MCCC
Spring 2015
MLT 215: Clinical Microbiology
Quiz 4
1) A 48 year-old man returned from Peru where he had become ill with a fever and an
unproductive cough. The patient presented in the ER with a temperature of 38.6°C (101.5°F).
Auscultation and percussion of his lungs were clear. No skin rash was evident. Notable
laboratory findings were: white blood cell count, 1,800 per mm3 (1.8 × 109 per L), decreased
neutrophils, lymphocytes and eosinophils; platelet count, 104,000 per mm3 (104 × 109 per L).
Examination of the thin smear of the patient’s blood sample showed the following:
a. What is the presumptive diagnosis?
b. Why is it important to speciate this organism?
2) A 32 year-old woman developed a temperature of 38.9°C (102°F), sweats, shaking chills and a
headache after returning from rural Indonesia. She was found to have a WBC of 28,000 per
mm3 (28 × 109 per L) with a left shift and toxic granulation. Serum liver enzymes were elevated.
A computed tomographic (CT) scan of the abdomen revealed three large abscesses in the right
lobe of the liver. The night the patient was admitted to the hospital, a stool sample was
collected and sent to the lab for a full O&P. The trichrome smear revealed the following:
Identify the amoeba.
3) A toddler was brought into the doctor’s office for persistent diarrhea. The physical exam
showed vital signs of P: 110, B/P: not taken, Temp: 100.1. The patient was alert and oriented.
Chest - normal in appearance with no dyspnea noted. Heart tones - unremarkable. Abdomen
had hyperactive bowel sounds in the lower quadrants; palpation was soft but patient indicated
tenderness in all quadrants. Anus and surrounding tissues appear aggravated from recent and
frequent cleaning following diarrhea. Runny, brown stool was noted in the patient's training
pants. Extremities and posterior thorax were normal and patient ambulated without assistance.
Samples for both UA and stool cultures were obtained and sent to the lab. All UA findings were
normal. A direct smear of the patient’s stool with iodine showed the following in high number.
What is the diagnosis?
4) A patient presented to the ER with abdominal pain, diarrhea, an upset stomach and nausea.
The patient also complained of fatigue and joint pain. A Stool culture and O&P were ordered.
The trichrome smear demonstrated the following parasite. What is the name of the organism?
5) In April of 1993, the Milwaukee Health Department battled an epidemic that began with
hundreds, thousands, then tens of thousands of people in the Milwaukee area. All of the
patients experienced relentless, watery diarrhea. The epidemic caused the deaths of at least 69
people, a with weakened immune systems, and 93% of them being AIDS patients. A few were
cancer patients. Some were children. State and city health officials determined that the city's
drinking water was involved. The epidemic prompted dramatic changes in how the city treated
its water.
During the epidemic, clinics and hospitals collected stool samples yet could not isolate any
common bacteria or virus. The Modified acid fast stained smear below was obtained from the
public water supply. What do you think was the causative agent of the epidemic?
6) The ‘Circular of Information’ distributed by the American Red Cross lists tests performed on
samples from blood donors. One such test screens for Chagas disease. Below is an image of a
blood smear with the causative agent of Chagas. Fill in the blanks with the genus and species of
the parasite.
“Testing of a sample of donor blood is performed before units of blood or blood components are distributed for
routine transfusion. The donor’s ABO group and Rh type have been determined, including testing for the
presence of weak D antigen. A sample from each donation intended for allogeneic use has been tested by FDA-
licensed tests and found to be nonreactive for antibodies to human immunodeficiency virus (anti-HIV-1/2),
hepatitis C virus (anti-HCV), human T-cell lymphotropic virus (anti-HTLV-I/II), and hepatitis B core antigen (anti-
HBc), and nonreactive for hepatitis B surface antigen (HBsAg). Licensed nucleic acid tests (NAT) for HCV
ribonucleic acid (RNA), HIV-1 RNA, and West Nile virus (WNV) RNA have been performed and found to be
nonreactive. A licensed nucleic acid test (NAT) for HBV DNA has been performed and found to be nonreactive. A
serologic test for syphilis has been performed and found to be nonreactive. All blood has been collected from
donors who have tested negative by a licensed test for antibodies to
_________________________ ____________________.”
7) A woman was seen by a gynecologist for the following symptoms: abnormal vaginal discharge,
vulvar itching, irritation and odor. A wet mount from a vaginal swab from the patient
demonstrated this motile, flagellated protozoan with an undulating membrane.
a. What is the name of the infectious agent?
b. Is the arrow pointing to a troph or a cyst?
8) A lab technician observed a parasitic egg in a urine sample when performing a microscopic
urinalysis. What is the genus and species of the organism? (Note the terminal spine on the egg)
9) An 18-year-old Vietnamese woman who had arrived in the United States eight months previously
was admitted with to the ER with nausea, clear emesis and right upper quadrant pain. On physical
examination, the patient was found to have a temperature of 37.1°C (98.8°F). Some laboratory
values were elevated: white blood cell count, 13,600 per mm3 (13.6 3 109 per L); serum alanine
transaminase (ALT), 63 U per L; total serum bilirubin, 3.2 mg per dL (55 µmol per L); serum alkaline
phosphatase (ALP), 142 U per L; serum aspartate transaminase (AST), 112 U per L; and serum lipase,
84 U per L. A concentrated smear of a stool sample revealed the parasitic egg seen below. The egg
was 30 um long with an operculum, shoulders and a small knob on the posterior end. It was
determined that the infection was acquired from eating infected freshwater fish. Her
gastrointestinal symptoms responded to praziquantel treatment. Base on the morphology of the
parasitic egg, what is the causative agent of the patient’s symptoms?
10) These eggs were seen on a ‘cellophane tape prep’ from a child experiencing perianal itch. What
is the genus and species of the Nematode that lays these eggs?
Bonus: A pregnant woman is being screen for Toxoplasma gondii. Which lab test should be
ordered and why?
