Prospective study of the usefulness of sputum Gram stain in the initial approach to community-acquired pneumonia requiring hospitalization

Clin Infect Dis. 2000 Oct;31(4):869-74. doi: 10.1086/318151. Epub 2000 Oct 12.


From February 1995 through May 1997, we prospectively studied 533 patients with community-acquired pneumonia requiring hospitalization in order to assess the current usefulness of sputum Gram stain in guiding the etiologic diagnosis and initial antibiotic therapy when applied routinely. Sputum samples of good quality were obtained in 210 (39%) patients, 175 of whom showed a predominant morphotype. Sensitivity and specificity of Gram stain for the diagnosis of pneumococcal pneumonia were 57% and 97%, respectively; the corresponding values for Haemophilus influenzae pneumonia were 82% and 99%. Patients with a predominant morphotype were more frequently treated with monotherapy than were patients without a demonstrative sputum sample (89% vs. 75%; P<.001). Analysis of our data shows that a good-quality sputum sample can be obtained from a substantial number of patients with community-acquired pneumonia. Gram stain was highly specific for the diagnosis of pneumococcal and H. influenzae pneumonia and may be useful in guiding pathogen-oriented antimicrobial therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / therapeutic use
  • Community-Acquired Infections / diagnosis*
  • Community-Acquired Infections / drug therapy
  • Community-Acquired Infections / microbiology
  • Female
  • Gentian Violet
  • Haemophilus Infections / diagnosis
  • Haemophilus Infections / microbiology
  • Haemophilus influenzae
  • Humans
  • Male
  • Middle Aged
  • Phenazines
  • Pneumonia, Bacterial / diagnosis*
  • Pneumonia, Bacterial / drug therapy
  • Pneumonia, Bacterial / microbiology
  • Pneumonia, Pneumococcal / diagnosis
  • Pneumonia, Pneumococcal / microbiology
  • Prospective Studies
  • Sensitivity and Specificity
  • Sputum / microbiology*
  • Staining and Labeling / statistics & numerical data


  • Anti-Bacterial Agents
  • Gram's stain
  • Phenazines
  • Gentian Violet