Fact Sheet: Enterococcus spp
- Enterococcus spp is a genus of Gram-positive cocci. Its species are facultative anaerobic, lactic acid bacteria
- M. E. Thiercelin described this genus first in 1899.
- Enterococci are often grouped in pairs (diplococci) or short chains.
- Enterococcus bacteria are present in the intestinal flora of humans and animals. Also, they are present in plants, soil, and water.
- This genus includes a large number of different species.
- Some Enterococcus spp can survive temperatures of 60ºC for short periods of time and can grow in high salt concentrations.
- The most common species of Enterococcus in humans are Enterococcus faecalis (E. faecalis) and Enterococcus faecium.
- Enterococcus species have been used in the food industry as probiotics or starter cultures as they are able to survive the digestive process and flourish in the gut.
- Although for many years Enterococcus spp were believed to be harmless to humans, they are now considered to be significant human pathogens.
- Their resistance to antibiotics, both intrinsic and acquired, is becoming increasingly common. Some species of Enterococcus are classified as “high priority” in the list of Antibiotic Resistant Bacteria, created by the World Health Organisation.
- Some of the most common infections cause by Enterococci are meningitis, bacterial endocarditis, urinary infections and diverticulitis.
- Enterococci are also some of the leading causes of hospital-acquired infections such as bacteraemia.
In the Lab / at Wickham Laboratories Ltd:
- Slanetz and Bartley Media (SBM) are used to examine for the presence of E. faecalis. This is then confirmed using identification techniques such as MALDI-ToF (Matrix Assisted Laser Desorption Ionization-Time of Flight).
- On blood agar plates, Enterococci appear as grey colonies and are usually alpha-hemolytic and on gram stain they appear as gram-positive cocci in pairs and short chains.
- Rapid biochemical tests can identify colonies of Enterococci within minutes based on the ability of almost all Enterococcal species to hydrolyze pyrrolidonyl-beta-naphthylamide (PYR).
- For identification of newer species of Enterococci, a combination of conventional biochemical tests and evaluation of DNA content is needed.
- E. faecalis is a faecal indicator organism and is one of the various microorganisms used as a positive control in the Microbial Examination of Water for human consumption as per The Water Supply (Water Quality) Regulations 2000 (SI2000 No. 3184).
- Laboratories should be alert to the possibility of contamination of specimens with vancomycin-resistant Enterococcus spp from the laboratory environment.