Characterization of two newly identified genes, vgaD and vatH, [corrected] conferring resistance to streptogramin A in Enterococcus faecium.
We characterized two new streptogramin A resistance genes from quinupristin-dalfopristin-resistant Enterococcus faecium JS79, which was selected from 79 E. faecium isolates lacking known genes encoding streptogramin A acetyltransferase. A 5,650-bp fragment of HindIII-digested plasmid DNA from E. faecium JS79 was cloned and sequenced. The fragment contained two open reading frames carrying resistance genes related to streptogramin A, namely, genes for an acetyltransferase and an ATP efflux pump. The first open reading frame comprised 648 bp encoding 216 amino acids with a predicted left-handed parallel β-helix domain structure; this new gene was designated vatH. [corrected] The second open reading frame consisted of 1,575 bp encoding 525 amino acids with two predicted ATPase binding cassette transporters comprised of Walker A, Walker B, and LSSG motifs; this gene was designated vgaD. vgaD is located 65 bp upstream from vatH, [corrected] was detected together with vatH [corrected] in 12 of 179 quinupristin-dalfopristin-resistant E. faecium isolates, and was located on the same plasmid. Also, the 5.6-kb HindIII-digested fragment which was observed in JS79 was detected in nine vgaD- and vatH-containing [corrected] E. faecium isolates by Southern hybridization. Therefore, it was expected that these two genes were strongly correlated with each other and that they may be composed of a transposon. Importantly, vgaD is the first identified ABC transporter conferring resistance to streptogramin A in E. faecium. Pulsed-field gel electrophoresis patterns and sequence types of vgaD- and vatH-containing [corrected] E. faecium isolates differed for isolates from humans and nonhumans.
Jung
Young-Hee
YH
Division of Antimicrobial Resistance, Center for Infectious Disease Research, National Institute of Health, 194 Tongil-Lo, Eunpyung-Gu, Seoul, Republic of Korea.
Shin
Eun Shim
ES
Kim
Okgene
O
Yoo
Jung Sik
JS
Lee
Kyeong Min
KM
Yoo
Jae Il
JI
Chung
Gyung Tae
GT
Lee
Yeong Seon
YS
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D015139:Blotting, Southern; D004251:DNA Transposable Elements / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D016984:Enterococcus faecium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005838:Genotype; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D025364:Streptogramin A / Q000494:pharmacology*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D025364:Streptogramin A