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| Yassien,M.A.M.; Elfaky,M.A.. |
| A spontaneous fluoroquinolone-resistant mutant (STM1) was isolated from its parent Salmonella enterica serovar Typhi (S. Typhi) clinical isolate. Unlike its parent isolate, this mutant has selective resistance to fluoroquinolones without any change in its sensitivity to various other antibiotics. DNA gyrase assays revealed that the fluoroquinolone resistance phenotype of the STM1 mutant did not result from alteration of the fluoroquinolone sensitivity of the DNA gyrase isolated from it. To study the mechanism of fluoroquinolone resistance, a genomic library from the STM1 mutant was constructed in Escherichia coli DH5α and two recombinant plasmids were obtained. Only one of these plasmids (STM1-A) conferred the selective fluoroquinolone resistance phenotype... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Salmonella enterica serovar Typhi; Fluoroquinolones; RecA. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2015001100990 |
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| Xu,Shungao; Zou,Xin; Sheng,Xiumei; Zhang,Haifang; Mao,Lingxiang; Du,Hong; Xu,Huaxi; Huang,Xinxiang. |
| Salmonella enterica serovar Typhi z66-positive strains have two different flagellin genes, fliC:d/j and fljB:z66, located on the chromosome and on a linear plasmid, respectively. To investigate the mechanism underlying the expressional regulation of fljB:z66, gene deletion mutants of the regulators FliA, FlhDC, and OmpR were constructed in this study. The expression levels of fliC and fljB:z66 were analyzed by qRT-PCR in the wild-type strain and mutants at high and low osmolarity. The results show that the expression levels of both fljB:z66 and fliC were greatly reduced in fliA and flhDC mutants under both high and low osmotic conditions. In the ompR mutant, the expression levels of fljB:z66, fliC, fliA, and flhD were increased at low osmotic conditions.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Salmonella enterica serovar Typhi; FljB:z66; FlhDC; FliA; OmpR. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822010000300025 |
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