| Popis: |
Objective To isolate and screen Pseudomonas aeruginosa (P. aeruginosa) phages from hospital sewage, identify their lysis spectra and biological characteristics, and explore their application value. Methods P. aeruginosa standard strain ATCC 27853 and the clinical isolates in our department were used as hosts to isolate and screen P. aeruginosa phages from the untreated hospital sewage of our hospital. Then the lysis spectra of the obtained phages were examined. The morphological and biological characteristics of the phage of highest lysis efficiency was studied. Results Six P. aeruginosa phages were isolated and purified from the sewage. The phage with the highest lysis efficiency (79.63%) to 162 clinical isolates with different drug susceptibilities (including 63 multi-drug resistant strains) was named PA-27-1, and the phage lysed 80.95% (51/63) resistant strains. The plaque of the phage PA-27-1 was circular, transparent, and about 2~3 mm in diameter with clear borders, on a double-layer agar plate. Its head was multi-faceted and symmetrical, its tail was short, and the optimal multiplicity of infection was 0.000 1. Eighty percent of the phage was adhered to the host after being mixed with the host bacterial solution, and the percentage was increased to 98% after incubation for 4 min. One-step growth curve of phage PA-27-1 showed that its latent period were 0 to 20 min, the burst period was 20 to 60 min, and the platform period was subsequently, and the average burst size was about 248 (tested on MOI=10). It was stable in the environment of pH 6~pH 10 and ≤50 ℃, and had high tolerance to chloroform. Its nucleic acid type was dsDNA. Conclusion P. aeruginosa phage PA-27-1 has a broad host spectrum, strong lysis ability to multi-drug resistant strains, large burst size, good acid-base and thermal stability. It could be used as a reserve phage and provide a scientific basis for the clinical treatment of P. aeruginosa infection. |
