Biochemistry Research Finds Antibiotic Resistance Enzyme

Aminoglycosides are a class of antibiotics that doctors prescribe for serious or life-threatening infections. Biochemistry researchers found a mobile gene that is resistant to this class of antibiotics, which could put people at an unwanted risk.

Researchers at Emory University School of Medicine discovered more information about a mobile gene called NpmA that is resistant to aminoglycosides and has the potential to spead various types of bacteria. The gene was discovered a few years ago in a Japanese patient that was sick with E. coli.

Aminoglycoside antibiotics include streptomycin (tuberculosis), kanamycin, tobramycin (cystic fibrosis), gentamicin, and neomycin. They're only prescribed in dire (and infrequent) situations because they can be toxic to the kidneys and inner ear, but now that the threat to their effectiveness is uncovered, many are concerned.

Through the use of X-ray crystallography, the researchers found that NpmA imparts a tiny chemical change that makes the ribosome, and thus, the bacteria resistant to aminoglycosides effects. The ribosome's resistance is the key to the whole discovery because the antibiotics bind to the ribosomes in order to interfere with the bacteria's protein production. NpmA completely modifies the ribsome, making it resistant to the drug and enabling the bacteria's progression.

Additionally, NpmA recognizes structural features that are common to all bacterial ribosomes, meaning it could be effective in various forms of bacteria. The researchers only examined its presence in E. coli, where it was first discovered, because that was the extent of their knowledge. Their results were published in the PNAS Early Edition.

This poses yet another problem for the topic of antibiotic resistance. Although the antimicrobial agents are helpful, many of them have been around for a long time, allowing the infectious bacteria to adapt and overcome their effectiveness. Because this finding features the resistance of a higher-class antibiotic used to treat serious infections, drug makers might have to begin investing even more money into developments for newer antibiotics.

To read more about the Emory University School of Medicine research, visit this EurekAlert! news release.