M023: TYPING BY ANTIBlOGRAM, PYOCIN SUSCETIBILTY, AND AP-PCR
OF P. AERUGINOSA FROM CYSTIC FIBROSIS PATIENTS.
Campana S.. Rovai C., *Marianelli L., *Taccetti G., *Chiappini
E., Dei R. Istituto di Microbiologia, Cystic Fibrosis Center -
Meyer Hospital University of Florence, Florence, Italy.
Chronic lung infection by P. aeruginosa affect seriously the condition of Cystic Fibrosis (CF) patients. As these patients normally attend specialized centres, the question arises about the risk that they are exposed to a common source of infection, as opposed to an endogenous infection from a pre-existing colonisation.
A better insight in to the transmission routes of P. aeruginosa, a prerequisite for the appropriate control of P. aeruginosa infection in these patients, can only be obtained by typing the individual isolates.
We studied 11 P. aeruginosa, isolated during the same scheduled check -up, from 9 persistently colonized CF patients, 2 of them yielded two morphotypes. Bacteria were compared by quantitative antibiogram (Kirby -Bauer method), by pyocin susceptibility (with a panel made up from the 16 Gillies and Gowan strains and 4 local isolates ), and by Arbitrarily Primed - PCR, AP-PCR (DNA was amplified with the M13RS primer ). For each typing method, the results were compared directly, and a matrix was constructed to allow numerical analysis.
Irrespective of the typing method used, no identical profile were obtained, and also very similar patterns were not frequent. The profiles of the 2 morphotypes isolated from a same patient were different. By cluster analysis source isolates appeared distantly related to each other, this being more evident with fine-typing, such as pyocin and AP-PCR .
Our results might not rule out the possibilities of cross-infection by P. aeruginosa in CF patients.