BigBrother GIT Microbiology Qs

GIT

MICROBIOLOGY Questions For 2nd year

Content

1. GIT infections……………………………………………………………………………………………………………1 2. Food poisoning…………………………………………………………………………………………………….…5 3. Diarrhea…………………………………………………………………………………………………………………..9 4. Viral hepatitis……………………………………………………………………………………………………..…15 5. Peritonitis & Typhoid fever …………………………………………………………………………………..21

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GIT infections

Previous exams & Formative: 1- Although mumps virus characteristically invades the parotid glands, this virus also commonly produces inflammation in the: a. b. c. d.

Tetes kidneys bones colon

2- Mumps infection mainly affects which part of the body? a. b. c. d. e.

Thyroid gland Parathyroid gland Thymus gland Adrenal gland Parotid gland

3- Mumps is a highly contagious viral infection transmitted from person to person. Which of the following is not the symptoms of the mumps virus? a. b. c. d.

fever muscle aches swollen salivary glands skin rashes

4- HSV-1 infection may result in the following except: a. b. c. d.

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encephalitis gingivostomatitis genital herpes keratitis

5- HSV-1 is? a. Double stranded DNA virus b. Replicate in the nucleus with the formation of intranuclear inclusion bodies. c. Characterized by latent infection. d. All of the above e. None of the above

6- The Urease test done to diagnostic of: a. b. c. d.

S. pyogen S. aureus Helicobacter pylori E. coli

7- Which one of the following outcomes is Most common following a primary herpes simplex virus infection? a. b. c. d.

Complete eradication of virus and virus- infected cells Persistent asymptomatic viremia Persistent cytopathic effect in infected cells Establishment of latent infection

8- Mumps is characterized by all except? a. b. c. d.

Caused by bacteria Occurs by droplet infection Occurs in children Enlarged parotid gland 1- a

2- e

3- d

4- c

5- d

6- c

7- d

8- a

9- A patient has gastric ulcer due to bacterial pathogen. Which characteristic appears to play a central role in the ability of this organism to colonize the stomach?

2

a. b. c. d.

Phospholipase production Urease production Microaerophilic lifestyle Capsular antigens

Extra: 1- Virulence factors of H. pylori include following except: a. b. c. d. e.

Urease enzyme Motility Coagulase enzyme Vacuolating toxin Interleukin 8 induction

2- The commonest cause of chronic gastritis is: a. b. c. d. e.

Drugs Helicobacter pylori Autoimmune Chemicals Unknown

3- All are true about H. pylori except: a. b. c. d.

It is a gram negative helical non-motile bacterium.

It gives positive catalase and oxidase test.

It doesn’t invade gastric mucosa.

One of the main causes of gastric ulcers.

9- b

4- Helicobacter pylori are: a. Rod-shaped bacilli b. S-shaped bacilli

3

1- c

2- b

3- a

c. Fusiform bacilli d. Spirochetes e. None of the above

5- For treatment of H.pylori, the following combination is recommended: a. b. c. d.

Proton pump inhibitors with tetracycline.

Tetracyclin with metronidazole.

Systemic sulphonamides with metronidazole.

Proton pump inhibitors with clarithromycin and metronidazole

6- H pylori is a risk factor for all the following conditions except? a. b. c. d.

Gastric adenocarcinoma Gastroesophageal reflux disorder (GERD) Mucosa-associated lymphoid tissue (MALT) lymphoma Duodenal ulcers

4- b

4

5- d

6- b

2

Food Poisoning

Previous exams & Formative: 1- In which of the following disease the man is the natural source and only reservoir for infection: a. b. c. d.

Bacillary dysentery Salmonella food poisoning Clostridial food poisoning botulism

2- Which is the incubation period of salmonella food poisoning: a. b. c. d.

1 – 6 hours 12 – 36 hours 2 – weeks 4 – weeks

3- Staphylococcal food poisoning is caused by: a. b. c. d.

Enterotoxin Neurotoxin Heat labile toxin Staphylococcal shock syndrome toxin

4- Detection of the source of staph aureus in outbreaks of food poisoning is done mainly by: a. b. c. d. e.

