[Pseudomonas aeruginosa and imipenem: correlation between membrane protein D2 and resistance in fifteen strains isolated from patients with mucoviscidosis].

A characteristic feature of imipenem-resistant strains of Pseudomonas aeruginosa is loss or decreased expression of the outer membrane protein (OMP) D2, whose molecular weight is 45 to 49 kDa. D2 was studied in 15 strains of P. aeruginosa with intermediate susceptibility or resistance to imipenem recovered from the sputum of 15 patients with cystic fibrosis. The OMP was extracted using Sarkosyl and separated by SDS-PAGE electrophoresis. Electrophoresis patterns were compared to those of reference strains 3B and 3C which are resistant and susceptible to imipenem, respectively. Expression of D2 was normal in three strains, weak or very weak in 11 strains and absent in one strain. For 12 strains, the alteration of the D2 protein was consistent with previous reports. However, the finding of normal D2 production in three strains is unusual and suggests the possible presence of another mechanism of resistance.