B. Host where the adult form of the parasite lives and reproduces
In general, six sequential fecal specimens should be examined for the presence of any intestinal parasites.
a. True
b. False
b. False
Formed unpreserved stool should be examined within 1 hour because trophozoites die rapidly.
a. True
b. False
b. False
Unpreserved formed stools need not be refrigerated because protozoa have already formed cysts.
a. True
b. False
b. False
What are the correct processes that should be performed on a stool collected for parasite exam on a 6 month old child recently adopted from Vietnam?
E. All of the above
What is the definitive host for Echinococcus granulosus?
C. Wolves
Which fluke's eggs are generally found in sputum?
D. Paragonimus westermani
Which of the hookworms has two ventral pairs of teeth?
A. Ancylostoma duodenale
Which amoeba trophozoite feeds on RBCs?
C. Entamoeba histolytica
Which amoeba has a nucleus with a heavy chromatin ring and an eccentually located karyosome?
A. Entamoeba coli
Which amoeba has a nucleus with an even chromatin ring and a centrally located karyosome?
C. Entamoeba histolytica
Which amoeba has four or less nuclei in a round cyst?
B. Entamoeba histolytica
Which amoeba cyst always contains a glycogen vacuole?
D. Iodamoeba butschlii
Which amoeba has a nucleus with a large karyosome and a nuclear membrane that is not visible?
C. Endolimax nana
Which protozoa does not form cysts?
B. Dientamoeba fragilis
Which amoeba causes intestinal ulcers and bloody dysentery?
D. Entamoeba histolytica
Which amoeba can invade liver an cause pathology in the organ?
D. Entamoeba histolytica
Which of the following parasites do not migrate to the lungs, are coughed up, and swallowed during their life cycle in humans?
B. Dipylidium caninum
Which Nematode can autoinfect their host?
C. Strongyloides
List two ways to differentiate between adult male and female Ascaris worms.
Males: smaller, curved tail
Females: larger, straight tail
What two parasites can be diagnosed by direct fluorescent antibody staining from a stool sample?
a. Cyclospora
b. Cryptosporidia
c. Acanthamoeba
d. Giardia
e. Entamoeba histolytica
Cryptosporidia and Giardia
Define hermaphroditic.
When the organism contains both male and female reproductive systems.
How do the proglottids of Diphyllobothrium lactum differ from those of other tapeworms?
D. latum's proglottids are wider than they are long. They have a central pore and the uterus has a rosette shape.
The infective stage of this roundworm is the filariform larva...
C. Strongyloides stercoralis
Eggs and/or larvae which are recovered in the stool are routinely used to diagnose infections caused by all of the following except:
A. Trichinella spiralis
Which of the following has the longer buccal cavity?
a. Hookworm rhabditiform larvae
b. Strongyloides rhabditiform larvae
a. Hookworm rhabditiform larvae
Blood films examed for microfilariae should be examined under what power?
B. 10x
A modified acid fast stain should be performed to detect which of the following parasites?
a. Giardia lamblia
b. Cyclospora cayetanesis
c. Isospora belli
d. Onchocerca volvulus
Cyclospora cayetanesis and Isospora belli
The gravid proglottids of this Cestode contain 7-13 uterine branches on each side:
C. Taenia solium
A stained fecal smear reveals mononucleate flagellates with a pointed posterior and lemon-shaped mononucleate cysts with a clear, nipple-like bleb at one end. You would name this as:
D. Chilomastix mesnili
This parasite was found in the blood smear on a patient who had a recent summer vacation in New England and reported many insect and tick bites.
D. Babesia spp.
Toxicariasis is a parasitic disease humans acquire whne they become the intermediate host to dog or cat Ascaris. The disease manifests itself in many different ways and is difficult to diagnose. What test would be performed if the patient was suspected of having Toxicariasis?
A. Serological testing for antibodies
Which of the following is typically the infective stage of Plasmodia for man?
A. Sporozoite
In which of the following are schizonts rarely seen?