5

Biochemical typing Antibiotic resistance patterns Phage typing Serologic typing All of the above 1- a 2- b

3- a

4- c

5- A previously healthy woman became nauseated and vomits 12 hours after eating home pickled eggs. Within 24 hours, she developed a diffuse flaccid paralysis and respiratory impairment, necessitating hospitalization and mechanical ventilation. Other symptoms included diplopia and dysarthria. What is the most likely diagnosis? a. b. c. d.

Botulinum Brucellosis Gastrointestinal anthrax Legionellosis

6- Symptoms of C. botulinum food poisoning include double vision, inability to speak, and respiratory paralysis. These symptoms are consistent with ......... a. b. c. d. e.

Invasion of the gut epithelium by C. Botulinum Secretion of an enterotoxin Endotoxin shock Ingestion of a neurotoxin Activation of cyclic AMP

7- Clostridium difficile can produce diarrhea by the following mechanism: a. Invasion of intestinal mucosa b. Production of enterotoxins which causes outpouring of fluids and cytotoxin which damage colonic mucosa c. Production of verotoxin d. Bacterial aggregation to the intestinal mucosa which leads to cupping of microvilli 5- a

6

6- d

7- b

8- Which of the following is not true about staphylococcal enterotoxin? a. b. c. d.

Heat–stable exotoxin Heat–labile exotoxin It is a super antigen It has several serotypes

Extra: 1- Food poisoning is caused by? a. b. c. d.

Clostridium tetani Clostridium Welchi Diphtheria Clostridium botulinum

2- Which pair of organisms below can be routinely responsible for food poisoning? a. b. c. d. e.

C. botulinum and B. anthracis C. tetani and B. anthracis C. difficile and C. botulinum C. tetani and B. cereus C. botulinum and B. cereus

3- The emetic form of bacillus cereus food poisoning resembles: a. b. c. d.

Botulism Cholera Bacillary dysentery Staph aureus food poisoning

8- b

7

1- d

2- e

3- d

4- The botulism exotoxin: a. b. c. d. e.

Blocks acetylcholine release from muscle cells Blocks acetylcholine breakdown in the gastrointestinal tract Blocks acetylcholine uptake by blood vessels Blocks acetylcholine release from nerve cells Blocks acetylcholine breakdown in the muscle tissue

5- Infant botulism is most often acquired by: a. b. c. d. e.

Fecal-oral contamination Inhaling aerosoled endospores Eating raw honey before the age of 1 year Eating canned beans before the age of 1 year Drinking breast milk contaminated by endospores

6- The symptoms of staphylococcal food poisoning are caused by: a. b. c. d.

Consuming preformed microbial toxins The foreign bacteria interacting with your normal gut microflora Consuming actively growing bacteria Hypovolemic shock

7- The main cause of staphylococcal food poisoning is: a. b. c. d.

Production of neurotoxins after ingestion of food Multiplication of bacteria from resting spores Preformed endotoxins Preformed exotoxins 4- d

8

5- c

6- a

7- d

3

Diarrhea

Previous exams & Formative: 1- All of the following organisms produce diarrhea by invading the intestinal mucosa except: a. b. c. d.

Salmonella typhi, Paratyphi Shigella Enteroinvasive Escherichia coli Vibrio cholera

2- Antibiotic associated diarrhea is caused by the following oragnism: a. b. c. d.

Clostriduim difficile Shigella sonnei Salmonella typhimurium Enteroviruses

3- All of the following are true as regarding rotaviruses except: a. b. c. d.

