New class of antibiotics discovered in dirt

Posted Feb 15, 2018 by Tim Sandle
U.S scientists have discovered a new antibiotic family discovered from dirt (samples of soil). The discovery could represent a step forwards in the quest to find new types of antibiotics and antimicrobials.
Agar plates for culturing bacteria (Tim Sandle s laboratory  UK)
Agar plates for culturing bacteria (Tim Sandle's laboratory, UK)
The discovery of the new compounds comes from Rockefeller University and it is hoped that drug products can be developed that will combat the most resistant bacteria (which cannot be treated with most existing antimicrobials; bacteria that pose a risk to human health.
The search for new antibiotics is of importance to human health , given that infectious diseases remain a leading cause of death worldwide. Furthermore, in the absence of new therapies, mortality rates due to untreatable infections are predicted to rise.
Initial tests indicate that the compounds, termed malacidins (or metagenomic acidic lipopeptide antibiotic-cidins), can destroy several types of bacteria, including those resistant to most existing antibiotics, including Methicillin-resistant Staphylococcus aureus (MRSA). Malacidins are a class of chemicals made by non-pathogenic bacteria found in soil that can kill some Gram-positive type bacteria; included within this morphological group are some of the organisms that cause the more serious diseases, including those associated with hospital acquired infections.
The class malacidins are forms of macrocycle lipopeptides. They become active against certain bacteria after they bind to calcium. Following this the calcium-bound molecule then appears binds to lipid II, which a bacterial cell wall precursor molecule. This then triggers bacterial cell destruction, killing the target bacterium.
Speaking with BBC Science about the discovery, lead researcher Dr Sean Brady said: "It is impossible to say when, or even if, an early stage antibiotic discovery like the malacidins will proceed to the clinic. It is a long, arduous road from the initial discovery of an antibiotic to a clinically used entity."
The research paper discussing the discover is published in Nature Microbiology and it is called "Culture-independent discovery of the malacidins as calcium-dependent antibiotics with activity against multidrug-resistant Gram-positive pathogens."
In related antibiotics news, Digital Journal has reported that the major pharmaceutical firm Pfizer is to work closely with the Indian Council of Medical Research (ICMR) in order to help combat antimicrobial resistance in India. This includes establishing a center in New Delhi to develop research, which will be part-funded by Pfizer.