C. Plasmodium falciparum
The following stages of the malarial parasite are found in man, except:
A. Gametes
Multiple infections of erythrocytes is most common with:
D. Plasmodium falciparum
Which of the following yields blood smears characterized by enlarged RBCs and exhibit Schuffner's stippling?
a. Plasmodium malariae
b. Plasmodium vivax
c. Plasmodium ovale
d. Plasmodium falciparum
Plasmodium vivax and Plasmodium ovale
Characteristic: rosette shaped uterus, egg is operculated
C. Diphyllobothrium latum
This tapeworm can autoinfect and migrate.
B. Taenia solium
Rats and humans can be the definitive host.
C. Hymenolepis nana
Characteristic: proglottids have 15-20 uterine branches and eggs are striated.
B. Taenia saginata
What is the common name of Strongyloides stercoralis?
Threadworm
What is the common name of Necator americanus?
New World Hookworm
What is the common name of Enterobius vermicularis?
Pinworm
What is the common name of Ascaris lumbricoides?
Large Roundworm
What is the common name of Trichuris trichiura?
Whipworm
What is the common name of Taenia saginata?
Beef Tapeworm
What is the common name of Taenia solium?
Pork Tapeworm
What is the common name of Fasciolopsis buski?
Large Intestinal Fluke
What is the common name of Clonorchis sinensis?
Chinese Liver Fluke
What is the common name of Ancylostoma duodenale?
Old World Hookworm
What criteria are used for morphological differentiation of blood and tissue microfilariae?
C. Placement of nuclei and presence of absence of sheath
How does an individual become infected with Toxoplasmosis?
A. Ingestion of undercooked meat and from cat feces
Define reservoir.
Hosts a parasite that is capable of infecting.
An ocular micrometer must be calibrated in order to measure and identify parasites accurately.
Low power: Stage = 0.8
Ocular = 45
If an objective measures 3 units, what is the size in microns?
A. 53.33
(0.8*1000)/45 = 17.75
17.75*3 = 53.33 microns
Which Cestode is associated with Vitamin B12 deficiency?
A. Diphyllobothrium latum
In a fecal exam obtained from a patient who had recently traveled to South America, the following was seen. A large protozoa that was ciliated and contained many vacuoles and a micronucleus and a macronucleus. What is the most likely parasite?
C. Balantidium coli
Dr. Marshall along with a team of other health care providers spent a week treating and caring for patients in a small clinic located in a remote village in the western part of Africa. Several individuals presented to the clinic with large blisters on the lower leg, ankles, and feet. Upon contact with water, the blisters ruptured and a small thin whitish worm could be seen.
What is this parasite and how should it be treated?
Draculculus medinensis (Guniea Worm). Wrap the worm around a match stick and slowly (only a couple cm at a time) retrieve the worm. May take days to weeks.
A 10 year old boy was admitted to the hospital with a severe headache, fever, nausea, and vomiting. Symptoms began suddenly 2 days after vacationing at a summer camp situated on an inland lake. A spinal tap revealed a purulent CSF with no bacteria. On direct examination of the liquid, a motile amoeba resembling a leukocyte was observed.
What is the most likely causative agent?
Naegheria
An elderly woman living in the Great Lakes area of the US went to her doctor. She had intermittent diarrhea and abdominal pain for several weeks. A case history was taken from the patient and it was found that she regularly prepared gefilite fish (fish and cracker mixture) and often tasted the recipe before cooking to make sure it was seasoned correctly. The bacterial cultures of her feces were negative but upon performing a parasite exam, eggs were seen. The eggs on close examination had a operculum that was hardly visible and a small knob at the opposite end.
What parasite do you suspect and how did she acquire it?
Diphyllobothrium latum; ingesting raw or undercooked fish.
River blindness is caused by:
C. O. volvulus
A principal role of the clinical microbiologist includes:
D. All of the above
The 5 basic steps in microbial identification and reporting are collection and transport, specimen processing, and identification of medically important organsims. What are the two remaining steps?
C. Antimicrobial susceptibility and reporting
What is a nosocomial infection?
A hospital-acquired infection.
Definitive ID of clinically significant isolates
A. Is not always cost effective and should be done based on source of the isolate, attending physicians request, and lab policy.
