Human Enterococcus ID™
DNA detection of Human fecal bacteria
(Target: Human Enterococcus)
- Service determines the presence of Human fecal contamination using Human specific enteroviruses.
- Results in as little as 2 working days.
- Send in as little as 1 liter of water.
- Uses DNA analytical technology called RT-PCR.
Enterococci are a subgroup of Fecal Streptococci and are characterized by their ability to grow in 6.5% sodium chloride, at low and elevated temperatures (10oC and 45oC), and at elevated pH (9.5). These microorganisms have been used as indicators of fecal pollution for many years and have been especially valuable in the marine environment and recreational waters as indicators of potential health risks and swimming-related gastroenteritis. Enterococci are benign bacteria when they reside in their normal habitat such as the gastrointestinal tracts of human or animals. Outside of their normal habitat, Enterococci are pathogenic causing urinary tract and wound infections, and life-threatening diseases such as bacteraemia, endocarditis, and meningitis. Enterococci easily colonize open wounds and skin ulcers.
Compounding their pathogenesis, Enterococci are also some of the most antibiotic resistant bacteria, particularly from human sources. Studies have shown that certain strains of Enterococci are resistant to expensive and potent antibiotics such as vancomycin. This is particularly worrisome for the medical community since these antibiotics are given as a last resort to fight severe bacterial infections. Several intrinsic features of the Enterococcus genus allow it to survive for extended periods of time, leading to its extended survivability and diffusion. For example, Enterococci have been shown to survive for 30 minutes at 60°C and persist in the presence of detergents. As such, the inherent ruggedness of Enterococcus confers it a strong tolerance to many classes of antibiotics.
The Human Enterococcus ID™ service is designed around the principle that certain strains of the Enterococcus genus are specific to humans. These Enterococci can be used as indicators of human fecal contamination. Strains of Enterococcus faecium, Enterococcus faecalis and yellow-pigmented Enterococci have been shown to be from human sources. Within these Enterococcus spp. are genes associated with Enterococci that are specific to humans. The Human Enterococcus ID™ service targets the esp human gene biomarker in Enterococcus faecium.
One of the advantages of the Human Enterococcus ID™ service is that the entire cultured population of Enterococci of the selected portion of the water sample is screened. This method avoids the randomness effect of selecting isolates. This is a particular advantage for highly contaminated water systems with multiple sources of fecal contamination.
Accuracy of the results is possible because the method uses quantitative PCR (qPCR) DNA technology. qPCR allows DNA to be amplified into large number of small copies of DNA sequences. This is accomplished with small pieces of DNA called primers that are complementary and specific to the genomes to be detected. Through a heating process called thermal cycling, the double stranded DNA is denatured and inserted with complementary primers to create exact copies of the DNA fragment desired. This process is repeated many times ensuring an exponential progression in the number of copied DNA. If the primers are successful in finding a site on the DNA fragment that is specific to the genome to be studied, then billions of copies of the DNA fragment will be detected in real-time. The accumulation of DNA product is plotted as an amplification curve. The absence of an amplification curve indicates that the esp Human gene biomarker is not present. To strengthen the validity of the results, the service should be combined with other DNA analytical services such as the Human Bacteroidetes ID™ and Human Fecal Virus ID™ services.