RESUMO
Objective To examine the clinical value of polymerase chain reaction (PCR) in rapid diagnosis of bacterial and fungal infection of central nervous system.Methods The cerebrospinal fluid (CSF) samples were collected from 137 patients for DNA extraction.PCR was used to amplify the DNA of pathogenic bacteria and fungi using universal primers.The PCR products were subjected to DNA sequencing analysis for identifying microbial species.The conventional culture of pathogens was carried out simultaneously as control.Results PCR revealed bacterial pathogen in 50 of the 137 CSF samples,fungal pathogen in 6 of the 137 CSF samples.Conventional culture of CSF reported positive bacterial infection in 38 cases,fungal infection in 5 cases.PCR provided diagnostic sensitivity of 40.9％,specificity 100％,positive predictive value 100％,negative predictive value 38.2％.The diagnostic efficiency was 56.7％.In contrast,the conventional culture achieved the results of 31.4％,100％,100％,34.7％,44.4％,respectively.The sensitivity,negative predictive value,and diagnostic efficiency of PCR were significantly better than conventional culture method.The coincidence rate between PCR and conventional culture was 97.7％.Conclusions Universal primer-based PCR is characteristic of short turnaround time,specificity,sensitivity and accuracy,which is very useful for rapid diagnosis of the pathogenic bacteria and fungi in central nervous system infections.