Dataset Information

Characteristics of polymerase chain reaction-positive syphilis cases in Manitoba, Canada, 2017 to 2020: Demographic analysis, specimen types, and Treponema pallidum gene targets.

ABSTRACT:

Background

A resurgence of syphilis infections has been described in a number of countries including Canada in the last decade.

Methods

This study identified polymerase chain reaction (PCR) positive syphilis cases based on detection of Treponema pallidum genes (polA, tpp47, and bmp) in 3,350 clinical specimens obtained from patients in the province of Manitoba, Canada between 2017 and 2020. Patient demographics were obtained from specimen requisition forms.

Results

PCR identified 740 syphilis cases: 718 were adolescents and adults, while 22 were congenital syphilis cases. For non-congenital syphilis investigation, the clinical specimens with the highest yield of positive PCR results were genital (632), oral (73), and anal (55), while for congenital syphilis, they were nasal or nasopharyngeal secretions (20), followed by blood (5) and umbilical cord (4). Female syphilis cases appeared younger (61.7% between 14 and 29 years), while male syphilis cases appeared older (58.4% between 30 and 65 years). Although, overall more syphilis cases (62.7%) occurred in the urban cities; the proportion of urban cases showed a significant decline from 87.0% in 2017 to 55.6% in 2020, while in rural regions it increased from 13.0% in 2017 to 44.4% in 2020. Most (98.8%) PCR- positive specimens were found to contain all three T. pallidum genes and 99.8% also displayed the macrolide resistance genotype.

Conclusions

This study identified the clinical specimen types and T. pallidum genes most suitable for PCR diagnosis of syphilis. Changing demographics of cases were noted over time.

SUBMITTER: Tsang RS

PROVIDER: S-EPMC9629728 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Characteristics of polymerase chain reaction-positive syphilis cases in Manitoba, Canada, 2017 to 2020: Demographic analysis, specimen types, and <i>Treponema pallidum</i> gene targets.

Tsang Raymond Sw RS Shuel Michelle M Hoang William W Hayden Kristy K Hink Rachel R Bullard Jared J Van Caeseele Paul P Alexander David C DC

Journal of the Association of Medical Microbiology and Infectious Disease Canada = Journal officiel de l'Association pour la microbiologie medicale et l'infectiologie Canada 20220927 3

<h4>Background</h4>A resurgence of syphilis infections has been described in a number of countries including Canada in the last decade.<h4>Methods</h4>This study identified polymerase chain reaction (PCR) positive syphilis cases based on detection of <i>Treponema pallidum</i> genes (<i>polA</i>, <i>tpp47</i>, and <i>bmp</i>) in 3,350 clinical specimens obtained from patients in the province of Manitoba, Canada between 2017 and 2020. Patient demographics were obtained from specimen requisition fo ...[more]

PMID: 36337605

Similar Datasets

Project description:Despite more than a century of research, genetic manipulation of Treponema pallidum subsp. pallidum (T. pallidum), the causative agent of syphilis, has not been successful. The lack of genetic engineering tools has severely limited understanding of the mechanisms behind T. pallidum success as a pathogen. A recently described method for in vitro cultivation of T. pallidum, however, has made it possible to experiment with transformation and selection protocols in this pathogen. Here, we describe an approach that successfully replaced the tprA (tp0009) pseudogene in the SS14 T. pallidum strain with a kanamycin resistance (kanR) cassette. A suicide vector was constructed using the pUC57 plasmid backbone. In the vector, the kanR gene was cloned downstream of the tp0574 gene promoter. The tp0574prom-kanR cassette was then placed between two 1-kbp homology arms identical to the sequences upstream and downstream of the tprA pseudogene. To induce homologous recombination and integration of the kanR cassette into the T. pallidum chromosome, in vitro-cultured SS14 strain spirochetes were exposed to the engineered vector in a CaCl2-based transformation buffer and let recover for 24 hours before adding kanamycin-containing selective media. Integration of the kanR cassette was demonstrated by qualitative PCR, droplet digital PCR (ddPCR), and whole-genome sequencing (WGS) of transformed treponemes propagated in vitro and/or in vivo. ddPCR analysis of RNA and mass spectrometry confirmed expression of the kanR message and protein in treponemes propagated in vitro. Moreover, tprA knockout (tprAko-SS14) treponemes grew in kanamycin concentrations that were 64 times higher than the MIC for the wild-type SS14 (wt-SS14) strain and in infected rabbits treated with kanamycin. We demonstrated that genetic manipulation of T. pallidum is attainable. This discovery will allow the application of functional genetics techniques to study syphilis pathogenesis and improve syphilis vaccine development.

