Open AccessCompetitive polymerase chain reaction for quantification of nonculturable Enterococcus faecalis cells in lake water
Author(s) -
Lleó Maria,
Tafi Maria Carla,
Signoretto Caterina,
Cero Cecilia,
Canepari Pietro
Publication year - 1999
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.1999.tb00662.x
Subject(s) - biology , viable but nonculturable , enterococcus faecalis , polymerase chain reaction , microbiology and biotechnology , enterococcus , bacteria , biochemistry , gene , genetics , staphylococcus aureus , antibiotics
Among the survival strategies developed by bacteria when faced with adverse environmental conditions, the viable but nonculturable (VNC) state has been described. In this state, bacteria are unable to form colonies but are still alive and capable of metabolic activity. The VNC state has been described in numerous Gram‐negative species, but recently also in Enterococcus faecalis , a Gram‐positive species which can be found in the environment. In this study we describe a competitive PCR (cPCR) protocol to detect and quantify a specific sequence of DNA from culturable and nonculturable E. faecalis cells present in water samples. The protocol was found to be specific and capable of detecting amounts of DNA up to 0.1 pg corresponding to approximately 2 cells ml −1 . Moreover, it allows an internal standard to be used to quantify the amount of specific DNA present in samples from different environments. The application of this cPCR method to water samples from Lake Garda enabled us to demonstrate the presence of nonculturable forms of E. faecalis in lake water and to quantify their DNA and the corresponding concentration of nonculturable cells.