MICROBIOLOGICAL FINDINGS IN PROLONGED CROUP SYNDROME

Background: Croup normally is characterized by acute onset and a self limited course of only few days. In 1990 and 1991 at the University Ch ildren's Hospital Freiburg an unexpected high number of patients were hospitalized for prolonged Croup syndrome. Expanded microbiological in vestigations were used to uncover etiologic factors. Methods: Of a tot al of 138 inpatients with Croup 60 (17 in their first year of life, 21 in the second year of life and 22 infants older than 2 years) had bac teriological (37 nasopharyngeal-, 4 tracheal-aspirates or 19 throat sw abs), and virological (antigen detection in nasopharyngeal aspirates, n = 28) tests. Of these patients 48 % were hospitalized longer than 3 days (mean 4,7; range 1-18 days). Results: Bacteria found: B. catarrha lis 24/11 (total/pure-culture), S. pneumoniae 15/6, H. influenzae 10/3 , S. group A 514 and S. aureus 4/1. Sixteen specimen yielded more than one pathogen, one specimen was sterile. Nasopharyngeal secretions had the most reliable results: Pure cultures (72%) and associations of tw o pathogens (87%) were found in these aspirates, and only 26% of the u nspecific mixed findings (p < 0,005; chi2-Test). Of the patients hospi talized longer than 3 days 27,6% had positive cultures for H. influenz ae, whereas only 6,5% of those hospitalized shorter (p<0,05; chi2 -Tes t). The only microorganism with an age-bound distribution was B. catar rhalis found predominantly (54,2%) in the 2nd year of life, with 62% o f patients positive (p < 0,05; chi2-Test). Virus found: RSV (n = 3), P arainfluenza 2 (1) and Parainfluenza 3 (1). Conclusions: Nasopharyngea l aspirate is the most reliable specimen for a bacteriologic diagnosis in Croup. In the second year of life B. catarrhalis is present in mos t Croup cases, and H. influenzae was associated with a prolonged cours e of the disease. An appropriate antibiotic therapy therefore must cov er these two pathogens.