Real-time fluorescence polymerase chain reaction for detecting Legionella in sputum specimens of patients with pulmonary infection / 国际检验医学杂志

ABSTRACT

Objective To establish a real‐time fluorescent polymerase chain reaction and detect 16S rRNA gene of Legionella strains isolated from sputum specimens of patients with pulmonary infection by using this method .Methods 16s rRNA gene of Le‐gionella was used to design primers and probes .The reaction system and reaction conditions were optimized and the specificity ,sen‐sitivity and repeatability of this method were verified by detecting Legionella pneumophila ,non‐Legionella pneumophila and other bacteria .A total of 557 sputum specimens of patients with pulmonary infection were detected ,and PCR‐digestion identification method was carried out as control .Otherwise ,sequences of 16S rRNA were verified in patients with positive detection results .Re‐sults The results showed that all reference strains of Legionella were positive ,while all of other bacteria were negative ,and the sensitivity was 102 CFU/mL .Among sputum specimens collected from 577 cases of patients with pulmonary infection ,the positive rate of Legionella detected by using real‐time fluorescent PCR and PCR‐digestion identification method was 23 .1% and 19 .9% re‐spectively ,while the positive rate was 17 .2% by verifying the sequences of 16s rRNA .There were no statistically significant differ‐ences of positive rate among the three methods(P>0 .05) .Conclusion The real‐time fluorescent PCR is fast and convenient in de‐tection of Legionella strains isolated from sputum specimens of patients ,which could be an assisted method for clinically diagnosing Legionella infection .