Allignet J, Aubert S, Morvan A, el Solh N
National Reference Center for Staphylococci, Unité des Staphylocoques, Institut Pasteur, Paris, France.
Antimicrob Agents Chemother. 1996 Nov;40(11):2523-8. doi: 10.1128/AAC.40.11.2523.
The levels of resistance to pristinamycin (Pt) and to its major constituents, pristinamycin IIA and IB (PIIA and PIB, respectively; classified as streptogramins A and B, respectively) were determined for 126 staphylococcal isolates. The results suggest tentative susceptibility breakpoints of < or = 2, < or = 8, and < or = 0.5 microgram/ml for PIIA, PIB, and Pt, respectively. Fifty-six isolates that were inhibited by > or = 4 micrograms of PIIA per ml were investigated for the presence of staphylococcal genes encoding resistance to PIIA (vga, vat, and vatB) and PIB (vgb). None of these genes was found in the 4 isolates inhibited by 4 micrograms of PIIA per ml or in 4 of the other 52 isolates tested. The remaining 48 isolates harbored plasmids carrying vatB and vga or combinations of genes (vga-vat-vgb or vga-vat). The absence of any known PIIA resistance gene from the four Staphylococcus aureus isolates inhibited by > or = 8 micrograms of PIIA per ml suggests that there is at least one PIIA resistance mechanism in staphylococci that has not yet been characterized.
测定了126株葡萄球菌分离株对 pristinamycin（Pt）及其主要成分pristinamycin IIA和IB（分别为PIIA和PIB；分别归类为链阳性菌素A和B）的耐药水平。结果表明，PIIA、PIB和Pt的初步敏感折点分别为≤2、≤8和≤0.5微克/毫升。对每毫升≥4微克PIIA抑制的56株分离株，研究了编码对PIIA（vga、vat和vatB）和PIB（vgb）耐药性的葡萄球菌基因的存在情况。在每毫升4微克PIIA抑制的4株分离株或其他52株测试分离株中的4株中均未发现这些基因。其余48株分离株携带含有vatB和vga或基因组合（vga-vat-vgb或vga-vat）的质粒。每毫升≥8微克PIIA抑制的4株金黄色葡萄球菌分离株中未发现任何已知的PIIA耐药基因，这表明葡萄球菌中至少存在一种尚未被鉴定的PIIA耐药机制。
