M045: Haemophilus Influenzae in Patients with Cystic Fibrosis
B. Przykenk (1) & A. Bauernfeind (2) (University Children's Hospital (1) & Max-von-Pettenkofer-lnstitute (2), Ludwig-Maximilians-University, Munich, Germany)

We evaluated the role of H.influenzae in a CF-population where most of the patients receive a long term antibiotic prophylaxis. The serological response of CF-patients with cultures positive for H. influenzae was determined to prove the etiological role of this species in the individual patient. Lipooligosaccharide (LOS) antigens of H. influenzae were prepared and used as antigens in an indirect IgG-, IgM-and IgA-ELISA with internal standardization.

Overall, H. influenzae was detected by anaerobic culture in 79/3498 (2.3%) samples in 55/386 (14.2%) CF-patients (observation period 1985-1992, mean 43 27 months; mean age 14 1 8 yrs). H. influenzae was found in 54/1118 (4.8%) samples without P. aeruginosa and in 25/2380 (1.1 %) samples with P. aeruginosa. The age distributions of the CF-patients with and without H. influenzae were similar. 6/136 (4.4%) of admissions to the ward because of an acute pulmonary exacerbation were associated with the detection of H. Infiuenzae on admission. As serum IgA- and IgM-antibodies against LOS of H. influenzae were found in very low concentrations, we focused on the IgG-response. The serum IgG-antibodies of a non CF-control group (n = 63) did not increase with age. Using the cut-off point of 2,1 mg IgG/l, 7.9 % of the control group and 17/22 (77%) of CF-patients with H. influenzae showed elevated IgG-antibodies. 9/18 (50%) of the CF-Patients with H. influenzae and longitudinal studies of the immune response showed antibodies significantly increasing or decreasing in parallel with the occurrence or eradication of H. influenzae. In addition, lgG-antibodies were determined in 234 serum samples of 24 CF-patients chronically infected with P. aeruginosa without any cultures positive for H. influenzae. 11/24 (46%) showed elevated serum IgG against H. influenzae at least once and 6/11 significant changes of the antibodies in the observation period. We conclude, that H. influenzae has to be considered as an infecting organism in about 50% of culture-positive cases. Furthermore, the microbiological methods to culture H. influenzae in CF-patients already colonized with P. aeruginosa have still to be further improved.