High-level amikacin resistance in Pseudomonas aeruginosa associated with a 3'-phosphotransferase with high affinity for amikacin.
- Torres, C. 3
- Perlin, M.H. 1
- Baquero, F. 5
- Lerner, D.L. 2
- Lerner, S.A. 4
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1
University of Louisville
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2
Washington University in St. Louis
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3
Universidad de La Rioja
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4
Wayne State University
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5
Hospital Ramón y Cajal
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ISSN: 0924-8579
Any de publicació: 2000
Volum: 15
Número: 4
Pàgines: 257-263
Tipus: Article
Altres publicacions en: International Journal of Antimicrobial Agents
Resum
This work describes the characterization of the phosphotransferase enzymatic activity responsible for amikacin resistance in two clinical Pseudomona aeruginosa strains, isolated from a hospital that used amikacin as first-line aminoglycoside. Amikacin-resistant P. aeruginosa PA40 and PA43 (MIC: 128 mg/l) were shown to have APH activity with a substrate profile similar to that of APH(3')-VI. The enzyme from P. aeruginosa PA40 was purified to >70% homogeneity. The K(m) of amikacin for this enzyme was 1.4 μM, the V(max)/K(m) ratio for amikacin was higher than for the other aminoglycosides tested and PCR and DNA sequencing ruled out the presence of aph(3')-IIps. Amikacin resistance in this strain was, therefore, associated with APH(3')-VI and the high affinity of this enzyme for amikacin could explain the high-level resistance that we observed.