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Gonorrhea Becoming More Resistant to One Antibiotic: CDC

One of several antibiotic treatment options for the sexually transmitted disease gonorrhea seems to be losing its effectiveness, U.S. health officials warn in a new report.HealthDay news image

The U.S. Centers for Disease Control and Prevention’s latest tracking suggests that although resistance to the antibiotic treatment cefixime went down between 2011 and 2013, it started to creep back up in 2014.

The good news is that cefixime isn’t usually the first drug of choice for treating gonorrhea infections. The CDC’s most recent guidelines for gonorrhea treatment (issued in 2012) recommend only using cefixime when the preferred option — ceftriaxone-based combination therapy — isn’t available. And the CDC’s new report doesn’t indicate any recent waning in the effectiveness of that combination therapy.

Still, indications of antibiotic resistance among any gonorrhea treatment is considered troubling, the study authors said.

“It is essential to continue monitoring antimicrobial susceptibility and track patterns of resistance among the antibiotics currently used to treat gonorrhea,” said study lead author Dr. Robert Kirkcaldy, an epidemiologist in the CDC’s division of STD prevention in Atlanta.

“Recent increases in cefixime resistance show our work is far from over,” he said.

The study findings are published as a research letter in the Nov. 3 issue of the Journal of the American Medical Association.

The CDC noted that gonorrhea is spread during unprotected vaginal, anal or oral sex. The sexually transmitted infection is particularly common among youth and young adults between the ages of 15 and 24.

Many people have no symptoms when infected. When symptoms do occur, they may include a painful or burning sensation when urinating; painful, swollen testicles and discolored discharge from the penis among men. In women, symptoms may include increased vaginal discharge and vaginal bleeding between periods. Rectal infections may spark soreness, itching, bleeding, discharge, and painful bowel movements, the CDC said.

If gonorrhea goes untreated, “serious health complications” can result, Kirkcaldy said. Those can include chronic pelvic pain, infertility and life-threatening ectopic pregnancy — an abnormal pregnancy that occurs outside of the uterus. In rare cases, gonorrhea can spread to your blood or joints, causing a potentially life-threatening infection, the CDC warned.

But when identified, antibiotics can provide an effective cure for those with gonorrhea.

The new CDC study looked at treatment outcomes among male gonorrhea patients who had been treated at public clinics across the United States between 2006 and 2014.

More than 51,000 samples were gathered across 34 cities. About one-third were collected in the western United States and one-third collected in the South. A little more than a quarter of the samples were drawn from men who either identified as gay or bisexual, the study said.

The investigators found that the CDC’s 2012 shift away from recommending cefixime and toward ceftriaxone-based combination therapy had a profound impact: while the combination therapy had been given to less than 9 percent of the patients in 2006, that figure shot up to nearly 97 percent by 2014.

Alongside that shift, the team found that cefixime-resistance went up from 0.1 percent in 2006 to 1.4 percent in 2011, and then back down to 0.4 percent in 2013. But by 2014 resistance trended upward to 0.8 percent, the research revealed.

What does this mean? “Trends of cefixime susceptibility have historically been a precursor to trends in ceftriaxone,” said Kirkcaldy. “So it’s important to continue monitoring cefixime to be able to anticipate what might happen with other drugs in the future.”

Dr. Kirsten Bibbins-Domingo, co-vice chair of the U.S. Preventive Services Task Force in Rockville, Md., emphasized the importance of routine screening.

“The task force recommends screening for gonorrhea in sexually active women age 24 years or younger, and in older women who are at increased risk for infection,” she said.

The task force doesn’t advocate for or against screening for men, saying more research is needed to prove effectiveness. However, Kirkcaldy said that the “CDC recommends an annual gonorrhea screening for high-risk sexually active women and for sexually active gay, bisexual, and other men who have sex with men.”


