أسئلة مهمة بالمايكرو

Question 1

……………. is the commonest cause of bronchiolitis and Pneumonia in infant .

Answer 1

Respiratory syncytial virus

Question 2

What are complications of Mumps ? النكاف

Answer 2

1 ) orchitis خصية & oophoritis مبيض rarely occurs»> sterilits عقم (( as testes and overy surrounded by غير مرنة non - elastic قاسية rigid tunica albuginea»غمد أبيض
lead to Pressure and necrosis)) .
2) Meningitis may occurs some cases .
3) Pancreatitis is a rare complication .

Question 3

Culture of staph aureus???

Answer 3

1) Nutrient aqar : Colonies golden yellow ( endopigment ) .
2) Blood agar : colonies surrounded by beta hemolysis .
3) Mannitol salt agar ( selective differential Staphylococci ) : colonies are surrounded by yellow halo هالة صفراء .

Question 4

Virulence factors of staph aureus
a) (structural factors) ???

Answer 4

1 - Protein “ A “ : antiopsonization.

2 - Capsule : antiphagocytic .

Question 5

Virulence factors of staph aureus
b) non structural factors (((enzymes)))
?????

Answer 5

1 ) Catalase : Break toxic H₂O₂ into water and O₂

. 2 ) Coagulase : clots plasma with deposition of fibrin on the surface of Staph that hinders يعيق ingestion of the bacteria by phagocytic cells .

3 ) Spreading enzymes :

a - hyalourinidase

b - Fibrinofysin ( staphylokinase ) dissolve fibrin clots but more slowly than streptokinase )

4 ) B - lactamase : To resist penicillin and ampicillin .

Question 6

Virulence factors of staph aureus
b) non structural factors (((Toxins)))???

Answer 6

1 ) Haemolysin : lyse erythrocytes platelets . يكسر الصفائح الدموية

2 ) Leucocidins : kill cause necrosis of tissues خاصة البيضاء

3 ) Enterotoxin : There are at least six soluble toxins produced by 50 % strains .
resistant heat “stable”
resistant to action of gut enzymes
- They cause carbohydrate rich food poisoning .

4 ) Toxic shock syndrome
( TSST - 1 ) :
-responsible for toxic shock syndrome occurs in (((“” menstruating young women using tampons “””))) and also in children or men with wound infections .

5 ) Exfoliative or epidermatolytic toxin :
-it has proteolytic يكسر بروتينات الجلد activity for that lead to bullous بثور أو فقاقيع formation of syndrome متلازمة أعراض ما الها علاقة ببعض تعمل تسمم وموت in young children Less than 5 years

Question 7

Treatment of staph aureus???
Or explain what is ((MRSA))
“Methicillin resistant Stavhyiococcus “ ???

Answer 7

Methicillin resistant Stavhyiococcus ( MRSA )
-About 90 % of hospital strains Staphylococci are resistant to penicillin due to production of
(((B - lactamase )))So DOC “drug of choice” is methicillin
- 20 % of S.aureus developed resistant to methicillin due to presence of a chromosomal gene ( MecA gene ) this resistance not due to destruction of the drug By B lactamase enzyme

-The drug of choice in treatment of infections caused by MRSA is glycopepetides e.g : vancomycin
- but now they are VRSA Vancomycin resistant staph aureus .

Question 8

Mode of infection of klebsiella???

Answer 8

1) endogenous ينتقل من مكان داخل الجسم

Question 9

Mode of infection of E.coli ??

Answer 9

endogenous 2 - feco oral 3 - maternal fecal flora 4 - EHEC بالجماميس : bovine fecal contamination ( raw or undercooked beef , milk )

Question 10

Mode of infection of salmonella food poisoning “ salmonellosis” ???

Answer 10

Infection occurs after consumptionتناول of :
1) Improperly cooked meat of infected animal or eggs off infected bird .
2) Any food or drink contaminated with excretaمخلفات “فضلات” of infected rodents قوارض

ملوث بمخلفات القوارض المصاب

Question 11

Mode of infection of Enteric Fever “salmonella typhi “ ?

Answer 11

The organism from the stool of a case or Carrier.
contaminates foods or drinks , milk or milk products , raw vegetables eggs and shellfish
-The organism is transferred contaminated hands or by flies . )

Question 12

Causative organism of salmonellosis?

Answer 12

S. typhimurium ( in birds and camels )
S. enteritidis ( natural human pathogen in rats )

Question 13

-Diarrhoeagenic strains of E. coli السلالات المسببة للاسهال

Answer 13

1- Enterotoxigenic E.coli ( ETEC ) -that produces 2 enterotoxins causing watery diarrhea called travelers diarrhea

2 - Enteroinvasive E.coli ( EIEC ) ] that Invades the intestinal epithelium and causes dysentery دم ومخاط بالبراز like diarrhea with blood and mucous in the stool

3 - Enteropathogenic E.coli ( EPEG . ) That adheres tightly بإحكام to the intestinal mucosa resulting in loss of microvilli preventing تمنع the normal function of absorption and secretion .

4- Enterohaemorrhagic.E.coli ( EHEC . )
secretes a toxin known as verotoxin or shiga toxin ,This strain ( 0157 : H7 ) is associatedمرتبطة with outbreakتفشي of hemorrhagic colitis which is a severe form of bloody diarrhea that follows ingestion of contaminated undercooked hamburger .