How Chlamydia Evolves into New Strains

The bacteria that chlamydia transmission, the world's most common sexually transmitted disease, seems to be sneakier than once thought, as a new study suggests it frequently exchanges DNA between different strains to form entirely new strains.

Chlaymydia is caused by the bacteria Chlamydia trachomatis, and though its symptoms are often mild, the sexually transmitted disease can cause infertility in women and a discharge from the penis of an infected man. Chlamydia is the most common bacterial STD in the world, including in the U.S. where more than 1.3 million cases were reported in 2010.  About 100 million cases of Chlamydia are reported each year across the globe.

Scientists know there are two groups of Chlamydia strains, one that seems to infect the eyes and urinary-genital areas, and another set known to spread through the lymphatic system, which is important to the body's immune system. Currently, an epidemic of the lymphatic types is progressing in Europe and North America, particularly in men who have sex with men, the researchers note online today (March 11) in the journal Nature Genetics.

However, little is known about how these different strains evolve and emerge.

"Scientists recently discovered that if two Chlamydia strains co-infect the same person at the same time, they can swap DNA by a process called recombination," lead researcher Dr. Simon Harris, from the Wellcome Trust Sanger Institute, said in a statement.

To find out how widespread this swapping is, Harris and colleagues compared the genome sequences of 53 strains of C. trachomatis, which were isolated from epidemics that occurred between 1959 and 2009; the strains were meant to represent the diversity of Chlamydia seen in clinical settings. Results showed that even when the Chlamydia strains had infected different parts of the body, they could still swap DNA with each other, leading to new strains. [Quiz: Test Your STD Smarts]

Recombination "was originally thought only to affect a few 'hotspots' within the genome," Harris said. "We were very surprised to find recombination is far more widespread than previously thought."

The results have implications for how the STD is diagnosed. Currently, doctors use a test that returns a positive or negative for Chlamydia infections, without any information on the particular strain. That means doctors can't tell, say, if a person who tests positive again after being treated with antibiotics has picked up a second strain of Chlamydia or if their treatment has failed.

While antibiotic-resistant Chlamydia has not been seen in patients, it does occur in the lab. If it did occur in the general population, current tests would not detect it.

"Until now a person treated with antibiotics with a reoccurring infection of C. trachomatis was assumed to have been re-infected," study researcher Dr. Nicholas Thomson, also of the Wellcome Trust Sanger Institute, said in a statement. "The current gaps in our understanding of the population makeup of Chlamydia limit our ability to implement health policies, because we do not fully understand how Chlamydia spreads within our population."

The scientists are now working with hospitals to bring technologies for whole-genome sequencing into clinical settings.

Female Condom to Protect Against STD

chlamydia transmission A female condom developed by researchers not only provides contraception but also wards off sexually transmitted diseases (STDs).

Researchers at the University of Washington (UW) developed the condom from tiny microfibres through a method called 'electrospinning'. They are then designed to dissolve after use, either within minutes or over several days.

Not only would the condom block sperm, it could time-release a potent mix of anti-HIV drugs and hormonal contraceptives, the Daily Mail reported.

Kim Woodrow, assistant professor of bio-engineering at Washington, said: "Our dream is to create a product women can use to protect themselves from HIV infection and unintended pregnancy. We have the drugs to do that. It's really about delivering them in a way that makes them more potent, and allows a woman to want to use it."

Woodrow presented the idea, and co-authors Emily Krogstad and Cameron Ball, both first-year graduate students, agreed to pursue the project, at a meeting held last year.

Ball added: "This method allows controlled release of multiple compounds. We were able to tune the fibres to have different release properties."

One of the fabrics dissolves within minutes, offering users immediate protection, while another fabric dissolves gradually over a few days, providing an alternative to the birth-control pill, to provide contraception and protect against HIV.

Chlamydia Damages Sperm, Experts Found

chlamydia transmission, which is often known as the silent disease because it has few symptoms, reduces a man's ability to produce children, they found.

 
Research has found Chlamydia damages sperm
 The disease, which is still on the rise in the UK, is more well known for making women infertile if left untreated.

But now researchers, led by Dr Jose Fernandez from Canalejo University Hospital in La Coruna, Spain, have discovered how chlamydia also affects men.

They looked at the damaged sperm of 143 men from infertile couples and compared it with sperm from 50 fertile men.

The infertile men had chlamydia and another common urinary tract infection called Mycoplasma.

