[Enterobacteriaceae isolated in eastern Romania: the evolution of ampicillin sensitivity in the 1970-1995 period]

The activity of ampicillin against 3383 Enterobacteriaceae (community and clinical isolates), collected in Eastern Romania, during 25 years was tested. Data were prelucrated by the box-plot method proposed by Simpson and Donnelly. The resistance degree for all species tested has progressively increased. In the studied region Enterobacteriaceae strains maintain their natural sensitivity only exceptionally: e.g., S. typhi and S. java, with limited circulation. Enterobacteriaceae which have contact with the resistance genic reservoir of the colon microbiota during the justified or nonjustified antibiotic treatment development resistance to usual antibiotics in the same ratio as most existent commensals present in this habitat.