Community-acquired pneumonia (CAP) (CAP) is an acute infection of the lung parenchyma. It is usually accompanied by auscultatory changes; patient presents respiratory symptoms and general symptoms. It is estimated that the incidence of CAP could reach 11.6 / 1000 individuals per year, increasing with age (at 65 years, until 44/1000 individuals per year) and the existence of co-morbidity. Mortality from CAP is 1 to 3%, increasing to 6 to 24% in hospitalized patients and for 22 to 57% in Intensive Care Units.
The most common symptoms of pneumonia are cough with sputum, chest pain, fever, chills and shortness of breath. These symptoms are usually related to the extent of the disease. The auscultation of patients with pulmonary pneumonia usually presents a characteristic modification of sounds transmission.
In most cases, the diagnosis is confirmed by chest radiography. Bacteriological examinations of sputum and blood in order to identify the responsible organism can also be made. However, in half of individuals with pneumonia we can't identify the causative agent.
Streptococcus pneumoniae is the main microorganism involved in CAP, accounting for a number of cases that may reach 66%. It is also responsible for about 2/3 of deaths from pneumonia. Other common pathogens are listed in Table 1.
The initial antibiotic therapy is usually empirical. The choice of antibiotic depends on several variables, including the severity of the disease, patient's age, symptoms, co-morbidity, concomitant medication, epidemiological context, contacts with other patients or with a specific type of environment and intolerance to a particular antibiotic or their side effects. There are guidelines published by several medical societies and in different countries for the empirical treatment of CAP, but has been noted that these standards are not always met and that the most commonly used antibiotics in CAP vary from region to region.
The ideal antibiotic to start empirical therapy of CAP should be one that will prove efficacy against the most important etiologic agents, this means pneumococci (including penicillin-resistant), H. influenzae and atypical intracellular microorganisms.