Universal precautions in the micro lab apply to
D. All clinical specimens
Material Safety Data Sheets (MSDS) are:
E. All of the above
How should a urine sample for culture be handled if it is delayed before reaching the lab for testing?
D. Refrigerate or preserve samples
The key to proper specimen collection is:
B. Collect during the acute phase of an illness
Which category of media would MAC best fit?
C. Selective and differential
Selective for gram negatives and differential for LF/NLF
Which category best describes HE media?
D. Selective and differential
Selective for Salmonella and Shigella and differential for H2S production
What role does normal flora play in protecting the body from disease?
A. NF reduce the pH in that site and competes for minerals
What is one critical test for distinguishing Staph aureus from Staph epidermidis?
A. Coagulase
Which of the following tests is the most specific for ID of GAS?
C. Serologic latex agglutination testing
Two positive tests for identifying Strep pneumoniae.
Optochin sensitivity
Bile solubility
Two positive tests for identifying GBS.
CAMP test
Hippurate hydrolysis
Two positive tests for identifying GAS.
Bacitracin sensitivity
PYR test
Three positive tests for identifying Enterococcus.
PYR test
6.5% NaCl tolerance positive
Esculin hydrolysis positive
One positive test for identifying Group D Strep.
Esculin hydrolysis positive
Hyalurionidase assists in the spread of disease caused by S. aureus by breaking down connective tissue.
a. True
b. False
a. True
The following information is obtained from a urine culture:
The most likely identification of this organism is:
C. Staph saprophyticus
Micrococcus is modified oxidase positive, S. aureus is coagulase positive
Match the following Staphylococcal virulence factors with the condition they cause: Hemolysins
D. Destroys RBCs
Match the following Staphylococcal virulence factors with the condition they cause: Exfoliating toxin
D. Scalded skin syndrome
Match the following Staphylococcal virulence factors with the condition they cause: Leukocidins
A. Destroys WBCs
Match the following Staphylococcal virulence factors with the condition they cause: TSST-1
B. Toxic shock syndrome
Match the following Staphylococcal virulence factors with the condition they cause: Enterotoxin
D. Food poisoning
Match the following Staphylococcal virulence factors with the condition they cause: Penicillinase
B. Inactivates antibiotics
Which statement(s) is/are true for Micrococcus?
E. All of the above
S. aureus is the species that has the most virulence in the genus. Which of the following infections does it cause?
a. Scarlet fever
b. Impetigo
c. Carbuncles
d. Food poisoning
e. All of the above
Impetigo, Carbuncles, and Food Poisoning
Scarlet fever is caused by GAS.
Which of the following is associated with GAS virulence?
D. All of the above
The drug of choice for most streptococcal infections is
D. Penicillin
What is the reaction that occurs when an organism is catalase positive?
2H2O2 --> O2 + 2H2O
Which is the correct description for Stomatococcus?
D. Sticky colonies
Which two infections are preceded by infection with beta-hemolytic streptococci?
D. Glomerulonephritis, rheumatic fever
List four characteristics which all Enterobacteriaceae share.
Gram negative
Oxidase negative
Glucose fermenters
Reduce nitrates to nitrites
A sputum culture on an alcoholic seen in the ER grows gray, mucoid colonies on BAP. The isolate grows readily on MAC and forms mucoid, dark pink colonies. The colonies yield the following reactions:
VP positive = Klebsiella, Enterobacter, or Serratia
A positive ONPG test tells us that the organism being tested can
D. Ferment glucose
Media for screening suspected cases of enterohemmorrhagic E. coli O157 must contain
B. Sorbitol
A positive lysine decarboxylation is indicated by a yellow butt in the LIA.
a. True
b. False
b. False - Purple indicates negative
Spot indole should always be performed off of BAP or CHOC agar.
a. True
b. False
a. True
CIN agar is used to isolate Yersinia enterocolitica.
a. True
b. False
a. True
All members of the Enterobacteriaceae are nitrate negative.
a. True
b. False
b. False - they are nitrate positive
Salmonella can be carried asymptomatically in the gallbladder.
a. True
b. False
a. True
Shigella infections occur only when a person is exposed to a large dose of organism.
a. True
b. False
b. False - small dose
A patient presented to the doctor with a severe case of gastroenteritis. The stool culture from the patient recovered an organism with the following characteristics/biochemical reactions:
BAP = large colony, gamma hemolytic
MAC = NLF gram negative rod
HE = clear colony with black center
Oxidase neg
Indole neg
Urea neg
Citrate pos
Which of the following organisms is the most likely pathogen?
