@article {HockingA26, author = {Jane Hocking}, title = {S16.1 Anatomical sites of infection {\textendash} biomedical considerations for STI prevention}, volume = {95}, number = {Suppl 1}, pages = {A26--A26}, year = {2019}, doi = {10.1136/sextrans-2019-sti.73}, publisher = {The Medical Society for the Study of Venereal Disease}, abstract = {Extragenital (anorectal and oropharyngeal) sexually transmitted infections (STIs), particularly chlamydia and gonorrhoea, are highly prevalent among men who have sex with men (MSM), but are now an increasing concern among heterosexual men and women with calls for anorectal testing in women. Further, there is ongoing debate about the role of oropharyngeal STIs driving transmission, particularly among MSM and about anorectal chlamydia in women causing urogenital infection via auto-inoculation. These issues highlight that site of infection is an important issue. Treatment efficacy can vary considerably by site of infection {\textendash} for example, treatment efficacy is lower for oropharyngeal gonorrhoea and anorectal chlamydia with some treatments. Factors related to the pharmacokinetic properties of the drug can affect its efficacy at different anatomic sites including its tissue distribution, protein binding and half-life. Factors related to the individual including the pH of the local tissue environment, immune response, drug side-effects and sexual practices can affect treatment efficacy. Finally, factors related to the microorganism itself such as organism load and antimicrobial resistance can also impact on treatment efficacy. These factors should play a role in guiding treatment guidelines as it is possible that treatment regimens need to vary by site of infection. The use of mouthwash and doxycycline prophylaxis have been raised as potential biomedical interventions to reduce STI transmission, although ongoing concern about antimicrobial stewardship threatens the widespread use of doxycycline. We also need to understand the natural history of extra-genital STIs, particularly in women where the importance of anorectal infections and whether they play an important role in inoculating and causing persistent urogenital infection is not well understood. This presentation will discuss the importance of the site of infection particularly when considering treatment options and the possible role of biomedical interventions to prevent infection.Disclosure No significant relationships.}, issn = {1368-4973}, URL = {https://sti.bmj.com/content/95/Suppl_1/A26.2}, eprint = {https://sti.bmj.com/content/95/Suppl_1/A26.2.full.pdf}, journal = {Sexually Transmitted Infections} }