Super wide spread despite antibiotics

Majority of disease transmissions „Super propagator“

21/10/2014

A minority of people, so-called „Super propagator“, They can also infect their fellow human beings with diseases, even though they themselves seem completely healthy. As a new study now shows, this is apparently not to be prevented by the treatment with antibiotics.

Antibiotic treatment does not stop spread of pathogens
There are people and animals that can spread pathogens even after antibiotic treatment. As a study on mice showed, these so-called super-worms („Super spreader“) the use of medication apparently better than a comparison group. The US researchers led by Denise M. Monack of Stanford University recently published their findings in the journal „Proceedings of the National Academy of Sciences“.

Minority disseminates majority of pathogens
Both in humans and in animals Superverbeiter occur. Again „mirror“ Food poisoning with salmonella and colibacteria has been reported „Super spreader“ returned to cattle herds. In addition, in recent years more and more studies have shown that a minority of super-wizards are responsible for the majority of disease transmissions. In general, the 80/20 rule of Mark Woolhouse is used, according to which 20 percent of infected carriers account for 80 percent of infections. So far, however, little was known about what distinguishes the Superverbreiter from other infected. Monack explained in a press release from her research organization: „Knowing how to quickly and easily identify Superspreaders could help to limit or even prevent epidemics.“

Immune system does not destroy bacteria
For their study, Stanford University physicians infected mice with Salmonella (Salmonella typhimurium) and then determined the level of fecal bacteria. It turned out that 30 percent of the animals belonged to the super-workers. These mice eliminated high levels of bacteria but had no symptoms, their immune system did not destroy the bacteria. They had a down regulated immune system and instead of fighting the bacteria, the super-workers lived with it. Both the super-workers and the other infected mice showed intestinal tract disorders after treatment with certain antibiotics. However, while the normally infected mice had increased bacterial excretion, inflammatory responses, and high morbidity, the super-wizards had no symptoms.

A weakened immune system helps super-wideners
In addition, it was observed that the mice that did not belong to the Superverbreitern lost on average 15 percent of their body weight, the superspreaders, however, only two percent. According to the scientists, this could be an indication that they also have a tolerance to the antibiotic-based intestinal damage and inflammatory reactions by virtue of their property as super-wideners. Here, too, their weakened immune system can help them. According to Monack, they have continued to be healthy enough to spread pathogens.

Unclear if results are transferable to humans
The administration of antibiotics has therefore achieved exactly the opposite of the desired effect in this case. „The Superverbreiter divulge after treatment with antibiotics less bacteria than the other mice. However, these are too weak to really spread the disease - unlike the superspreaders“, so Monack. The doctor further stated that it was not yet clear how the results could be transmitted to humans. It may also help in the development of therapies for chronic inflammatory bowel diseases such as Chron's disease, as it continues to explore how the immune system is attenuated by super-wizards.

Thousands of infections attributed to Chinese doctor
One of the examples showing the importance of researching the super-predators as a whole is the first global epidemic of the millennium: In 2003, a Chinese doctor infected about a dozen people with Severe Acute Respiratory Syndrome (Sars). Later, the World Health Organization (WHO) calculated that about half of the world's approximately 8,000 registered cases of viral disease were male. The other example that Monack refers to lags behind. Beginning of the 20th century was the so-called „Typhoid Mary“ („Typhoid Mary“) has been one of the most notorious super-wizards in the US. Immigrating from Ireland, Mary Mallon was the first person in the United States identified as a non-malignant carrier of typhus.

Identification only possible by stool examination
The woman excreted large amounts of the bacterium Salmonella typhi, but did not develop any symptoms herself. As a cook, she changed the households she worked for several times and infected more than 50 people with the infectious disease typhus. After Mallon started a new job, family members often became sick with fever and diarrhea. She was later forcibly quarantined and died of pneumonia at the age of 69. „Typhoid Mary“ shows for Monack how helpful fast detection of super-wizards would be for people working with food, for example. The current study results could give new hints here. An identification of Superverbreitern is currently possible only through a stool examination. „And this process is uncomfortable even in the case of livestock“, said Monack. (Ad)