Physiology and antibiotic susceptibility of Staphylocoecus aureus small colony variants
Physiology and antibiotic susceptibility of Staphylocoecus aureus small colony variants
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DOI：
10.1089/10766290260469507
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发表时间：
2002-12-01
影响因子：
2.6
通讯作者：
Sahl, HG
中科院分区：
文献类型：
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作者：
Baumert, N;Von Eiff, C;Sahl, HG
小菌落变体（SCV）是生长缓慢的亚群，具有改变的代谢和降低的抗生素敏感性，在金黄色葡萄球菌的情况下，可导致持续和复发性感染。我们研究了四个SCV及其相应的亲本菌株：一个临床菌株对，一个甲基萘醌缺陷的自发突变株，和两个构建的突变株，通过在S. aureus 8325-4和COL。发现在具有葡萄糖限制和增强的缓冲能力的化学成分确定的培养基（CDM）中生长的SCV产生-120至-140 mV的Δ Psi，这与亲本菌株相当。然而，葡萄糖消耗效率低，生长产量小。与野生型菌株相反，当葡萄糖过期并且其他营养物如乙酸盐和乳酸盐不允许进一步生长时，Δ Psi立即下降到低于-100 mV的值。因此，当在常规MIC测定条件下与亲本菌株相比时，SCV对已知通过DeltaPsi摄取的抗生素（例如氨基糖苷类）的敏感性下降了10至30倍。当生长在CDM中时，SCV的敏感性根据DeltaPsi的大小而变化。
Small colony variants (SCV) are slow-growing subpopulations with altered metabolism and reduced antibiotic susceptibility which, in the case of Staphylococcus aureus, can cause persisting and recurrent infections. We studied four SCVs and their corresponding parent strains: one clinical strain pair, one menaquinone-deficient spontaneous mutant, and two constructed mutants obtained by inactivation of hemB in S. aureus 8325-4 and COL, respectively. SCVs growing in chemically defined medium (CDM) with glucose limitation and enhanced buffering capacity were found to generate DeltaPsi of - 120 to - 140 mV, which is comparable to the parent strains. However, glucose is consumed inefficiently with small growth yields. In contrast to wild-type strains, DeltaPsi dropped immediately to values below - 100 mV when glucose expired and other nutrients such as acetate and lactate did not allow for further growth. Accordingly, the sensitivity of SCVs toward antibiotics known to be taken up through DeltaPsi, such as aminoglycosides, dropped 10- to 30-fold when compared to the parent strain under routine MIC determination conditions. When growing in CDM, the susceptibility of SCVs varied according to the magnitude of DeltaPsi.