To identify some of the virulence features (hemolysine, gelatenase, and biofilm formation) to study the gene expression of esp gene responsible for biofilm formation in E. faecalis bacteria.

Seventy isolates of E. faecalis were collected from diverse clinical causes, containing (urine, stool, wounds, uterine secretions) from numerous hospitals clinics in Baghdad city; Central Child Teaching Hospital, Baghdad Teaching Hospital, and the National Center for Educational Laboratories, during the period 1-7-2022 until 1-9-2022. Detection of some virulence factors (Hemolysin, Gelatinase, biofilm), Antibiotics sensitivity antibiotics was determined using VITEK2 system. esp gene expression responsible for formation of biofilm was measured by Real time PCR using esp and 16SrRNA primers as a control based on the SYBR green method.

In this study, thirty two isolates of Enterococcus faecalis bacteria were investigated from different clinical cases in Baghdad hospitals, containing; Central Child and Ibn Al-Baladi Medical Hospital in addition to Educational Laboratories. This isolates were including 15(46.87%) isolates urine, 6(18.75%) for every one of the stool and secretion of uterine, and 5(15.62%) of the wounds. The isolates confirmed to be the species Enterococcus faecalis after microscopic, biochemical tests and final identification with the VITEK system. Some virulence factors were detected in E. faecalis, which included (hemolycin, biofilm formation, Gelatinase). The results showed that E. faecalis bacteria have the ability to analyze red blood cells by 53.12% and the type of analysis was β-hemolysis, and the component of the biofilm by 90.62%, and the producer of the enzyme Gelatinase by 65.62%. The results displayed that the bacteria are sensitive to each of the antibiotics (Linezolid, Teicoplanin Vancomycin, Tigecycline) with 100% resistant to the erythromycin antibiotic, while the rest of the antibiotics were between sensitive and resistant to them in different proportions, the results of the esp gene expression showed when treated with the erythromycin antibiotic at a concentration of 0.8 ml /L and a concentration of 1.6 ml / L, it was noted that no significant increase in gene expression of the esp gene.

The E. faecalis possesses some of the virulence factors, including hemolycin and gelatinase, biofilm formation, as well as all isolates appeared with their resistance to the Erythromycin antibiotic. As for the Tetracycline, most isolates have shown resistance to this antibiotic and there was no increase in esp gene expression after the bacteria were treated with the antibiotic erythromycin.