4.7.2013(micro-gram Positive Bacteria)

Question 0

Temperature of culture of staph for pigment production

Answer 0

22 C

Question 1

Selective medium for staphylococci

Answer 1

Salt milk agar(8-10% Nacl)
Mannitol salt agar(7.5% Nacl)
Ludlam Lithium chloride and tellurite media

Question 2

Cause for golden yellow pigmentation of s.aureus colonies

Answer 2

Carotene

Question 3

Gram positive bacteria that produces endotoxins

Answer 3

Listeria

Question 4

Gram negative cocci

Answer 4

Neisseria

Veilonella

Question 5

Gram positive bacteria with pili

Answer 5

Corynebacterium renale

Question 6

Catalase positive gram positive cocci

Answer 6

S.aureus

Micrococci

Question 7

Diff btw staph and Micrococci

Answer 7

Micrococci are
Oxidase Positive
Furazolidone resistant
Bacitracin sensitive

Question 8

Staph which is slide coagulase positive but tube coagulase negative

Answer 8

S.lugdunensis

Question 9

Slide coagulase positivity is because of

Answer 9

Bound coagulase(clumping factor)

Tube coagulase test requires free coagulase which needs coagulase reacting factor in plasma

Question 10

Which is a virulence factor free or bound coagulase?

Answer 10

Free coagulase(it is heat Labile)

Question 11

Basis of coagglutination reaction

Answer 11

Protein A of staph.aureus which binds to Fc fragment of IgG

Question 12

Most consistent association of virulence of S.aureus

Answer 12

Coagulase

Fermentation of mannitol

Question 13

Factor of S.aureus that exhibits hot cold phenomenon

Answer 13

Beta hemolysin

Question 14

Coagulase acts by

Answer 14

Activation of prothrombin

Question 15

Toxin associated with community acquired MRSA

Answer 15

Leukocidin/panton valentine toxin

Question 16

Hemolysins in S.aureus

Answer 16

A,B,G,D

Question 17

Vomiting in staph food poisoning

Answer 17

Activation of vagus and vomiting centre

Question 18

The S.aureus toxin that is inactivated at 70C and activated paradoxically at 100 c

Answer 18

Alpha Hemolysins

At 100 c an inhibitor is inactivated

Question 19

Bio component toxins of s.aureus

Answer 19

Leukocidin

Gamma hemolysin

Question 20

Hemolysins of staphylococci that lyses only sheep RBC

Answer 20

Beta hemolysin

Question 21

Exfoliative toxin of staph belongs to

Answer 21

Bacteriophage II group

Question 22

Epidermolytic toxin causes

Answer 22

Ritter disease(children)
TEN(adults)

Question 23

Types of Exfoliative toxin of S.aureus

Answer 23

A - heat stable,chromosome mediated

B- heat Labile,plasmid mediated

Question 24

Most common type of enterotoxin

Answer 24

Type A

Question 25

Staph enterotoxin is heat _______

Answer 25

Stable

Question 26

Toxic shock syndrome toxin belongs to

Answer 26

Phage group 1

Question 27

Rx of toxic shock syndrome

Answer 27

Clindamycin

Question 28

TSST

Answer 28

Enterotoxin F Pyrogenic exotoxin C(most common) Enterotoxin B,C

Question 29

Examples for super antigens

Answer 29

Staph- TSST,Exfoliative toxin,enterotoxins Strep- strep Pyrogenic exotoxin A,B,C mycoplasma arthritidis,yersinia enterocolitica Malassezia furfur Virus-EBV,CMV,HIV,rabies

Question 30

Mechanism of MRSA

Answer 30

Chromosomally mediated mecA gene | Altered pencillin binding protein 2a

Question 31

BORSA

Answer 31

Borderline oxacillin resistant s.aureus | Hyper production of betalactamase

Question 32

Rx of MRSA

Answer 32

Vancomycin(DOC) Linezolid Teicoplanin Streptogramin

Question 33

Newer drugs for MRSA

Answer 33

Daptomycin Ceftabiprole Tigecycline Oritavancin

Question 34

VISA

Answer 34

Vancomycin intermediate s.aureus- MIC 8-16ug/ml | VRSA-MIC 32ug/ml

Question 35

Mechanism of VRSA

Answer 35

Increased thickness of cell wall

Question 36

Rx of VRSA

Answer 36

All drugs given for MRSA except vanco and teicoplanin

Question 37

S.aureus is MC agent for

Answer 37

``` Skin and soft tissue infection Postoperative parotits Postoperative wound infection Botryomycosis Paronychia Epidural abscess Tropical pyomyositis Osteomyelitis ```

Question 38

Most common cause of acute bacterial Myositis

Answer 38

Group A streptococci

Question 39

Most common cause of prosthetic valve endocarditis

Answer 39

Saph.epidermidis

Question 40

MC cause of subacute endocarditis

Answer 40

Strep viridans

Question 41

Most common cause of late prosthetic valve endocarditis (>12months)

Answer 41

Strep viridans

Question 42

Most common method for typing of s.aureus

Answer 42

Phage typing

Question 43

Mechanism of penicillin resistance in S.aureus

Answer 43

Beta lactamase transferred by transduction

Question 44

Most common site of colonisation of staph aureus

Answer 44

Anterior nares

Question 45

Most common way of spread of s.aureus in hospital

Answer 45

Hands of hospital staff

Question 46

Most effective way to prevent hospital infection due to s.aureus

Answer 46

Hand washing

Question 47

MC CONS

Answer 47

S.epidermidis

Question 48

S.saprophyticus causes

Answer 48

UTI in sexually active females

Question 49

Diff btw s.epidermidis and saprophyticus

Answer 49

Saprophyticus is novobiocin resistant

Question 50

Optimum temperature for s.aureus Pigment production Enterotoxin production MRSA expression

Answer 50

Pigment- 22 C Enterotoxin- 37 C (same as opt temp for S.aureus growth) MRSA-30 C in 4% Nacl

Question 51

Foods associated with staph food poisoning

Answer 51

Meat Fish Milk Milk products

Question 52

Transfer of drug resistance in staph is by

Answer 52

Transduction(common) | Conjugation

Question 53

Sites of colonisation of staph

Answer 53

``` Skin of Anterior nares Perineum Axilla Groin ```

Question 54

Role of PBP

Answer 54

Trans or carboxy peptidase essential for cell wall synthesis

Question 55

Theromonuclease test for staph

Answer 55

Only aureus is positive

Question 56

Phosphatase test for staph

Answer 56

Aureus and epidermidis are positive

Question 57

Causes of botryomycosis

Answer 57

``` S.aureus CONS Streptococcus Peptostreptococcus Pseudomonas E.coli Proteus ```

Question 58

MC route of staph infection

Answer 58

Skin

Question 59

Lancefield grouping is based on

Answer 59

Carbohydrate antigen on cell wall of beta Hemolytic streptococci 20 subtypes,A to V except I and J

Question 60

Lancefield antigens are extracted by

Answer 60

HCl Formamide(fuller) Enzymatic(maxted) Autoclaving

Question 61

Griffith typing is based on

Answer 61

Proteins M,T,R | more than 80 M types are present