USE OF OLIGONUCLEOTIDE PROBES TO ANALYZE THE HOMOLOGY OF THE OPRF GENE AMONG CLINICAL AND HETEROLOGOUS IMMUNOTYPE STRAINS OF PSEUDOMONAS-AERUGINOSA

The conservation of oprF gene among 25 clinical Pseudomonas aeruginosa strains and a set of 17 serotype-specific representative strains of t he international antigen typing scheme (IATS) was analysed by dot-blot ting using five specific oligonucleotide probes. The oligo 1, 2, 3, 4, 5 correspond to five different regions of the oprF gene and hybridize d strongly with respectively 88%, 88%, 76%, 94% and 71% of the IATS st rains and 88%, 96%, 92%, 88% and 92% of the clinical strains. A parall el study performed with the whole oprF gene showed a lack of specifici ty of this probe: indeed, the probe hybridized not only with the 42 Ps eudomonas aeruginosa strains but also with Escherichia coil and Salmon ella minnesota. This study suggests that the gene sequence encoding th e protein F is not totally conserved among Pseudomonas aeruginosa stra ins.