Whole-Genome Sequencing of a Clinically Isolated Antibiotic-Resistant Enterococcus faecium EntfacYE

Abstract

Background and Objective: Enterococcal infections are considered the most common nosocomial infections. Nowadays, enterococci show high resistance to common antibiotics, especially vancomycin. Vancomycin-resistant Enterococcus faecium is one of the most common nosocomial infections, which is included in the World Health Organization priority pathogens list for research and development of new antibiotics. In this case, we focused on the E. faecium EntfacYE genome and its antibiotic-resistant genes to understand the reasons that caused this bacteria to be resistant to antibiotics. Materials and Methods: In total, 25 enterococcal samples were isolated from patients' blood. Bacteriophages were isolated on a multidrug-resistant Enterococcus faecium EntfacYE in our previous study. In this study, the isolated E. faecium EntfacYE strain was verified using Sanger partial sequencing of the bacterial elongation factor Tu. EntfacYE strain was assessed for antibiotic resistance, and the bacterial genome was extracted and completely sequenced. The sequenced genome was analyzed, and the genes were annotated in the DNA Data Bank of Japan. Results: Totally, EntfacYE genome subsystems included 23 various categories with 59 genes belonging to antimicrobial resistance genes, such a way that 49 antibiotic resistance genes were included in specific subsystems, while ten genes lacked specific subsystems. Moreover, cadmium, cobalt, copper, zinc, and mercury resistance genes were identified in the EntfacYE genome. Conclusion: In conclusion, studies on bacterial genomes help researchers to identify characteristics of common pathogens, including virulence and antibiotic-resistance genes, and hence better understand bacterial pathogenesis to provide novel solutions for the treatment of common infections.

Keywords

• antibiotic resistance
• clinical sample
• enterococcus faecium
• whole-genome sequencing