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posted on 05.04.2018, 04:30 authored by Chi Zhang, Leshan Xiu, Yan Xiao, Zhengde Xie, Lili Ren, Junping Peng

Pneumonia and meningitis continue to present an enormous public health burden and pose a major threat to young children. Among the causative organisms of pneumonia and meningitis, bacteria are the most common causes of serious disease and deaths. It is challenging to accurately and rapidly identify these agents. To solve this problem, we developed and validated a 12-plex PCR coupled with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) method (bacterial pathogen-mass spectrometry, BP-MS) that can be used to simultaneously screen for 11 key bacterial pathogens related to pneumonia and meningitis. Forty-six nasopharyngeal swabs and 12 isolates were used to determine the specificity of the method. The results showed that, using the BP-MS method, we could accurately identify the expected bacteria without cross-reactivity with other pathogens. For the 11 target bacterial pathogens, the analytical sensitivity of the BP-MS method was as low as 10 copies/reaction. To further evaluate the clinical effectiveness of this method, 204 nasopharyngeal swabs from hospitalized children with suspected pneumonia were tested using this method. In total, 81.9% (167/204) of the samples were positive for at least one of the 11 target pathogens. Among the 167 bacteria-positive samples, the rate of multiple infections was 55.7% (93/167), and the most frequent combination was Streptococcus pneumoniae with Haemophilus influenzae, representing 46.2% (43/93) two-pathogen mixed infections. We used real-time PCR and nested PCR to confirm positive results, with identical results obtained for 81.4% (136/167) of the samples. The BP-MS method is a sensitive and specific molecular detection technique in a multiplex format and with high sample throughput. Therefore, it will be a powerful tool for pathogen screening and antibiotic selection at an early stage of disease.