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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Oropharyngeal gonorrhoea detection using mouthwash overtime (OMEGA3)
Scientific title
Investigating the impact of zero alcohol mouthwash on the detection rates of oropharyngeal gonorrhoea in gonorrhoea-positive adults
Secondary ID [1] 304438 0
Universal Trial Number (UTN)
Trial acronym
Linked study record
This study is developed after the completion of the OMEGA1 (ACTRN12616000247471) and OMEGA2 (ACTRN12618001380280) trials

Health condition
Health condition(s) or problem(s) studied:
Gonorrhoea 322264 0
Condition category
Condition code
Infection 319947 319947 0 0
Sexually transmitted infections

Study type
Description of intervention(s) / exposure
The intervention is Listerine® Zero mouthwash.
At the commencement of the study (i.e. before receiving the mouthwash intervention, t=0), the research nurse will take two throat swabs (covering the tonsillar fossae and posterior pharyngeal wall) at baseline before they receive the mouthwash intervention. Participants will be asked to provide a saliva sample with the instruction provided by the research nurse.

After collecting the throat swabs and saliva samples at baseline (t=0), participants will be instructed to use the allocated mouthwash by rinsing and gargling 10mls of the mouthwash into the back of their throat for 30 seconds (rinse for 15 seconds then gargle for 15 seconds) and then to discard the mouthwash. They will then be instructed to use the spray bottle provided to spray the mouthwash 15 times to the back of their throat and spitting the excess. The same composition of mouthwash will be used for rinsing/gargling as well as spraying with no alteration. Participants will be asked to use the mouthwash once at t=0, no mouthwash will be used after this time point. Participants will be supervised by a research nurse when using the mouthwash. The mouthwash intervention will be administered by the research nurse.

After the mouthwash regime has been completed, the research nurse will set a timer for five minutes (t=5). At five minutes the research nurse will then take two throat swabs and a saliva sample. This process will be followed the same at time points of 30 minutes (t=30), 60 minutes (t=60), and 120 minutes (t=120).

Composition of Listerine® Zero mouthwash: Water, Sorbitol, Propylene Glycol, Sodium Lauryl Sulfate, Poloxamer 407, Eucalyptol, Benzoic Acid, Sodium Benzoate, Methyl Salicylate, Thymol, Sodium Saccharin, Menthol, Sodium Fluoride, Flavour, Sucralose, CI 42053.
Intervention code [1] 320793 0
Intervention code [2] 321018 0
Treatment: Other
Comparator / control treatment
Participants who are allocated to the control group will not receive any mouthwash and they will only have the specified sample collection taken at the specified times.
Control group

Primary outcome [1] 327823 0
The detection of Neisseria gonorrhoeae by throat swab over the study time points assessed by culture.
Timepoint [1] 327823 0
At 0, 5, 30, 60, and 120 minutes after randomisation.
Primary outcome [2] 328102 0
The bacterial load of Neisseria gonorrhoeae by throat swab over the study time points assessed by PCR.
Timepoint [2] 328102 0
At 0, 5, 30, 60, and 120 minutes after randomisation.
Secondary outcome [1] 396704 0
The viability of Neisseria gonorrhoeae by throat swab over the study time points assessed by Insignia Viability Assay.
Timepoint [1] 396704 0
At 0, 5, 30, 60, and 120 minutes after randomisation.
Secondary outcome [2] 397635 0
The microbial composition of the specimens by throat swab over the study time points using 16S rRNA gene sequencing.
Timepoint [2] 397635 0
At 0, 5, 30, 60, and 120 minutes after randomisation.
Secondary outcome [3] 398311 0
The detection of Neisseria gonorrhoeae by saliva over the study time points assessed by culture.
Timepoint [3] 398311 0
At 0, 5, 30, 60, and 120 minutes after randomisation.

