Deck 9: Clues for Distinguishing Causative Infectious Agents Systems Approach

Question 1

One week postdelivery, an infant boy becomes extremely irritable and continuously rubs his right eye, which contains a mucopurulent exudate. An examination of the eye shows papillae on the conjunctiva. No bacteria are seen in the exudate. The most likely causative infectious agent is

A) Candida albicans
B) Chlamydophila trachomatis
C) Cytomegalovirus
D) Herpes simplex virus

Answer 1

Chlamydophila trachomatis

Question 2

A 58-year-old man presents at your office complaining of extreme pain in his right testicle. Physical examination shows considerable swelling. A small amount of urethral exudate could be aspirated. Microscopic examination and Gram staining showed the presence of bacteria. Those bacteria most likely are

A) Gram-negative cocci
B) Gram-negative diplococci
C) Gram-positive cocci
D) Gram-positive rods

Answer 2

Gram-positive cocci

Question 3

A 22-year-old woman presents with symptoms of vaginitis, including a yellowish discharge. She claims to have not been sexually active for 18 months. When KOH is added to the discharge, a "fishy" odor appears. She is most likely infected with

A) Candida albicans
B) Chlamydophila trachomatis
C) Gardnerella vaginalis
D) Herpes simplex virus 2

Answer 3

Gardnerella vaginalis

Question 4

A known alcoholic appears at the emergency department with chest pain, a 40°C/104°F fever, chills, and a productive cough. He has no history of chronic pulmonary disease. There are red blood cells an encapsulated Gramnegative rods in the sputum. The symptoms are most likely caused by

A) Haemophilus influenzae
B) Klebsiella pneumoniae
C) Nocardia asteroides
D) Pseudomonas aeruginosa

Question 5

There is an outbreak of gastrointestinal disease involving six children at a day care center. The children all have symptoms of fever, watery stool, and vomiting. Recent activities at the center involved playing with animals including kittens, turtles, birds, and hamsters. What types of bacteria are most likely to be observed in the stool?

A) Gram-positive cocci
B) Gram-negative cocci
C) Gram-positive rods
D) Gram-negative rods

Question 6

A 75-year-old man is brought by his daughter to the community health center. He appears confused and has a stiff neck and severe headache. She indicates that the previous week he had a runny nose and other symptoms consistent with sinusitis. What organism would you expect to find in his cerebrospinal fluid?

A) Coxsackie virus
B) Haemophilus influenzae
C) Neisseria meningitis
D) Streptococcus pneumoniae

Question 7

While on winter semester break, a 21-year-old male college student appears at his family physician's office with several skin lesions on his right arm. They consist of a central pustule within a raised erythematous area. He reports that the only recent unusual activities that have involved skin exposure have been hot tub parties at his friend's cabin during the previous two weekends. What is the most likely causative infectious agent?

A) Pseudomonas aeruginosa
B) Streptococcus pyogenes
C) Staphylococcus aureus
D) Papillomavirus

Question 8

In July, you are called to a rural nursing home where several of the residents have developed a gastrointestinal disease consisting of fever, vomiting, and bloody stool. Lab analysis of the stool shows the presence of PMNs and Gram-negative rods. Epidemiological discussions with the residents indicate they all shared the same raw milk brought to one resident by his farmer son. The most likely cause of the infection is

A) Campylobacter jejuni
B) Clostridium perfringens
C) Staphylococcus aureus
D) Vibrio parahaemolyticus

Question 9

An 18-month-old female infant is brought to the emergency department by her mother. The mother reports an abrupt onset of symptoms consisting of continual crying, high fever (40°C/104°F), and a cough
Producing rusty colored sputum. What would you expect a chest x-ray and lab findings to show?

A) Lobar pattern and Gram-positive cocci
B) Lobar pattern and Gram-negative cocci
C) Bronchopneumonia pattern and Gram-positive cocci
D) Bronchopneumonia pattern and Gram-negative rods