Host-pathogen-microbiome interactions in mycoplasma genitalium pathology and treatment: experiments in a 3D organotypic cervical epithelium model to strengthen clinical guidelines

The National Institute of Allergy and Infectious Diseases awarded $194,375 to the University of Maryland, Baltimore on June 10, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to investigate Mycoplasma genitalium pathology, host-pathogen-microbiota interactions, and potential treatment approaches using a three-dimensional organotypic cervical epithelium model.

The research addresses gaps in clinical understanding of M. genitalium, an emerging sexually transmitted pathogen with poorly characterized outcomes in women. The CDC does not recommend M. genitalium screening in asymptomatic women because the frequency with which asymptomatic infection leads to adverse reproductive outcomes such as cervicitis, pelvic inflammatory disease, infertility, and ectopic pregnancy remains unclear. Existing mechanistic data rely on models that do not faithfully recapitulate in vivo cervical microphysiological conditions, particularly the presence of cervical mucus and the cervicovaginal microbiota. Preliminary epidemiologic data suggest M. genitalium and bacterial vaginosis may synergize to promote cervicitis. The research will also evaluate the therapeutic potential of metronidazole and tinidazole—antibiotics available in the United States and currently used to treat bacterial vaginosis—for improving M. genitalium treatment outcomes, particularly as resistance-guided therapies and novel antibiotics remain unavailable domestically.

The recipient developed an innovative in vitro three-dimensional organotypic model using primary human cervical cells to investigate M. genitalium pathology, host-pathogen-microbiota interactions, and potential therapies. Performance occurs in Baltimore, Maryland, with a period of performance through May 31, 2028. This is a Project Grant assistance type award.

Abstract

Mycoplasma genitalium (MG) is an emerging sexually transmitted pathogen whose clinical outcomes in women are poorly understood. Unlike other bacterial sexually transmitted infections (STI), the CDC does not recommend MG screening for asymptomatic women because IT is unclear how often asymptomatic MG leads to adverse reproductive outcomes like cervicitis, which can lead to further adverse outcomes, including pelvic inflammatory disease, infertility, and ectopic pregnancy. Epidemiologic data on MG and cervicitis are mixed, and mechanistic data primarily come from models that did not faithfully recapitulate in vivo cervical microphysiological conditions. Key elements they lacked are cervical mucus, which mediates host-pathogen interactions, and the cervicovaginal microbiota. The microbiota appears to contribute to MG outcomes, and our preliminary epidemiologic data indicate that MG and bacterial vaginosis (BV) may synergize to promote cervicitis. MG care is further complicated by its ongoing rise in antibiotic resistance. Resistance-guided therapy and novel antibiotics improve treatment outcomes, but these are not available in the US. Recent clinical and in vitro data indicate that metronidazole and tinidazole, two antibiotics that are available in the US and used to treat BV, may hold promise for improving MG treatment outcomes. The overall objective of this R21 is to generate robust experimental data to clarify MG pathology, evaluate potential therapies, and inform more thorough and actionable clinical recommendations. We developed an innovative in vitro 3D organotypic model of the cervical epithelium that is ideally suited for investigating MG pathology, host-MG-microbiota interactions, and potential therapies. The model uses primary human cervical cells and better recapitulates cervical epithelial structure and physiology (including cervical mucus production) than prior 2D models. IT also allows for simultaneous STI infection and CO- culture of live cervicovaginal microbiota. Using the 3D organotypic cervical epithelium model, we will determine if MG causes microbiota-dependent cervical epithelial damage, a hallmark of cervicitis (aim 1), and we will test if metronidazole and tinidazole arrest MG infection (aim 2). In both aims, we will interrogate the potential mediating role of the microbiota by inoculating models with live representative cervicovaginal microbiota, and we will assess host-MG-microbiota interactions via transcriptomics. We hypothesize that a polymicrobial BV-like microbiota will exacerbate MG-induced cervical epithelial damage, and removal of a polymicrobial BV microbiota will partially mediate metronidazole's and tinidazole's anti-MG activity. The proposed aims have high translational potential and will provide crucial pre-clinical evidence to inform more thorough and actionable MG testing and treatment guidelines and improve reproductive health outcomes. This R21 will generate some of the first experimental data on MG-host and MG-microbiota interactions, which we will use to support an R01 to validate these interactions during in vivo MG infection and identify novel therapeutic targets for MG.