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First test to predict Alzheimer’s years in advance

The death of nerve cells makes the brains of people with Alzheimer's disease (left) smaller than those of people showing no signs of dementia (right) <i>(Image: Pasieka/Science Photo Library)</i>

The death of nerve cells makes the brains of people with Alzheimer’s disease (left) smaller than those of people showing no signs of dementia (right) 

The world’s first blood test to predict Alzheimer’s disease before symptoms occur has been developed. The test identifies 10 chemicals in the blood associated with the disease two to three years before symptoms start, but it might be able to predict Alzheimer’s decades earlier.

Globally, 35 million people are living with Alzheimer’s. It is characterised by a toxic build up of amyloid and tau proteins in the brain, which destroys the neurons. Several blood tests can diagnose the disease, but until now, none has had the sensitivity to predict its onset.

Howard Federoff at Georgetown University in Washington DC and his colleagues studied 525 people aged 70 and over for five years. The group showed no signs of mental impairment at the start of the study. Each year, the team performed a detailed cognitive examination and took blood samples from all the participants. During this time, 28 people developed Alzheimer’s or mild cognitive impairment, thought to be the earliest noticeable sign of dementia, including Alzheimer’s disease.

An analysis of the participants’ blood highlighted 10 metabolites that were depleted in those with mild cognitive impairment who went on to get Alzheimer’s compared with those who didn’t. In subsequent trials, the team showed these chemicals could predict who would go on to get Alzheimer’s within the next three years with up to 96 per cent accuracy.

Decades of warning?

The 10 metabolites play a key role in supporting cell membranes, maintaining neurons or sustaining energy processes. “We think the decrease in these chemicals reflects the breakdown of neural populations in the brain,” says team member Mark Mapstone at the University of Rochester Medical Center in New York.

Once verified in a larger group, the test should provide a cheap and quick way of predicting Alzheimer’s. Mapstone says that it may even be able to predict the disease much earlier, because the brain changes associated with Alzheimer’s begin many years before symptoms occur. “These metabolic changes might occur 10 or 20 years earlier – that would give us a real head start on predicting the disease,” he says.

The team is hoping to investigate this by looking back at other dementia studies in which blood has been taken over decades and seeing whether the chemical changes can be detected that early, says Federoff.

The group also analysed the full genome sequence of all of the participants in the study. That work has yet to be published, but Federoff says the changes in genes over the five years of the study are even more powerful than the metabolites at predicting who will develop dementia. “The gene changes are linked to the metabolite changes, so we’re hoping to put all this together to provide a more complete description of the underlying pathology of the disease,” he says. “What’s most exciting is that we know the function of all the affected genes so if we can intercept these changes, they might make good candidates for new drugs.”

Knowledge is power

But with no treatments available, would anyone want to take these tests?

Mapstone says yes. “In my experience, the majority of people are very interested to know whether they will get Alzheimer’s. They believe that knowledge is power – particularly when it comes to your own health. We may not have any therapy yet but there are things we can do – we can get our financial and legal affairs in order, plan for future care, and inform family members.”

If the test could predict the disease 20 years before symptoms appear, the implications are huge, he says. “Imagine what you would do in your early 40s to slow the onset of the disease. You could eat the right foodsavoid head trauma or do more exercise.”

“In the short term, I think some people would want to know and some wouldn’t,” says Tracy Young-Pearse, a neurologist at Harvard Medical School. However, if treatments are developed that are only effective before neurons have started dying in large numbers, then it will be an easy decision to choose to take the blood test, she says.

Meanwhile, the new test will be valuable for drug discovery efforts, she says. Years of failed drugs trials have shown that you have to catch the disease early to have any influence.

Three studies starting this year hope to do just that. One will test anti-amyloid drugs on healthy people with a rare mutation that gives them early onset Alzheimer’s by age 45 (see “Testing a drug for the memory curse“).

The second will take advantage of a chemical developed last year that can be injected into the body and which accumulates in tau tangles. It will allow researchers to track the progression of tau in the living brain.

A third trial will investigate whether anti-amyloid drugs can prevent Alzheimer’s in older people who don’t yet have memory problems but do have amyloid building up in their brain.

“If an even earlier pre-clinical population could be identified with this blood test, it could be game changing,” says Young-Pearse.

Journal reference: Nature Medicine, DOI: 10.1038/nm.3466