It can be prevented by Rotateq, Rotarix vaccines Common in children between the age of 6 months and 2 years It is the most common cause of viral gastroenteritis Disease occurs in the form of epidemics

4- A 53-year-old woman with diarrhea and lower abdominal pain of 3 days ‘duration comes to her physician after various home remedies fail to relieve her symptoms. She denies any recent travel. There is blood and pus in her stool. Fecal cultures yield several flagellated, curved, oxidase-positive, gramnegative rods. Which of the following is the most likely pathogen? a. Escherichia coli b. Shigella sonnei

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c. Campylobacter jejuni d. Salmonella typhimurium

5- A 50-year-old man develops non-bloody watery diarrhea while working as an aid worker in a refugee camp in Bangladesh. He arrived in the area 2 days ago. A stool smear shows no WBCs. He subsequently develops dehydration and electrolyte abnormalities leading to cardiac and renal failure. Which of the following organisms is the most likely cause of this man’s enterocolitis? a. b. c. d.

Vibrio cholera Helicobacter pylori Salmonella species Clostridium difficile

6- For which one of the following enteric illnesses is a chronic carrier state most likely to develop? a. b. c. d.

Campylobacter enterocolitis Shigella enterocolitis Cholera Typhoid fever

7- In a case suspected to have typhoid fever, which one of the following is the least likely laboratory finding? a. b. c. d.

1-d

10

Culture of the blood reveals gram-negative rods Culture of the stool grows lactose-negative colonies in EMB agar His serum contains antibodies that agglutinate salmonella typhi His serum contains antibodies that cause a positive Weil-felix reaction 2-a

3-d

4-c

5-a 6-d

7-d

8- Regarding Rotavirus, which one of the following is correct? a. Rotavirus is a major cause of adult diarrhea b. The vaccine against rotavirus contain live attenuated virus as the immunogen c. Rotavirus has a non-segmented, single-stranded RNA genome, and there is no polymerase in the virion d. The diagnosis of rotavirus diarrhea is typically made by virus culture on cell line

9- Your patient is a 30-year-old woman with bloody diarrhea for the past 12 hours. Which one of the following organisms is most likely to cause this illness? a. b. c. d.

Rota virus Streptococcus pyogens Shigella dysenteriae ETEC

10- A 6-month-old child has had watery diarrhea for 6 days. The stools have no blood and no pus. The causative organism has doublestranded RNA as genetic material. Which of the following is the most likely causative organism? a. b. c. d.

Bacillus cereus Rota virus Giardia lambila Salmonella enteritidis

11- Choose the wrong answer, shigella : a. b. c. d.

Cause bacillary dysentry No animal reservoir Produce shiga toxin affecting GIT and CNS Chronic carriers are very common

12- Traveller’s diarrhea is caused by:

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a. b. c. d.

Enteroinvasive E.coli Enterotoxigenic E.coli Enterohemorrhagic E.coli Enteropathogenic E.coli

13- Which of the following is false as regarding enterohemorrhagic E.coli? a. b. c. d.

Its serotype is O157:H7 It produces hemorrhagic colitis Hemolytic uraemic syndrome occurs as a common complication None of the above

14- Typhoid fever is commonly acquired by: a. b. c. d.

Droplet infection Transplacental Contaminated food and drink Air borne

15- In the first week, typhoid fever is diagnosed by: a. b. c. d.

Widal test Stool culture Urine culture Blood culture

16- Choose the correct answer; vibrio cholera characterized by: a. b. c. d.

11-d

12

Require alkaline PH for growth, highly aerobic, high infectious dose Associated with bacteraemia and can be isolated in blood culture No animal reservoir It produced dysentery

12-b 13-d

14-c

15-d

16-a

17- As regarding the pathogenesis of vibrio cholera, all of the following is true except: a. b. c. d.

It has a high infectious dose Diarrhea is acute watery resembling rice water Blood invasion typically occurs Infection is transmitted by contaminated food and water

18- Choose the wrong answer; as regarding Widal test: a. It should be performed in the 1st week of illness b. It detects antibodies to O and H antigens of Salmonella species in the patients’ serum c. It is used for diagnosis of enteric fever d. It is a serological test

19- Clostriduim difficile can produce diarrhea by the following mechanism: a. Invasion of intestinal mucosa b. Production of enterotoxins which cause outpouring of fluids and cytotoxin which damage colonic mucosa c. Production of verotoxin d. Bacterial aggregation to the intestinal mucosa which leads to cupping of microvilli

20- Which of the following organisms produce dysentery-like diarrhea? a. b. c. d.

