Immunolocalisation of Burkholderia cepacia in the lungs of cystic fibrosispatients

Infection by Burkholderia cepacia is sometimes fatal in patients with cysti c fibrosis (CF), as the organism can cause necrotising pneumonia and septic aemia (the cepacia syndrome), and is resistant to antibiotics. To increase knowledge of the pathogenesis of lung infection, the present study investig ated the distribution of B, cepacia in lung explants from nine CF recipient s of double lung transplants, of which six were colonised with both B, cepa cia and Pseudomonas aeruginosa and the other three with P. aeruginosa only, In one case, explants of the donor lung (allograft) became available after the patient succumbed post-operatively to the cepacia syndrome. Further au topsy sections were examined from two patients who had chronic and then acu te infection with B, cepacia, A specific antibody reactive with all five ge nomovars of the B, cepacia complex and another antibody specific for the 22 -kDa adhesin of cable pill, were used to localise bacteria in situ, In chro nic infection, the organisms were diffusely distributed, but most concentra ted in hyperplastic bronchiolar epithelium, inflamed peribronchial and peri vascular areas, between adjacent airway epithelial cells and in pathologica lly thickened alveolar septae and luminal macrophages, Tn acute infections the distribution was more focal, with B, cepacia on injured airway surfaces and in sites of pneumonia and abscess formation. In autopsy sections from one of the patients with chronic, then acute infection, S, cepacia was also observed in the lumen of blood capillaries, These results suggest that B, cepacia has the capacity to be highly invasive, migrating from the airways across the epithelial barrier to invade the lung parenchyma and capillaries , thereby initiating septicaemia.