An Primary Study Of "Suspected Trachoma" Etiology

PART ONE DETECTING AND GENOTYPING OF ISOLATED CT STRAINS FROM"SUSPECTED TRACHOMA"PATIENTSObjective: To investigate the distribution of CT serovars and characterize the Omp1 gene by sequencing DNA from detected trachoma cases of"suspect trachoma"patients. Acquire an initial knowledge of final diagnosis rate of"suspected trachoma"patients and the epidemiological characterization of their CT infection.Methods: Screening was made at Qiqiao Junior Middle School of Liangping County, Chongqing. Conjunctival swab of those clinical diagnosed"suspected trachoma"was collected and tested with immunochromatographic method. Special primer was designed, about 282bp gene fragment of the MOMP gene (omp1) was amplified by PCR.The reference sequences were obtained from GeneBank. Every clinical isolates were sequenced, and the BLAST analysis was conducted of sequence acquired. Then a cladogram was constructed to illustrate the evolutionary relationship between clinical isolates and reference strain. Cervical canals swab of Chlamydial cervicitis patients was collected at the First Affiliated Hospital of Chongqing Medical University, CT positive samples after immunochromatographic method and PCR was acquired for comparison.Result: Among the 478 pupils, there were 64 cases in which the patients displayed symptoms of"suspected trachoma", 0 positive case for immunochromatographic method and 0 positive case for PCR. Sequencing DNA and sequence analysis were not conducted due to shortage of CT positive samples.Conclusion: CT is no longer the main cause of"suspected trachoma"and other factors may also contribute to the problem. Scrupulous care must be taken when making the diagnosis of"suspected trachoma". Large scale epidemiological investigation is necessary to confirm the real cause.PART TWO DETECTING AND GENOTYPING OF ETIOLOGICAL AGENTS THAT FREQUENTLY LEAD TO"SUSPECTED TRACHOMA"PATIENTS'CONJUNCTIVAL INFECTIONObjective: Eukaryon bacterium, HSV and HadV were chosen as target agents. Conjunctival swabs of"suspected trachoma"patients were detected and analyzed. Definiting the genetype of virus and the genus of bacterium. Acquire an initial knowledge of the etiological agents with"suspected trachoma"patients.Methods: Bacterium's general primer, HSV's and HadV's special primers were designed respectively, and conjunctival swab of the 64 cases mentioned above was tested by PCR. Every clinical isolates were sequenced, and the BLAST analysis was conducted of sequence acquired. Then a cladogram was constructed to illustrate the evolutionary relationship between clinical isolates and reference strain.Result: In 9 out of the 64 cases, there emerged 152bp or so target segment, 287bp in the 10 cases, the size of which is as expected. In 4 of which, both length segments are positive. According to DNA sequencing and BLAST analysis, 9 agents belong to the enterobacter. Nucleotide evolution tree indicates that they are most closely related to salmonella; HadV of the 10 agents belong to HadV5. The relationship between viruses tested and between HadV is close.Conclusion: Etiological agents lead to"suspected trachoma"patients'conjunctival infection include enterobacter and HadV5; the etiological agents have to do with sanitation conditions, living environment and living habits of the those involved.