Community-acquired pneumonia: microbial investigations were occasionally helpful.

Clinical bottom line (level 4)

  1. In patients with community-acquired pneumonia, microbial investigation found no causative pathogen in three-quarters of cases.
  2. In patients with community-acquired pneumonia, microbial tests directed a change in antibiotic therapy in less than a tenth of cases.
Woodhead et al: Respiratory Medicine 1991; 85: 313-317
Expires March 2003

The study

Setting: one teaching and one general hospital, UK

106 patients (aged 39% under the age of 65 years, 54% male) Under the care of the general or respiratory physicians with a diagnosis of community-acquired pneumonia (defined with features of lower respiratory tract infection, ie. cough, purulent sputum, pleuritic chest pain, pyrexia, plus radiographic pulmonary parenchymal shadowing considered to be likely to be new).

Excluded if
  • = 15 years old
  • admission directly to geriatric wards or communicable diseases unit
  • known malignant disease or immunosuppression
  • case notes unable to be located



    • Independent ?blinded reference standard, applied in all patients from a consecutive inappropriate spectrum.
    Reference standard:
    • microbial investigations was performed- blood culture, sputum culture or serology

    The evidence


    differential diagnosis number of patients prevalence
    (95% CI)
    no causative pathogen found 78 73.6%
    (65.2% to 82.0%)
    microbial tests directed a change in antibiotic therapy 8 7.55%
    (2.52% to 12.6%)

    • Blood cultures were performed in 81% of cases, sputum was examined in 45% and complete serological tests were performed in 28%.

    Comments

    1. Clinical value of the proportion of decisions altered is difficult to quantify - wide variation in how important the information is felt to be.

    Citation

    1. Woodhead MA, Arrowsmith J, Chamverlain-Webber R, et al: The value of routine microbial investigation in community-acquired pneumonia. Respiratory Medicine 1991; 85: 313-317
    Search Terms: community-acquired pneumonia and diagnosis in Medline
    Contributor: Clare Wotton and Musab Hayatli, November 1999
    Reviewer: Mitsuhiro Kamei

    Clinical Question.
    Patient community-acquired pneumonia
    Intervention or Exposure routine microbial investigation, sputum culture
    Outcome clinical use