Key inclusion criteria
1. Individuals that are 18 years or older; and
2. Have a positive test result for oropharyngeal gonorrhoea by NAAT and return to MSHC for treatment within 10 days since screening; and
3. Provide written and informed consent; and
4. Have sufficient English language proficiency to understand the study requirements; and
5. Willing to comply with all requirements of the study.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Individuals who attend for treatment of oropharyngeal gonorrhoea after day 10 since day of screening, or
2. Any antibiotic use within 14 days prior to the day of enrolment; or
3. Self-report contraindications to mouthwash such as an allergy; or
4. Concurrent participation in other clinical trials; or
5. Individuals that do not have sufficient English language to provide informed consent; or
6. Any other reason/s in the opinion of the principal co-investigators that should exclude the individual from enrolling in the study.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
This is an open-labelled randomised controlled trial.
A staff member will place the allocated arms, 'nothing' (control) and Listerine® Zero (intervention) into a sealed and opaque envelope (one per envelope). These envelopes will be labelled as per the allocation sequence (this will also be the unique number of the study participant). After performing the screening and eligibility assessments, the research nurse will open a sealed, numbered, opaque envelope containing the allocation of the group. All sealed envelopes will be placed in a locked filing cabinet in a locked office, with access restricted to the study team, and sequentially taken for each new recruit. The research nurse will enrol the participants and assign them to any of the two groups after opening the envelope.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A computer-generated randomisation sequence with a block size of 4 or 6 will be generated using a statistical software (e.g. Stata) by an independent biostatistician/researcher and held by a staff member at MSHC who is not an investigator of this study until the end of the study. A 1:1 randomisation ratio to one of the two groups (with a block size of 4 or 6) will be used. Enrolled participants will be randomised to one of the two arms of the study in equal proportions.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Data will be analysed using a statistical package such as Stata.

The demographic characteristics and sexual risk behaviours will be compared between the control and intervention arm to ensure the balance in the baseline characteristics in both arms.

The primary analysis will be the growth and detection of Neisseria gonorrhoeae over time. We will compare the growth and detection between arms.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 19699 0
Melbourne Sexual Health Centre (MSHC) - Carlton
Recruitment postcode(s) [1] 34330 0
3053 - Carlton

Funding & Sponsors
Funding source category [1] 308797 0
Government body
Name [1] 308797 0
National Health and Medical Research Council (NHMRC)
Address [1] 308797 0
Level 1, 16 Marcus Clarke Street, Canberra, ACT 2601
Country [1] 308797 0
Primary sponsor type
Alfred Health
55 Commercial Rd, Melbourne VIC 3004
Secondary sponsor category [1] 309713 0
Name [1] 309713 0
Monash University
Address [1] 309713 0
Wellington Road, Clayton VIC 3800
Country [1] 309713 0
Other collaborator category [1] 281849 0
Name [1] 281849 0
The Peter Doherty Institute for Infection and Immunity
Address [1] 281849 0
792 Elizabeth Street, Melbourne, VIC 3000
Country [1] 281849 0

Ethics approval
Ethics application status
Ethics committee name [1] 308712 0
Alfred Health Ethics Committee
Ethics committee address [1] 308712 0
55 Commercial Rd, Melbourne VIC 3004
Ethics committee country [1] 308712 0
Date submitted for ethics approval [1] 308712 0
Approval date [1] 308712 0
Ethics approval number [1] 308712 0

Brief summary
The aim of this study is to examine whether Neisseria gonorrhoeae bacteria from the oropharynx will grow after using a mouthwash over a two-hour time period.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 111642 0
A/Prof Eric Chow
Address 111642 0
Melbourne Sexual Health Centre
580 Swanston Street, Carlton, VIC 3053
Country 111642 0
Phone 111642 0
Fax 111642 0
Email 111642 0
Contact person for public queries
Name 111643 0
Ms Kate Maddaford
Address 111643 0
Melbourne Sexual Health Centre
580 Swanston Street, Carlton, VIC 3053
Country 111643 0
Phone 111643 0
Fax 111643 0
Email 111643 0
Contact person for scientific queries
Name 111644 0
A/Prof Eric Chow
Address 111644 0
Melbourne Sexual Health Centre
580 Swanston Street, Carlton, VIC 3053
Country 111644 0
Phone 111644 0
Fax 111644 0
Email 111644 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
This is not covered under the current ethics approval.
What supporting documents are/will be available?
No other documents available
Summary results
No Results