摘要
Reliable diagnostics are a major challenge for the detection and treatment of Helicobacter pylori(H.pylori)infection.Currently at the forefront are non-invasive urea breath test(UBT)and stool antigen test(SAT).Polymerase chain reaction(PCR)is not endorsed due to nonspecific primers and the threat of false-positives.The specificity of DNA amplification can be achieved by nested PCR(NPCR),which involves two rounds of PCR.If the primers are properly designed for the variable regions of the 16S rRNA gene,it is not difficult to develop an NPCR assay for the unambiguous identification of H.pylori.Elaborate NPCR for a 454 bp amplicon was validated on 81 clinical biopsy,stool,and saliva samples,each from the same individuals,and compared with available H.pylori assays,namely histology,rapid urease test,SAT,and 13C-UBT.The assay was much more sensitive than simple PCR,and it was equally sensitive in biopsy samples as the 13CUBT test,which is considered the gold standard.In addition,it is sufficiently specific because sequencing of the PCR products exclusively confirmed the presence of H.pylori-specific DNA.However,due to the threshold and lower abundance,the sensitivity was much lower in amplifications from stool or saliva.Reliable detection in saliva also complicates the ability of H.pylori to survive in the oral cavity aside from and independent of the stomach.The reason for the lower sensitivity in stool is DNA degradation;therefore,a new NPCR assay was developed to obtain a shorter 148 bp 16S rRNA amplicon.The assay was validated on stool samples from 208 gastroenterological patients and compared to SAT results.Surprisingly,this NPCR revealed the presence of H.pylori in twice the number of samples as SAT,indicating that many patients are misdiagnosed,not treated by antibiotics,and their problems are interpreted as chronic.Thus,it is unclear how to properly diagnose H.pylori in practice.In the first approach,SAT or UBT is sufficient.If samples are negative,the 148 bp amplicon NPCR assay should be performed.If problems
基金
by Slovak Research and Development Agency,No.PPCOVID-20-0051.
