, 2025-04-18 10:07:00
At European Society of Clinical Microbiology and Infectious Diseases Global 2025, held recently in Vienna, Austria, one of the oral sessions focused on key updates regarding sexually transmitted infections (STIs).
Among the presentations, two stood out due to their clinical relevance. The first, titled “Post-Exposure Prophylaxis with Doxycycline (doxy-PEP): Uses and Results in the Detroit Metropolitan Area,” was presented by Christen Arena from Henry Ford Hospital’s Department of Pharmacy in Detroit. The presentation highlighted data from the implementation of HIV PEP with the addition of doxycycline, a topic that has gained attention recently due to its proven effectiveness in reducing infections caused by other STIs, specifically syphilis, chlamydia, and gonorrhea. This experience is highly relevant in clarifying the role of this regimen, which is not yet included in clinical practice guidelines in Europe.
The program began in May 2023. A prescription module with predetermined guidelines and doses was created to facilitate prescribing by infectious disease doctors, primary care physicians, and nurse practitioners, who have prescribing authority in the United States. Patients are responsible for self-administering 200 mg doxycycline within 72 hours of engaging in high-risk oral, vaginal, or anal sex. According to the Centers for Disease Control and Prevention, the target population includes men who identify as gay, bisexual, other men who have sex with men, and transgender women with a history of at least one bacterial STI in the past 12 months. Currently, there is no recommendation for cisgender women, heterosexual men, or other queer individuals due to lack of evidence, and thus, this study does not address that question. For further insight, key clinical trials include IPERGAY (France, 2024), DoxyPEP (the United States, 2023), and ANRS 174 DOXYVAC (France, 2024).
The Detroit program found very few doxyPEP prescriptions — only about 7% of the 312 PEP prescriptions made during the study period were given to patients who met the criteria for candidates. Of those doxyPEP prescriptions, only one patient tested positive for syphilis. It appears that this regimen could be effective, but it is underutilized.
The second presentation of note was titled “Gonococcal Bacterial Load Measured by Ct (Cycle Threshold) in Urine Samples Correlates with Symptoms.” This study, presented by Guillaume Beraud, MD, PhD, professor of infectious diseases at the Orléans University Hospital, Orléans, France, addressed the challenge clinicians face when deciding whether to treat a gonococcal infection. While there is consensus that patients who are symptomatic should be treated, what about the more than 10% of patients who are asymptomatic?
The authors investigated whether bacterial load, measured by Ct from PCR testing of urine, could serve as a reliable proxy for patient infectivity and correlate with the presence of symptoms.
They recruited 301 men between 2019 and 2024 who tested positive for Neisseria gonorrhoeae in urine PCR tests and had not received antibiotics in the previous 7 days. They found that bacterial load measured by Ct did not correlate with baseline patient characteristics (sexual orientation, number of sexual partners, previous gonococcal infection history, etc.). However, patients who are asymptomatic (21% of the total) had higher Ct values, indicating a lower bacterial load. The role of bacterial load in transmission remains unclear, and it is not yet established whether a lower bacterial load implies lower infectivity, supporting the hypothesis that these patients may potentially be left untreated.
This story was translated from Univadis Spain using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.