Public health officials are often the first point of contact for people who think they might have a sexually transmitted infection (STI). But they do so much more than that. These lab medicine professionals, clinicians, and others are part of a world-wide effort to detect and track which STIs are circulating within a population, identify which strains are becoming drug resistant, and influence how physicians can best test, treat, and help their patients.
CLN spoke to Tabatha E. East, MBA, MLS(ASCP), assistant director of clinical and environmental microbiology in the division of laboratory services at the Tennessee Department of Health, about STI testing and surveillance in the state. The discussion also tackles how public health laboratory professionals help the local communities they serve while also playing a role in the global fight against antimicrobial resistance.
Have you observed an increase in STIs? What’s been surprising or unusual?
We’ve been seeing an increase in Hepatitis B, but we believe that likely is attributed to the updated Centers for Disease Control and Prevention (CDC) screening and testing recommendations.
In March of 2023, CDC updated their hepatitis B screening and testing recommendations to expand risk-based testing to include persons currently or formerly incarcerated in a jail, prison, or other detention setting; persons with a history of STIs or multiple sex partners; and persons with a history of hepatitis C virus infection.
We haven’t seen this yet in the numbers, but anecdotally we’re also observing an increase in syphilis—and it’s more than the ordinary, transient cases.
In some ways, I don’t know what is unusual anymore because during the pandemic, we saw a drastic decrease in STI testing. We’re working hard to learn what our new normal is as we start to see a rebound in testing volumes: Are these new cases or cases that have been there for a given period?
Have you implemented new strategies for increasing access to testing and connecting patients to care?
STI testing is available at local health departments and a subset of community-based organizations. Both insured and uninsured residents of Tennessee have access through local health departments. We also have a strong outreach program to our rural and underserved populations within the state.
We have 95 counties in Tennessee, and every county has a minimum of one health department. We have an extensive reach.
How is molecular testing helping to tackle the rise in STIs?
The main advantage of molecular testing is the speed at which labs can deliver results. On top of the sensitivity and the specificity, there are also differences in collection devices. Some organisms, like Neisseria gonorrhoeae, are not viable long outside the body, and with culture-based technologies, those organisms can die before the sample arrives at the laboratory.
But with the media solution used for molecular collection devices, it’s okay if organisms die. Since molecular platforms detect genetic material, the organism doesn’t have to be viable for diagnosis. This is hugely advantageous for rural areas. For certain specimen types and assays, samples can remain at room temperature for approximately a month.
For culture-based collections, by the time specimens are collected and returned to the laboratory, specimen integrity has been compromised—often rendering the test unusable.
What factors do you consider in whether molecular or other types of testing are most appropriate?
It depends on where the patient needs to be serviced. If we need to have that easier specimen transport, that would tend to make molecular testing the preferred option.
It’s true that molecular testing is also more expensive than culture-based testing. But even though that’s an expense we incur on the laboratory side, the fact that it offers a faster turnaround time— sometimes several days before they would have a culture result — makes patient impact huge.
In addition to what is being done on the laboratory side for identification and the clinician’s side for treatment, epidemiologists are playing a pivotal role in the containment of disease through data monitoring, contact tracing, and so much more.
How do you view multiplex testing of STIs versus single pathogen testing?
From a laboratory efficiency standpoint, it’s beneficial to have multiplex testing, especially for screening at-risk populations. On the other hand, because we do see patients with a previous positive status for one organism, it’s still useful to have the singleplex option.
For example, most assays have chlamydia and gonorrhea testing together as a multiplex test. But if a patient already had a positive chlamydia test, received antibiotics, and the clinician ordered testing again to make sure that the infection has cleared, there may not be a need a multiplex assay.
What is your approach on testing for unexpected STI pathogens based on symptoms and epidemiology of the local population?
We have performed prevalence studies here at the Tennessee Public Health Laboratory. There are some organisms—like Mycoplasma genitalium and Trichomonias vaginalis—which are not common STIs that the public knows of, and not commonly screened for, so they can go undiagnosed.
Due to how slow growing these pathogens are, we cannot allow patients to go undiagnosed and untreated for that long. For these pathogens, the introduction of nucleic acid amplification testing has been a game changer for turnaround times.
Since these organisms do not present like textbook infections or are asymptomatic, it is important to include them in routine screening of at-risk populations. While men typically present with symptomatic or asymptomatic urethritis, complications in women can be much more severe. Mycoplasma genitalium infections in women often are asymptomatic but can lead to pelvic inflammatory disease, spontaneous abortions, and infertility.
Furthermore, studies have shown co-infection of HIV and M. genitalium increase shedding of the HIV virus in patients not taking antiretroviral therapy (ART).
The caveat to adding unexpected or unanticipated STI pathogen testing is that we must ensure we are good stewards of laboratory resources.
Where do you see opportunities for more collaboration?
Here in Tennessee, we all work closely together and communicate often, including the STI program directors, epidemiologists, clinicians, nurses, and other providers. For example, if there is an emerging issue, we might call the team together and say, “what do you think about doing a pilot study to see if we do need to onboard this testing?” Right now, we have a couple of Trichomonas pilots so we can make solid, data-driven decisions.
Recently, Tennessee participated in a M. genitalium prevalence study with our state public health laboratory partners in the Southeast region. We were able to use the data from that study in cost expansion requests to legislators. All of us working together—and seeking out the best data—helps make those decisions.
How important is molecular testing in antimicrobial resistance surveillance and managing STIs?
We’re not yet performing molecular antimicrobial resistance testing (AMR) in our lab. There’s still a lot that’s being done through agar dilution or automated AST. I know it would be helpful for clinicians to have those AST results when they receive a a positive, and it’s also beneficial when patients have drug allergies.
Tennessee is one of seven CDC Antimicrobial Resistance Laboratory Networks (ARLN), testing current and emerging organism resistance. Part of ARLN is Gonococcal (GC) ARLN, where the state is one of four regional laboratories in the country. This program does extensive AMR work, specifically with Neisseria gonorrhoeae. So, if you’re hearing about super gonorrhea—yes, it is real.
We work with a lot of clinics across the country that send gonorrhea isolates to us to do drug susceptibility testing where we use the agar dilution method. While agar dilution is the gold standard for AMR, disk diffusion and Etest are also available. Commercial assays have yet to be deployed for molecular or automated AMR testing for gonorrhea.
How are you using these tests to detect drug-resistant strains and guide treatment?
We’re using them for both. They help us know the right treatment route and alert us to when we’re starting to see resistance and need to take other actions. As surveillance data has shown drug resistance in gonorrhea, the pathogen has received global recognition and overdue attention.
Jen A. Miller is a freelance journalist who lives in Audubon, New Jersey. Twitter: @byJenAMiller