Legionnaires’ Disease Treatments and Prognosis

Legionnaires’ disease can be life threatening. It is imperative to begin treatment as early as possible. Death rates are higher when a patient starts antibiotics late, in patients who are already ill and in patients who contract Legionnaires’ disease while in the hospital (close to 50 percent in this last group). Treatment continues until the completion of antibiotic therapy and symptoms are gone. With early and completed treatment, the prognosis in healthy individuals is good, and patients can expect full recovery from the disease.


Most patients with Legionnaires disease require initial hospitalization for intravenous antibiotics. Treatment starts as soon as Legionnaires’ disease is suspected. Lab tests will accurately confirm the diagnosis. Early intervention leads to a better outcome. There are several antibiotics that are very effective against Legionella bacteria, often replacing Erythromycin, which was the antibiotic of choice for killing the bacteria.

The two most potent antibiotics used are the following:

  • Macrolides (azithromycin)
  • Quinolones (ciprofloxacin, levofloxacin, moxifloxacin, gemifloxacin or trovogloxacin)

These are others that are also effective:

  • Tetracycline
  • Doxycycline
  • Minocycline
  • Trimethoprim-sulfamethoxazole

Other Legionnaire’s disease treatments might include these:

  • IV fluids for electrolyte replacement
  • Oxygen

After initial hospitalization and intravenous antibiotics, patients require monitoring. When there is steady improvement, patients can then switch to oral antibiotics. With continued improvement for at least a day on the oral medication, some patients can be discharged to outpatient care. Continued monitoring is still necessary to detect any relapse or deterioration. Final discharge would occur when all symptoms have resolved and the patient has finished all medication.


Annual reported cases of Legionnaires disease outbreaks range from 8,000 to 18,000 and many more unreported cases are suspected. Isolated cases show up throughout the year, but most community outbreaks happen in the warmer months of summer and early fall. With early and proper diagnosis and treatment, most patients recover from Legionnaires’ disease. It is, however, the second most frequent cause of severe pneumonia resulting in hospitalization and admission to intensive care.

When patients receive treatment with antibiotics known to be highly effective for killing the Legionella bacteria, the prognosis is excellent. This is particularly true in otherwise healthy individuals. If there is a delay of the correct treatment, the patient is a transplant recipient or the patient has a compromised immune system, then a lengthy hospitalization, complications and death can result. Patients who are cigarette smokers should cease smoking.

Full recovery can take up to a year for some people. After the illness is gone, some lingering symptoms may remain.

These symptoms can include the following:

  • Fatigue
  • Loss of energy
  • Difficulty concentrating
  • Joint pain
  • Muscle weakness

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