NEW YORK (GenomeWeb) — In the hope of preventing gonorrhea from becoming the next antimicrobial-resistant "superbug," researchers at the University of California, Los Angeles have been awarded a two-year, $270,000 National Institutes of Health grant to validate a real-time PCR assay for drug resistance and incorporate it into routine gonorrhea testing.
Jeffery Klausner, a professor of medicine and public health at UCLA and a well-known public health researcher in the field of sexually transmitted infections, is spearheading the efforts based on a PCR assay he previously developed.
In 2013, the US Centers for Disease Control and Prevention "sounded the alarm" about the looming threat of a gonorrhea superbug in an article in New England Journal of Medicine, Klausner told PCR Insider in an interview this week. A report earlier this year in PLoS One speculated that the expanding use of nucleic acid diagnostic testing may inadvertently lead to over-prescribing of antibiotics, exacerbating the spread of antimicrobial-resistant gonorrhea.
Now, Klausner is working with the clinical laboratory at UCLA to verify an antimicrobial susceptibility test that he developed in 2007, he said. That test, published in the Journal of Molecular Diagnostics, is a real-time PCR assay for detecting mutations in the Ser91 codon of the gyrA gene of Neisseria gonorrhoeae in urine specimens, to determine the potential for fluoroquinolone resistance. If the verification process meets CLIA requirements, the lab would then be able to offer the test to physicians as part of routine gonorrhea testing.
Klausner said he believes the assay will prove accurate, since it did so in its original development. "We want to offer it, and then evaluate the impact on doctor's prescribing practices," he said. "Based on the test result, will doctors change how they treat gonorrhea? We need to understand what changes physician treatment behavior."
Gonorrhea is the second most frequent notifiable communicable disease in the US after chlamydia. In one recent case in Japan, antimicrobial-resistant gonorrhea required intravenous antibiotics and hospitalization, Klausner said.
"Right now we have to treat [gonorrhea] with two different antibiotics, which is unprecedented," he said. "For 75 years we have been treating it with one, and now we are on the verge of having no antibiotics to treat gonorrhea with, such that it would become untreatable."
The CDC estimates there are over 800,000 gonorrhea infections per year in the US. It is among the most common STDs, and rates have been increasing in the past few years.
"The bacteria has acquired resistance to nearly all of the antibiotics that have been used for treatment," Robert Kirkcaldy, a medical epidemiologist in CDC’s Division of STD Prevention told PCR Insider in an email this week.
Kirkcaldy affirmed that there is only one remaining therapy recommended by CDC, and "it is only a matter of time before gonorrhea gains resistance to this treatment," he said.
"With treatment options dwindling and the very real threat of untreatable gonorrhea on the horizon, it is critically important that we work to develop new, effective drug combinations and enhance our ability to monitor emerging drug resistance," Kirkcaldy said.
With this in mind, Kirkcaldy believes assays like Klausner's might hold a key to preventing the emergence of a new superbug.
A molecular test that could predict antimicrobial susceptibility of gonorrhea bacteria "could substantially bolster the ability of clinicians and the public health community to rapidly detect resistant strains and respond to the threat of gonococcal resistance," he said, adding, "the availability of such a test at the point of care may allow providers to avoid empiric therapy, and instead tailor the choice of antimicrobial treatment for individual patients; providers may [also] be able to utilize previously recommended antibiotics, thus expanding the treatment options available to patients."
Kirkcaldy said that because researchers first need to understand the validity of these tests and how providers will utilize them, "the research by Dr. Klausner is critically important."
Meanwhile, Klausner said that the test could ultimately be replicated and picked up by laboratories around the country. "I worked in that model in the past," he said. "I invented the use of a molecular test to diagnose STDs of the throat and the rectum, we went through the same process of verifying it in a laboratory in San Francisco, and over time it got disseminated and it is now routinely available across the US," he said.
That test is "not marketed or sold by a specific diagnostic test company," he said, "but every laboratory developed their own test," based on these studies.
Unfortunately, Klausner said, although there are over a half a million cases of gonorrhea in the US annually, "it is still not commercially viable for a company to invest in the development of its own PCR-resistance or susceptibility test, so depending on companies to address this important public health issue is not happening."
The work, however, is vitally important, he said. "I've been actively involved in public health as a health official for nearly 20 years ... We need to do this."