They develop a protocol for the simultaneous detection of the three main legionella species in just 8 hours

 A team of researchers belonging to the Water Chemistry and Microbiology area of ​​the Water and Environment Engineering Institute of the Polytechnic University of Valencia (IIAMA-UPV) has developed a protocol for the simultaneous detection of three pathogenic species of Legionella spp ( L. pneumophila , L. micdadei and L. longbeachae ) that allows locating the focus of the infection in just eight hours.

The development of this new protocol is the result of a final degree project led by researchers Yolanda Moreno Trigos and Jorge García Hernández, and its innovation lies in the use of an enzymatic detection system using multiplex-PCR (chain reaction of polymerase) coupled to a pre-treatment with PMA (propidium monoazide) that determines its viability in a short space of time, "so it is not necessary for the bacteria to grow in a synthetic laboratory medium and then identify it, as is done with the traditional method ", indicates Moreno.

PMA pretreatment allows DNA from dead cells to be discarded

The project was born, initially, from a study carried out by a group of Japanese researchers who wanted to simultaneously locate four species of Legionella. However, the IIAMA-UPV scientists, after verifying the non-viability of this option, carried out experimentation with 3 species. In addition, they incorporated the PMA treatment and a multiplex PCR key to the success of the project.

"We", explains Moreno, "concentrate the sample, break the bacteria to extract the DNA and then identify the different Legionella species by multiplex-PCR. The previous treatment with PMA allows us to discard the DNA of the dead cells, therefore We only consider viable cells, which is another of the great differences with respect to the culture method, since in an environmental sample you can have viable non-culturable cells ".

The most widespread procedure today takes 14 days to generate results

This pioneering technique contrasts with the more widespread detection procedure, which is carried out through cultural methods and takes fourteen days to generate results. With this system, according to the IIAMA-UPV, viable non-culturable bacteria cannot be detected and there are many isolation difficulties in highly contaminated samples.

"This advance will allow the three most important Legionella species to be located simultaneously. Among them is L. pneumophila , which is the one most frequently isolated in man, since it is present in 90% of cases. and it manifests itself through lung infection or Legionnaires' disease and Pontiac fever, "highlights Moreno.

The first is characterized by being the most severe form of infection with pneumonia, high fever, chills and a dry cough, while the second is less serious and is associated with muscle aches and flu symptoms.