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  2. Gonococcal resistance to zoliflodacin could emerge via transformation from commensal Neisseria species. An in-vitro transformation study

Gonococcal resistance to zoliflodacin could emerge via transformation from commensal Neisseria species. An in-vitro transformation study

  • Sci Rep. 2024 Jan 12;14(1):1179. doi: 10.1038/s41598-023-49943-z.
Saïd Abdellati # 1 Jolein Gyonne Elise Laumen # 1 2 Tessa de Block 3 Irith De Baetselier 3 Dorien Van Den Bossche 3 Christophe Van Dijck 1 2 Sheeba Santhini Manoharan-Basil # 4 Chris Kenyon # 1 5
Affiliations

Affiliations

  • 1 STI Unit, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
  • 2 Laboratory of Medical Microbiology, University of Antwerp, Wilrijk, Belgium.
  • 3 Clinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
  • 4 STI Unit, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium. sbasil@itg.be.
  • 5 Division of Infectious Diseases and HIV Medicine, University of Cape Town, Cape Town, South Africa.
  • # Contributed equally.
Abstract

One of the most promising new treatments for gonorrhoea currently in phase 3 clinical trials is zoliflodacin. Studies have found very little resistance to zoliflodacin in currently circulating N. gonorrhoeae strains, and in-vitro experiments demonstrated that it is difficult to induce resistance. However, zoliflodacin resistance may emerge in commensal Neisseria spp., which could then be transferred to N. gonorrhoeae via transformation. In this study, we investigated this commensal-resistance-pathway hypothesis for zoliflodacin. To induce zoliflodacin resistance, ten wild-type susceptible isolates belonging to 5 Neisseria species were serially passaged for up to 48 h on gonococcal agar plates containing increasing zoliflodacin concentrations. Within 7 to 10 days, all strains except N. lactamica, exhibited MICs of ≥ 4 µg/mL, resulting in MIC increase ranging from 8- to 64-fold. The last passaged strains and their baseline were sequenced. We detected mutations previously reported to cause zoliflodacin resistance in GyrB (D429N and S467N), novel mutations in the Quinolone resistance determining region (QRDR) (M464R and T472P) and mutations outside the QRDR at amino acid positions 28 and 29 associated with low level resistance (MIC 2 µg/mL). Genomic DNA from the laboratory evolved zoliflodacin-resistant strains was transformed into the respective baseline wild-type strain, resulting in MICs of ≥ 8 µg/mL in most cases. WGS of transformants with decreased zoliflodacin susceptibility revealed presence of the same zoliflodacin resistance determinants as observed in the donor strains. Two inter-species transformation experiments were conducted to investigate whether zoliflodacin resistance determinants of commensal Neisseria spp. could be acquired by N. gonorrhoeae. N. gonorrhoeae strain WHO P was exposed to (i) pooled genomic DNA from the two resistant N. mucosa strains and (ii) a gyrB amplicon of the resistant N. subflava strain 45/1_8. Transformants of both experiments exhibited an MIC of 2 µg/mL and whole genome analysis revealed uptake of the mutations detected in the donor strains. This is the first in-vitro study to report that zoliflodacin resistance can be induced in commensal Neisseria spp. and subsequently transformed into N. gonorrhoeae.

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