Shigella is common in symptomatic and asymptomatic men who have sex with men visiting a sexual health clinic in Amsterdam

Asymptomatic enteric pathogen carriage and its association with proton pump inhibitors use in men who have sex with men in Taiwan, 2019-2022

OBJECTIVES

Currently recognized risk factors for sexually transmitted enteric infections (STEIs) among men who have sex with men (MSM) include oroanal sex, multiple sexual partners, and chemsex. This study aimed to investigate the prevalence of the asymptomatic carriage of enteric pathogens in men who have sex with men (MSM) and to identify the associated risk factors.

METHODS

Questionnaires were completed by 375 MSM in Taiwan from December 2019 to November 2022. Fecal samples were analyzed by multiplex PCR to determine whether seven enteric pathogens, including Entamoeba histolytica, Giardia duodenalis, Shiga toxin-producing Escherichia coli, Cryptosporidium, Campylobacter, Salmonella, and Shigella species, were present.

RESULTS

Among 375 fecal samples from asymptomatic MSM, 27 (7.2%) fecal samples tested positive for at least one enteric pathogen. The recent use of proton pump inhibitors (PPIs) was significantly associated with asymptomatic fecal carriage (22.2% vs. 2.0%, P < 0.001). G. duodenalis (2.1%, 8 cases), E. histolytica (1.6%, 6 cases), and Shigella species (1.3%, 5 cases) were commonly detected. Oroanal sex and PPI use were associated with the asymptomatic carriage of enteric pathogens. Specifically, Shigella, Salmonella, or Campylobacter carriage was significantly correlated with PPI use. In contrast, rectal gonorrhea was associated with multiple sexual partners and prior syphilis.

CONCLUSIONS

Recent use of PPIs was associated with the asymptomatic carriage of enteric pathogens. Therefore, targeted education about the appropriate use of PPIs is necessary to mitigate the risk of STEIs among MSM.

Estimated prevalence and associations of sexually transmissible bacterial enteric pathogens in asymptomatic men who have sex with men: a systematic review and meta-analysis

OBJECTIVE

The reservoir of sexually transmissible bacterial enteric pathogens in asymptomatic men who have sex with men (MSM) may impact future outbreaks, and the evolution of antimicrobial resistance. We aimed to estimate the pooled prevalence and explore any factors associated with Shigella spp, Campylobacter spp, diarrhoeagenic Escherichia coli and Salmonella spp in asymptomatic MSM using the random effects model.

METHODS

We searched Embase, MEDLINE, CINAHL and Web of Science Core Collections for manuscripts published up to February 2024. One author screened citations and abstracts; two authors independently conducted a full-text review. We included manuscripts which measured the prevalence of Shigella spp, Campylobacter spp, diarrhoeagenic E. coli and Salmonella spp in asymptomatic MSM. Quality and risk of bias was assessed independently by two authors using the Joanna Briggs Institute critical appraisal tools. We calculated pooled prevalence and CIs using the random effects model.

RESULTS

Six manuscripts were included in the final review. The manuscripts were from Australia (n=2), the UK (n=2), the Netherlands (n=1) and the USA (n=1) and included data from 3766 asymptomatic MSM tested for bacterial enteric pathogens. The prevalence of Shigella spp was 1.1% (95% CI 0.7% to 1.7%), Campylobacter spp 1.9% (95% CI 1.5% to 2.5%), diarrhoeagenic E. coli 3.8% (95% CI 2.1% to 6.7%) and Salmonella spp 0.3% (95% CI 0.1% to 0.6%). Two manuscripts demonstrated that the detection of bacterial enteric pathogen was more frequent in asymptomatic MSM using HIV-pre-exposure prophylaxis (PrEP), living with HIV, reporting <5 new sexual partners in the past 3 months, reporting insertive oral-anal sex and group sex compared with MSM testing negative.

CONCLUSION

Despite a small number of manuscripts, this review has estimated the pooled prevalence, and highlighted some possible associations with sexually transmissible bacterial enteric pathogens in asymptomatic MSM, which can inform future clinical guidelines, public health control strategies and research to increase our understanding of transmission and the evolution of antimicrobial resistance.

PROSPERO REGISTRATION NUMBER

CRD42024518700.

The re-emergence of sexually transmissible multidrug resistant Shigella flexneri 3a, England, United Kingdom

Shigellosis is an enteric infection that transmits through the faecal-oral route, which can occur during sex between men who have sex with men (MSM). Between 2009 and 2014, an epidemic of sexually transmissible Shigella flexneri 3a occurred in England that subsequently declined. However, from 2019 to 2021, despite SARS-CoV-2 restrictions, S. flexneri 3a continued to re-emerge. We explored possible drivers of re-emergence by comparing host demography and pathogen genomics. Cases were primarily among 35-64 year old men in London. Genomic analyses of 502 bacterial isolates showed that the majority (58%) of re-emerging MSM strains were a clonal replacement of the original, with reduced antimicrobial resistance, conservation of plasmid col156_1, and two SNPs with 19 predicted effects. The absence of major changes in the pathogen or host demographics suggest that other factors may have driven the re-emergence of S. flexneri 3a and highlight the need for further work in the area.

