corynebacterium

Question 1

What’s the common characters of Coryneforms «diphtheriods» with C. d?

Answer 1

Morphology
occurs as normal flora on skin and mucus mem.
some are opurtinistics

Question 2

Mention aerobic and nonaorobic non spore forming gram+ bacilli

Answer 2

aerobic: coryne
listeria
E. rhusiopathiea

non: Actinomycetes
Nocardia

Question 3

Mention species of corynebacterium.

Answer 3

1_C. diph
2_C. psedotuberclosis: cause ulcerative lymphangitis, abscess, chronic purlenet infections in sheep. goat. horse. man
3_C. xerosis: non. pathogenic, in mucos mam. and conjunctival sac,skin in man
4_C. renal: non. pathogenic for man, cause cystitis, pyelonephritis in cattle.

Question 4

Mention the biotypes of C. di.

Answer 4

gravis
mitis
belfanti
intermedius lipophyl

Question 5

What’s habitat of C. d

Answer 5

Nasopharynx, skin lesions of humen carriers resorvoir

Question 6

what’s the morphology of C. d

Answer 6

gram + bacilli, catalase+
club shape
pleomorphic rods with swallowen end 
Chinese letter arrangment
beaded, metachromatic granules

Question 7

How dose volute granules stain?

Answer 7

methylene blue
Alberts stain
Neissers stain
ponders stain

Question 8

When can we see numerous clear metachromatic granules?

Answer 8

when culture in pn rich media, loeffler media, dorset egg media.

Question 9

mention the culture characters of C. d according to:
O2
T
media

Answer 9

aerobic , facultative anaerobes
can grow at 37 c
1_blood agar, B-hymolysis in gravis, mitis
2_loeffler serum. gray small granular colonies
3_blood tullerite medium: selective differntial medium, colonies gray «gravis» to black «mi»
4_other selective media:
CTBA cystein tull.. blo. agar
CAN.. colistin nalidixic agar

Question 10

How can you defferentiate between different bootypes?

Answer 10

colony morphology on BTm

biochemical reaction

Question 11

what suger dose C. d ferment?

produce cystinase or pyrizinamidase?

Answer 11

glucose, maltose with acid production
Gravis ferment starch, glycogen, produce hemolysis on rabbit red cell
mitis produce hemolysis on rabbit, ox red cells

cystinase

Question 12

what’s thw factors influncing toxin production?

why?

Answer 12

lysogenic prophage
amount by extracellular conc. of iron:
high conc. activate d. toxin repressor which binds to toxin gene operator and prevent toxin production.

Question 13

Mention the characters of diph. toxin

Answer 13

1_heat labile
2_highly toxic
3_highly antigenic
4_can be convert to toxoid

Question 14

why only one exotoxin can inactivate EF2 in cell?

Answer 14

1_the turn over of EF is slow

2_only one molecule per ribosome is present in a cell.

Question 15

Mention the mode of transmission for each type of diphe

Answer 15

1_Tonsillar by airborne droplets
2_conjunctival or skin by contact
3_cutenous appears as a papule then chronic non healing ulcer coverd by grayish mem.

Question 16

what’s the clinical findings in diphe?

Answer 16

Generlized due to toximia
local due to multiplication of organism

1_sore throat, mild fever, ill health
gross swelling of tonsills and pharynx 
2_enlarged cervical nodes «bull neck» 
3_grayish mem. covering tonsills and may extend to pos. pharyngeal wall and larynx
4_laryngeal obstructin and suffocation. 

5_Nerve involvement may lead to paralysis of muscles of soft palate and pharynx leading to difficulties in swallowing and speach.

6_peripheral neuritis «paralysis of limbs»
7_myocarditis (arythimias, circualtory failure, death)

Question 17

Mention the tests for toxogeicitiy detection.

Answer 17

1_Eliks test
2_pcr
3_ELISA
4_immunochromographic
5_Tissue culture cytotoxic assay
6_historical test

Question 18

How can we diadnose diph?

Answer 18

1_clinically
2_microscopic exam«direct smear». of throat swab
3_culture
4_PCR
5_toxogenicity tests

Question 19

Describe the cutanous diph pathogenesis.

Answer 19

a puncture of wound or cut can induce the organism to the subcutaneous tissue, leading to chronic non healing ulcer with a grey mem.
rarly exotoxin production leads to degeneration and death of tissue

Question 20

How can you treat diph.?

Answer 20

1_ antitoxin at once, 20000/100000 unites intramasculary or intravenously.
2_Antibiotics: pencillin erythromycin in adequate doses
3_prophylaxis

Question 21

how ti prepare diphi. toxoid?

Answer 21

filtrate of broth culture of a toxogenic strain is treated with 0.3 formalin to remove toxocity and retain antigenecity.
the fluid purified, standaralized, and adsorbed onto Aluminium hydroxide or Al phosphate as adjuvant