The effects of insulin and glucose on growth and expression of mar regulon in E. coli

Abstract

Aim: Host factors are known to modulate virulence, antibiotic susceptibility and growth of bacteria. In the present study we aimed to investigate the effect of human insulin and glucose on growth and expression of mar regulon (marA, marR, ompF, acrA, acrB and tolC) of E. coli SPC105. Material and Methods: E. coli SPC105 was grown in tryptic soy broth (TSB-control) and TSB containing 20 µU/mL insulin, 200 µU/mL insulin, 0.1% glucose and 200 µU/mL insulin + 0.1% glucose. Growths were determined via turbidimetric method. Quantitative polymerase chain reaction (qPCR) was used to determine the gene expression levels. Statistical analysis were performed via Tukey's post hoc-test. Results: According to absorbance values, it has been shown that 0.1% glucose and 200 µU/mL insulin + 0.1% glucose have led a significant decrease on growth. Expression of acrA gene was shown to be decreased in the presence of 200μIU insulin. Expressions of marR and marA were also decreased in 200μU insulin, 0.1 % glucose+200μU insulin and 0.1% glucose added TSB. Decreasing of marA, marR and acrA expressions were shown to be statistically significant (p<0.05). Conclusion: The results of the present study has shown once more that, host factors may influence the growth of a bacterium as well as gene expressions associated with antibiotic susceptibilities.