Enterococcus durans: Introduction, Classification, Morphology, Pathogenicity, Lab Diagnosis, Treatment, and Prevention

Introduction

Enterococcus durans is a Gram-positive, facultative anaerobic bacterium that belongs to the family Enterococcaceae. It is commonly found in the gastrointestinal tract of humans and animals, as well as in soil and water. It is known for its ability to survive in harsh environments, including high salt concentrations and low pH.

E. durans is a non-pathogenic bacterium that rarely causes infections in humans, although it can cause infections in animals. It is often used in food fermentation and production, particularly in cheese-making, as it produces lactic acid and contributes to the flavor and texture of the cheese.

The identification of E. durans can be challenging, as it shares many characteristics with other members of the Enterococcus genus. It is often identified through a combination of biochemical tests, molecular methods, and antimicrobial susceptibility testing.

Classification

Scientific classification of E.durans–

Domain: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Enterococcaceae
Genus: Enterococcus
Species: Enterococcus durans

Morphology

Enterococcus durans is a Gram-positive, spherical or ovoid-shaped bacterium that typically grows in pairs, short chains, or clusters. Its size ranges from 0.5-1.5 micrometers in diameter. Its colonies on agar plates are usually small, round, and white to cream-colored. The bacterium is facultatively anaerobic, meaning it can grow both in the presence and absence of oxygen.

Like other members of the Enterococcus genus, It is non-motile, lacks spores, and has a cell wall that contains peptidoglycan. The cell wall of Enterococcus durans also contains teichoic acids, which give the bacterium a net negative charge and aid in adhesion to surfaces.

Pathogenicity

E. durans is generally considered to be a non-pathogenic bacterium and is not commonly associated with infections in humans. However, in rare cases, it can cause infections in humans, particularly in immunocompromised individuals, such as those with cancer or HIV/AIDS, or in patients with medical devices such as catheters or prosthetic heart valves.

It can cause a variety of infections, including urinary tract infections, wound infections, endocarditis, and bacteremia. The bacterium can also exhibit resistance to multiple antibiotics, which can complicate treatment.

Lab Diagnosis

The laboratory diagnosis of E. durans typically involves a combination of microbiological and biochemical tests, as well as molecular methods and antimicrobial susceptibility testing.

Microscopic examination: It appears as Gram-positive cocci in pairs or short chains when viewed under a microscope after Gram staining.

Culture: It can be grown on a variety of agar plates, such as blood agar or MacConkey agar. Colonies are usually small, round, and white to cream-colored.

Biochemical tests: E. durans is a member of the Enterococcus genus and can be identified through a variety of biochemical tests, such as the catalase test, bile-esculin test, and the Voges-Proskauer test.

Molecular methods: Polymerase chain reaction (PCR) and other molecular methods can be used to identify E. durans based on the presence of specific genes or DNA sequences.

Antimicrobial susceptibility testing: It can exhibit resistance to multiple antibiotics, so antimicrobial susceptibility testing is important to determine appropriate treatment options.

Treatment and Prevention

Treatment for Enterococcus durans infections typically involves antibiotics, although the choice of antibiotic may depend on the severity of the infection, the location of the infection, and the patient’s underlying health condition. It is often resistant to multiple antibiotics, so susceptibility testing is important to determine the most effective treatment options.

In addition to antibiotic therapy, supportive care may be necessary for patients with E. durans infections, such as wound care for skin infections or fluid and electrolyte management for patients with severe infections.

Prevention of Enterococcus durans infections includes proper infection control measures, such as frequent hand washing, use of personal protective equipment, and proper sterilization of medical equipment. In healthcare settings, isolating patients with E. durans infections and implementing contact precautions can also help prevent the spread of the bacterium.

Keynotes

E. durans is an important bacterium that plays a beneficial role in food production and the environment, although it can also cause infections in certain circumstances.

It is known for its ability to survive in harsh environments, including high salt concentrations and low pH. It is often found in the gastrointestinal tract of humans and animals, as well as in soil and water.

It should be noted that E. durans is also commonly found in food and dairy products, where it is used as a starter culture for fermentation. In this context, it is considered to be a beneficial bacterium and is not a cause for concern. Overall, while Enterococcus durans has the potential to cause infections in certain circumstances, it is generally not considered to be a significant human pathogen.

Overall, the laboratory diagnosis of this bacterium involves a combination of tests to accurately identify the bacterium and determine its susceptibility to antibiotics.

In food production and processing, proper sanitation and hygiene practices are important to prevent contamination with E. durans and other bacteria. The use of starter cultures with known microbial properties can also help ensure the safety and quality of food products.

Further Readings

1. Bhardwaj A, Gupta R. Enterococcus durans: an emerging pathogen in urinary tract infections. J Clin Diagn Res. 2016;10(5):DD01–DD02. doi:10.7860/JCDR/2016/18180.7804
2. Cattoir V, Giard JC. Antibiotic resistance in Enterococcus faecium clinical isolates. Expert Rev Anti Infect Ther. 2014;12(2):239-248. doi:10.1586/14787210.2014.869562
3. Hanchi H, Mottawea W, Sebei K, Hammami R. The genus Enterococcus: between probiotic potential and safety concerns-an update. Front Microbiol. 2018;9:1791. doi:10.3389/fmicb.2018.01791
4. Lebreton F, Willems RJ, Gilmore MS. Enterococcus diversity, origins in nature, and gut colonization. In: Gilmore MS, Clewell DB, Ike Y, Shankar N, eds. Enterococci: From Commensals to Leading Causes of Drug Resistant Infection. Boston: Massachusetts Eye and Ear Infirmary; 2014. Chapter 1. doi:10.1128/microbiolspec.VMBF-0013-2014
5. Sava IG, Heikens E, Huebner J. Pathogenesis and immunity in enterococcal infections. Clin Microbiol Infect. 2010;16(6):533-540. doi:10.1111/j.1469-0691.2010.03208.x