**2. Epidemiology**

Reported frequencies of neonatal pneumonia range from 1 to 35 %, the most commonly quoted figures being 1 percent for term infants and 10 percent for preterm infants (8). The incidence varies according to gestational age, intubation status, diagnostic criteria or case definition, the level and standard of neonatal care, race and socioeconomic status. In a retrospective analysis of a cohort of almost 6000 neonates admitted to our NICU pneumonia was diagnosed in all gestational age classes. The incidence of bacterial pneumonia including Ureaplasma urealyticum (Uu) pneumonia was 1,4 % with a median patient gestational age of 35 weeks (range 23-42 weeks) and a mortality of 2,5%. There was only one case of viral pneumonia, due to RSV-infection and no case of fungal pneumonia. The mortality rate associated with pneumonia is in general inversely related to gestational age and birthweight, being higher in cases of early onset compared to late onset, and especially high in low socioecomomic groups and developing countries (2,3,4). Group B Streptococcus accounts for most cases of early onset pneumonia, the commonest bacteria causing late-

© 2013 Reiterer, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 Reiterer, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

onset pneumonia are gram-negative bacilli such as E coli or Klebsiella spp.(8). Frequently bacterial pathogens found in early and late onset sepsis/pneumonia are listed in Table 1.

Neonatal Pneumonia 21

**5. Diagnosis** 

The clinical diagnosis of pneumonia is challenging and may not always be correct (over- or underestimated). Early tracheal aspirate cultures obtained within the first 8 to 12 hours of age may help in diagnosing congenital pneumonia (14,15), especially in certain clinical conditions, including maternal fever, clinical chorioamnionitis and leukopenia. But even a positive blood culture or proven airway colonization do not necessarily correlate with the clinical picture of sepsis or pneumonia (16). In the clinical routine pneumonia is diagnosed based on a combination of perinatal risk factors, signs of neonatal respiratory distress, positive laboratory studies, radiological signs and a typical clinical course. Some clinical scenarios are more or less suspicious **.** For example VAP, reported to be responsible for up to one third of all nosocomial infections, may be suspected two or more days after the initiation of mechanical ventilation when new or persistent infiltrates are noticed in 2 or more chest radiographs (5). Additional definition criteria developed by the Centers for disease control and prevention (17) include an increase in oxygen and ventilator requirements and at least three of the following signs and symptoms: temperature instability, wheezing, tachypnea, cough, abnormal heart rate, change in respiratory secretions, and abnormal peripheral white blood count. The most common organisms in VAP in extremely preterm infants have been shown to be Staphylococcus aureus and especially gram-negative organisms like Pseudomonas aeruginosa , Enterobacter spp. and Klebsiella spp. (18). Pneumonia caused by Ureaplasma species, Eubacteria mainly colonizing the mucosal surface of the respiratory and urogenital tract, may be diagnosed by direct isolation of the organism from endotracheal aspirates using culture or PCR-techniques, by typical chest-x-ray patterns showing disseminated, patchy infiltrates bilaterally with progression to cystic dysplasia, and elevated inflammatory serum-parameters like CRP or an increased white cell count (19,20,21). An organism frequently associated with early onset pneumonia is Group B Streptococcus. The clinical manifestation occurs usually within 6 of 8

hours of life and can initially mimic surfactant deficiency syndrome (16, 22).

As pneumonia is often associated with or non distinguishable from bacterial sepsis initial therapy at the NICU includes broad spectrum intravenous antibiotics according to local protocols. In our unit we start with a combination of ampicillin and a second generation cephalosporine. Although there is no evidence from randomized controlled trials that any antibiotic regime is superior for suspected early onset neonatal sepsis (23), the WHO recommends as first line treatment ampicillin plus gentamycin (24). In cases where we detect pathogens in blood, or in endotracheal aspirates we treat according to susceptibility from antibiogram results. A problem which is increasing worldwide in NICU´s is the occurrence of multidrug resistant pathogens, mainly gram-negative bacilli (25). As an alternative to systemic treatment aerosolized antibiotics like colistin have been used successfully in patients with VAP caused by multidrug resistant gram negative bacteria (26, 27). In patients where we suspect or diagnose an U infection we initiate treatment with intravenous clarithromycin (10mg/kg/day), a macrolid antibiotic. In a recently published randomized controlled placebo single-center study clarithromycin treatment resulted in

**6. Treatment, prevention** 
