Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition

ABSTRACT Several bacterial vaginosis (BV)-associated bacteria have been associated with elevated risk of human immunodeficiency virus (HIV) acquisition; however, susceptibility of these bacteria to antibiotics is poorly understood. Vaginal samples were collected from 22 persons daily for 2 weeks fol...

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Main Authors: D. J. Valint, Tina L. Fiedler, Congzhou Liu, Sujatha Srinivasan, David N. Fredricks
Format: Article
Language:English
Published: American Society for Microbiology 2024-12-01
Series:mBio
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Online Access:https://journals.asm.org/doi/10.1128/mbio.01110-24
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author D. J. Valint
Tina L. Fiedler
Congzhou Liu
Sujatha Srinivasan
David N. Fredricks
author_facet D. J. Valint
Tina L. Fiedler
Congzhou Liu
Sujatha Srinivasan
David N. Fredricks
author_sort D. J. Valint
collection DOAJ
description ABSTRACT Several bacterial vaginosis (BV)-associated bacteria have been associated with elevated risk of human immunodeficiency virus (HIV) acquisition; however, susceptibility of these bacteria to antibiotics is poorly understood. Vaginal samples were collected from 22 persons daily for 2 weeks following BV diagnosis. Metronidazole treatment was prescribed for 5–7 days. Changes in bacterial concentrations were measured with taxon-specific 16S rRNA gene quantitative PCR (qPCR) assays. A culture-based antimicrobial assay confirmed presence of antibiotics in vaginal swab samples. Bacterial DNA concentrations decreased during antibiotic administration for all 13 bacterial taxa tested. Comparison of bacterial DNA concentrations in samples before administration of antibiotics to samples taken on the last day of antimicrobial assay-confirmed antibiotic presence showed a 2.25–4.78 log10-fold decrease across all taxa. Concentrations were frequently reduced to the qPCR assay’s limit of detection, suggesting eradication of bacteria. Mean clearance time varied across taxa (1.2–7.9 days), with several bacteria (e.g., Sneathia spp., Vaginal TM7, and Eggerthella-like sp.) taking >7 days to suppress. Metronidazole reduces quantities of bacterial taxa associated with increased HIV acquisition risk.IMPORTANCEHuman immunodeficiency virus (HIV) transmission through sex remains a major public health challenge despite efforts at risk reduction and use of anti-retroviral pre-exposure prophylaxis. Many bacterial vaginosis (BV)-associated vaginal bacteria have been associated with increased HIV infection risk among women. If these bacteria help mediate HIV infection risk, then eradication of these bacteria is one potential strategy to reduce this risk. However, the best approach to eradicate HIV-high risk bacteria from the vagina is not known. We analyzed vaginal swabs collected daily from women with BV to determine the impact of metronidazole treatment on 13 vaginal bacterial taxa linked to elevated risk of HIV infection through use of taxon-directed quantitative PCR assays. We conclude that eradication of high-risk vaginal bacteria using metronidazole is one promising avenue for reducing HIV acquisition risk, and we provide evidence that a 5–7-day treatment course may not be sufficient to suppress all bacteria.
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spelling doaj-art-0ea5471ad8de4173b3cb613f02ef9bb72024-12-11T14:02:31ZengAmerican Society for MicrobiologymBio2150-75112024-12-01151210.1128/mbio.01110-24Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisitionD. J. Valint0Tina L. Fiedler1Congzhou Liu2Sujatha Srinivasan3David N. Fredricks4Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USAVaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USAVaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USAVaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USAVaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USAABSTRACT Several bacterial vaginosis (BV)-associated bacteria have been associated with elevated risk of human immunodeficiency virus (HIV) acquisition; however, susceptibility of these bacteria to antibiotics is poorly understood. Vaginal samples were collected from 22 persons daily for 2 weeks following BV diagnosis. Metronidazole treatment was prescribed for 5–7 days. Changes in bacterial concentrations were measured with taxon-specific 16S rRNA gene quantitative PCR (qPCR) assays. A culture-based antimicrobial assay confirmed presence of antibiotics in vaginal swab samples. Bacterial DNA concentrations decreased during antibiotic administration for all 13 bacterial taxa tested. Comparison of bacterial DNA concentrations in samples before administration of antibiotics to samples taken on the last day of antimicrobial assay-confirmed antibiotic presence showed a 2.25–4.78 log10-fold decrease across all taxa. Concentrations were frequently reduced to the qPCR assay’s limit of detection, suggesting eradication of bacteria. Mean clearance time varied across taxa (1.2–7.9 days), with several bacteria (e.g., Sneathia spp., Vaginal TM7, and Eggerthella-like sp.) taking >7 days to suppress. Metronidazole reduces quantities of bacterial taxa associated with increased HIV acquisition risk.IMPORTANCEHuman immunodeficiency virus (HIV) transmission through sex remains a major public health challenge despite efforts at risk reduction and use of anti-retroviral pre-exposure prophylaxis. Many bacterial vaginosis (BV)-associated vaginal bacteria have been associated with increased HIV infection risk among women. If these bacteria help mediate HIV infection risk, then eradication of these bacteria is one potential strategy to reduce this risk. However, the best approach to eradicate HIV-high risk bacteria from the vagina is not known. We analyzed vaginal swabs collected daily from women with BV to determine the impact of metronidazole treatment on 13 vaginal bacterial taxa linked to elevated risk of HIV infection through use of taxon-directed quantitative PCR assays. We conclude that eradication of high-risk vaginal bacteria using metronidazole is one promising avenue for reducing HIV acquisition risk, and we provide evidence that a 5–7-day treatment course may not be sufficient to suppress all bacteria.https://journals.asm.org/doi/10.1128/mbio.01110-24vaginal microbiotabacterial vaginosisHIV riskmetronidazolequantitative PCR
spellingShingle D. J. Valint
Tina L. Fiedler
Congzhou Liu
Sujatha Srinivasan
David N. Fredricks
Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition
mBio
vaginal microbiota
bacterial vaginosis
HIV risk
metronidazole
quantitative PCR
title Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition
title_full Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition
title_fullStr Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition
title_full_unstemmed Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition
title_short Effect of metronidazole on concentrations of vaginal bacteria associated with risk of HIV acquisition
title_sort effect of metronidazole on concentrations of vaginal bacteria associated with risk of hiv acquisition
topic vaginal microbiota
bacterial vaginosis
HIV risk
metronidazole
quantitative PCR
url https://journals.asm.org/doi/10.1128/mbio.01110-24
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