The proposed study will build on the NIH/NIDA funded mSTUDY (U01 DA036267 PIs Gorbach and
Shoptaw), which is a longitudinal study designed to assess the impact of substance use
and HIV on minority MSM. Participants in the proposed study will be those enrolled in the
mSTUDY and the objectives of this study are to measure the preliminary efficacy and
acceptability of antibacterial mouthwash use for the prevention of pharyngeal gonorrhea
among a cohort of high risk HIV-negative and HIV-positive MSM. In order to achieve this
goal the investigators propose to conduct a double-blind, randomized, crossover trial of
daily antibacterial mouthwash use as compared to a placebo mouthwash among mSTUDY
participants at high risk for pharyngeal gonorrhea (i.e. previously diagnosed with
pharyngeal gonorrhea). Participants will be followed for a total of 24 weeks, with each
participant receiving 12-weeks of antibacterial mouthwash and 12-weeks of placebo
mouthwash.
After providing written informed consent, participants will complete a computer-based
questionnaire, provide biological specimen, and will be randomly allocated to their study
group. The study survey will include questions that are collected as part of mSTUDY as
well as questions relevant to the proposed study. Following the questionnaire,
participants will provide a bio-specimen for STI testing including: (1) urine, for
chlamydia and gonorrhea testing; (2) rectal and pharyngeal swabs for gonorrhea and
chlamydia testing; and (3) blood, which is used for syphilis and HIV testing, and HIV-1
RNA levels (for HIV-positive).
Participants will be randomly allocated to either first receive a 12-week antibacterial
mouthwash followed by 12-weeks of placebo mouthwash or start with 12-weeks of placebo
mouthwash and crossover to 12-weeks of antibacterial mouthwash. The antibacterial
mouthwash and placebo are commercially available products (Cool Mint Listerine®
Antiseptic mouthwash and Biotene® Oral Rinse respectively) and are selected based on
evidence demonstrating inhibitory effects of the antibacterial mouthwash (Cool Mint
Listerine® Antiseptic mouthwash) against N. gonorrhoeae. In order to ensure concealment
of study allocation and to allow for blinding, the following procedures will be
instituted:
the investigators will generate a computerized randomization sequence (active
condition first, placebo second or placebo first, active condition second). The
randomization sequence will be linked to the study identification number and
maintained by study staff not involved in participant contact or data
management/analysis;
the mouthwash will be in bottles in such a way to ensure that the placebo and active
product have an identical look. While the products packaging will have a similar
look a label with the study ID will allow us to link the bottle to the content. At
the time of study enrollment, all participants will receive a 12-week supply of
mouthwash according to their randomized study group (antibacterial or placebo) and
will be instructed on how to rinse and gargle with the mouthwash on a daily basis.
When participants return for the 12-week visit, they will receive another 12-week supply,
which will be the crossover condition to what was assigned at baseline. Participants will
be instructed to stop using any other mouthwash they may have been using prior to study
enrollment. All participants will be asked to return to the study site for a 12-week
follow-up visit. This visit is a study specific visit and is the only visit of the three
study visits that does not overlap with an mSTUDY follow-up visit. Participants will be
asked to complete a computer-based survey to collect information comparable to what was
collected at baseline including information on sexual behaviors, substance use, and oral
hygiene practices. Additionally, participants will be asked to complete questions
regarding study mouthwash us including frequency and timing of mouthwash use (i.e.,
intervention fidelity) and acceptability of mouthwash. Pharyngeal swabs will be collected
in order to test for gonorrhea including nucleic acid amplification testing (NAAT) and
culture testing. All participants will be asked to return in 12-weeks (i.e., 24-weeks
from baseline) which will coincide with an mSTUDY visit and data collection procedures
from baseline will be repeated including laboratory testing for STIs and survey
administration.