In a study of proteins historic in its scope, researchers at
Oregon State University have pushed closer both to a vaccine for gonorrhea and
toward understanding why the bacteria that cause the disease are so good at
fending off antimicrobial drugs.
The
findings, published in Molecular and Cellular Proteomics, are especially
important since the microbe, Neisseria gonorrhoeae, is considered a
"superbug" because of its resistance to all classes of antibiotics
available for treating infections.
Gonorrhea, a sexually transmitted disease that results in 78
million new cases worldwide each year, is highly damaging if untreated or
improperly treated.
It can lead to endometritis, pelvic inflammatory disease,
ectopic pregnancy, epididymitis and infertility.
Babies born to infected mothers are at increased risk of
blindness. Up to 50 percent of infected women don't show any symptoms, but
those asymptomatic cases can still lead to severe consequences for the
patient's reproductive health, miscarriage or premature delivery.
Aleksandra Sikora, a researcher with the OSU College of Pharmacy
and OHSU's Vaccine and Gene Therapy Institute, helped lead an international
collaboration that performed proteomic profiling on 15 gonococcal strains;
proteome refers to all of the proteins any given organism produces.
Among the isolates in the study were the reference strains
maintained by the World Health Organization that show all known profiles of
gonococcal antimicrobial resistance.
For each strain, researchers divided the proteins into those
found on the cell envelope and those in the cytoplasm. More than 1,600 proteins
-- 904 from the cell envelopes and 723 from the cytoplasm -- were found to be
common among the strains, and from those, nine new potential vaccine candidates
were identified.
A vaccine works by introducing an "invader" protein
known as an antigen that triggers the body's immune system and subsequently
helps it quickly recognize and attack the organism that produced the antigen.
Researchers also found six new proteins that were distinctively
expressed in all of the strains, suggesting they're markers for or play roles
in drug resistance and thus might be effective targets for new antimicrobials.
In addition, scientists looked at the connection between
bacterial phenotype -- the microbes' observable characteristics and behavior --
and the resistance signatures that studying the proteins revealed; they found
seven matching phenotype clusters between already-known signatures and the ones
uncovered by proteomic analysis.
See:
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology
