Comprehensive Analysis of blaCTX-M1 Gene Expression Alongside iutA, csgA, and kpsMII Virulence Genes in Septicemic Escherichia coli Using Real-Time PCR.

Abstract

Background: Sepsis is a serious worldwide health concern, and Escherichia coli (E. coli) is the main cause. This study investigates the co-expression of blaCTX-M1 and iutA, csgA, and kpsMII genes in E. coli isolated from septicemic patients, aiming to clarify the interaction between virulence and resistance. Methods: This study evaluated 100 E. coli isolates from septicemic patients. With the disc diffusion method, antibiotic susceptibility was confirmed. The use of ceftazidime-clavulanic acid allowed for the confirmation of ESBL. PCR and real-time PCR were used to detect virulence and beta-lactamase genes. The expression levels of important genes were compared between isolates in LB and blood. Results: Antibiotic resistance was common in isolates carrying blaCTX-M1, including tetracycline (93%) and erythromycin (99%). Instead, there was no resistance to fosfomycin and 3% resistance to carbapenems. Real-time PCR revealed more expression levels in blood for the virulence genes kpsMII and csgA. Pathogenicity and resistance increased with blaCTX-M1 co-expression with the kpsMII and csgA genes. Conclusions: The coexistence of ESBL and virulence genes in E. coli isolates significantly increases antibiotic resistance and infection severity. Monitoring of these genes is critical for developing effective therapeutic strategies. The key to treating these diseases is having sophisticated diagnostic tools and using antibiotics cautiously.