CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

1287 Prevalence of Tetracycline-Resistant Gonorrhea in British Columbia’s HIV Treatment and PrEP Program Raquel M. Espinoza 1 , Paul Sereda 1 , K. Junine Toy 1 , Peter Phillips 1 , Victor Leung 2 , Rolando Barrios 1 , Julio S. G. Montaner 1 1 British Columbia Centre for Excellence in HIV/AIDS, Vancouver, Canada, 2 St Paul's Hospital, Vancouver, BC, Canada Background: British Columbia’s (BC) publicly-funded HIV treatment (HIV Tx) has been available since 1992, and HIV Pre-Exposure Prophylaxis (PrEP) for key populations since 2018. On 1-Dec-2023, a doxycycline for bacterial sexually transmitted infection (b-STI) initiative ( Doxy-P ) was launched among HIV Tx and PrEP clients, enrolling >3000 clients in 9 months. In light of increasing use of Doxy-P and treatment and its potential impact on antimicrobial resistance (AMR), we examined the prevalence of tetracycline resistance in gonorrhea (GC) cultures in HIV Tx and PrEP clients during various periods of interest. Methods: We included all PrEP clients, and known or presumed gay, bisexual and other men who have sex with men (gbMSM) and transwomen in HIV Tx, who had ≥1 program prescription dispensed between 1-Jan-2018 and 30-Jun 2024, and ≥1 GC culture and sensitivity ordered between 1-Jan-2017 and 31 Aug-2024. Client tests within 30 days (all specimens, any site) were considered one testing episode (TE). TE’s positive for GC, and tetracycline minimum inhibitory concentrations (MIC) available for GC cultures were described annually and for 5 periods of interest from 1-Jan-2017 through 31-Aug-2024 (Pre-publicly-funded PrEP to Doxy-P scale-up). Results: Overall, 2,629 clients [98% cismen, 0.8% transwomen, 0.5% ciswomen, 0.3% transmen; with median age 36 (Q1-Q3, 31-43) years] were included. 1998 were PrEP, 605 in HIV Tx, and 26 in PrEP who transitioned to HIV Tx. There were 4143 GC TE’s (range 133-1077 per year), of which 686 (17%) were positive and 528 (77%) had tetracycline MIC values reported (range 9-116 per year). The mean (range) GC tetracycline MIC (mg/L) increased from 2.25 (0.25-16) pre-public PrEP (n=9) to 3.99 (0.06-64) during PrEP scale up (n=206) (See Figure). It then decreased during COVID-19 (n=135) to 1.05 (0.13-32), and remained low during the early Doxy-P period (n=100) at 1.42 (0.06-16). During the first 9 months of Doxy-P scale-up (n=78), the mean GC tetracycline MIC increased to 3.96 (0.13-32), similar to that seen during PrEP scale up. Conclusions: In this preliminary analysis, a COVID-19 pandemic-related decline in tetracycline resistance rates and levels was observed in GC cultures amongst PrEP and HIV Tx clients, with rates and levels appearing to return to pre pandemic levels with the introduction of Doxy-P. Close monitoring is warranted, including more routine culture and sensitivity testing for breakthrough cases of GC while on Doxy-P, and on the AMR impacts on off-target organisms.

