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

English version

Autoři: Lara E. Pereira ^aff001; Samantha S. Katz ^aff001; Yongcheng Sun ^aff001; Patrick Mills ^aff002; Willie Taylor ^aff002; Patricia Atkins ^aff003; Charles M. Thurlow ^aff004; Kai-Hua Chi ^aff001; Damien Danavall ^aff001; Nicholas Cook ^aff004; Tamanna Ahmed ^aff004; Alyssa Debra ^aff004; Susan Philip ^aff005; Stephanie Cohen ^aff005; Kimberly A. Workowski ^aff001; Ellen Kersh ^aff001; Yetunde Fakile ^aff001; Cheng Y. Chen ^aff001; Allan Pillay ^aff001
Působiště autorů: Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States of America ^aff001; Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, GA, United States of America ^aff002; Charles River Laboratories, Wilmington, MA, United States of America ^aff003; Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States of America ^aff004; San Francisco Department of Public Health, San Francisco, CA, United States of America ^aff005; Emory University Department of Medicine, Atlanta, GA, United States of America ^aff006
Vyšlo v časopise: PLoS ONE 15(1)
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pone.0227769

Souhrn

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.

Klíčová slova:

Blood – Euthanasia – Lesions – Rabbits – Syphilis – Testes – Ulcers – Treponema pallidum

Zdroje

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

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