Resistance mechanism associated to resistant Pseudomonas aeruginosa in Argentina

PACE J; ROSSI A; MOLLERACH M; GALAS M; MASSA R; LOPARDO H; COUTO E; GOMEZ N; GUTKIND G

Londres

Conferencia; Third International Conference of the Hospital Infection Society; 1994

Hospital Infection Society

Pseudomonas aeruginosa is a problematic opportunistic pathogen. As imipenem is one of the few drugs that remain active against multiresistant strains, it constitutes an essential therapeutic alternative in treatment of infected patients. In our country data obtained from five hospitals and compiled trough the WHONET program in 1991-2, showed than more than 7% of our local isolates were resistant to this drug. In order to characterize the resistant mechanism associated to our resistant strains we analyzed 22 clinical isolates obtained from five different hospitals, through the search of carbapenemases presence and analysis of their outer membrane profiles. None of our strains showed carbapenemase activity in the nitrocefin assay. Apparent diminution or lack of the 45 kDa (OprD2) makes impermeability through the outer membrane the more feasible way for explaining our resistant levels. It is known that this mechanism is selective for carbapenems, not implying acquisition to other antimicrobial agents like ceftazidime and fluorquinolones.