Near-Universal Resistance to Macrolides of Treponema pallidum in North America.
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ABSTRACT:
SUBMITTER: Lieberman NAP
PROVIDER: S-EPMC11345850 | biostudies-literature | 2024 Jun
REPOSITORIES: biostudies-literature
Publications
Near-Universal Resistance to Macrolides of <i>Treponema pallidum</i> in North America.
Lieberman Nicole A P NAP Reid Tara B TB Cannon Chase A CA Nunley B Ethan BE Berzkalns Anna A Cohen Stephanie E SE Newman Lori M LM Aldrete Sol S Xu Linda H LH Thornlund Clinton P CP Pettus Kevin K Lundy Stephanie S Kron Michael M Soge Olusegun O OO Workowski Kimberly K Perlowski Charlotte C Hook Edward W EW Dionne Jodie A JA Golden Matthew R MR Lieberman Joshua A JA Lee Min-Kuang MK Morshed Muhammad M Naidu Prenilla P Cao Weiping W Pillay Allan A Giacani Lorenzo L Greninger Alexander L AL
The New England journal of medicine 20240601 22
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Project description:Treponema pallidum macrolide resistance and clinical treatment failure have emerged rapidly within communities where macrolides have been used as convenient, oral therapeutic alternatives to benzathine penicillin G for syphilis or for other clinical indications. Macrolides are not included in the South African syndromic management guidelines for genital ulcer disease; however, in 2015, a 1-g dose of azithromycin was incorporated into treatment algorithms for genital discharge. We determined the prevalence of 23S rRNA macrolide resistance-associated point mutations in 135 T. pallidum-positive surveillance specimens from Botswana, Zimbabwe, and South Africa between 2008 and 2018. Additionally, we investigated the association between macrolide resistance, T. pallidum strain type, and HIV coinfection. A significant increase in the prevalence of the A2058G macrolide resistance-associated point mutation was observed in specimens collected after 2015. There was a high level of molecular heterogeneity among T. pallidum strains circulating in the study communities, with strain type 14d/f being the most predominant in South Africa. Fourteen novel strain types, derived from three new tpr gene restriction fragment length polymorphism patterns and seven new tp0548 gene sequence types, were identified. There was an association between A2058G-associated macrolide resistance and T. pallidum strain types 14d/f and 14d/g but no association between T. pallidum macrolide resistance and HIV coinfection. The majority of T. pallidum strains, as well as strains containing the A2058G mutation, belonged to the SS14-like clade. This is the first study to extensively detail the molecular epidemiology and emergence of macrolide resistance in T. pallidum in southern Africa.
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| S-EPMC7593977 | biostudies-literature
Project description:BackgroundThe increasing incidence of syphilis and the limitations of first-line treatment with penicillin, particularly in neurosyphilis, neonatal syphilis, and pregnancy, highlight the need to expand the therapeutic repertoire for effective management of this disease. We assessed the in-vitro efficacy of 18 antibiotics from several classes on Treponema pallidum subspecies pallidum (T pallidum), the syphilis bacteria.MethodsUsing the in-vitro culture system for T pallidum, we exposed the pathogen to a concentration range of each tested antibiotic. After a 7-day incubation, the treponemal burden was evaluated by quantitative PCR targeting the T pallidum tp0574 gene. The primary outcome was the minimum inhibitory concentration (MIC) at which the quantitative PCR values were not significantly higher than the inoculum wells. We also investigated the susceptibility of macrolide-resistant strains to high concentrations of azithromycin, and the possibility of developing resistance to linezolid, a proposed candidate for syphilis treatment.FindingsAmoxicillin, ceftriaxone, several oral cephalosporins, tedizolid, and dalbavancin exhibited anti-treponemal activity at concentrations achievable in human plasma following regular dosing regimens. The experiments revealed a MIC for amoxicillin at 0·02 mg/L, ceftriaxone at 0·0025 mg/L, cephalexin at 0·25 mg/L, cefetamet and cefixime at 0·0313 mg/L, cefuroxime at 0·0156 mg/L, tedizolid at 0·0625 mg/L, spectinomycin at 0·1 mg/L, and dalbavancin at 0·125 mg/L. The MIC for zoliflodacin and balofloxacin was 2 mg/L. Ertapenem, isoniazid, pyrazinamide, and metronidazole had either a poor or no effect. Azithromycin concentrations up to 2 mg/L (64 times the MIC) were ineffective against strains carrying mutations associated to macrolide resistance. Exposure to subtherapeutic doses of linezolid for 10 weeks did not induce phenotypic or genotypic resistance.InterpretationCephalosporins and oxazolidinones are potential candidates for expanding the current therapeutic repertoire for syphilis. Our findings warrant testing efficacy in animal models and, if successful, clinical assessment of efficacy.FundingEuropean Research Council.
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