Staphylococcus epidermidis infections

Answer 14

part of the usual skin flora, but can be an opportunistic
pathogen
* Hospital acquired urinary tract infections (UTI)
* Infection associated with IV catheters, CSF shuts, prosthetic
joints, and prosthetic heart valves

Question 15

Virulence Factors

Answer 15

Biofilm production

Question 16

Laboratory identification

Answer 16

Medium-sized white/grey colonies, gamma hemolytic
* Slide and tube coagulase - negative
* Not typically identified to species level – reported as
Coagulase-negative Staph

Question 17

Micrococcus sp infections

Answer 17

normal part of flora and rarely a pathogen

Question 18

Streptococcus pyogenes - Infections

Answer 18

bacterial pharyngitis (strep), scarlet fever, pyodermal skin infections, necrotizing fasciitis flesh eating disease,

Question 19

Streptococcus pyogenes what can follow Infections

Answer 19

rheumatic fever and acute glomerulonephritis

Question 20

Streptococcus pyogenes – Virulence
Factors

Answer 20

adhesion molecules, Hyaluronic acid capsule

Question 21

Streptococcus pyogenes colony morphology

Answer 21

β-hemolytic
* Large zone hemolysis
* Hemolysis enhanced with agar “stabbing”
* Small, transparent, grey colonies

Question 22

Streptococcus agalactiae - Infections

Answer 22

neonatal streptococcal disease, endometritis, diabetic foot ulcers,

Question 23

Streptococcus agalactiae - colony morphology

Answer 23

β-hemolytic
* Small zone hemolysis
* Grayish white colonies

Question 24

group B strep is

Answer 24

Streptococcus agalactiae

Question 25

Streptococci spp. are what groups in lancefield

Answer 25

C and G

Question 26

Streptococci spp. colony morphology

Answer 26

β-hemolytic * Large-zone hemolysis * Large or small colonies * Grey, transparent colonies

Question 27

Streptococci spp. infections

Answer 27

uncommon human pathogens, can sometimes cause pharyngitis

Question 28

Streptococcus pneumoniae infections

Answer 28

pneumococcal pneumonia, bacterial meningitis bacteremia

Question 29

Streptococcus pneumoniae virulence factors

Answer 29

Capsular polysaccharide * Antigenic – allows for serotyping the isolate specifically * Antigenic structure * C-substance on cell wall * Chemically reacts with C-reactive protein (CRP) in human serum * Reaction with CRP forms a precipitate

Question 30

Strep pneumoniae gram stain

Answer 30

lancet in pairs

Question 31

STrep pneumoniae colony morphology

Answer 31

olony Morphology * Large zone of α- hemolysis * Round, concave colonies, sometimes wet and mucoid * Concave colony form caused by autolytic changes Increased CO2 is Required for growth

Question 32

viridans streptococci is normal flora in what three tracts?

Answer 32

upper respiratory, female genital , and gastrointestinal

Question 33

Viridans Streptococci – Infections

Answer 33

Opportunistic pathogens * Most common cause of bacterial endocarditis or abcesses

Question 34

Viridans Streptococci - colony morphology

Answer 34

Most strains are α – hemolytic * Small colonies, sometimes pinpoint

Question 35

Enterococcus spp infections

Answer 35

Part of the usual gastrointestinal flora * Common cause of urinary tract infections * Frequent cause of nosocomial infections (like bacteremia and endocarditis)

Question 36

Enterococcus spp infections colony morphology

Answer 36

Usually α-hemolytic or non-hemolytic; can sometimes be β – hemolytic * Grey colonies

Question 37

gram positive cocci catalase negative testing

Answer 37

1. is it betahemolytic? if yes do lancefield (group A- pyr if pos pyogens, if not beta group A). If lancefield test other its that group _) 2. If negative is it black on BEA? posiitve then do PYR. if positive it is enterococcus, if not strep group D. if negative look at hemolysis. gamma- strep viridans. alpha- do optochin (if pos strep pneumoniae whcih needs CO2, if negative then strep viridans)