the microbiome is unknown. This study assessed rectal microbiome changes over 48 weeks in participants on HIV PrEP enrolled in a doxyPrEP trial. Methods: The Dual Daily HIV and STI PrEP (DuDHS) study is an open-label, randomized pilot trial comparing immediate versus deferred doxycline (doxy) (100 mg daily) in HIV-negative GBM and transgender women on tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for HIV PrEP. Fifty-two participants with a syphilis diagnosis within the past three years were recruited in Vancouver, Canada. All participants received 48 weeks of TDF/FTC for HIV PrEP, and were randomized 1:1 to the immediate (imm.) doxy arm (100 mg PO daily started immediately and continued to week 48) or the deferred (def.) arm (100 mg PO daily starting at week 24, continued to week 48). Rectal swabs for microbiome analysis were collected at baseline (BL), week 24, and week 48 and analyzed by 16S rRNA sequencing. Microbiome changes were evaluated using Wilcoxon signed rank and Mann-Whitney U tests, with p-values adjusted for multiple comparisons (FDR=5%). Results: Among 311 operational taxonomic units (OTUs), the most prevalent were Finegoldia, Prevotella, Corynebacterium, and Streptococcus. At baseline, alpha diversity (Shannon’s H mean: imm: 2.58, def: 2.60, p=0.91), beta diversity (Bray-Curtis), and taxa composition were similar (p>0.05). No significant changes in alpha or beta diversity at the genus and family levels were observed between baseline, week 24, and week 48 (p>0.05). However, a slight decrease in alpha diversity at the order, class, and phylum levels was noted at week 48 in the immediate arm (mean: 0.84 vs. 0.66 at Phylum, p<0.05), but not in the deferred arm. Fusobacterium abundance showed a minor decrease at weeks 24 and 48 in both arms (mean difference from BL: 0.017 and 0.019 for imm. arm, 0.003 and 0.00005 for def arm, p<0.05), although this finding did not pass multiple hypothesis testing. Beta diversity remained similar between groups at weeks 24 and 48 (p>0.05) Conclusions: This study is the first to assess microbiome changes due to doxyPrEP, showing minimal impact over 12 months. Further research is needed to explore the impact of doxycycline for STI prevention on microbiome function and antimicrobial resistance. 1289 Testing Healthcare System Resilience Using Microsimulation Modeling Under Various Shocking Scenarios Viviane D. Lima, Jielin Zhu, K. Junine Toy, Jason Trigg, Morris Chan, Paul Sereda, Rolando Barrios, Julio S. G. Montaner British Columbia Centre for Excellence in HIV/AIDS, Vancouver, Canada Background: People living with HIV (PLWH) and health systems caring for them were hit hard by the COVID-19 epidemic and illicit drug toxicity crisis. These challenges have been further compounded by voluntary and involuntary migration and displacement due to war, political violence, and, for PLWH, stigma and discrimination. These crises have tested the resilience of healthcare systems (i.e., the capacity to predict, absorb, recover from, and adapt to shocks). We developed a micro-simulation model to assess the resilience of a healthcare system under different shocking scenarios. Methods: We used individual-based longitudinal data (2014-2023) from the HIV Drug Treatment Program (DTP) in British Columbia (BC), which provides free ART and care to all PLWH. Three scenarios were modeled: the COVID-19 pandemic, the illicit drug toxicity crisis, and migration into BC. The microsimulation included 8583 PLWH, representing DTP participants alive by December 2014, with age and sex randomly sampled from the DTP. The model simulated monthly status transitions from 2015 to 2033, classifying each individual as actively on ART, experiencing short- or long-term (i.e., >18 months) ART discontinuation, migrating to BC, or deceased (from overdose or other causes). New DTP participants were dynamically added over time. Transition probabilities were based on age, sex, and current state. Population projections were made for 2024-2033. Results: Among the modeled scenarios, the COVID-19 pandemic had the least impact on the size and composition of the DTP population. In contrast, overdose mortality disproportionately affected females and individuals aged 50+. The DTP population is aging rapidly, with the proportion of those aged 70+ increasing eightfold between 2014 and 2033. This demographic shift is contributing to a rise in non-AIDS-related mortality, reshaping the DTP population. Migration (>100 PLWH per quarter) had the largest and most uncertain impact on population projections. Sustained migration for >2 years is projected to increase the DTP population by 10-22% over the next decade, especially among PLWH aged 30-50, a group prone to treatment churn (on-off ART).

Poster Abstracts

1288 DoxyPrEP Impact on the Microbiome of Men Who Have Sex With Men and Transgender Women on HIV PrEP Adam D. Burgener 1 , Troy Grennan 2 , Samantha Knodel 1 , Marlon de Leon 1 , Alana Lamont 3 , Joshua Edward 2 , Saira Mohammed 2 , Tessa Tattersall 2 , Jason Wong 2 , Mark Hull 4 , Amit Gupta 5 1 Case Western Reserve University, Cleveland, OH, USA, 2 BC Centre for Disease Control, Vancouver, Canada, 3 University of Manitoba, Winnipeg, Canada, 4 BC Centre for Excellence in HIV/AIDS, Vancouver, Canada, 5 Gilead Sciences, Inc, Foster City, CA, USA Background: Doxycycline pre-exposure prophylaxis (doxyPrEP) has shown potential in preventing bacterial sexually transmitted infections (STIs) in gay, bisexual and other men who have sex with men (GBM). However, its impact on

CROI 2025 427