ABSTRACT
Acute lower respiratory tract infections are a persistent public health problem. Despite the remarkable advances in antibiotic therapies, diagnostic tools, prevention campaigns and intensive care, respiratory infections are still among the primary causes of death worldwide, and there have been no signifi cant changes in mortality in the last decades (Mizgerd 2008). With the widespread use of broad-spectrum antimicrobial agents and the increasing number of immunocompromised hosts, the etiology and the drug resistance patterns of pathogens responsible for respiratory infections have changed. Streptococcus pneumoniae, Haemophilus infl uenzae, and Moraxella catarrhalis remain the leading causes of respiratory infections in immunocompetent
patients. Opportunistic infections with organisms such as Pneumocystis jiroveci and Mycobacterium tuberculosis and other opportunistic fungal pneumonias are also considered in the differential diagnosis of pneumonia in immunocompromised patients (Apisarnthanarak and Mundy 2005). Childhood acute community-acquired pneumonia is one of the leading causes of morbidity and mortality in developing countries. In children who have not received prior antibiotic therapy, the main bacterial causes of clinical pneumonia in developing countries are S. pneumoniae and H. infl uenzae type b, and the main viral cause is respiratory syncytial virus (RSV) (Falade and Ayede 2011). Moreover, studies of aetiology of acute pneumonia in severely malnourished children have implicated S. pneumoniae, respiratory viruses and tuberculosis as the main pathogens causing mortality (Falade and Ayede 2011).
