microbiology ch 11( streptococci, staphylococci, and micrococci

Question 1

Name the 3 different ways streptococci causes haemolysis

Answer 1

alpha- partial haemolysis with green color
beta- wide clear zone of complete lysis
gamma- no lysis

Question 2

Name the 4 groups of streptococci

Answer 2

A- streptococcus pyogenes, human disease
B- streptococcus agalactiae ( female genital tract)
C- animals
D- Enterococci, human disease

Question 3

Strep. Pyogenes

Answer 3

Nasopharynx & skin, Beta haemolysis, causes tonsillitis, pharyngitis, peritonsillar abcess, scarlet fever etc…

Question 4

what toxins does strep pyogense have?

Answer 4

streptokinase- lyses fibrin
Hyaluronidase- attacks material which binds connective tissue thus causing increased permeability ( spreading factor
DNAases- destroy DNA
Haemolysins- erythematous rash in scarlet fever.

Question 5

Strep. agalactiae

Answer 5

human vagina and passed to kid during nursing, Causes neonatal meningitis and sepsis, beta haemolytic

Question 6

Oral streptococci

Answer 6

in oropharynx, mostly alpha but beta and gamma are present,.

Question 7

oral streptococci role in dentistry

Answer 7

Secrete sticky polysacharide which allows binding to enamel. Can cause infective endocarditis after dental procedure

Question 8

Name the 4 groups of oral streptococci

Answer 8

mutans, salivarius, anginosus, mitis

Question 9

Streptococcus pneumoniae

Answer 9

upper respiratory tract, causes pneumonia, & meningitis and otitis media in children, gram positive lancet- shaped cocci ( diplococcic), alpha haemolytic

Question 10

staphylococci

Answer 10

high in adults ove 70., grapelike clusters, includes aureus and epidermidis and saprophyticus, causes absesses of organs, endocarditis, gastroenteritis and toxic shock syndrome

Question 11

Staph aureus

Answer 11

skin, anterior nares, perineum, transmitted via hands, catalase positive, positive for protein A-latex agglutination test

Question 12

how can you tell aures and epidermis apart?

Answer 12

aureus coagulates blood, epidermis doesnt

Question 13

toxins of staph aureus

Answer 13

coagulase- clots plasma

enterotoxin- diarrhoea

Question 14

some staph aureus have a beta lactamase plasmid. What does this do ?

Answer 14

provides resistants to penicillin

Question 15

staphylococcus epidermis

Answer 15

skin, coagulase negative, resistant to penicillin and methicillin, sensative to vancomyocin

Question 16

staphylococcus saprophyticus

Answer 16

UTI’s in woman, infections with intercourse, Can be differentiated by using the mannitol fermentation reaction test.

Question 17

micrococci

Answer 17

coagulase negative, stomatococcus mucilagenosus is found on tongue and makes slime