RESUMEN

Twenty-four gentamicin-resistant isolates of Enterobacteriaceae, obtained from the clinical laboratories of three health centres in Nablus, Palestine, were tested for susceptibility to neomycin, kanamycin, tobramycin and amikacin. Resistance rates were 29.2% for neomycin, 58.3% for kanamycin, 45.8% for tobramycin and 8.3% for amikacin. Fourteen (58.3%) isolates were noted to be multiresistant, i.e., resistant to gentamicin and two or more other aminoglycosides; resistance to gentamicin, kanamycin and tobramycin was the most common pattern of multiple resistance. This pattern implies the involvement of adenyltransferase ANT(")-I activity. Plasmid profiles and curing experiments suggested a plasmid localisation of gentamicin, neomycin, kanamycin and tobramycin resistance genes. However, a chromosomal location is proposed for plasmid-deficient strains. Cross-resistance in two isolates to all aminoglycosides tested suggested membrane impermeability to aminoglycosides as the mechanism of resistance.

Asunto(s)

Antibacterianos/farmacología , Enterobacteriaceae/efectos de los fármacos , Amicacina/farmacología , ADN Bacteriano/análisis , Farmacorresistencia Microbiana/genética , Enterobacteriaceae/genética , Etidio/farmacología , Colorantes Fluorescentes/farmacología , Gentamicinas/farmacología , Humanos , Resistencia a la Kanamicina/genética , Pruebas de Sensibilidad Microbiana , Neomicina/farmacología , Factores R/efectos de los fármacos , Factores R/genética , Factores R/fisiología , Tobramicina/farmacología