C. Salmonella spp.
The major etiologic agent of UTIs is
A. E. coli
Which of the following ferments glucose:
D. Morganella morganii
The oxidase test is positive for which organism?
B. Pseudomonas aeruginosa - we use this organism for our OX control
A positive deaminase test is important for which organism:
B. Providencia rettgerii
What common GNR swarms on BAP?
Proteus mirabilis
What Enterobacteriaceae can produce a distinct red to pink pigmentation?
D. Serratia marcescens
Which of the following characteristics does NOT describe a nonfermenting GNR?
C. Grow anaerobically only
List the three types of infection caused by Yersinia pestis.
Bubonic
Septicemia
Pneumonic
What test can you use to differentiate Klebsiella pneumoniae and Klebsiella oxytoca?
C. Indole - K. pneumonia is negative, K. oxytoca is positive
How would you treat an intestinal infection caused by Salmonella vs. Shigella?
C. Salmonella is supportive therapy unless it is extra-intestinal
A Lysine Iron Agar (LIA) shows a reaction of Red/Yellow. Based on this reaction, the organism tested positive for what reaction?
A. Glucose fermentation positive and lysine deaminase positive
E. coli O157:H7 causes bloody diarrhea. What is an additional complication that can occur especially in children as a result of being infected by this organism?
B. HUS
An organism that cannot utilize carbohydrates as an energy source is:
C. Asaccharolytic
An organism that utilizes carbohydrates anaerobically is:
B. Fermenter
An organism that cannot utilize carbohydrates anaerobically:
D. Nonfermenter
An organism that utilizes carbohydrates aerobically:
B. Oxidizer
Which of the following organisms are nonfermenting GNR? (more than one)
a. Sphingomonas paucimobilis
b. Chryseobacterium meningosepticum
c. Serratia marcescens
d. Chromobacterium violaceum
e. Salmonella enteritidis
This organism has a very, very, very strong fruity odor.
B. Alcaigenes faecalis
This organism colonizes the respiratory tract of cystic fibrosis patients.
C. Burkholderia cepacia
Which of the following is associated with Pseudomonas aeruginosa?
E. All of the above
Which type of gram negative bacilli is resistant to most currently available antimicrobial agents except Trimethoprim/Sulfamethoxazole, leaving it as the primary drug of choice for infections caused by this species?
D. Stenotrophomonas
In oxidation-fermentation determinations, when acid production is detected in the open, aerobic tube only, the organism is identified as a
A. Glucose oxidizer - nonfermenter, oxidizer
Which organism has a violet pigment and is oxidase positive?
D. Chromobacterium violaceum
Which organism has a yellow colony and earthy odor?
A. Burkholderia cepacia
This organism has non-lactose fermenting colonies with a purple hue.
A. Acinetobacter baumanii
This Pseudomonas aeruginosa virulence factor inhibits protein biosynthesis.
C. Toxin A
This Pseudomonas aeruginosa virulence factor is toxic to alveolar macrophages.
C. Heat-stable hemolysin
This Pseudomonas aeruginosa virulence factor causes terminal shock.
B. Endotoxin
This Pseudomonas aeruginosa virulence factor causes hydrolysis of lecithin.
D. Phospholipase
This Pseudomonas aeruginosa virulence factor destroys protein elastin.
A. Protease
This Pseudomonas aeruginosa virulence factor impairs function of cilia.
D. Pigment
This Pseudomonas aeruginosa virulence factor protects organisms from phagocytosis and complement activity.
B. Biofilm
This Pseudomonas aeruginosa virulence factor assists in attachment, promoting colonization.
D. Pili
This Pseudomonas aeruginosa virulence factor destroys leukocytes.
C. Leukocidin
This Pseudomonas aeruginosa virulence factor impairs the function of phagocytic cells.
