What Is Enterococcus?

Enterococci are Gram-positive (G +) cocci, widely distributed in the natural environment and in the digestive tract of humans and animals. Since the 1980s, the incidence and mortality of severe enterococcal infections have increased significantly, and due to the inherent resistance and acquired resistance of enterococci, many commonly used antibacterial drugs have failed to treat enterococcal infections. Therefore, the study of enterococcus pathogenic factors and the mechanism and treatment of infection caused by enterococci appears to be particularly important at the molecular level.

Enterococcus is an important pathogen of nosocomial infection, which can not only cause

Generally speaking,

Enterococcal infection is the third cause of neonatal sepsis, and the incidence of enterococcal sepsis in newborns and children has increased six-fold. Enterococci is reported to be the second largest pathogen of endogenous and exogenous nosocomial infections, with the detection rate second only to E. coli. According to statistics, among the pathogens that cause urinary tract infections, enterococcal infections rank second; abdominal and pelvic infections, enterococci ranks third; sepsis, enterococci ranks third, and the mortality rate is 12.6% 57. %.

When antibiotics are used extensively or the host's immunity is low, the symbiotic state between the host and Enterococcus is imbalanced. Enterococci leave the normal colony site and enter other tissues and organs. It first accumulates locally in the host tissue to a threshold density, and then Under the action, it adheres to the extracellular matrix proteins of the host cell, secretes cytolysin, gelatinase and other virulence factors to invade and damage the host tissue cells, and spreads pathogenicity among enterococcus species through plasmid junction transfer, and tolerates the host The non-specific immune response causes the occurrence and development of infectious diseases.

At the same time, enterococci are also prone to develop drug resistance, including three types of resistance: inherent resistance, acquired resistance, and tolerance. Due to its strong cell wall, Enterococcus appears to be inherently resistant to many antibiotics. Enterococcus drug resistance in the 1970s showed resistance to aminoglycosides, such as gentamicin and streptomycin, in the 1980s it was resistant to -lactams and glycopeptides, and was first discovered in 1986 Vancomycin-resistant Enterococcus (VRE). After the 1990s, due to the widespread application of antibacterial drugs, coupled with invasive treatment and excessive use of fluoroquinolones and oral cephalosporins, the number of strains and cases of infection caused by enterococcus resistant bacteria has increased, and it has become a nosocomial infection. The main cause. Due to the difficulty of treating drug-resistant infections caused by such bacteria, and the antibiotic resistance of enterococci is more complicated, many clinically isolated enterococci are multi-resistant strains.

In-hospital surveillance systems in the United States indicate that nosocomial infections caused by VRE were 0.3% in 1989, 7.9% in 1993, and increased to 13% in the ICU. By 1997, more than 15% of nosocomial enterococcal infections were VRE. VRE has a broad spectrum of resistance, is prone to infection and epidemics, and can transfer vancomycin-resistant genes to other Gram-positive bacteria, such as Staphylococcus aureus. At the same time, Enterococcus can survive on the surface of dry objects for several days to several weeks, and it can undoubtedly be carried and spread from the surface of contaminated hands and clothing. Enterococcus is virulent and epidemic, and it can also produce the ability to mediate inflammatory reactions, as well as its drug resistance and dissemination (including the dissemination of resistance factors), which are potentially harmful to clinical patients Aggravate the progress of the condition.

In addition, American researchers published an article in the Journal of Medical Microbiology that Enterococcus faecalis can produce harmful chemicals, destroy DNA, and cause genetic activities that promote rectal cancer. In the laboratory, they studied the response of rectal cells to Enterococcus faecalis. It was found that in the fermentation state, Enterococcus faecalis will produce an oxygen molecule called "superoxide", which will destroy the DNA of surrounding cells, but the effect of Enterococcus faecalis far beyond this. This superoxide sends a strong signal to immune cells called macrophages, changes the way some intestinal parasitic cells grow and divide, and even enhances the activity of oncogenes. Studies have confirmed that in the fermentation state, 42 cell genes related to important physiological processes of the human body are affected by Enterococcus faecalis.