Zeiss DSM 962 SEM
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Copyright: Darthmouth College Electron Microscope Facility / These images are in the public domain
The natural ability of bacteria to adapt to various environmental stimuli can also make them resistant to drugs that would kill or slow their growth. In an article published in PLoS Genetics, microbiologist Dr Salvador Almagro-Moreno uncovers the evolutionary origins of antimicrobial resistance (AMR) in bacteria. His studies on the cholera-causing bacterium Vibrio cholerae show that mutations in a bacterial membrane protein, OmpU, are linked to developing antimicrobial resistance.
These findings provide insight into deciphering what conditions must occur for infectious agents to become resistant.
Dr Almagro-Moreno studied genetic variants of a protein found in bacterial membranes called OmpU. Using computational and molecular approaches, his team found that several OmpU mutations in the cholera bacteria led to resistance to numerous antimicrobial agents. This resistance included antimicrobial peptides that act as defences in the human gut. The researchers found that other OmpU variants did not provide these properties, making the protein an ideal system for deciphering the specific processes that occur to make some bacteria resistant to antimicrobials.
By comparing resistant and antibiotic sensitive variants, the researchers were able to identify specific parts of OmpU associated with the emergence of antibiotic resistance. They also discovered that the genetic material encoding these variants, along with associated traits, can be passed between bacterial cells, increasing therisk of spreading AMR in populations under antibiotic pressure.
By understanding how mutations occur, researchers can better understand and develop therapeutics to combat resistant infections. Dr Almagro-Moreno is also looking at environmental factors such as pollution and warming of the oceans, as possible causes of resistant bacteria. “We are studying the genetic diversity of environmental populations, including coastal Florida isolates, to develop a new approach to understanding how antimicrobial resistance evolves,” he explained.
Understanding the bacteria that causes cholera, an acute diarrhoeal illness linked to infected water and foods, has global implications. The disease sickens up to 4 million people worldwide and severe cases can cause death within hours.
Source: University of Central Florida
