Chlamydia as a cause of late neonatal pneumonia at Kenyatta National Hospital, Nairobi.

BACKGROUND: Neonatal pneumonia is a common cause of morbidity and mortality all over the world. The problem is known to be higher in resource poor third world countries. Organisms (such as chlamydia) not covered by routine laboratory tests and regular antibiotic regimes may frequently contribute towards the causation of late neonatal pneumonia. It is therefore useful to gather epidemiological evidence to guide in the routine diagnosis and treatment of such infections. OBJECTIVE: To determine the prevalence of chlamydia associated pneumonia among infants developing the disease between the 7th and 30th days of life (late neonatal pneumonia). DESIGN: Cross sectional survey. SETTING: Newborn Unit, Kenyatta National Hospital. SUBJECTS: Fifty two newborns clinically diagnosed as having late neonatal pneumonia. They were all subjected to chest X-rays to confirm the clinical diagnosis. Nasopharyngeal aspirates for chlamydia antigen detection tests were then performed on all patients. The study was undertaken during the months of September through to November 2000. MAIN OUTCOME MEASURES: The proportion of newborns with late neonatal pneumonia that have chlamydia trachomantis as the sole or contributory causative agent. RESULTS: Fifty two newborns of postnatal age between seven and 30 days were recruited. Their sex distribution was about 1:1. Thirty three (63.5%) of these infants were found with chlamydia in their upper airways. Thirty out of 47 available chest X-rays, representing 63.8% had evidence of interstitial pneumonitis. Chlamydia associated pneumonia indicated by the presence of both interstitial pneumonia and colonization of the upper air ways was present in 24 out of 47 patients, 51% of the total cases of late neonatal pneumonia. When X-rays alone were compared with our gold standard for the diagnosis of chlamydia pneumonia (radiology and colonization), we computed a sensitivity of 100%, specificity 73%, negative predictive value 100% and positive predictive value of 80%. Mode of delivery, birth weight and gestation had no association with nasopharyngeal colonization by chlamydia or actual diagnosis of chlamydia pneumonia. CONCLUSION: The prevalence of chlamydia associated infection among newborns with late neonatal pneumonia at Kenyatta National Hospital is 51%, eight times more than that reported elsewhere. Chest X-rays appear to be a reliable diagnostic tool in this group. The use of antichlamydial drugs in addition to the regular antibiotics whenever a diagnosis of late neonatal pneumonia is made is justifiable.