Enterotoxigenic E.coli Vibrio cholera Rota virus Enteroinvasive E.coli

21- Vibrio cholera produces a toxin which:

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a. Inhibits protien synthesis b. Activate adenylate cyclase enzyme, resulting in hypersecretion of water and electrolytes c. Causes a rash d. Prevents nerve impulse transmission 17-c

14

18-a

19-b

20-d

21-b

4

Viral hepatitis

Previous exams & Formative: 1- Which of the following statement not true about hepatitis A virus infection? a. b. c. d.

May result in chronic infections May be prevented by immunoglobulin May be prevented by vaccinatios Most HAV infections are asymptomatic

2- Hepatitis B virous infection is characterized by the follwing except? a. b. c. d.

May result in chronic infections May result in hepatocellular carcinoma Is high infectious when postive for ani-HbeAg antibody May respond to interferon therapy

3- Which of the following is best described the presently available vaccine for hepatitis B? a. b. c. d.

Synthetic peptide vaccine Killed virous vaccine Inactivated virous vaccine Recombinant viral vaccine

4- A nurse develops clinical symptoms consistent with hepatitis. She recalls sticking heresef with a needle approximately 4 months before after drawing blood from a patient serelogic test for HBsAg antibodies to HbsAg &hepatitis A virous are all negative, she is postive for IgM core antibody. The nurse is? a. Doesn't have hepatitis B

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b. Has hepatitis A c. Is the large stage of hepatitis B infection d. Is the window phase (after the disappearance of HBs Ag &before the appearance of anti HBs Ag) e. Has hepatitis C

5- Hepatitis C virous (HCV) is a usually a clinically mild disease with only minimal elevation of liver enzymes. Hospitalization is unusual, which one of the following statements best characterized HCV? a. b. c. d. e.

Few cases progress to chronic liver disease It often occurs in post transfusions patients HBV but not HCV infections occurs in lV drugs abusers It's DNA virous Blood product are not tested for antibody to HCV

6- Delta hepatitis only occurs in patients who also have either acute or chronic infection with hepatitis B virus the delta agent is? a. b. c. d. e.

An incomplete hepatitis B virous Related to hepatitis A virous Hepatitis B mutant An incomplete RNA virus Hepatitis c 1- a

2- c

3- d

4- d

5- b

6- c

Extra: 1- Hepatitis A is a membrane of what virous family? a. b. c. d.

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Satellite Flavivirous Picornavirous Hepadnavirous

2- The diagnosis of hepatitis A virous infection is carried out from the method based on? a. b. c. d.

Aminotransferase levels Detection of facial HAV by immunoelectron microscopy Both (a)&(b) Detection of IgM anti-HAV by Elisa

3- You can get hepatitis A from? a. b. c. d.

Having hepatitis c HIV Contaminated food Blood transfusions

4- Regarding hepatitis A viral infection? a. b. c. d. e.

It can be prevented by an inactived vaccine Liver enzymes are usually decreased Diagnosis is routinely done by isolating the virous in cell cultures It usually cauese a chronic form of hepatitis that end in liver cirrhosis It's commonly aquired through contact with blood from an infectious person

5- The marker that is closely associated with HBV infectively is? a. b. c. d.

HBSA9 HBeAg Anti-HBs Anti-Hbe 1- c

2- d

3- c

4- a

5- b

6- This hepatitis virous is not an RNA virus? a. b. c. d.

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Hepatitis G virous Hepatitis A virous Hepatitis B virous Hepatitis E virous

7- A 36 years old nurse is found to be both HbsAg postive &HBeAg positive the nurse must likely select one ? a. Has a chronic HB infection b. Has acute hepatitis &is infectious c. Has previously immunized with HBV vaccine prepared from healthy HbsAg postive carrier d. Has both HBV &HEV e. Has cleared a past HBV infection

8- Which of the following is the most reasonable explanation for the ability of hepatitis B virous to cause chronic infections? a. b. c. d.

