Role of Sputum Gram Stain And Culture In A Patient With Pneumonia

A 30-year-old male with sickle cell anemia is admitted with cough, rusty sputum, and a single shaking chill. Physical examination reveals increased tactile fremitus and bronchial breath sounds in the left posterior chest. The patient is able to expectorate a purulent sample.
Which of the following best describes the role of sputum Gram stain and culture?

a. Sputum Gram stain and culture lack the sensitivity and specificity to be of value in this setting.
b. If the sample is a good one, sputum culture is useful in determining the antibiotic sensitivity pattern of the organism, particularly Streptococcus pneumoniae.
c. Empirical use of antibiotics for pneumonia has made specific diagnosis unnecessary.
d. There is no characteristic Gram stain in a patient with pneumococcal pneumonia.
e. Gram-positive cocci in clusters suggest pneumococcal infection.

Answer And Discussion:

The answer is b. ( If the sample is a good one, sputum culture is useful in determining the antibiotic sensitivity pattern of the organism, particularly Streptococcus pneumoniae.)

The Infectious Disease Society of America’s guidelines on the treatment of community-acquired pneumonia still recommend the use of sputum Gram stain and culture. This is particularly important in the era of multiantibiotic-resistant S pneumoniae. Sputum culture and sensitivity can direct specific antibiotic therapy for the patient as well as provide epidemiologic information for the community as a whole. A good sputum sample showing many polymorphonuclear leukocytes and few squamous epithelial cells can give important clues to etiology. A Gram stain that shows gram-positive lancet shaped diplococci intracellularly is good evidence for pneumococcal infection. Gram-positive cocci in clusters would suggest staphylococcal infection, which would be uncommon in this setting. Empirical antibiotic therapy becomes more difficult in communityacquired pneumonia as more pathogens are recognized and as the pneumococcus develops resistance to penicillin, macrolides, and even quinolones.