MICROBIOLOGICAL RESULTS IN BELGIAN CHILDREN WITH NON-RESPONDING OR RECURRENT COMMUNITY ACQUIRED LOWER RESPIRATORY TRACT INFECTION (CA-LRTI).

Background and aims:
Non-responding and recurrent CA-LRTI are frequent in children and known causes of high morbidity. Documentation of etiology is difficult but important for prevention and treatment strategies.
We aimed to document the possibly responsible pathogens.
Methods:
Retrospective analyses of bronchoalveolar lavage fluid (BAL) (aerobe and viral culture, viral PCR), nasopharyngeal aspirate (viral PCR and culture) and blood culture, for all (otherwise healthy) children, who underwent a flexible bronchoscopy with BAL, for CA-LRTI, from 2005- 2007.
Results:
384 children (128 acute non-responding (broncho)-pneumonia, 123 recurrent (broncho)-pneumonia, 92 persistent X-ray abnormalities and 41 persistent wheezers) were included. The median age was 33.1m (range: 1.0-171.6m) and female:male ratio was 1:1.2.
143/384 (37.2%) patients received antibiotics with certainty before BAL. Bacterial cultures were negative in 156/384 (40.6%) patients. BAL-cultures were positive in 227/384 (59.1%) patients and blood cultures in 3/384 (all S. pneumoniae).
In BAL, Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae were most often isolated, in respectively 164, 55 and 33 patients. 148/164 (90.2%) H. influenzae strains were not typable, 2 belonged to serotype e and 1 to serotype b. Biotypes 2 and 3 were predominant and 42/164 (25.6%) were ?-lactamase producers. SGT's 23, 19 and 6 were the predominant pneumoccoccal serotypes. In 96/380 (25.2%) patients viral PCR and/or cultures were positive: RSV, parainfluenzavirus type 3 and human metapneumovirus being most isolated.
Mixed bacterial/viral infections were found in 62/380 (16.3%) patients.
Conclusions:
Non-typable H. influenzae was the most isolated pathogen, possibly responsible for the non-responding or recurrent character of the CA-LRTI.