The level of damage - or DNA fragmentation - in the infertile men's sperm was more than three times higher than in healthy men.

The concentration of their sperm, its ability to swim quickly and defects in the shape of it were also poor when compared with the healthy volunteers.

The experts then treated 95 of the infertile men with antibiotics and found their DNA sperm damage improved an average of 36% after four months.

During that period, 13% of the couples got pregnant and, after the treatment was finished, 86% got pregnant.

The findings were released today at the American Society for Reproductive Medicine conference in Washington DC.

Figures published in July by the Health Protection Agency showed a 4% rise in chlamydia between 2005 and 2006, from 109,418 cases to 113,585.

Experts have been particularly concerned about rates of chlamydia among young people, with the NHS launching a national screening programme.

In 2006/07, 115,073 women under 25 were screened but experts are urging more young men to get tested, with only 31,126 screened during the same period.

Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield and Secretary of the British Fertility Society, said more needed to be done to target the younger generation.

He said: "The message is that we might think of chlamydia as a disease that damages female fertility, but we need to think again.

"It does damage female fertility, but it appears to damage male fertility too.

"The thing that drives most men to sexual health clinics is symptoms, and chlamydia is often symptom-free.

"Chlamydia is getting out of control. We have got to encourage men as well as women to go for screening, but men are more reluctant to do this if they don't have symptoms.

"It is the 18 to 25 age group that is of most concern. There should be a page on Facebook you can log onto and sort screening out."

Dr Fernandez said more research was needed to follow up his study.

And he added: "We've developed a new technique that allows us to look at the extent of DNA fragmentation in sperm cells using a microscope. "The purpose of our work was to analyse if there's an increase in fragmentation of DNA with infection.

"It was found after four months of treatment there was a significant decrease in DNA damage that could improve pregnancy rates in these couples.

"Fertility clinics should check for these infections."

How Chlamydia Evolves into New Strains

The bacteria that chlamydia transmission, the world's most common sexually transmitted disease, seems to be sneakier than once thought, as a new study suggests it frequently exchanges DNA between different strains to form entirely new strains.

Chlaymydia is caused by the bacteria Chlamydia trachomatis, and though its symptoms are often mild, the sexually transmitted disease can cause infertility in women and a discharge from the penis of an infected man. Chlamydia is the most common bacterial STD in the world, including in the U.S. where more than 1.3 million cases were reported in 2010.  About 100 million cases of Chlamydia are reported each year across the globe.

Scientists know there are two groups of Chlamydia strains, one that seems to infect the eyes and urinary-genital areas, and another set known to spread through the lymphatic system, which is important to the body's immune system. Currently, an epidemic of the lymphatic types is progressing in Europe and North America, particularly in men who have sex with men, the researchers note online today (March 11) in the journal Nature Genetics.

However, little is known about how these different strains evolve and emerge.

"Scientists recently discovered that if two Chlamydia strains co-infect the same person at the same time, they can swap DNA by a process called recombination," lead researcher Dr. Simon Harris, from the Wellcome Trust Sanger Institute, said in a statement.

To find out how widespread this swapping is, Harris and colleagues compared the genome sequences of 53 strains of C. trachomatis, which were isolated from epidemics that occurred between 1959 and 2009; the strains were meant to represent the diversity of Chlamydia seen in clinical settings. Results showed that even when the Chlamydia strains had infected different parts of the body, they could still swap DNA with each other, leading to new strains. [Quiz: Test Your STD Smarts]

Recombination "was originally thought only to affect a few 'hotspots' within the genome," Harris said. "We were very surprised to find recombination is far more widespread than previously thought."

The results have implications for how the STD is diagnosed. Currently, doctors use a test that returns a positive or negative for Chlamydia infections, without any information on the particular strain. That means doctors can't tell, say, if a person who tests positive again after being treated with antibiotics has picked up a second strain of Chlamydia or if their treatment has failed.

While antibiotic-resistant Chlamydia has not been seen in patients, it does occur in the lab. If it did occur in the general population, current tests would not detect it.

"Until now a person treated with antibiotics with a reoccurring infection of C. trachomatis was assumed to have been re-infected," study researcher Dr. Nicholas Thomson, also of the Wellcome Trust Sanger Institute, said in a statement. "The current gaps in our understanding of the population makeup of Chlamydia limit our ability to implement health policies, because we do not fully understand how Chlamydia spreads within our population."

The scientists are now working with hospitals to bring technologies for whole-genome sequencing into clinical settings.