Overproduction of 3'-aminoglycoside phosphotransferase type I confers resistance to tobramycin in Escherichia coli.

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Menard R, Molinas C, Arthur M, Duval J, Courvalin P, Leclercq R

Overproduction of 3'-aminoglycoside phosphotransferase type I confers resistance to tobramycin in Escherichia coli.

Antimicrob Agents Chemother. 1993 Jan;37(1):78-83.

PubMed ID

8381641 [ View in PubMed

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Abstract

Escherichia coli HM69, isolated from urine, was resistant to high levels of kanamycin (MIC, > 1,000 micrograms/ml) and a low level of tobramycin (MIC, 8 micrograms/ml). Phosphocellulose paper-binding assays and molecular cloning indicated that resistance to both aminoglycosides was due to synthesis of a 3'-aminoglycoside phosphotransferase type I, an enzyme that phosphorylates kanamycin but not tobramycin. The structural gene for the enzyme was borne by an 80-kb conjugative plasmid, pIP1518, and was nearly identical to aphA1 of Tn903. Incubation of extracts of resistant cells with tobramycin or kanamycin led to a decrease (> 80%) of antibiotic activity as determined by a microbiological assay. Heat treatment showed that loss of activity was reversible and dependent upon the native enzyme. In the presence of ATP, only inactivation of kanamycin was reversible. These results suggest that resistance to low levels of tobramycin was due to formation of a complex between the enzyme and the antibiotic.

DrugBank Data that Cites this Article

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Kanamycin	Aminoglycoside 3'-phosphotransferase	Protein	Escherichia coli	Unknown	Substrate	Details

Polypeptides

Name	UniProt ID
Aminoglycoside 3'-phosphotransferase	P00551	Details