Evaluation of applicability for two types of DNA probes in detection of Streptococcus pneumoniae

Objective To study the diagnostic value of oligonucleotide probe and long-chain DNA probe in detection of Streptococcus pneumoniae (SP).Methods The 21 bp oligonucleotide probe and 263 bp DNA probe of streptococcus pneumoniae were synthesized and labeled with biotin.The two types of probes were hybridized with genomic DNA of streptococcus pneumoniae respectively to compare their sensitivity and specificity of the detection.Clinical sputum samples were also detected by the 2 types of probe simultaneously.Results Both the two probes exhibited high specificity.The sensitivities of oligonucleotide probe and 263 bp DNA probe were 100ng and 1ng of DNA respectively in the detection for SP DNA.The positive rates of culture,hybridization by 21 bp probe and 263 bp probe were 7%,6% and 17% respectively in the detection of 100 sputum samples.Conclusions The 263 bp DNA probe is the optimal choice for the detection of streptococcus pneumoniae by dot-blot hybridization.