In the present study, it was shown that insulin and glucose can modulate UPEC's gene expression while the growth rate was not affected.

No abstract

The host is the main environment for bacteria, and they also expose to many antibiotics during the treatment of infectious diseases in host body. In this study, it was aimed to investigate possible changes in growth rate and expression levels of three virulence genes (foc/foc, cnf1, and usp) in a uropathogenic E. coli standard strain within the presence of ciprofloxacin, nitrofurantoin, and trimethoprim-sulfamethoxazole. The UPEC C7 strain was grown on tryptic soy broth-TSB (control), TSB + ciprofloxacin, TSB + nitrofurantoin, and TSB + trimethoprim-sulfamethoxazole for determination of both growth rate and gene expression level. Antibiotics were added according to their sub-minimal inhibition concentrations. E-test was used to determine MIC values of antibiotics. Growth changes were measured in absorbance 600 nm during 24-h period. Total RNA isolations were performed after incubation for 24 h at 37 °C. Gene expression levels were determined by quantitative PCR. Tukey's post hoc test was used for statistical analysis. According to absorbance values, it has been shown that only ciprofloxacin and trimethoprim-sulfamethoxazole have lead significant decrease on growth rate. We also detected statistically significant differences in each gene expression levels for all antibiotics via relative quantification analysis. Fold changes in gene expression was found 0.65, 1.42, 0.23 for foc/foc gene; 0.01, 0.01, 2.84 for cnf1 gene; and 0.1, 0.01, 0.01 for usp gene in the presence of ciprofloxacin, nitrofurantoin, and trimethoprim/sulfamethoxazole, respectively. This investigation has shown that antibiotics can play a role as an environmental factor which may determine the pathogenicity of bacteria in vivo.

No abstract

AbstractUropathogenic Escherichia coli (UPEC) is the most prevalent pathogen causing urinary tract infections (UTIs). UPECs have various virulence factors such as adhesins, biofilm forming and toxin producing etc., to survive in urinary tract. Under certain circumstances probiotics are preferred for prevention and treatment of UTIs. In this study, we aimed to investigate the in-vitro effects of four different Lactobacillus spp. cell-free supernatants on growth and biofilm formation inhibition in clinically isolated UPEC strains. Growths of 50 UPEC strains were determined in 96-well microplate and measured in a spectrophotometer after four hours incubation at 37°C. Biofilm formation was detected by crystal violet staining method on three UPEC strains. Statistical analysis of growth and biofilm formation experiments were performed by Kruskal-Wallis and one-way ANOVA Tukey’s multiple-comparison tests, respectively. All tested cell-free supernatans of lactobacilli inhibited growths (p<0. 0001) and biofilm formation (p<0.05) of UPECs. All results were found to be statistically significant. As a conclusion, our findings supported previous studies which reported the high efficiency of these four Lactobacillus spp. in the prevention of UTIs.