Evaluation of a rapid microbial detection method via phage lytic amplification assay coupled with live/dead fluorochromic stains

Aims: To develop a method for rapid detection of bacteria via bacteriophage amplification coupled with exogenous fluorochromic stains. Methods and Results: A method for the rapid detection of bacteria was developed which consisted of exposing the sample suspected to contain target cells to host-specific phage. After at least one infection cycle, bacteria known to be infected by the phage (helper cells) were added and the number of nascent phage particles was estimated using the Live/Dead BacLight Bacterial Viability kit. Using Pseudomonas aeruginosa, it was shown that the dead helper cell population following phage infection was proportional to the initial number of target cells present in the original sample. Approximately 1 x 10(1) CFU per ml of P. aeruginosa could be detected within 4 h without the need for enrichment. Conclusions: The phage lytic amplification assay coupled with exogenous fluorochromic stains was able to detect approx. 1 x 10(1) CFU per ml of the target bacterium within 4 h. Significance and Impact of the Study: A method to detect low number of bacterial cells in a sample within 4 h without the need for enrichment was developed.