Project description:BackgroundThe spirochete bacterium Treponema pallidum ssp. pallidum is the etiological agent of syphilis, a chronic multistage disease. Little is known about the global T. pallidum proteome, therefore mass spectrometry studies are needed to bring insights into pathogenicity and protein expression profiles during infection.Methodology/principal findingsTo better understand the T. pallidum proteome profile during infection, we studied T. pallidum ssp. pallidum DAL-1 strain bacteria isolated from rabbits using complementary mass spectrometry techniques, including multidimensional peptide separation and protein identification via matrix-assisted laser desorption ionization-time of flight (MALDI-TOF/TOF) and electrospray ionization (ESI-LTQ-Orbitrap) tandem mass spectrometry. A total of 6033 peptides were detected, corresponding to 557 unique T. pallidum proteins at a high level of confidence, representing 54% of the predicted proteome. A previous gel-based T. pallidum MS proteome study detected 58 of these proteins. One hundred fourteen of the detected proteins were previously annotated as hypothetical or uncharacterized proteins; this is the first account of 106 of these proteins at the protein level. Detected proteins were characterized according to their predicted biological function and localization; half were allocated into a wide range of functional categories. Proteins annotated as potential membrane proteins and proteins with unclear functional annotations were subjected to an additional bioinformatics pipeline analysis to facilitate further characterization. A total of 116 potential membrane proteins were identified, of which 16 have evidence supporting outer membrane localization. We found 8/12 proteins related to the paralogous tpr gene family: TprB, TprC/D, TprE, TprG, TprH, TprI and TprJ. Protein abundance was semi-quantified using label-free spectral counting methods. A low correlation (r = 0.26) was found between previous microarray signal data and protein abundance.ConclusionsThis is the most comprehensive description of the global T. pallidum proteome to date. These data provide valuable insights into in vivo T. pallidum protein expression, paving the way for improved understanding of the pathogenicity of this enigmatic organism.

Project description:BackgroundPenicillin G, the current standard treatment for syphilis, has important drawbacks, but virtually no preclinical or clinical studies have been performed to identify viable alternatives. We tested, both in vitro and in vivo, three marketed antibiotics with adequate pharmacological properties to treat syphilis.MethodsWe used an in vitro culturing system of T. pallidum to perform drug susceptibility testing and applied quantitative PCR targeting the tp0574 gene to measure bacterial growth. To confirm in vivo efficacy, fifteen rabbits were infected intradermally with T. pallidum at eight sites each and randomly allocated to an experimental treatment (linezolid, moxifloxacin, clofazimine) or a control arm (benzathine penicillin G [BPG], untreated). The primary outcome was treatment efficacy defined as the time to lesion healing measured from the date of treatment start. Secondary outcomes were absence of treponemes or treponemal mRNA in injection sites, absence of seroconversion, and cerebrospinal fluid (CSF) abnormalities and negative rabbit infectivity tests (RIT).FindingsLinezolid showed in vitro bactericidal activity at concentrations of 0.5 µg/mL or higher. When administered orally to experimentally infected rabbits, it induced healing of early lesions at a time similar to BPG (hazard ratio 3.84; 95% CI 2.05-7.17; p < 0.0001 compared to untreated controls). In linezolid-treated animals, dark-field microscopy and qPCR assessment showed no presence of treponemes after day 3 post-treatment start, serologic test did not convert to positive, CSF had no abnormalities, and RIT was negative. Moxifloxacin and clofazimine failed to inhibit bacterial growth in vitro and could not cure the infection in the rabbit model.InterpretationLinezolid, a low-cost oxazolidinone, has in vitro and in vivo activity against T. pallidum, with efficacy similar to BPG in treating treponemal lesions in the animal model. Our findings warrant further research to assess the efficacy of linezolid as an alternative to penicillin G to treat syphilis in human clinical trials.FundingEuropean Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant agreement No. 850450).