Publications by authors named "Kai-Hua Chi"

Ocular syphilis is a serious complication of infection that can occur at any stage of syphilis and affect any eye structure. It remains unknown if certain strains are associated with ocular infections; therefore, we performed genotyping and whole genome sequencing (WGS) to characterize strains from patients with ocular syphilis. Seventy-five ocular or non-ocular specimens from 55 ocular syphilis patients in 14 states within the United States were collected between February 2016 and November 2020.

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Downstream next-generation sequencing (NGS) of the syphilis spirochete Treponema pallidum subspecies (T. pallidum) is hindered by low bacterial loads and the overwhelming presence of background metagenomic DNA in clinical specimens. In this study, we investigated selective whole-genome amplification (SWGA) utilizing multiple displacement amplification (MDA) in conjunction with custom oligonucleotides with an increased specificity for the T.

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Article Synopsis
  • The study aimed to assess the effectiveness of a multiplex PCR (M-PCR) test for identifying herpes simplex virus types 1 and 2 in genital ulcer disease specimens from public health labs.
  • A total of 186 specimen tests were conducted across four public health laboratories, compared to results from the CDC's reference lab, showing a high agreement rate of 94%-100% for herpes detection.
  • The M-PCR assay was successful in detecting HSV and found 12 suspected syphilis cases, indicating its potential to enhance diagnostics for genital ulcer infections in state and local health departments.
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Lymphogranuloma venereum (LGV) can be differentiated from non-LGV chlamydial infection using Sanger sequencing or molecular assays, including those that are commercially-available internationally. Here, we describe the performance of a rapid real-time PCR (RT-PCR)-based strategy in differentiating Chlamydia trachomatis infections associated with LGV or non-LGV serovars. One hundred three rectal swabs, previously genotyped using Sanger sequencing of the ompA gene as a reference method, were tested in the RT-PCR assays.

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WHO and its partners aim to interrupt yaws transmission in countries of endemicity and to certify others as being yaws-free. Transmission can be assessed using rapid plasma reagin (RPR) tests, reflecting current or recent infection, but RPR is operationally impractical. We evaluated changes in antibody levels against two recombinant treponemal antigens, rp17 (also known as Tp17) and TmpA, after antibiotic treatment given as part of a randomized controlled trial for yaws in Ghana and Papua New Guinea.

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Clinical isolates of Treponema pallidum subspecies pallidum (T. pallidum) would facilitate study of prevalent strains. We describe the first successful rabbit propagation of T.

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Article Synopsis
  • The study investigates how a history of violence victimization impacts women's susceptibility to sexually transmitted infections (STIs) by analyzing immune responses in the female reproductive tract.
  • Women who experienced repeated victimization showed changes in immune barrier properties, regardless of demographic factors or bacterial vaginosis presence.
  • Findings suggest a biological connection between past trauma and increased STI risk, with evidence of immune dysfunction affecting barrier integrity in areas exposed to STIs.
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Lymphogranuloma venereum is a sexually transmitted infection caused by serovars L1, L2, and L3 of . We here report a case of Lymphogranuloma venereum, confirmed by PCR testing, which mimicked malignancy on CT imaging.

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A guanine mononucleotide repeat in the rpsA (tp0279) gene was evaluated for improved strain discrimination using 72 Treponema pallidum-positive specimens. The tandem repeat combined with the enhanced Centers for Disease Control and Prevention typing system resulted in increased discrimination and should be useful for molecular epidemiologic studies on syphilis especially in outbreaks and among men who have sex with men.

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Yaws is a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue. The disease primarily affects children under 15 years of age living in low socioeconomic conditions in tropical areas. As a result of a renewed focus on the disease owing to a recent eradication effort initiated by the World Health Organization, we have evaluated a typing method, adapted from and based on the enhanced Centers for Disease Control and Prevention typing method for T.

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Introduction: The WHO yaws eradication strategy consists of one round of total community treatment (TCT) of single-dose azithromycin with coverage of > 90%.The efficacy of the strategy to reduce the levels on infection has been demonstrated previously in isolated island communities in the Pacific region. We aimed to determine the efficacy of a single round of TCT with azithromycin to achieve a decrease in yaws prevalence in communities that are endemic for yaws and surrounded by other yaws-endemic areas.

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Background: Community mass treatment with 30 mg/kg azithromycin is central to the new WHO strategy for eradicating yaws. Both yaws and trachoma--which is earmarked for elimination by 2020 using a strategy that includes mass treatment with 20 mg/kg azithromycin--are endemic in the Pacific, raising the possibility of an integrated approach to disease control. Community mass treatment with azithromycin for trachoma elimination was conducted in the Solomon Islands in 2014.

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Yaws, caused by Treponema pallidum ssp. pertenue, is a neglected tropical disease closely related to venereal syphilis and is targeted for eradication by 2020. Latent yaws represents a diagnostic challenge, and current tools cannot adequately distinguish between individuals with true latent infection and individuals who are serofast following successful treatment.

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Yaws, caused by Treponema pallidum ssp. pertenue, is reportedly endemic in Ghana. Mass distribution of azithromycin is now the cornerstone of the WHO yaws eradication campaign.

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We developed a TaqMan-based real-time quadriplex polymerase chain reaction (PCR) to simultaneously detect Treponema pallidum subspecies pallidum, T. pallidum subsp. pertenue, and T.

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During a survey of yaws prevalence in the Solomon Islands, we collected samples from skin ulcers of 41 children. Using PCR, we identified Haemophilus ducreyi infection in 13 (32%) children. PCR-positive and PCR-negative ulcers were phenotypically indistinguishable.

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Syphilis is a systemic disease caused by the spirochete Treponema pallidum that is usually acquired through sexual exposure.

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Macrolide treatment failure in syphilis patients is associated with a single point mutation (either A2058G or A2059G) in both copies of the 23S rRNA gene in Treponema pallidum strains. The conventional method for the detection of both point mutations uses nested PCR combined with restriction enzyme digestions, which is laborious and time-consuming. We initially developed a TaqMan-based real-time duplex PCR assay for detection of the A2058G mutation, and upon discovery of the A2059G mutation, we modified the assay into a triplex format to simultaneously detect both mutations.

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Objectives: The objectives of this study were to evaluate the use of a real-time multiplex polymerase chain reaction (M-PCR) assay to differentiate between trachoma and lymphogranuloma venereum (LGV) biovars of Chlamydia trachomatis and to validate its performance with the conventional genotyping method.

Study: Swab specimens from 115 patients with anorectal symptoms or syndromes associated with LGV were tested by a real-time M-PCR assay and the results compared with the PCR-based restriction fragment length polymorphism analysis of the major outer membrane protein gene (omp1).

Results: A high agreement of 96.

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We report on a case of gastric syphilis in a patient with chronic dyspepsia. The diagnosis was established by serology and the demonstration of spirochetes in diffusely inflammed gastric mucosa by staining with a fluorescent monoclonal antibody specific for pathogenic treponemes and by the detection of specific treponemal DNA sequences by a real-time PCR.

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