Many classes of antibiotics can treat pneumonia. Which antibiotic your doctor chooses generally will be based on:

• Your age.
• Your symptoms.
• How severe your pneumonia is.
• Other medical problems that you might have.
• What type of bacteria may be causing your pneumonia. Most cases of bacterial pneumonia in otherwise healthy people are caused by Streptococcus pneumoniae and Mycoplasma pneumoniae. Several other bacteria may cause pneumonia in the very young, older adults, and those with other diseases.
• Whether you have a type of bacteria that some medications can no longer kill (resistant bacteria).
• Whether you are allergic to any antibiotics.

Your doctor's choice of antibiotics may also depend on whether you:

• Are otherwise healthy and do not have to go to a hospital for treatment.
• Have other medical conditions but still do not have to go to the hospital.
• Have to go to the hospital.
• Have to go to an intensive care unit.

Choosing an antibiotic based on these factors avoids the need for extensive culture and sensitivity testing and allows for rapid treatment that has a high rate of cure.