APPLICATION OF PYROLYSIS MASS-SPECTROSCOPY AND SDS-PAGE IN THE STUDY OF THE EPIDEMIOLOGY OF PSEUDOMONAS-CEPACIA IN CYSTIC-FIBROSIS

Representative isolates of Pseudomonas cepacia from 15 cystic fibrosis (CF) patients attending the Respiratory Unit of Alder Hey Childrens' Hospital were investigated by SDS-PAGE of whole-cell polypeptides and by pyrolysis mass spectroscopy (PMS). SDS-PAGE was less discriminatory than PMS. Eleven isolates were indistinguishable by PMS and considere d to represent re-isolates of an endemic strain; four isolates were di stinct from this group, and from one another. P. cepacia was first iso lated on the unit in July 1989 from a patient who had attended a UK se lection meeting for a Canadian CF camp. A ward and outpatient segregat ion policy was introduced, but colonisation of further patients occurr ed. In August 1991, the Adult CF Association recommended that all soci al activities involving colonised patients should cease. This, and an increased awareness amongst older CF patients of the risks of person-t o-person transmission, was associated with a marked decline in new cas es. Social activity and hospital admissions were compared for colonise d patients during the year before colonisation with P. cepacia, and ma tched patients who did not acquire the endemic strain. This showed a s ignificantly higher attendance at CF social events for colonised patie nts, but no significant association between colonisation and hospital admission. These results are strong indirect evidence that transmissio n of P. cepacia occurs through social contact outside the hospital env ironment.