Early onset neonatal pneumonia results from infection acquired by aspiration after early rupture of membranes or
during labour, or an initially lower grade intrauterine infection associated with maternal chorioamnionitis
not of a magnitude sufficient to cause death or severerespiratory distress at birth). Table 3 lists the bacterial causes
found in studies from developing countries that clearly distinguished early from late onset neonatal sepsis and
pneumonia. Escherichia coli, group B Streptococcus, Klebsiella spp, Staphylococcus aureus and Streptococcus pneumoniae were the most commonly isolated bacteria. In a further study that did not make a clear distinction between early and late causes,among 150 Indian neonates presenting at a median of164 hours of life with respiratory distress, of whom 103 were diagnosed with pneumonia, blood cultures were positive in 49 cases (48%): Klebsiella in 28, Staph aureus in seven,
coagulase negative Staphylococci in seven.9