Recurrent urinary tract infection (rUTI) is a common and difficult to treat problem with limited treatment option; postmenopausal women are disproportionately affected. The genitourinary syndrome of menopause (GSM) describes the broad spectrum of signs and symptoms caused by the loss of endogenous sex steroids. The combined effects of urogenital epithelial tissue thinning and changes to the vaginal and bladder microbiome can predispose to ascending UTIs. Recurrent UTIs is a component of GSM.

Intravaginal laser therapy has been shown to be safe and effective for the treatment of GSM, however, the role of laser for treatment of recurrent UTIs is unknown. We hypothesis that the incidence of UTI will be reduced as CO2 laser restores vaginal epithelium to a state similar to that of a pre-menopausal woman, preventing microtrauma, and increases Lactobacillus and normal flora (Athanasiou et al., 2016). Lactobacillus is considered the bacteria that helps keep the vagina healthy and infection free through its production of lactic acid which lowers vaginal pH, this more acidic environment may be protective from uropathogens.

We therefore aim to conduct a single-blinded, multi-centre, randomised controlled trial comparing the use of intravaginal CO2 laser therapy to sham in post-menopausal women with rUTIs and to determine the impact on the microbiome.

Urinary tract infections (UTIs) are the most common outpatient infection with a prevalence of 20% in women over 65, compared with 11% in the overall population (Chu and Lowder, 2018).

The genitourinary syndrome of menopause (GSM) is the accepted term used to describe the broad spectrum of genitourinary tract symptoms and signs caused by the loss of endogenous sex steroids that occurs at the time of and after the menopause. Global improvements in healthcare have resulted in an aging population. Today women are spending 40% of their lives in the postmenopausal state with 50-70% of postmenopausal women reporting symptomatic GSM. The combined effects of urogenital epithelial tissue thinning and changes to the vaginal and bladder microbiome can predispose to ascending UTIs. Recurrent UTIs is a component of GSM.

Current interventions for recurrent urinary tract infections in women include lifestyle and behavioural advice, complimentary therapies and antibiotics. These treatment regimens are not always effective or acceptable. Intravaginal Laser therapy is an alternative non-hormonal treatment of GSM as it stimulates tissue repair and restores normal vaginal function.

Currently intravaginal laser therapy has been shown to be safe and effective for the treatment of GSM, as described in a recent network analysis of 29 randomised controlled studies, incorporating 8311 patients (Li et al., 2021). Provisional results using FemTouch®, fractional CO2 laser, appear promising with 9/12 (75%) of post-menopausal women UTI free at 12 months follow-up (Yang and Foley). However, there is a scarcity of studies available looking at the impact of this novel technology for the treatment of recurrent UTIs.

The investigators aim to conduct a single-blinded, randomised controlled trial comparing the use of intravaginal CO2 laser therapy to sham in post-menopausal women with rUTIs and to determine the impact on the microbiome. The investigators hypothesise that this treatment will be effective in reducing the incidence of urinary tract infection as CO2 laser through a process of thermomodulation, simulates tissue repair by restoring vaginal epithelium to a state similar to that of a pre-menopausal woman. In addition, a study assessing the effect of micro-ablative functional CO2 laser reported an increase in Lactobacillus and normal flora (Athanasiou et al., 2016). Lactobacillus is considered the bacteria that helps keep the vagina healthy and infection free through its production of lactic acid which lowers the vaginal pH, this more acidic environment may be protective from uropathogens. The role and impact of Laser on other microbial communities is still not fully understood, this study aims to expand this knowledge base.

Recurrent UTIs is a common and difficult to treat problem with limited treatment options, this study endeavors to expand the knowledge pool and provide alternative non-pharmacological options using this novel technology.

Inclusion Criteria:

• Postmenopausal women
• History of recurrent UTI (Defined as women who have suffered at least three episodes of symptomatic UTI within the preceding 12 months or two episodes in the last six months, or at least one episode of UTI requiring hospitalisation, or if previously prescribed prophylactic antibiotics for UTI, have completed a 3-month washout period without antibiotic prophylaxis)
• Able to give informed consent for participation in the trial
• Able and willing to adhere to a 17-month study period

Exclusion Criteria:

• Not willing to abstain from vaginal intercourse for 48 hours following laser-therapy
• Use of vaginal hormonal therapy in the three months before study start
• History of a genital fistula, a thin recto-vaginal septum as determined by the investigator or history of a fourth-degree laceration during physical screening exam (e.g., deficient perineal body)
• Active sexually transmitted disease upon vaginal exam (as determined by the investigator) that precludes treatment or any other vaginal infection
• History of lichen sclerosis
• History of radiotherapy for cervical or uterine cancer
• A medical condition that may interfere with participants' compliance with the protocol
• Women with correctable urinary tract abnormalities that are considered to be contributory to the occurrence of rUTI
• Women taking Methenamine Hippurate and unable to undergo a three-month washout period
• Undiagnosed genital bleeding
• Women who self-catheterise, or have an indwelling/suprapubic catheter
• Unable to give informed consent

Will be available at request

Sham