New gonorrhea treatment targets enzyme needed for respiration

June 26, 2017
Credit: CDC

Researchers have identified a possible new treatment for gonorrhea, using a peptide that thwarts the infection-causing bacterium by interfering with an enzyme the microbe needs to respirate.

The findings are especially important since Neisseria gonorrhoeae is considered a "superbug" due to its resistance to all classes of antibiotics available for treating infections.

Gonorrhea, a whose numbers grow by 78 million new cases worldwide each year, is highly damaging to reproductive and neonatal health if untreated or improperly treated.

It can lead to endometritis, pelvic inflammatory disease, ectopic pregnancy, epididymitis and infertility. And babies born to infected mothers are at increased risk of blindness.

"The infections very often are silent," said Oregon State University researcher Aleksandra Sikora. "Up to 50 percent of infected women don't have symptoms, but those asymptomatic cases can still lead to some very severe consequences for the patient's reproductive health, miscarriage or premature delivery."

The need for better antibiotic therapy, and a vaccine, is pressing. N. gonorrhoeae strains resistant to the last effective treatment options have emerged, and failures in treatment are occurring.

Researchers led by Sikora, an associate professor in the OSU College of Pharmacy, have identified a new therapy target, an enzyme known as AniA. The need the surface-exposed enzyme to respirate without oxygen, or anaerobically, which is their preferred method of respiration in the biofilms of the genitourinary tract.

A biofilm is a group of one or more types of microorganisms that grow on a wet surface, such as dental plaque on teeth.

Sikora and her team identified a peptide - multiple amino acids linked in a chain - that inhibits the AniA enzyme's nitrite reductase activity. That in turn damages the bacteria's ability to grow in the oxygen-poor biofilm environment.

"Bacteria in biofilms display increased resistance to antimicrobials," Sikora said. "The enzyme is only necessary for cell viability when these bacteria grow under anaerobic conditions, including when they grow in the biofilm. Most antibiotics target essential cell functions; this one doesn't. It's only at a certain stage of growth that the bacteria are affected, which means the development of resistance won't be as fast."

Through a technique known as biopanning, OSU scientists and collaborators at the University of Kentucky found 29 unique that bound with the targeted enzyme. One of them, C7-3, was identified as most promising for inhibiting the protein's interaction with nitrite, necessary for anaerobic respiration.

"Imagine this research approach as having a pond with a lot of fish, and you're using the protein as the bait," Sikora said. "The peptides bind with the protein, and you go through multiple rounds to identify the peptides that have the strongest binding ability. You start with a billion peptides and end up with one that strongly inhibits the and ultimately kills the bacteria."

Findings were recently published in Antimicrobial Agents and Chemotherapy, and Sikora has applied for a provisional patent.

Explore further: Proteins discovered in gonorrhea may offer new approach to treatment

More information: Aleksandra E. Sikora et al, Peptide inhibitors targeting the Neisseria gonorrhoeae pivotal anaerobic respiration factor AniA, Antimicrobial Agents and Chemotherapy (2017). DOI: 10.1128/AAC.00186-17

Related Stories

Proteins discovered in gonorrhea may offer new approach to treatment

March 31, 2014
Researchers at Oregon State University have discovered novel proteins in, or on the surface of the bacteria that causes gonorrhea, which offer a promising new avenue of attack against a venereal disease that is showing increased ...

Blocking yeast-bacteria interaction may prevent severe biofilms that cause childhood tooth decay

June 20, 2017
Though most tooth decay can be blamed on bacteria, such as Streptococcus mutans, the fungus Candida albicans may be a joint culprit in an alarmingly common form of severe tooth decay affecting toddlers known as early childhood ...

Plant-made antimicrobial peptide targets dental plaque and gum tissues

September 23, 2016
Protein drugs, which derive from biological sources, represent some of the most important and effective biopharmaceuticals on the market. Some, like insulin, have been used for decades, while many more based on cloned genes ...

Recommended for you

Drug found that induces apoptosis in myofibroblasts reducing fibrosis in scleroderma

December 15, 2017
(Medical Xpress)—An international team of researchers has found that the drug navitoclax can induce apoptosis (self-destruction) in myofibroblasts in mice, reducing the spread of fibrosis in scleroderma. In their paper ...

How defeating THOR could bring a hammer down on cancer

December 14, 2017
It turns out Thor, the Norse god of thunder and the Marvel superhero, has special powers when it comes to cancer too.

Researchers track muscle stem cell dynamics in response to injury and aging

December 14, 2017
A new study led by researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP) describes the biology behind why muscle stem cells respond differently to aging or injury. The findings, published in Cell Stem Cell, ...

'Human chronobiome' study informs timing of drug delivery, precision medicine approaches

December 13, 2017
Symptoms and efficacy of medications—and indeed, many aspects of the human body itself—vary by time of day. Physicians tell patients to take their statins at bedtime because the related liver enzymes are more active during ...

Study confirms link between the number of older brothers and increased odds of being homosexual

December 12, 2017
Groundbreaking research led by a team from Brock University has further confirmed that sexual orientation for men is likely determined in the womb.

Potassium is critical to circadian rhythms in human red blood cells

December 12, 2017
An innovative new study from the University of Surrey and Cambridge's MRC Laboratory of Molecular Biology, published in the prestigious journal Nature Communications, has uncovered the secrets of the circadian rhythms in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.