A genomic library from a strain of Salmonella enterica serovar Paratyphi B that exhibits multiple drug resistance (MDR) was constructed in Escherichia coli. Two of the recombinant plasmids, pNOR5 and pNOR5, conferred resistance only to fluoroquinolones in E. coli, whereas the third, pNCTR4, conferred the MDR phenotype. Sequence and subcloning analysis showed that it is the presence of RecA on t...

The MarA protein of Escherichia coli can both activate and repress the initiation of transcription, depending on the position and orientation of its degenerate 20-bp binding site ("marbox") at the promoter. For all three known repressed genes, the marbox overlaps the promoter. It has been reported that MarA represses the rob promoter via an RNA polymerase (RNAP)-DNA-MarA ternary complex. Under ...

OBJECTIVES The purpose of this study was to characterize decreased susceptibility to tigecycline in clinical isolates of Escherichia coli obtained during Phase 3 clinical trials. METHODS Gene expression was analysed by transcriptional profile analysis and RT-PCR. Transposon mutagenesis with IS903kan was used for selection of transposon mutants. Transposon insertions were mapped by DNA sequenc...

Exposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selected Escherichia coli and Klebsiella pneumoniae mutants. E. coli and K. pneumoniae mutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chl...

Organizational learning capabilities (OLC) is defined as the organizational and managerial characteristics of factors that encourage learning process or enabling an organization to learn while knowledge performance can be explained as the ability of individual, group and organization to understand what they have learned. This study aims to determine the perceptions and relationships of organiza...

The Escherichia coli MarA protein mediates a response to multiple environmental stresses through the activation or repression in vivo of a large number of chromosomal genes. Transcriptional activation for a number of these genes has been shown to occur via direct interaction of MarA with a 20-bp degenerate asymmetric "marbox" sequence. It was not known whether repression by MarA was also direct...

OBJECTIVES Multidrug efflux pumps mediate resistance to antibiotics and other toxic compounds. We studied the role of AcrAB-TolC, the main efflux pump in Escherichia coli, in regulating gene expression. METHODS Deletion mutants, an acrABp-lacZ fusion and reverse transcription-real-time quantitative PCR experiments were used to study the role of AcrAB-TolC and metabolism in regulating gene exp...

We previously reported that overexpression of the soxS or robA gene causes in several Escherichia coli strains the acquisition of higher organic solvent tolerance and also increased resistance to a number of antibiotics (H. Nakajima, K. Kobayashi, M. Kobayashi, H. Asako, and R. Aono, Appl. Environ. Microbiol. 61:2302-2307, 1995). Most E. coli strains cannot grow in the presence of cyclohexane. ...

In order to understand the role of the mar locus in Salmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella enterica serovar Typhimurium DT104 background. Salicylate induced marA, whereas a number of antibiotics, disinfectants, and various g...

OBJECTIVE To assess the effects produced by the MARA appliance in the treatment of Angle's Class II, division 1 malocclusion. METHODS The sample consisted of 44 young patients divided into two groups: The MARA Group, with initial mean age of 11.99 years, treated with the MARA appliance for an average period of 1.11 years, and the Control Group, with initial mean age of 11.63 years, monitored ...