Viral DNA can persist within the host cell The liver is an immunologically tolerant sheltered site Many humans are immunologically tolerant to HBs antigen Infection doesn't elicit the production of antibodies

9- Serologic test results from a hepatitis patient reveal anti-HBc postive, HbsAg postive, &ani-HBs negative. The correct interpretation of the patient's status is? a. b. c. d. e.

No longer contagious Evidence of receiving hepatitis B vaccination Immune to hepatitis B virous Impossible to have both surface antigen &core antibody postive Hepatitis B virous chronic carrier state

10- Regarding hepatitis c virous (HCV)which of the follwing statement is most accurate? a. Chronic infection with HCV occurs less frequently than chronic infection with HBV b. HCV is a defective virous that requires concurrent HBV infection in order to replicate c. The killed vaccine against HCV is poorly immunogenic so booster doses must be given at least every 5 years d. Chronic infection with HCV predisposes to hepatocellular carcinoma

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6 -c

7- b

8- a

9-e

10- d

11- Which is the difference between hepatitis A & hepatitis B, hepatitis c? a. b. c. d.

They cause diffirent symptoms Hepatitis A doesn't become chronic Only hepatitis A affected the liver There is a vaccine for hepatitis c but not for A

12- What is the most common form of hepatitis? a. b. c. d.

Hepatitis A Hepatitis B Hepatitis C Other forms of hepatitis

13- In most people what are symptoms of hepatitis c when initially infected? a. b. c. d.

Itching Iaundice Back pain Most people don't experience symptoms

14- ……virus is a defective virus? a. b. c. d.

Influenza SARS Marburg Hepatitis D

15- The most serious infection is? a. b. c. d.

19

Superinfection of an HBSAg carrier by HDV Infection with HBV alone Coinfection of HBV &HDV None of the above

16- The most reliable detection test for hepatitis E is? a. b. c. d.

11- b

20

Elisa test for IgG anti HEV Polymerase chain reaction for detection of HEV RNA Western blot assay for IGM anti-HIV Elisa test for IgM anti HEV

12- c

13- d

14- d

15- a

16- b

5

Peritonitis & Typhoid fever

Previous exams & Formative:

4

1- Incubation period of typhoid fever is: a. b. c. d.

Two weeks Two days Two months Two hours

2- High titer of Salmonella O antibody indicates: a. b. c. d.

Past infection Immunization Recent infection Non-Salmonella infection

3- Salmonella typhi lives in: a. b. c. d.

Human Inanimate surfaces Dogs Cattle

4- Persons with chronic typhoid fever carry the bacteria in: a. b. c. d.

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Their bloodstream and intestinal tract Their Pulmonary tract Their genital tract Biliary and urinary tract

5- Choose the wrong answer; as regarding Widal test: a. It should be performed in the 1st week of illness. b. It detects antibodies to O and H antigens of Salmonella species in the patients' serum. c. It is used for diagnosis of enteric fever. d. It is a serological test

6- Symptoms of C. botulinum food poisoning includes double vision, inability to speak, and respiratory paralysis. These symptoms are consistent with…. a. b. c. d. e.

Invasion of the gut epithelium by C. botulinum Secretion of an enterotoxin Endotoxin shock Ingestion of a neurotoxin Activation of cyclic AMP

7- In chronic carriers, Salmonella typhi could be isolated from the following sample (s): a. b. c. d. e.

Urine Blood stool Blood and urine urine and stool

8- Typhoid fever is commonly acquired by a. b. c. d. e.

Droplet infection Transplacental Contaminated food and drink Air borne Dirty toilet seats

9- All of the following organisms produce diarrhea by invading the intestinal mucosa except:

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a. b. c. d. e.

Salmonella typhi Salmonella paratyphi Shigella sonnei Enteroinvasive Escherichia coli Vibrio cholera

10- In the first week, typhoid fever is diagnosed by: a. b. c. d. e.

Widal test Stood culture urine culture Blood culture ELISA

11- Choose the wrong answer; as regarding Widal test: a. b. c. d. e.

