A Way Our of Our Antibiotic Crisis

July 24, 2015

By Medical Discovery News

A petri dish

Antibiotic resistance occurs when strains of bacteria that infect people – such as staph, tuberculosis, and gonorrhea – do not respond to antibiotic treatments. In America, 2 million people become infected with resistant bacteria every year and at least 23,000 die each year because of those infections. If nothing is done to stop or slow the resistance of bacteria to antibiotics, the World Health Organization (WHO) warns that we will find ourselves in a post-antibiotic world, in which minor injuries and common infections will be life-threatening once again.

The crisis arose primarily from three conditions. First, when people are given a weeks’ worth of antibiotics and stop taking them as soon as symptoms improve, they often expose the bacteria causing their infection to the medicine without killing it. This allows the bacteria to quickly mutate to further avoid the effects of the antibiotic. Second, antibiotics are over-prescribed. Most common illnesses like the cold, flu, sore throat, bronchitis, and ear infection are caused by viruses, not bacteria, so antibiotics are essentially useless against them. Yet they are prescribed 60-70 percent of the time for these infections. This once again provides bacteria in the body unnecessary contact with antibiotics. Third, tons of antibiotics are used every year in the agriculture industry. They are fed to livestock on a regular basis with feed to promote growth and theoretically for good health. But animals are also prone to bacterial infections, and now, to antibiotic-resistant bacteria, which spreads to humans who eat their meat or who eat crops that have been fertilized by the livestock. The good news is that the Food and Drug Administration (FDA) is working to focus antibiotic use on bacterial infections and regulate its use in livestock.

An easy solution to this problem might be to create new antibiotics, but it’s not that simple. It takes an average of 12 years and millions of dollars to research new antibiotics and make them available on the market, which is a huge investment considering they are normally only taken for up to 10 days. But there’s an even bigger challenge: microbiologists can only cultivate about 1 percent of all bacteria in the lab, including specimens that live in and on the human body. The ability to grow diverse bacteria is important because most antibiotics actually come from bacteria, produced as a defense against other microbes.

Slava Epstein, a professor of microbial ecology at Northeastern University, came up with an ingenious approach to solving this problem. He speculated that we are unable to grow these bacteria in the lab because we were not providing the essential nutrients they needed to grow. Working with soil bacteria, which are a huge source for developing antibiotics, he created the iChip. The iChip allows bacteria to grow directly in soil, which is their natural environment, while being monitored.

To date, about 24 potential antimicrobials have been identified from 50,000 bacteria that remain unable to grow in the lab. With possibly billions of bacteria left to grow and examine, the number of new drugs awaiting discovery is seemingly endless.

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New Weapons Against TB

Jan. 18, 2013

By Medical Discovery News

Tuberculosis (TB), the world’s No. 2 killer from a single infectious agent, has a knack for resisting antibiotics. Doctors discovered combining antibiotics had better results, until recent years when TB evolved beyond existing antibiotic cocktails. That may change with a new drug combination that seems to work. 

The new therapy couldn’t come at a better time. Even though TB had been well controlled, it began to make a dramatic comeback in the 1980s. TB, caused by a bacterium called Mycobacterium tuberculosis, infects one person in the world every second. It’s among the top three killers of women and left 10 million children orphaned in 2009.

TB is also the leading cause of death for people with HIV because their weaker immune systems make them vulnerable to the disease. The rise of global HIV infections is largely to blame for the reemergence of TB. Currently, an estimated 14 million people worldwide are co-infected with HIV and TB, and most of them will die without treatment.

TB’s resurgence is also due to drug resistance. To treat people with active, extensively drug resistant strains of TB, doctors prescribe a combination of four drugs: isoniazid, rifampin, pyrazinamide, and ethambutol. Yet in recent years completely drug resistant strains of TB have developed and pose a global threat.

TB is transmitted by inhaling the droplets of an infected person’s sneeze or cough, but also through ingestion. Most infections start in the lungs and initially have no symptoms or at worst feel like the flu. The immune system can wall off the bacteria in what is called a granuloma, a round structure with a core that encases the bacteria and infected cells. Nine out of 10 infections stop at this stage, but some people live with a latent infection for years.

In about 5 percent of cases, the latent TB bacteria reactivate after one to two years. The bacteria replicate rapidly and spread throughout the body. Signs and symptoms of active TB include long-lasting cough bringing up sputum and blood, unexplained weight loss, fatigue, fever, night sweats, chills, loss of appetite, pain with breathing or coughing, and chest pain. Though TB most often affects the lungs, it can also involve the genitourinary system, bones, joints, lymph nodes, and peritoneum.

If TB bacteria’s proliferation is not controlled by the immune system, a severe form of the disease called miliary TB develops. The bacteria eventually cause extensive and progressive damage to the structure of the lungs and ultimately death.

With the new drug combination, fewer people will suffer these ravaging consequences. One new cocktail is called PA-824 and consists of moxifloxacin, a relatively new antibiotic, and pyrazinamide, an older TB drug. The combination works faster than current therapies, and doesn’t seem to interact with HIV drugs.

At least three other drugs or combinations are in the testing phase, just in time to treat multiple-drug-resistant forms of this deadly disease. If effective, the drugs will help a global initiative to reverse the spread of TB by 2015.

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