An Online HIV Self-Sampling Strategy for Gay, Bisexual and Other Men Who Have Sex with Men and Trans Women in Spain

We aimed to evaluate the feasibility of an online self-sampling pilot intervention for HIV testing addressed to gay, bisexual, and other men who have sex with men (GBMSM) and trans women (TW) users of dating apps in Spain. The website https://www.testate.org/ was designed to offer self-sampling kits for HIV testing and online consultation of the results. It was advertised on gay dating apps. Participants requested the delivery of a saliva self-sampling kit by mail and a postage-paid envelope to send the sample to the reference laboratory. An anonymous acceptability survey was conducted. The cascade of care was estimated. From November 2018 to December 2021, 4623 individual users ordered self-sampling kits, 3097 returned an oral fluid sample to the reference laboratory (67.5% return rate). 87 reactive results were detected. 76 were confirmed to be HIV-positive, we estimated an HIV prevalence of 2.45% (95% CI 1.9-3.0%). 100% of those referred to specialized care are in treatment. 45.8% of participants took more than one test. 23 incident cases were detected among repeat testers, of which 20 were confirmed. The estimated incidence was 1.00 confirmed case per 100 individual-years of follow-up. 98.01% of participants would recommend it to a friend. The most identified advantages were convenience and privacy. We demonstrated that the online offer of oral self-sampling kits for HIV detection and reporting results online among GBMSM and TW users of dating apps is feasible. The intervention counted with a high acceptability and high efficacy (in terms of reactivity, confirmation and linkage to care rates).

Pathogenicity and virulence of Shigella sonnei: A highly drug-resistant pathogen of increasing prevalence

Shigella spp. are the causative agent of shigellosis (or bacillary dysentery), a diarrhoeal disease characterized for the bacterial invasion of gut epithelial cells. Among the 4 species included in the genus, Shigella flexneri is principally responsible for the disease in the developing world while Shigella sonnei is the main causative agent in high-income countries. Remarkably, as more countries improve their socioeconomic conditions, we observe an increase in the relative prevalence of S. sonnei. To date, the reasons behind this change in aetiology depending on economic growth are not understood. S. flexneri has been widely used as a model to study the pathogenesis of the genus, but as more research data are collected, important discrepancies with S. sonnei have come to light. In comparison to S. flexneri, S. sonnei can be differentiated in numerous aspects; it presents a characteristic O-antigen identical to that of one serogroup of the environmental bacterium Plesiomonas shigelloides, a group 4 capsule, antibacterial mechanisms to outcompete and displace gut commensal bacteria, and a poorer adaptation to an intracellular lifestyle. In addition, the World Health Organization (WHO) have recognized the significant threat posed by antibiotic-resistant strains of S. sonnei, demanding new approaches. This review gathers knowledge on what is known about S. sonnei within the context of other Shigella spp. and aims to open the door for future research on understanding the increasing spread of this pathogen.

Challenges and Solutions to STI Control in the Era of HIV and STI Prophylaxis

PURPOSE OF REVIEW

This article reviews current efforts to control bacterial sexually transmitted infections (STIs) among HIV pre-exposure prophylaxis (PrEP) users and outlines the opportunities and challenges to controlling STIs within HIV PrEP programs.

RECENT FINDINGS

The incidence of STIs continues to rise globally especially among HIV PrEP users, with an estimated 1 in 4 PrEP users having a curable bacterial STI. STIs and HIV comprise a syndemic needing dual interventions. The majority of STIs are asymptomatic, and when testing is available, many STIs occur in extragenital sites that are missed when relying on urine testing or genital swabs. Optimal testing and treatment, including testing for antimicrobial resistance, pose difficulties in high income countries and is essentially non-existent in most low- and middle-income countries. Novel STI primary prevention strategies, like doxycycline post-exposure prophylaxis (PEP) for STI prevention, have proven to be highly efficacious in some populations. A few jurisdictions have issued normative guidelines and position statements for doxycycline PEP; however, clinical standards for implementation and data on public health impact are limited. STI incidence rates are high and rising in sexually active populations. Sexual health programs should leverage the expansion of HIV PrEP delivery services to integrate STI testing, surveillance, and novel STI prevention services.

Factors associated with sexually transmitted shigella in men who have sex with men: a systematic review

BACKGROUND

Outbreaks of sexually transmitted shigella have been reported in men who have sex with men (MSM) since the 1970s and present a major public health issue. Understanding the factors associated with the sexual transmission of shigella may inform future control strategies.

METHODS

We systematically searched four bibliographical databases (January 2000-February 2022) for manuscripts in English. We used a two-stage process to assess eligibility: the primary author conducted an initial screen and then three authors conducted independent full-text reviews to determine the final eligible manuscripts. We only included manuscripts that included MSM diagnosed with sexually transmitted shigella where specific factors associated with transmission were identified.

RESULTS

Thirteen manuscripts met the inclusion criteria that included 547 individuals. Sexually transmitted shigella in MSM was associated with: residing in a capital city/urban region, living with HIV (including engaging in seroadaptive sexual behaviour, having a low CD4 count, having a HIV viral load >100 000 and not engaging with HIV care), using HIV pre-exposure prophylaxis, use of geospatial mobile phone applications to meet sexual partners, visiting sex on premises venues, chemsex and recreational drug use, sexual behaviour (including multiple non-regular sexual partners and oral-anal sexual contact) and concomitant STIs.

CONCLUSION

We have highlighted some important risk behaviours and factors that are associated with sexually transmitted shigella in MSM that can be used to target future shigella control interventions.