Colony identification using PCR and ISO methods | Sponsored |

All of the microbiological methods for the isolation of bacterial colonies belonging to single species, genera or groups, normally require methods for confirmation. ISO 7218 defines the basic requirements and guidance for microbiological examinations, and includes a chapter defining the possible methods to identify microbial colonies. Molecular methods based on probes like Real-Time PCR are listed among them.  

Generon S.p.A. developed PATHfinder, a portfolio of Real-Time PCR kits for the identification of bacteria isolated from food, feed, the environment, and water samples. All of the products are based on internationally peer reviewed scientific literature. Therefore, according to ISO 7218, PATHfinder Real-Time PCR kits can be used for colony identification in ISO 17025 accredited schemes as is currently the case for biochemical and serological identification methods.  

Legionella represents a major public health concern, as it can reside and persist in water pipes and can be easily spread in the environment through aerosolization giving potential access to humans through lung exposure which may give rise to significant infections causing a severe form of pneumonia. Legionella can be detected in water with both molecular and culture-based methods according to ISO 12869 and ISO 11731 respectively. The use of PCR to identify Legionella colonies isolated on selective agar plates represents a merger of these two approaches. Identification of colonies with Generon PATHfinder kits does not require any DNA extraction step and allows the typing down to the serogroup level.  

In general, PCR has both economic and practical advantages versus traditional biochemical and serological identification methods. Benefits include: the overall workflow is significantly reduced; it is not necessary to subculture colonies in non-selective media; it is not prone to biochemical variants of bacteria; it is not necessary to have plated positive controls to confirm results and results are objective and traceable.