SALICYLATE INDUCTION OF ANTIBIOTIC-RESISTANCE IN ESCHERICHIA-COLI - ACTIVATION OF THE MAR OPERON AND A MAR-INDEPENDENT PATHWAY
SALICYLATE INDUCTION OF ANTIBIOTIC-RESISTANCE IN ESCHERICHIA-COLI - ACTIVATION OF THE MAR OPERON AND A MAR-INDEPENDENT PATHWAY
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DOI：
10.1128/jb.175.24.7856-7862.1993
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发表时间：
1993-12-01
影响因子：
3.2
通讯作者：
ROSNER, JL
中科院分区：
文献类型：
--
作者：
COHEN, SP;LEVY, SB;ROSNER, JL
由于野生型大肠杆菌在水杨酸盐中的生长导致与染色体mar基因座的组成型突变体（Mar）相似的多重抗生素抗性表型，因此研究了水杨酸盐对marRAB操纵子表达的影响。在用水杨酸钠（5.0 mM）培养的野生型细胞中，与MAR特异性DNA探针杂交的RNA量比未处理的对照高5至10倍。未经处理的Mar突变体的Mar特异性RNA是野生型细胞的三到五倍。当用水杨酸处理Mar突变体时，可以看到Mar特异性RNA增加了30至50倍。在染色体上带有mar启动子-lacZ融合的野生型细胞中，水杨酸盐使β-半乳糖苷酶活性增加了6倍。因此，水杨酸盐诱导marRAB操纵子的转录。表型多重抗生素抗性的其他诱导物，例如，苯甲酸盐、水杨醇和对乙酰氨基酚也增加了MAR启动子的转录，但程度低于水杨酸盐。无论是在野生型和MAR缺陷型菌株中，水杨酸盐的生长导致抗生素耐药性增加，外膜对头孢噻啶的渗透减少，micF转录增加，OmpF量减少。然而，这些变化的幅度通常在野生型（含MAR）细胞中更大。因此，水杨酸盐和其他化合物可以诱导mar操纵子的转录，并推测通过该途径引起多种抗生素耐药性。然而，水杨酸盐也可以激活一种未鉴定的、不依赖于MAR的途径，从而产生多种抗生素耐药性。
Since the growth of wild-type Escherichia coli in salicylate results in a multiple antibiotic resistance phenotype similar to that of constitutive mutants (Mar) of the chromosomal mar locus, the effect of salicylate on the expression of the marRAB operon was investigated. The amount of RNA hybridizing with a mar-specific DNA probe was 5 to 10 times higher in wild-type cells grown with sodium salicylate (5.0 mM) than in untreated controls. Untreated Mar mutants had three to five times more mar-specific RNA than wild-type cells did. When a Mar mutant was treated with salicylate, a 30- to 50-fold increase of mar-specific RNA was seen. In wild-type cells bearing a mar promoter-lacZ fusion on the chromosome, salicylate increased beta-galactosidase activity by sixfold. Thus, salicylate induces transcription of the marRAB operon. Other inducers of phenotypic multiple antibiotic resistance, e.g., benzoate, salicyl alcohol, and acetaminophen, but not acetate, also increased transcription from the mar promoter but to a lesser extent than did salicylate. Both in wild-type and mar-deficient strains, growth in salicylate resulted in increased antibiotic resistance, decreased permeation of the outer membrane to cephaloridine, increased micF transcription, and decreased amounts of OmpF. However, the magnitude of these changes was generally greater in wild-type (mar-containing) cells. Thus, salicylate and other compounds can induce transcription of the mar operon and, presumably, give rise to multiple antibiotic resistance via this pathway. However, salicylate can also activate an unidentified, mar-independent pathway(s) which engenders multiple antibiotic resistance.