Alterations of growth rate and gene expression levels of UPEC by antibiotics at sub-MIC

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.

Evaluation of the Synergistic Effect of Amikacin with Cefotaxime against Pseudomonas aeruginosa and Its Biofilm Genes Expression

“…Exposure to each antibiotic caused a decreased level of biofilm expression ranging between 0.1-and 0.7-fold changes, while the repression was strong and most significant with amikacin-cefotaxime combination treatment with fold change reaching 0.08, i.e., the consequence of treatment on the average expression profile among all biofilm involving genes constituting the bacterial communities studied. As described in this paper and by others [59][60][61], sub-MICs of combinations have potent effects on attenuating biofilm formation which are totally different from each antibiotic alone.…”

Effect of Sub-Inhibitory Concentrations of Nitrofurantoin, Ciprofloxacin, and Trimethoprim on In Vitro Biofilm Formation in Uropathogenic Escherichia coli (UPEC)

“…It has been suggested that the sub-lethal doses that most microbial communities are naturally exposed to play a role in cell-to-cell signaling and communication [ 28 ]. In laboratory settings, exposing bacteria to sub-inhibitory concentrations of antibiotics has been demonstrated to have a variety of effects including many that may potentially increase virulence [ 10 , 11 , 29 ]. Our study shows that the effect of sub-inhibitory concentrations of antibiotics on biofilm formation are strain dependent ( Table 1 ).…”

“…The sfa operon encodes mannose-resistant adhesions, allowing adhesion to mucosal, endothelial cells, and tissue matrices [ 33 ]. Sub-inhibitory concentrations of both nitrofurantoin and ciprofloxacin have previously been shown to upregulate genes encoding S fimbrial adhesion (sfa) and FiC fimbriae (foc) proteins in UPEC [ 10 ]. Ciprofloxacin has also been shown to increase the hemagglutination titer and surface hydrophobicity of UPEC strains, resulting in a higher expression of surface proteins, which can increase adhesiveness [ 29 ].…”

“…Within the urinary tract and bladder, bacteria can aggregate into biofilms, forming reservoirs of infection that are difficult to eradicate even with antibiotic concentrations that far exceed the minimum inhibitory concentration [ 7 ], and the ability of a uropathogenic Escherichia coli (UPEC) isolate to form biofilms has previously been shown to be associated with recurrent infection [ 8 ]. Bacteria, which are exposed to concentrations of antibiotics that are below the minimum inhibitory concentration (MIC), have been shown to exhibit changes in gene expression [ 9 , 10 ]. Sub-MIC concentrations of ciprofloxacin have been reported to increase biofilm formation in E. coli in some studies [ 11 ], while in others, it has been reported to reduce biofilm formation [ 12 ].…”

Protein expression profiling, in silico classification and pathway analysis of cariogenic bacteria Streptococcus mutans under bacitracin stress conditions

“…In this way, the effect of a drug can be studied. There are hundreds of research papers evaluating the effect of different antibiotics at different sub-MIC concentrations [26,27]. For instance, the in vivo effects of different sub-inhibitory concentrations of the antibiotic rufloxacin on the adherence properties of E. coli and Staphylococcus aureus were investigated.…”