Friday December 13, 2019

Novel Drug May Shorten Treatment Duration For Tuberculosis

Despite significant progress in combating tuberculosis, it remains the leading infectious cause of death worldwide, he said

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A new experimental antibiotic for tuberculosis (TB) has been shown to be more effective against TB than Isoniazid, a decades old drug which is currently one of the standard treatment for the disease, finds a study on mice.

The new drug, called AN12855, has several advantages over Isoniazid as Isoniazid requires conversion to its active form by a Mycobacterial enzyme, KatG, in order to kill the pathogen, which creates some problems.

In some M. tuberculosis, KatG is nonfunctional. That does not make M. tuberculosis any less pathogenic, but it prevents the drug from working. Consequently, this creates an easy avenue for the development of drug resistance.

In the study, the new drug showed a much lower tendency to develop resistance, and it remains in the tissues where the Mycobacterium tuberculosis bacteria reside for longer, killing them more effectively.

WHO will start working towards ending Tuberculosis
Dr. Simon Angelo (L) examines Iman Steven suffering from tuberculosis, held by her mother (R) at the hospital of Doctors Without Borders (MSF), June 15, 2016, at the Protection of Civilians (PoC) site in Malakal, South Sudan. VOA

The goal of TB drug development programmes is to develop universal treatment regimens that will shorten and simplify TB treatment in patients, which typically takes at least six months, and sometimes more than a year, said lead author Gregory T. Robertson, Assistant Professor at the Colorado State University in Fort Collins in the US.

For the study, the researchers used a new TB mouse model that develops these M. tuberculosis-containing granulomas to compare Isoniazid and AN12855.

Granuloma refers to a mass of granulation tissue, typically produced in response to infection, inflammation, or the presence of a foreign substance.

“We discovered that the drugs differed dramatically with respect to their abilities to kill the pathogen in highly diseased tissues,” said Robertson.

Tuberculosis
New TB drug may shorten treatment duration: Study. IANS

AN12855 proved more effective, “without selecting for appreciable drug resistance”, added Robertson in the study published in the journal Antimicrobial Agents and Chemotherapy.

Despite significant progress in combating tuberculosis, it remains the leading infectious cause of death worldwide, he said.

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“Multidrug resistance is a further challenge to the mission to control TB globally. Collectively, our group has pioneered the use of new TB mouse efficacy models to help advance innovative new therapies designed to shorten the length of TB treatment.” (IANS)

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Researchers Develop a New Vaccine to Stop Bovine TB

The Bacille Calmette Guerin (BCG) vaccine, which is currently used to protect humans against TB and is effective in cattle, is incompatible with the PPD test

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Bovine TB
This potentially allows farmers and veterinarians to protect their animals with the new BCG vaccine, whilst still maintaining a diagnostic test that will detect Bovine TB. Pixabay

Researchers have developed a novel vaccine and complementary skin test to protect cattle against bovine tuberculosis also known as Bovine TB.

The study, published in the journal Scientific Reports, revealed that the research team from University of Surrey created a vaccine that is compatible with a synthetic form of the tuberculin skin test(PPD), a legally required test used for the surveillance of TB in cattle throughout the UK.

“This new vaccine provides protection against bovine TB and will help in the fight against this deadly disease which infects over 50 million cattle worldwide and is economically devastating to farmers,” said study researcher Johnjoe McFadden

Bovine TB is an infectious disease in cattle affecting their lungs, and those that test positive for the disease are culled.

The Bacille Calmette Guerin (BCG) vaccine, which is currently used to protect humans against TB and is effective in cattle, is incompatible with the PPD test.

Bovine TB
Bovine TB is an infectious disease in cattle affecting their lungs, and those that test positive for the disease are culled. Wikimedia Commons

During this study, researchers sought to make a new BCG vaccine strain that lacks some of the proteins that are shared with the pathogen Mycobacterium bovis by identifying genes that contain encoded immunogenic proteins that could be removed from BCG without affecting its ability to work as a live vaccine.

To do this, a collection of BCG strains that had each lost a single gene were injected into cows and survival rates measured. This allowed the team to identify genes that could be removed without compromising the BCG vaccine’s effectiveness.

These dispensable genes encoding immunogenic proteins were then deleted from the BCG chromosome to make a BCG-minus strain.

The deleted immunogenic proteins were then used to develop a new synthetic skin test that, like PPD, will be positive for animals that have been exposed to TB but, unlike PPD, will be negative for animals that have been vaccinated with the BCG-minus strain.

The protective efficiency of the new strain was tested in guinea pigs.

Bovine TB
Researchers have developed a novel vaccine and complementary skin test to protect cattle against bovine tuberculosis also known as Bovine TB. Pixabay

It was found that TB-infected guinea pigs tested positive for the disease using the synthetic skin test whilst guinea pigs vaccinated with the BCG-minus strain did not.

So, unlike PPD, the new skin test also works in animals that are protected from TB by BCG-minus vaccination.

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This potentially allows farmers and veterinarians to protect their animals with the new BCG vaccine, whilst still maintaining a diagnostic test that will detect TB. (IANS)