SERUM IGG RESPONSE TO AN OUTER-MEMBRANE PORIN PROTEIN OF BURKHOLDERIA-CEPACIA IN PATIENTS WITH CYSTIC-FIBROSIS

Early and accurate diagnosis of Burkholderia cepacia infection Is impo rtant, particularly if segregation is to prevent patient-to-patient tr ansmission. We have examined the serum response to a B. cepacia-specif ic 80-kDa outer membrane protein, 21 patients colonised with B. cepaci a and Pseudomonas aeruginosa for 2-51 months (mean 11 months) were age - and sex-matched with 21 patients colonised with P. aeruginosa but no t B. cepacia. The 80-kDa protein was recovered by electroelution from outer membrane proteins, separated by SDS-PAGE, coated onto ELISA plat es, reacted with patient sera diluted 1:200, protein A-peroxidase and chromogenic substrate. We found that 19/24 patients colonised with B. cepacia and P. aeruginosa had high values, 2/24 patients had intermedi ate values, and 2/24 patients had a low value. 20/21 patients colonise d with P. aeruginosa alone had low values and 1/21 had an intermediate value. We found that in the longitudinal serum samples studied from f our patients only one patient developed high values after the first is olation of B. cepacia suggesting that seroconversion does not occur im mediately after the first sputum culture of B. cepacia. We conclude th at an ELISA test using B. cepacia-specific 80-kDa outer membrane prote in can distinguish B. cepacia colonised and non-colonised patients and may be useful in the early diagnosis of B. cepacia infection.