Saturday, April 08, 2023

21st CENTURY ALCHEMY
Gold-based antibiotics could be key to fighting superbugs, research suggests
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New research that will be presented next week at a conference in Copenhagen suggests that gold-based antibiotics could be the key to fighting so-called drug-resistant superbugs. 
Photo by Petr Kratochvil/Public Domain Pictures

April 7 (UPI) -- For years, scientists have searched for a silver bullet to treat multidrug-resistant superbugs. Now, they may have found the solution in another precious metal: gold.

Several gold-based compounds have shown efficacy against hard-to-treat bacteria, according to new research to be presented at the European Congress of Clinical Microbiology and Infectious Diseases in Copenhagen, Denmark next week.

In a paper prepared for the conference, researchers said they found that gold-based antibiotics showed "great potential," especially against diseases that have proven resistant to other drugs.

Sara Soto Gonzalez, of the Barcelona Institute for Global Health in Barcelona, Spain, and fellow researchers studied the activity of 19 gold compounds against a range of multidrug-resistant bacteria isolated from patients.


Those bacteria studied included Methicillin-resistant Staphylococcus aureus, or MRSA; Staphylococcus epidermidis; pseudomonas aeruginosa; stenotrophomonasmaltophilia; acinetobacter baumannii; and pneumonia.

Scientists found that 16 of the 19 gold compounds were highly effective against MRSA and S. epidermis, and 16 were effective against the other bacteria, all of which are gram-negative. Researchers said that "gram negative" bacteria have a greater resistance to antibiotics, and they need new treatments.

Overall, all 19 compounds tested were effective against at least one of the hard-to-treat bacterium and some were effective against several.

"It is particularly exciting to see that some of the gold complexes were effective against MRSA and multidrug-resistant A. baumannii, as there are two biggest causes of hospital-acquired infections," Soto Gonzalez said.

"The type of gold complexes we studied, known as gold (III) complexes, are relatively straightforward and inexpensive to make. They can also be easily modified and so provide a vast amount of scope for drug development."

Drug-resistant infections kill roughly 700,000 people annually around the world. The World Health Organization classifies antibiotic resistance as one of the greatest public health threats facing humanity.



The Centers for Disease Control and Prevent said that such antimicrobial resistance happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them, making them almost impossible to treat.

Gold is known to have antibacterial properties, making gold metalloantibiotics -- compounds with a gold ion at their core -- one of the most promising new approaches.

"Gold complexes use a variety of techniques to kill bacteria," Soto Gonzalez said. "They stop enzymes from working, disrupt the function of the bacterial membrane and damage DNA.

"With research on other types of gold metalloantibiotics also providing promising results, the future is bright for gold-based antibiotics."

Future is bright for gold-based antibiotics


Reports and Proceedings

EUROPEAN SOCIETY OF CLINICAL MICROBIOLOGY AND INFECTIOUS DISEASES

New research being presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Copenhagen, Denmark, (15-18 April) has identified several gold-based compounds with the potential to treat multidrug-resistant “superbugs”.

With all 19 compounds tested effective against at least one hard-to-treat bacterium and some effective against several, the Spanish researchers say that the gold-based drugs hold great potential as new antibiotics.

Drug-resistant infections kill an estimated 700,000 people a year globally and, with the figure projected to rise to 10 million by 2050 if no action is taken, the World Health Organisation (WHO) classes antibiotic resistance as one of the greatest public health threats facing humanity.

However, the development of new antibiotics has stalled and the few new antibiotics that are developed are mainly derivatives of existing treatments.

Gold is known to have antibacterial properties, making gold metalloantibiotics – compounds with a gold ion at their core – an exciting potential new approach.

To find out more, Dr Sara M. Soto González, of the Barcelona Institute for Global Health, Barcelona, Spain, and colleagues studied the activity of 19 gold complexes against a range of multidrug-resistant bacteria isolated from patients.

The complexes all belong to the same family but have slightly different structures.

The six bacteria studied were: Methicillin-resistant Staphylococcus aureus (MRSA, which causes skin and other infections), Staphylococcus epidermidis (which can cause catheter-associated infections), Pseudomonas aeruginosa (which causes infections including pneumonia), Stenotrophomonas maltophilia (pneumonia and other infections), Acinetobacter baumannii (blood and urinary tract infections and pneumonia) and Escherichia coli (blood and urinary tract infections and pneumonia).

All of the strains studied were multidrug-resistant. Four (S. aureusP. aeruginosaA. baumannii and E. coli) are on the World Health Organisation’s list of antibiotic resistant ‘priority pathogens’1 – meaning they are among the bacteria judged to pose the greatest risk to human health.  Multidrug-resistant S. maltophilia is increasingly being found in the lungs of people with cystic fibrosis.

In tests, 16/19 (84%) of the gold complexes were highly effective against MRSA and S. epidermis.

Another 16 of the complexes were effective against the other bacteria, all of which are gram negative. Gram negative bacteria have greater inbuilt resistance to antibiotics and the need for new treatments is particularly pressing.

Gold complexes use a variety of techniques to kill bacteria.  They stop enzymes from working, disrupt the function of the bacterial membrane and damage DNA. Crucially, this multimodal mechanism should prevent antimicrobial resistance from developing.

Dr Soto González concludes: “All of the gold compounds were effective against at least one of the bacterial species studied and some displayed potent activity against several multidrug-resistant bacteria.

“It is particularly exciting to see that some of the gold complexes were effective against MRSA and multidrug-resistant A. baumannii, as there are two biggest causes of hospital-acquired infections.

“The type of gold complexes we studied, known as gold (III) complexes, are relatively straightforward and inexpensive to make.  They can also be easily modified and so provide a vast amount of scope for drug development.

“With research on other types of gold metalloantibiotics also providing promising results, the future is bright for gold-based antibiotics.”

Dr Sara M. Soto González, Barcelona Institute for Global Health, Barcelona, Spain. M) +34 6555 11177 E) sara.soto@isglobal.org

Please note that Dr Soto González is travelling until April 14.  For urgent enquiries during that time, please contact co-author Raquel Soengas

Professor Raquel Soengas, University of Oviedo, Oviedo Spain. M):+34 6040 07552 E) rsoengas@uniovi.es

Alternative contact: Tony Kirby in the ECCMID Media Centre. T) +44 7834 385827 E) tony@tonykirby.com

Notes to editors:

References:

1. https://www.who.int/news/item/27-02-2017-who-publishes-list-of-bacteria-for-which-new-antibiotics-are-urgently-needed

The authors declare no conflicts of interest.

This press release is based on abstract 1079 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) annual meeting. The material has been peer reviewed by the congress selection committee. There is no full paper available at this stage.

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