Published: 25/11/21 13:40 Categories: Microbiology

When a bottle of water is purchased anywhere, the last thing the buyer expects is for it to be contaminated with pathogenic microorganisms. This is thanks to the quality assurance systems that drinking water passes through before it reaches the end consumer.  


The microorganisms that are blacklisted in these products include Enterococcus 


What we know and what we don't know about enterococci  


These microorganisms are Gram-positive, non-spore-forming microorganisms. They have a great survival ability, growing optimally between 35-37ºC, but can survive between 10-45ºC, wide pH ranges, desiccation conditions or even direct contact with sunlight.  


Thanks to these metabolic characteristics, their survival in hostile environments such as the gastrointestinal tract of humans is a given, causing potentially serious health problems such as bacteremia or urinary tract infections. In addition, their increasing adaptations have allowed them to acquire new antibiotic resistance, thus increasing their clinical relevance. 



Current estimates as to the resistance of different enterococci indicate that 10% of E. faecalis are resistant to vancomycin, while 80% of E. faecium are resistant to this antibiotic. These two strains are the most important in the family, as together they account for 75% of total enterococcus infections, and one of their most important routes of transmission in the industry is through drinking water.  


Enterococcus detection  


This transmission route highlighted the need to monitor enterococcus populations in water, with the establishment of a reference method for the numbering of these pathogens for their control, resulting in ISO 7889Condalab offers all the media for the due fulfillment of this regulation. 


However, this method proposes a long protocol comprising several phases, so the availability of alternative methods is particularly useful. For this reason, Condalab, in response to market needs, offers its chromogenic culture media for enterococci detection. Detection with these media is faster than with the standard ISO method, more affordable than genetically based methods, and offer high levels of sensitivity, selectivity and specificity 




Our wide range of chromogenic culture media enables us to offer three products for Enterococcus detection:  


  • M-EI Chromogenic Agar Base: Detection and numbering of enterococcus by single-step membrane filtration, growing in a blue color. Gram-negative and the rest of Gram-positive growth is inhibited. In addition, culturing at 41ºC increases the selectivity of the medium. Results obtained after 24h. 



  • Modified m-EI Chromogenic Agar BaseThis medium differentiates between E. faecalis and E. faecium (greenish and deep blue respectively) by culturing at 41ºC for 18 to 24 hours. 



  • Chromogenic Agar for Vancomycin Resistant-Enterococci (VRE): Given the increasing urgency for the detection of multidrug-resistant strains of enterococcus, we offer this chromogenic medium with vancomycin to differentiate between strains resistant to this antibiotic, cultured at 35°C for 18 to 24 hours.  



Do not hesitate to contact us if you would like further information.