Scientists Sequence Chlamydia Trachomatis Genome

October 22, 1998

Researchers in California supported by the National Institute of Allergy and Infectious Diseases (NIAID) have completed sequencing the Chlamydia trachomatis genome, providing new insights into chlamydial infection, the most prevalent bacterial sexually transmitted disease (STD) in the United States and a major cause of STDs worldwide. C. trachomatis also is the etiologic agent of ocular trachoma, the leading cause of preventable blindness in the developing world. A report describing the project appears in the Oct. 23, 1998 issue of Science.

This project was a collaborative effort between scientists at the University of California at Berkeley, the University of California at San Francisco, and the DNA Sequencing and Technology Center at Stanford University. Richard S. Stephens, Ph.D., M.P.H., primary investigator of the project, led the microbiology team at the University of California at Berkeley, and Ronald Davis, Ph.D., led the sequencing effort at Stanford. The sequenced genome has already been entered into a new on-line database, the STD Relational Database (, funded by NIAID and designed to accelerate research on STDs.

"Their accomplishment has important implications for vaccine development," comments Anthony S. Fauci, M.D., director of NIAID. "The genome sequence has revealed surface proteins about which we knew nothing, and the organism's unique biochemical pathways provide promising new leads for developing antibiotics."

More than 4 million new cases of chlamydial infection occur in the United States each year, and associated medical costs are estimated to exceed $2 billion. Control of chlamydial infection is complicated by the frequency of asymptomatic disease, the cost and complexity of many available diagnostic tests, and the inadequacy of prevention and control programs.

In women, 20 to 40 percent of untreated or inadequately treated chlamydial infections result in pelvic inflammatory disease (PID), an infection of the upper reproductive tract. The resulting tubal scarring leads to infertility, tubal pregnancy and chronic pelvic pain. Chlamydial infection also increases the risk for HIV infection.

Researchers have found the study of C. trachomatis challenging because unlike most bacteria, this organism only grows inside the host cell, just like a virus. Also, many aspects of C. trachomatis - its physiology, structure, developmental biology and genetics - are poorly understood. Its genome, however, has already revealed some extraordinary secrets. Over time, it appears that this bacterium has borrowed genetic information from its human hosts, and it uses this information to tap the resources of the cells and get essential nutrients that it cannot make.

"The Chlamydia trachomatis genome represents a molecular gold mine for the research community," says Dr. Stephens. "Even the establishment of a genetic system, which we can manipulate to study the organism, is within reach. This would enable scientists to use molecular tools to investigate, for example, how the organism gets inside the cells, how it causes scarring and how Chlamydia might escape the effects of antibiotic therapy."

The last few years have yielded critical advances in the battle against this devastating STD. A highly sensitive and specific urine test to diagnose the illness has been developed. The pharmaceutical industry has made a safe and effective single-dose oral therapy. NIAID-funded researchers have used these new tools to document the enormous problem in adolescent populations and to show that early screening and treatment for chlamydial infection can prevent PID.

"Despite significant progress, the more we look, the more chlamydial infections we find. Clearly we need better prevention tools if we are going to stop the spread of this silent plague," says Penelope J. Hitchcock, D.V.M., chief of NIAID's STD branch. "Of particular interest is a better understanding of the early steps in the infectious process - this knowledge will lead to vaccines to prevent PID and topical microbicides to prevent infection."
NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose and treat illnesses such as HIV disease and other sexually transmitted diseases, tuberculosis, malaria, asthma and allergies. NIH is an agency of the United States Department of Health and Human Services.

Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at

NIH/National Institute of Allergy and Infectious Diseases

Related Genome Articles from Brightsurf:

Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.

Breakthrough in genome visualization
Kadir Dede and Dr. Enno Ohlebusch at Ulm University in Germany have devised a method for constructing pan-genome subgraphs at different granularities without having to wait hours and days on end for the software to process the entire genome.

Sturgeon genome sequenced
Sturgeons lived on earth already 300 million years ago and yet their external appearance seems to have undergone very little change.

A sea monster's genome
The giant squid is an elusive giant, but its secrets are about to be revealed.

Deciphering the walnut genome
New research could provide a major boost to the state's growing $1.6 billion walnut industry by making it easier to breed walnut trees better equipped to combat the soil-borne pathogens that now plague many of California's 4,800 growers.

Illuminating the genome
Development of a new molecular visualisation method, RNA-guided endonuclease -- in situ labelling (RGEN-ISL) for the CRISPR/Cas9-mediated labelling of genomic sequences in nuclei and chromosomes.

A genome under influence
References form the basis of our comprehension of the world: they enable us to measure the height of our children or the efficiency of a drug.

How a virus destabilizes the genome
New insights into how Kaposi's sarcoma-associated herpesvirus (KSHV) induces genome instability and promotes cell proliferation could lead to the development of novel antiviral therapies for KSHV-associated cancers, according to a study published Sept.

Better genome editing
Reich Group researchers develop a more efficient and precise method of in-cell genome editing.

Unlocking the genome
A team led by Prof. Stein Aerts (VIB-KU Leuven) uncovers how access to relevant DNA regions is orchestrated in epithelial cells.

Read More: Genome News and Genome Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to