Long-Term
 In Vitro
 Culture of the Syphilis Spirochete
 Treponema pallidum
 subsp.
 pallidum

Edmondson, Diane G.; Hu, Bo; Norris, Steven J.

doi:10.1128/mbio.01153-18

Cited by 179 publications

(199 citation statements)

References 55 publications

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“…Our study was limited by the passage in rabbits used to amplify the T. pallidum strains. Until recently, an in vitro culture system did not exist for T. pallidum [52] and passage through rabbits was helpful for obtaining sufficient treponemal genetic material for whole-genome sequencing. As a result, the genetic changes we observed between the two strains may reflect adaptations to the rabbit or, in the case of TprK, gene conversion that occurred in the rabbits, and thus may not be fully reflective of T. pallidum sequence in humans.…”

Section: Plos Neglected Tropical Diseasesmentioning

confidence: 99%

Comparative genomics and full-length Tprk profiling of Treponema pallidum subsp. pallidum reinfection

et al. 2020

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Developing a vaccine against Treponema pallidum subspecies pallidum, the causative agent of syphilis, remains a public health priority. Syphilis vaccine design efforts have been complicated by lack of an in vitro T. pallidum culture system, prolific antigenic variation in outer membrane protein TprK, and lack of functional annotation for nearly half of the genes. Understanding the genetic basis of T. pallidum reinfection can provide insights into variation among strains that escape cross-protective immunity. Here, we present comparative genomic sequencing and deep, fulllength tprK profiling of two T. pallidum isolates from blood from the same patient that were collected six years apart. Notably, this patient was diagnosed with syphilis four times, with two of these episodes meeting the definition of neurosyphilis, during this interval. Outside of the highly variable tprK gene, we identified 14 coding changes in 13 genes. Nine of these genes putatively localized to the periplasmic or outer membrane spaces, consistent with a potential role in serological immunoevasion. Using a newly developed full-length tprK deep sequencing protocol, we profiled the diversity of this gene that far outpaces the rest of the genome. Intriguingly, we found that the reinfecting isolate demonstrated less diversity across each tprK variable region compared to the isolate from the first infection. Notably, the two isolates did not share any full-length TprK sequences. Our results are consistent with an immunodominant-evasion model in which the diversity of TprK explains the ability of T. pallidum to successfully reinfect individuals, even when they have been infected with the organism multiple times.

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Section: Plos Neglected Tropical Diseasesmentioning

confidence: 99%

Comparative genomics and full-length Tprk profiling of Treponema pallidum subsp. pallidum reinfection

et al. 2020

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“…Because of the variation in sensitivity of the two assays used here and the fact that no hosts for T. paraluisleporidarum have been detected in flies in TNP, samples that yielded a Treponema sequence in the polA assay were tentatively considered TPE positive for the analyses presented below. TPE is microaerophilic and cannot grow on standard culture media (Edmondson, Hu, & Norris, 2018), requiring direct culture of the treponemes in laboratory animals. We were unable to perform such culture experiments, so it was not possible to determine the viability of the TPE and these results should be interpreted with caution.…”

Section: Pathogen Screeningmentioning

confidence: 99%

“…Note: Only flies for which data were available for each of the four parameters were included in this analysis (98 flies for a subspecies distinction of these treponemes will be extremely helpful, as would systems for culturing TPE (Edmondson et al, 2018).…”

Section: 030mentioning

confidence: 99%

Tropical rainforest flies carrying pathogens form stable associations with social nonhuman primates

et al. 2019

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Living in groups provides benefits but also incurs costs such as attracting disease vectors. For example, synanthropic flies associate with human settlements, and higher fly densities increase pathogen transmission. We investigated whether such associations also exist in highly mobile nonhuman primate (NHP) Groups. We studied flies in a group of wild sooty mangabeys (Cercocebus atys atys) and three communities of wild chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire. We observed markedly higher fly densities within both mangabey and chimpanzee groups. Using a mark–recapture experiment, we showed that flies stayed with the sooty mangabey group for up to 12 days and for up to 1.3 km. We also tested mangabey‐associated flies for pathogens infecting mangabeys in this ecosystem, Bacillus cereus biovar anthracis (Bcbva), causing sylvatic anthrax, and Treponema pallidum pertenue, causing yaws. Flies contained treponemal (6/103) and Bcbva (7/103) DNA. We cultured Bcbva from all PCR‐positive flies, confirming bacterial viability and suggesting that this bacterium might be transmitted and disseminated by flies. Whole genome sequences of Bcbva isolates revealed a diversity of Bcbva, probably derived from several sources. We conclude that flies actively track mangabeys and carry infectious bacterial pathogens; these associations represent an understudied cost of sociality and potentially expose many social animals to a diversity of pathogens.

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“…Sustained passage has been limited or unattainable, with low yields, contamination, and/or loss of viability, virulence and pathogenicity being reported [1][2][3][4][5][6][7]. However, a recent study suggests that in vitro propagation of T. pallidum is possible using a microaerobic, nutrient-defined rabbit cell culture system, with sustained propagation of viable treponemes for >6 months [8]. Further refinement of the culture system is ongoing to determine its applicability for propagation of T. pallidum strains directly from clinical specimens.…”

Section: Introductionmentioning

confidence: 99%

Successful isolation of Treponema pallidum strains from patients’ cryopreserved ulcer exudate using the rabbit model

et al. 2020

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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. pallidum from cryopreserved ulcer specimens. Fresh ulcer exudates were collected and cryopreserved with consent from syphilis-diagnosed patients (N = 8). Each of eight age-matched adult male rabbits were later inoculated with a thawed specimen, with two rabbits receiving 1.3 ml intratesticularly (IT), and six receiving 0.6 ml intravenously (IV) and IT. Monitoring of serology, blood PCR and orchitis showed that T. pallidum grew in 2/8 rabbits that were inoculated IV and IT with either a penile primary lesion specimen (CDC-SF003) or a perianal secondary lesion specimen (CDC-SF007). Rabbit CDC-SF003 was seroreactive by T. pallidum Particle Agglutination (TP-PA) and Rapid Plasma Reagin (RPR) testing, PCR+, and showed orchitis by week 6. Euthanasia was performed in week 7, with treponemal growth in the testes confirmed and quantified by qPCR and darkfield microscopy (DF). Serial passage of the extract in a second age-matched rabbit also yielded treponemes. Similarly, rabbit CDC-SF007 showed negligible orchitis, but was seroreactive and PCR+ by week 4 and euthanized in week 6 to yield T. pallidum, which was further propagated by second passage. Using the 4-component molecular typing system for syphilis, 3 propagated strains (CDC-SF003, CDC-SF007, CDC-SF008) were typed as 14d9f, 14d9g, and 14d10c, respectively. All 3 isolates including strain CDC-SF011, which was not successfully propagated, had the A2058G mutation associated with azithromycin resistance. Our results show that immediate cryopreservation of syphilitic ulcer exudate can maintain T. pallidum viability for rabbit propagation.

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Long-Term In Vitro Culture of the Syphilis Spirochete Treponema pallidum subsp. pallidum

Cited by 179 publications

References 55 publications

Comparative genomics and full-length Tprk profiling of Treponema pallidum subsp. pallidum reinfection

Comparative genomics and full-length Tprk profiling of Treponema pallidum subsp. pallidum reinfection

Tropical rainforest flies carrying pathogens form stable associations with social nonhuman primates

Successful isolation of Treponema pallidum strains from patients’ cryopreserved ulcer exudate using the rabbit model

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