Characterization of a staphylococcal plasmid related to pUB110 and carrying two novel genes, vatC and vgbB, encoding resistance to streptogramins A and B and similar antibiotics.
We isolated and sequenced a plasmid, named pIP1714 (4,978 bp), which specifies resistance to streptogramins A and B and the mixture of these compounds. pIP1714 was isolated from a Staphylococcus cohnii subsp. cohnii strain found in the environment of a hospital where pristinamycin was extensively used. Resistance to both compounds and related antibiotics is encoded by two novel, probably cotranscribed genes, (i) vatC, encoding a 212-amino-acid (aa) acetyltransferase that inactivates streptogramin A and that exhibits 58.2 to 69.8% aa identity with the Vat, VatB, and SatA proteins, and (ii) vgbB, encoding a 295-aa lactonase that inactivates streptogramin B and that shows 67% aa identity with the Vgb lactonase. pIP1714 includes a 2,985-bp fragment also found in two rolling-circle replication and mobilizable plasmids, pUB110 and pBC16, from gram-positive bacteria. In all three plasmids, the common fragment was delimited by two direct repeats of four nucleotides (GGGC) and included (i) putative genes closely related to repB, which encodes a replication protein, and to pre(mob), which encodes a protein required for conjugative mobilization and site-specific recombination, and (ii) sequences very similar to the double- and single-strand origins (dso, ssoU) and the recombination site, RSA. The antibiotic resistance genes repB and pre(mob) carried by each of these plasmids were found in the same transcriptional orientation.
Allignet
J
J
National Reference Center for Staphylococci, Unité des Staphylocoques, Institut Pasteur, Paris, France.
Liassine
N
N
el Solh
N
N
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial; D004352:Drug Resistance, Microbial / Q000235:genetics; D004357:Drug Synergism; D005798:Genes, Bacterial; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011815:R Factors / Q000235:genetics* / Q000302:isolation & purification; D016415:Sequence Alignment; D013210:Staphylococcus / Q000187:drug effects* / Q000235:genetics*; D014769:Virginiamycin / Q000494:pharmacology*
D004269:DNA, Bacterial; D014769:Virginiamycin; D000123:Acetyltransferases; D006867:Hydrolases