Investigating the effect of sub MIC concentrations of ciprofloxacin, ceftriaxone and imipenem on the expression of virulence and toxin-antitoxin genes of Escherichia coli strains isolated from blood infections in leukemia patients.

Bloodstream infections (BSIs) pose significant risks to individuals with leukemia, and Escherichia coli stands out as a prevalent cause in these infections. This research sought to explore the impact of sub-inhibitory concentrations (sub-MIC) of ciprofloxacin, imipenem, ceftriaxone, and the combined use of ceftriaxone and ciprofloxacin on the expression of virulence factors and toxin-antitoxin genes in E. coli strains obtained from leukemia patients. Twelve clinical strains of E. coli that demonstrated resistance to ciprofloxacin, imipenem, and ceftriaxone and contained the chosen virulence and toxin-antitoxin genes were included in the study. The minimum inhibitory concentration (MIC) of ciprofloxacin, imipenem, and ceftriaxone was determined using the microbroth dilution method. Furthermore, the expression levels of virulence genes (iutA, traT, afaA, hlyA) and toxin-antitoxin genes (relE, mazF) were assessed via Real-time PCR both before and after exposure to ciprofloxacin, ceftriaxone, and imipenem. According to our findings, the sub-MIC concentrations of ciprofloxacin, imipenem, and ceftriaxone resulted in decreased expression levels of virulence factor genes (iutA, traT, afaA) and toxin-antitoxin genes (relE, mazF), with the exception of an increase in hlyA gene expression. The findings indicate that prophylactic and experimental use of sub-MICs of ciprofloxacin, imipenem, ceftriaxone, and a combination of ciprofloxacin and ceftriaxone can diminish the expression of virulence factors and toxin-antitoxin genes in E. coli. Further research is necessary to explore the interactions between antibiotic resistance and virulence genes, particularly in the blood infections.