Characterization of the chromosomal aminoglycoside 2'-N-acetyltransferase gene from Mycobacterium fortuitum.
A novel gene encoding an aminoglycoside 2'-N-acetyltransferase (AAC) was cloned from Mycobacterium fortuitum. DNA sequencing results identified an open reading frame that we have called aac(2')-Ib encoding a putative protein with a predicted molecular mass of 24,800 Da. The deduced AAC(2')-Ib protein showed homology to the AAC(2')-Ia from Providencia stuartii. This is the second member of a subfamily of AAC(2')-I enzymes to be identified. No homology was found with other acetyltransferases, including all of the AAC(3) and AAC(6') proteins. The aac(2')-Ib gene cloned in a mycobacterial plasmid and introduced in Mycobacterium smegmatis conferred resistance to gentamicin, tobramycin, dibekacin, netilmicin, and 6'-N-ethylnetilmicin. DNA hybridization with an intragenic probe of aac(2')-Ib showed that this gene was present in all 34 strains of M. fortuitum tested. The universal presence of the aac(2')-Ib gene in M. fortuitum was not correlated with any aminoglycoside resistance phenotype, suggesting that this gene may play a role in the secondary metabolism of the bacterium.
Departamento de Microbiología, Facultad de Medicina, Universidad de Zaragoza, Spain. Jose.Ainsa@msf.unizar.es
J A
JA
Aínsa
C
C
Martin
B
B
Gicquel
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R
Gomez-Lus
D000123:Acetyltransferases / Q000235:genetics*; D000595:Amino Acid Sequence; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D002876:Chromosomes, Bacterial / Q000201:enzymology*; D004269:DNA, Bacterial / Q000378:metabolism; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D009161:Mycobacterium / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics; D011532:Providencia / Q000235:genetics
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D000123:Acetyltransferases; C019681:aminoglycoside acetyltransferase