Nonlytic Recombinant Phage Tail Fiber Protein for Specific Recognition of Pseudomonas aeruginosa

Rapid and accurate bacterial detection is crucial to an early diagnosis for treating various infectious diseases. A recombinant tail fiber protein (P069) of the Pseudomonas aeruginosa (P. aeruginosa) phage was expressed in Escherichia coli. After renaturation at a low temperature, the inclusion body of P069 was successfully transformed to an aqueous soluble protein that retained the capacity for recognizing P. aeruginosa. The recombinant P069 did not show lytic activity to P. aeruginosa, which facilitated the capture and manipulation of bacterial whole cells with a high flexibility for downstream identification and detection. Bioluminescent and fluorescent methods using this biorecognition element allowed P. aeruginosa detection with the detection limits of 6.7 × 102 CFU mL–1 and 1.7 × 102 CFU mL–1, respectively. Moreover, the specificity investigations showed that P069 was a species-specific protein. Therefore, it avoided the potential false negative results originating from the excessive high specificity of phage toward a given strain. It has been successfully applied to detect P. aeruginosa in spiked samples with acceptable recovery values ranging from 88% to 98%. The above results demonstrate that P069 is an ideal biorecognition element for the detection of P. aeruginosa in complicated sample matrixes.