Quantitative detection of Proteus species by real-time polymerase chain reaction using SYBR Green I

A SYBR Green real-time polymerase chain reaction (PCR) method for rapid detection of Proteus species was developed and evaluated. Of 322 clinical and food samples tested, 75 samples were positive for Proteus species by using conventional PCR and real-time PCR assays. The results were consistent with standard culture methods and the Vitek auto-microbe system, indicating a 100 % specificity obtained by both PCR assays. For the real-time PCR method, the minimum detectable level was 10 colony forming units (CFU) /ml, which was a 103 multiple higher than the conventional PCR method. Correlation coefficients of standard curves which were constructed using the threshold cycle (Ct) versus copy numbers of Proteus showed good linearity (R 2 = 0.997). In conclusion, several significant advantages such as higher sensitivity and rapidness were observed by using the SYBR Green real-time PCR method for identifying Proteus species.