Detection and clinical application of the isothermal amplification of Mycoplasma pneumonia RNA in bronchoalveolar lavage fluid from children

Abstract

Objective To assess the ability of simultaneous amplification and testing (SAT) in bacteria detection, bronchoalveolar lavage fluid from children was collected and detected by SAT, combined with in vitro culture experiment, providing theoretical support for the application of SAT in the diagnosis and treatment of mycoplasma pneumonia (MP). Methods A total of 572 bronchoalveolar lavage fluid from children with community acquired pneumonia during October 2015 and December 2017 in Tianjin Children′s Hospital were collected and detected by Mycoplasma pneumonia(MP)nucleic acid quantitative assay and SAT technology. Among them, 161 bronchoalveolar lavage fluid were also detected using in vitro culture and the positive ones for MP were analyzed by nucleic acid quantification and SAT after exposing to high concentration of antibiotic. Results The positive rates of MP by nucleic acid quantitative assay and SAT technology in 572 samples were 74.7% (427/572) and 71.9% (411/572), respectively. These two detection methods have high consistency (χ2=1.142, P=0.285). According to the test results of SAT, the positive rates of male and female were 72.7% (224/308) and 70.8% (187/264), respectively. There was no significant difference of positive rate between different sex (χ2=0.252, P=0.616). The positive rate of MP in 4-14 years old children (78.1%, 317/416) was higher than that in infants (≤3 years) (56.6%, 94/166) (χ2=26.811, P=0.000). After adding azithromycin (5 MIC) to MP positive medium for 5 days, the result of nucleic acid quantification was positive but SAT was negative. Conclusions SAT technology is a rapid, sensitive and specific method for detection of MP. In addition, SAT technology could identify the dead and live bacteria and could evaluate the effect of clinical treatment effectively.(Chin J Lab Med, 2018, 41: 770-774) Key words: Mycoplasma pneumoniae; Bronchoalveolar lavage fluid; Nucleic acid amplification techniques; Microbial sensitivity tests