Lab 8

Question 1

Corynebacterium diptheriae

Answer 1

causes diptheria from and the pseudomembrane from the local colonization and tissue damage on the back of the throat as well as forming an exotoxin that disseminated though the body from the site of production.

can cause damage to the myocardium, adrenal cortex or other organs

Question 2

Diptheria toxoid

Answer 2

purified toxin treated so that it is no longer toxic but remains antigenic

Question 3

physiological characterisitics of diptheria

Answer 3

gram postive, non-motile, non-sporulating bacili

as common as staph

C dip is thinner and more beaded than diptheroids which are short and thick
=> not reliable for diagnosis

Question 4

non pathenogenic cornyformes

Answer 4

called siptheroids because they resemble c. diptheriae in microscopic morphology

rods stain irregulary = metachromatic because of the granules inside them
=> give a beaded or clumped apperance in patterns of V’s and Y’s

Question 5

Growth of cornyforms

Answer 5

in culture, not highly fastidious and grow well aerobically on nutrient media

throat swab to blood agar

loefflers serum

potassium tellurite for isolation
=> blackened colony growth

Question 6

loeffler’s serum

Answer 6

for isolation of C. diptheria

throat swabs

firm coagulated serum medium with nutrient broth on a slant. enriched for the growth of fastidious organisms

Question 7

Metabolism of C. diptheria

Answer 7

differentaion of diptheria from other cornyforms based on carb fermentation

toxin production to identify toxogenic strains of c. diptheria

virulence tests by using lil bunny rabbits or with Eleks test (in virto) and antitoxin strips on an agar plate

Question 8

Haemophilus influenzae

Answer 8

fastidious, small pleomorphic gram neg bacilli.

microaerophilic, and fastidious growth on chocolate agar

normal floral of the upper respiratory tract

leading cause of bacterial meningitis, especially in infants and yound childern.

Question 9

lab tests for ID of Haemophilus influenzae

Answer 9

throat swab, sinus drainage, sputum, conjuctival swab, spinal fouil, blood etc

Direct smear from psinal fluid or exudate of the eye with rapid and presumptive information

smears from the upper respiratory tract have little value as there is too much junk

latex or co-agglutination antibody tests for haemophilus antigen

Question 10

what serotype are most serous haemphilus disease caused by

Answer 10

H. influenzae and serogroup b

Question 11

factors X and V

Answer 11

required by some Haemophilus species

X factor = hemin, is a heat-stable derivative of hemoglobin

V factor is a heat-lable coenzyme (NADH)
=> important suppliment in yeast extract

Staph aureus secreates V factor into the media, and growth depented on SA colonies is called staleitism
=> prgegnation of factor V and X on disks and incubate

Question 12

Most common diseases aquired through the urinary tract

Answer 12

STDs

gonorrhoea, syphilis and chlamydial urethritis

all caused by bacteria, but chlamydiae require techniques for isolation

Question 13

Gonorrhoea is caused by

Answer 13

neisseria gonorrhoease

many other species are non pathogenic including those of normal flora

Question 14

syphilis caused by

Answer 14

treponema polidum a spirochete

many other species are non pathogenic including those of normal flora

Question 15

chlamydia is caused by

Answer 15

chlamydia trachomatis

Question 16

Neisseria genus

Answer 16

contains two pathogenic species (gonorrhoea and meningitidis)

all are gram negative diplococci indistinguishable with microscopy

pathogens are fastidious CO2 at 35C, non-pathogenic are not fastidious
=> these have a yelow pigment (subflava and flavescens) but most are colourless

all oxidase positive, to differentiate need to look at carbohydrate degredation

Question 17

Gonorrhea

Answer 17

begins as a acute local infection of the genital tract.

for males leaad to purulent discharge from the urethra, when this is gram stains shows many ppolymorphonuclear cells which contain intracellular gram negative diplococci

in the female acute infection begins in ther cervix, and smears of this show the same as in males but there more more extraneous organisms. (normal flora may mask the presence of gonococci) thus cultural techniques must be utalized (this can also sometimes occur in males)

Question 18

menigitis

Answer 18

an inflammation of the meniges of the brain
=> neisseria meningitidis a gram negative diplococcus.

portal of entry = respiratory tract

systemeatic dissemination and damage in the immunocompromised individual

Question 19

culturing nessiera

Answer 19

nesseria (gonococcia nd menigococci) are very sensitive to enviromental conditions outside the huaman body, especially to temp and atmosphere

can easily be destroyed in transit to the lab from temp too far above or below 35 C, heavy contamination from normal flora or low CO2 (should be placed in a candle jar)