It is used for serological diagnosis of enteric fever.

It should be performed in the first week of illness.

High titer of O and H antibodies (≥1/160) indicates recent active infection.

It is a tube dilution agglutination test.

Early antibiotic treatment lowers the antibody titer.

12- which organism is characteristically transmitted by healthy carrier: a. b. c. d.

Salmonella typhi HAV Vibrio cholera Shigella dysentery

13- In chronic carriers, Salmonella typhi, paratyphi could be isolated from the following sample(s); a. b. c. d.

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Blood Stool.

Urine Both b and c

14- High titer of Salmonella O antibody indicates: a. Past infection b. Immunization c. Recent infection d. Non-Salmonella infection

15- Incubation period of typhoid fever is: a. b. c. d.

Two weeks Two days Two months Two hours

16- Blood cultures from the previous patient grow a non-lactosefermenting gram-negative bacillus.

Which of the following is likely to be a constituent of this organism? a. b. c. d. e.

Urease O antigen 157. H antigen 7 (0157:H7) Vi antigen (capsule: virulence antigen) O antigen 139 (0139) KI (capsular type 1)

17- A 68-year-old patient with alcoholic cirrhosis is hospitalized with ascites and esophageal varices. The patient's temperature is C (38.5 °C). Paracentesis reveals a polymorphonuclear cell count of 300/mm3. Which of the following is the most likely Infecting organism? a. b. c. d. e.

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Bacillus cereus Escherichia coli Entamoeba histolytica Giardialambila Clostridium difficile

18- A surgical patient develops an abdominal abscess. The abscess was drained, and culture reveals a polymicrobial infection. The predominant organism identified is a gram-negative anaerobic rod.

Which of the following is the most likely causal agent? a. b. c. d. e.

Bacteroides fragilis Escherichia coli Pseudomonas aeruginosa Staphylococcus aureus Staphylococcus epidermidis

19- For which one of the following enteric illnesses is a chronic carrier state most likely to develop? a. b. c. d.

Cholera Shigella enterocolitis Campylobacter enterocolitis Typhoid fever

20- A 70-year-old man who underwent bowel surgery for colon cancer 3 days ago. He now has a fever and abdominal pain. You are concerned that he may have peritonitis. Which one of the following pairs - of organisms is Most likely to be the cause? a. b. c. d.

Actinomyces israelli and Campylobacter jejune Clostridium botulinum and Shigella dysenteriae Bacteroides fragilis and Klebsiella pneumoniae Bordetella pertussis and Salmonella enteritidis

Answers 1- a

2-c

3-a

4-d

5-a

11-b

12-a

13-d

14-c

15-a

25

6-d 16- c

7-e 17-b

8-c

9-e

18-a

19-d

10-d 20-c

Extra: 1- A 37 year old female admitted to hospital because of fever é increasing anorexia, headache epistasis, constipation. Blood cultures are done most likely cause of her illness is: a. b. c. d.

ETEC Salmonella typhi Shigella sonnei EIEC

2- To diagnose salmonella enteric fever in 1st week, we isolate the organism from: a. b. c. d.

Urine Blood Stool All of the Above

3- Which salmonella produce Vi Ag: a. b. c. d.

S. typhi & Para typhi A S. typhi & Para typhi C S. Para A & B S. typhi & Para B

4- To isolate organism in typhoid fever bacteremia, we use: a. b. c. d.

DCA MacConkey's agar SS both a & b

5- On DCA Salmonella typhi produce: a. Lactose fermenting colonies b. Late lactose fermenting colonies c. Non lactose fermenting colonies

26

d. None of the above

6- Diagnostic titer of Enteric fever in Widal test is a. b. c. d.

1/80 1/40 1/160 None of the above

7- Salmonella carriers are best treated with: a. b. c. d.

Chloramphenicol Ampicillin Norfloxacin trimethoprim

8- Onset of clinical illness in enteric fever occurs after: a. b. c. d.

