Enterococcus faecalis vs. Enterococcus faecium

Attribute	Enterococcus faecalis	Enterococcus faecium
Scientific Name	Enterococcus faecalis	Enterococcus faecium
Gram Stain	Positive	Positive
Shape	Cocci	Cocci
Cell Arrangement	Pairs, chains, clusters	Pairs, chains, clusters
Optimal Growth Temperature	37°C	37°C
Pathogenicity	Opportunistic pathogen	Opportunistic pathogen
Resistant to	Antibiotics, disinfectants	Antibiotics, disinfectants
Common Infections	Urinary tract infections, wound infections	Bloodstream infections, urinary tract infections

Introduction

Enterococcus faecalis and Enterococcus faecium are two species of bacteria that belong to the Enterococcus genus. Both species are commonly found in the gastrointestinal tract of humans and animals, and they can also be found in various environmental sources. While they share some similarities, there are also notable differences between these two species in terms of their attributes, pathogenicity, and antibiotic resistance.

Attributes

Enterococcus faecalis and Enterococcus faecium are both gram-positive, facultative anaerobic bacteria. They are non-motile, non-spore-forming, and have a spherical shape. Both species can grow in a wide range of temperatures, from 10°C to 45°C, and they can tolerate a pH range of 4.5 to 9.6. Additionally, they are capable of growing in the presence of bile salts, which contributes to their ability to colonize the gastrointestinal tract.

One of the key differences between Enterococcus faecalis and Enterococcus faecium lies in their ability to produce biofilms. Enterococcus faecalis is known to have a higher capacity for biofilm formation compared to Enterococcus faecium. Biofilms are complex communities of bacteria that adhere to surfaces and are encased in a protective matrix. This attribute of Enterococcus faecalis contributes to its ability to persist in various environments and makes it more difficult to eradicate during infections.

Pathogenicity

Both Enterococcus faecalis and Enterococcus faecium can cause infections in humans, particularly in individuals with compromised immune systems or those undergoing invasive medical procedures. However, Enterococcus faecalis is generally considered to be more pathogenic than Enterococcus faecium. Enterococcus faecalis is responsible for the majority of enterococcal infections, including urinary tract infections, endocarditis, and intra-abdominal infections.

Enterococcus faecium, on the other hand, has emerged as a significant nosocomial pathogen in recent years. It is often associated with healthcare-associated infections, such as bloodstream infections and surgical site infections. Enterococcus faecium is known for its ability to acquire and transfer antibiotic resistance genes, which contributes to its increased virulence and makes it more challenging to treat.

Antibiotic Resistance

Antibiotic resistance is a major concern when it comes to Enterococcus faecalis and Enterococcus faecium. Both species have developed resistance to multiple antibiotics, including vancomycin, which is often considered the drug of last resort for treating enterococcal infections. However, Enterococcus faecium is generally more resistant to antibiotics compared to Enterococcus faecalis.

Enterococcus faecium has acquired various resistance mechanisms, such as the production of enzymes that inactivate antibiotics, alterations in the target sites of antibiotics, and efflux pumps that remove antibiotics from the bacterial cell. This high level of antibiotic resistance in Enterococcus faecium has made it a significant concern in healthcare settings, as it limits treatment options and increases the risk of treatment failure.

Enterococcus faecalis, although less resistant compared to Enterococcus faecium, can still exhibit resistance to several antibiotics. It is important to note that both species can transfer their resistance genes to other bacteria, further contributing to the spread of antibiotic resistance in the environment.

Conclusion

Enterococcus faecalis and Enterococcus faecium are two species of bacteria that share some similarities but also have distinct attributes, pathogenicity, and antibiotic resistance profiles. While both species are commonly found in the gastrointestinal tract and can cause infections in humans, Enterococcus faecalis is generally considered more pathogenic, while Enterococcus faecium has emerged as a significant nosocomial pathogen. Additionally, Enterococcus faecium exhibits higher levels of antibiotic resistance compared to Enterococcus faecalis, posing challenges in the treatment of infections caused by these bacteria. Understanding the differences between these two species is crucial for effective management and prevention of enterococcal infections.