Syphilis Patients In Shanghai Treponema Pallidum Genotyping And Preliminary Study Of The Correlation With Neurosyphilis

Section1Molecular typing of Treponema pallidum:five-year surveillance in Shanghai, ChinaBackground:Previously a small study showed14f was the predominant genotype in Shanghai, China. The result was quite different from genotype distribution in other areas in China. This study aims to identify strain types of Treponema pallidum in large samples through5years period in Shanghai.Methods:From2007to2011, genital swabs were collected from syphilis patients from the Shanghai Skin Disease Hospital. tp47gene was used for Treponema pallidum screening. Positive specimens were typed with the enhanced typing method by adding a tp0548gene to the existing arp and tpr genotype system.Results:In total,304of the372enrolled patients yielded fully typable DNA. Ten arp types (4,6,8,9,11,12,1314,15and19),3tpr types (a,d,o), and5tp0548gene types (a, c,f, g and i) were identified. Totally12genotypes were identified with combination of the arp and tpr gene. Genotype14d was found in270samples (88.8%). By enhancing the typing method with combination of tp0548gene,12CDC subtypes were divided into14strain types. The predominant type was14d/f(88.8%), followed by15d/f (3.6%),13d/f (1.3%) and19d/c(1.3%). Of the304patients who had fully typed sample,52had undergo Lumbar Puncture. Two of the4414d/f and2of the219d/c type infected patients who undertook lumbar puncture were diagnosed as neurosyphilis.Conclusion:This study showed the predominant type circulating in Shanghai was subtype14d, specifically, strain type14d/f. It was similar to data from other areas in China while different from the early report of14f being the most common genotype in Shanghai. Further studies are needed to better understand the association between strain types and neurosyphilis.Section2Treponema pallidum DNA extraction from blood specimens and Molecular typingBackground:Most of the specimens used for Treponema pallidum DNA extraction are from moist skin lesions. Limited typing studies had been done from blood or CSF specimens and none had been reported in China. In clinical practice, only a small proporation of patients have moist skin lesions when they come to clinics.Methods:Blood specimens were collected from untreated primary, secondary and latent syphilis patients from the Shanghai Skin Disease Hospital. Extraction of DNA was performed using the QIAamp DNA Blood mini kit (Qiagen). We used diagnostic polymerase chain reaction (PCR) assay that amplifies tp47gene. Positive specimens were typed with combination of tpO548gene, arp and tpr gene.Results:Treponema pallidum DNA extraction were performed from60blood samples., including15plasma and45whole blood samples. Of the45whole blood sample,10were collected from primary,25were from secondary and10from latent syphilis patients respectively. None of the plasma samples were positive for Treponema pallidum DNA screening. Totally10of the45whole blood sample were positive for tp47screening, with0from primary (0%,0/10),8from secondary (36%,9/25) and2from latent syphilis patients (20%,2/10). Of the10tp47positive samples, arp gene positive rate was45.5%(5/11) and tpr gene positive rate was54.5%(6/11).Conclusion:We have set up Treponema pallidum DNA extraction method for blood specimens. Whole blood from untreated secondary syphilis patients had a higher positive rate for Treponema pallidum DNA.