Match the clinical description with the most likely organism.

Match the clinical description with the most likely organism.
a. Streptococcus pneumoniae
b. Staphylococcus aureus
c. Viridans streptococci
d. Providencia stuartii
e. Actinomyces israelii
f. Haemophilus ducreyi
g. Neisseria meningitidis
h. Listeria monocytogenes

A 30-year-old female with mitral valve prolapse and mitral regurgitant murmur develops fever, weight loss, and anorexia after undergoing a dental procedure.

Answer: c. Viridans streptococci

An 80-year-old-male, hospitalized for hip fracture, has a Foley catheter in place when he develops shaking chills, fever, and hypotension.

Answer: d. Providencia stuartii

A young man develops a painless, fluctuant purplish lesion over the mandible. Cutaneous fistula is noted after several weeks

Answer: e. Actinomyces israelii

A sickle cell anemia patient presents with high fever, toxicity, signs of pneumonia, and stiff neck.

Answer: a. Streptococcus pneumoniae

Discussion:


The 30-year-old-female with mitral valve prolapse has developed subacute bacterial endocarditis. The likely etiologic agent is a viridans streptococci. Viridans streptococci cause most cases of subacute bacterial endocarditis. No other agent listed is likely to cause this infection.

The 80-year-old-male with a Foley catheter in place has developed a nosocomial infection likely secondary to urosepsis. Providencia species frequently cause urinary tract infection in the hospitalized patient.

The young man with a fluctuant lesion and fistula over the mandible presents a classic picture of cervicofacial actinomycosis.

The sickle cell anemia patient who presents with concomitant pneumonia and meningitis has overwhelming infection with S. pneumoniae due to functional asplenia. S. pneumoniae causes a particularly severe infection associated with sickle cell disease.