Nav: Home

Researchers identify how vaginal microbiome can elicit resistance to chlamydia

August 13, 2019

Baltimore, MD., August. 13 -- The vaginal microbiome is believed to protect women against Chlamydia trachomatis, the etiological agent of the most prevalent sexually transmitted infections (STIs) in developed countries. New research by the University of Maryland School of Medicine (UMSOM) shows how the microbiome can either protect or make a woman more susceptible to these serious infections. The research is important amid a rising number of cases of chlamydia worldwide. In the U.S. alone, 1.7 million cases of chlamydia were reported in 2017, a 22% increase since 2013, according to data from the Centers for Diseases Control and Prevention (CDC).

"Chlamydia is a major growing health issue in the U.S., and more work is needed to understand why some women are apparently naturally protected while other are not," commented Jacques Ravel, PhD, Professor of Microbiology and Immunology, Associate Director and Senior Scientist at the Institute for Genome Sciences (IGS) at UMSOM. Dr. Ravel is also a Principal Investigator for this research.

"Our novel research aims to decipher the mechanistic and functional underpinnings of communication between the host and the cervicovaginal microbiome to better understand resistance and susceptibility to this infection."

An Important Mechanism in Vaginal Microbiome


While Lactobacillus-dominated microbiota in a woman's vagina has long been suspected to provide a protective barrier against STIs like chlamydia, investigators at IGS and the University of Maryland School of Dentistry (UMSOD) are reporting for the first time a mechanism enabling specific types of cervicovaginal microbiome to predispose cells in the vagina and cervix to resist chlamydial infection.

"We will now be able to leverage these microbiomes to identify women at risk of infections, but more importantly to develop improved strategies to restore an optimal protection when it is lacking. Unlike our genes, the vaginal microbiome can be modulated to increase protection against chlamydia, but also against other sexually transmitted infections, including HIV," said Dr. Ravel of the research, which was published today in mBio, "Cervicovaginal Microbiota-Host Interaction Modulates Chlamydia trachomatis Infection."

The investigators have shown previously that five major types of vaginal microbiome exist, four of which are dominated by a different species of Lactobacillus, while the fifth has very low numbers of Lactobacillus bacteria and is associated with an increased risk of adverse outcomes including STIs, such as HIV, and even premature births.

The current research showed that Lactobacillusiners, a bacterium actually commonly found in the vagina did not optimally protect human cells against chlamydial infection, while products of Lactobacillus crispatus, another Lactobacillus species frequently found in the vagina, did.

Previously published research has hinted at L. iners being a risk factor for STI; however, the mechanism by which these bacteria were specifically suboptimal at protecting women against STI has remained elusive. Like other Lactobacillus, L. iners produces lactic acid, but only the L isoform. The researchers found that D-lactic acid, not L-lactic acid, down-regulates cell cycling through epigenetic modifications thus blocking C. trachomatis entry into the cell, one of the pathogen key infectious process, among other processes.

Thus, a rather unexpected result of this study is that the vaginal microbiome does not affect the pathogen per se, but drives susceptibility or resistance to infection, by modifying the cells that line up the cervicovaginal epithelium. The researchers further demonstrated that exposure to optimal vaginal microbiota provided long term protection, which has major implication on how a woman is protected. These mechanisms are now being exploited to develop strategies to optimize protection against C. trachomatis infections but also other STIs.

Patrik Bavoil, PhD, Professor & Chair, Department of Microbial Pathogenesis, University of Maryland School of Dentistry, a well-known expert in C. trachomatis biology and pathogenesis, is a Co-Principal Investigator with Dr. Ravel on the NIH funding that supported this study. The investigators also collaborated with Larry Forney, PhD at the University of Idaho.

"Chlamydia is reputed to be a most difficult microorganism to study. By hiding inside cells, the pathogen routinely avoids antimicrobial host defenses. By causing mostly asymptomatic infection, it often escapes detection by both the infected host and the physician alike," said Dr. Bavoil. "What we have done in this study through several years of hard work by dedicated researchers is to provide, for the first time, a huge, new stepping stone on which future translational research to exploit the microbiome in the fight against chlamydial infection and disease, can be based."
-end-
This research was supported by the National Institute for Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) under award numbers U19A1084044 and UH2A1083264.

"This groundbreaking research will stimulate the development of novel antibiotic sparing solution to modulate the cervicovaginal microbiota to protect women from STI, but also from adverse reproductive outcomes such as preterm birth," said UMSOM Dean E. Albert Reese, MD, PhD, MBA, who is also the Executive Vice President for Medical Affairs, University of Maryland and the John Z. and Akiko K. Bowers Distinguished Professor.

University of Maryland School of Medicine

Related Science Articles:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.
Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.
Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.
Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.
World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.
PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.