2ry bacteremia Reinfection of small intestine 1ry bacteremia Gall bladder affection

9- Salmonella food poisoning is Characterized by the following except: a. b. c. d.

Transmitted from animals Fever Enterotoxin production Localization in intestine

10- Shiga toxin is characterized by all of following except: a. b. c. d.

27

Inhibits protein synthesis Neurotoxin Increase CAMP leading to fluid & electrolyte loss Cause Hemolytic uremic syndrome

11- The following statements describing Salmonella species are all correct EXCEPT: a. b. c. d. e.

They are gram-negative bacilli.

They grow as pink colonies on MacConkey and DCA media.

They are urease-negative.

They cause food poisoning.

They cause enteric fever.

12- All the following reactions are correct for Salmonella spp. EXCEPT: a. b. c. d. e.

Fermentation of glucose, maltose & mannite Indole negative Oxidase positive Formation of H2S gas Urease negative

13- Salmonella and Shigella are similar in all the following EXCEPT: a. b. c. d. e.

They are lactose non-fermenters They invade the blood stream They are transmitted through faeco-oral route They are Gram-negative bacilli They possess O (somatic) antigens

14- Intestines of humans and other mammals are the natural habitats of enteric organisms, a large family of bacteria is present as a normal flora, which of the following is less likely to be found as the normal flora of the intestine? a. b. c. d.

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Escherichia spp Salmonella spp Staphylococcus spp Proteus spp

15- Some gram-negative bacteria are a part of normal inhabitants and incidentally cause disease but others such as.................is an important pathogen and the common cause of foodborne and waterborne illnesses all around the world. a. b. c. d.

Pseudomonas spp Streptococcus spp Salmonella spp Proteus spp

16- All are the important general characteristics of enteric bacteria, EXCEPT? a. b. c. d. e. f.

Aerobic and facultatively anaerobic Non-spore forming Grow in media with bile salts Nitrate negative Ferment glucose Produce only catalase but no oxidase

17- Enteric bacteria are mainly classified based on their ability to ferment various sugars including lactose. Which of the following bacteria is a non-lactose fermenter? a. b. c. d.

Klebsiella spp Salmonella spp Enterobacter spp Citrobacter spp

18- Enteroinvasive E. coli (EIEC) is nonmotile, non-lactose, or late lactose fermenters which are predominantly found in developing countries infecting children and travelers. Which of the following infection is similar to EIEC infection? a. Bacillary dysentery b. Shigellosis c. Typhoid

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d. Hay fever

19- Salmonella typhi enter the human body through an oral route penetrating into the intestine, reaching the lymphatics and the bloodstream that ultimately cause the infection known as "Typhoid".

Which of the following is most likely the area where the pathogenesis occurs? a. Mononuclear phagocytic cells in the liver and Peyer’s patches of the small intestine b. Liver, spleen, lymph nodes, and large intestine c. Isolated follicles and Peyer’s patches of a large intestine d. None of the above

20- Which type of salmonellae is primarily infectious for humans? a. b. c. d.

Salmonella typhi A Salmonella paratyphi A, B, and C Salmonella paratyphi A and B Salmonella paratyphi A

21- The symptoms of typhoid fever develop in one to three weeks after exposure to S. typhi, which of the following is the least common symptom? a. b. c. d.

Weight gain Headache High-grade fever Rashes

22- The Widal test is used for the detection of Salmonella typhi and other subspecies. This test is based on the principle.........................................? a. the antigens are detected using the neutralization assay

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b. the antigen combines with its soluble antibody and form a lattice with a visible precipitate c. the antigens bind to RBCs and form the agglutination d. None of the above

23- Salmonella typhi and S. paratyphi are the two major pathogens that cause enteric fever, which of the following are Not the possible specimen taken for the routine diagnosis of the disease? a. b. c. d.

Blood Sputum Feces Urine

Answers 1- b

2-b 3- b

11-b

12-c

20-c

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21-a

13-b 22-b

4-d 14-c 23-b

5-c

6-c

7-b

15-c

16- d

17-b

8-a 18-b

9-c

10-c

19-a

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