STEIM Study: Sexually transmitted enteric infections in men who have sex with men (MSM)

Project summary

There are a range of microbes (bugs) such as bacteria and viruses that live in the gut (e.g. Shigella). Some of these bugs can make you sick; causing diarrhoea, stomach cramps and fever. We also think that some of these bugs might occur in people who do not have any symptoms (asymptomatic carriage). The bugs can be passed on in several ways, including by small traces of poo getting into your mouth during and after sex.

The purpose of this study is to investigate the carriage of gut bugs (e.g. Shigella) in gay, bisexual and other MSM to help us understand the extent to which these bugs are spreading, to identify who may be at higher risk of being infected and to determine how we can best treat the infections.

The pilot phase of our research study will begin in early 2022 and will involve around 200 people attending sexual health clinics in Brighton and Sussex. Participants will be asked to complete a questionnaire and to provide a rectal swab every week for up to 3 months. They will also be asked to provide one poo sample, but this is optional. We will conduct individual interviews with some participants to understand their experiences of taking part in the study, and their motivations and reservations about collecting samples. The pilot study will help us to make sure that we are conducting the study in the best way.



Technical information

Within the last two decades, there have been an increasing number of enteric pathogen outbreaks among gay, bisexual, and other MSM globally. Some pathogens are becoming difficult to treat as they have developed resistance to antimicrobial treatments. Evidence suggests that asymptomatic infection might play an important role in sustaining transmission among MSM.

The overall aim of our research is to better understand the epidemiology of enteric pathogens in MSM, to inform the development, targeting and delivery of clinical and public health measures that seek to control transmission.

As a first step towards this aim, we are conducting an observational pilot study to assess the acceptability and feasibility of longitudinal sample and epidemiological data collection among MSM attending sexual health clinics. The pilot phase will assess faecal sample and rectal swab collection, and willingness to return rectal swabs over a period of several months. In addition, the study will provide preliminary findings on the duration of asymptomatic infection with enteric pathogens and will compare the use of rectal swabs with faecal samples for enteric pathogen detection and molecular typing. The results will inform the design and implementation of a larger study that will explore the drivers of sustained transmission of, and development of antimicrobial resistance in, enteric infections among MSM.



Research Team

The STEIM Study is funded by the National Institute for Health and Care Research Health Protection Research Unit (NIHR HPRU) in Blood Borne and Sexually Transmitted Infections (Theme A) at University College London (UCL) in partnership with the UK Health Security Agency (UKHSA, formerly Public Health England), and the NIHR HPRU in Gastrointestinal Infections (Theme 4) at University of Liverpool in partnership with UKHSA and the University of Warwick.

The pilot phase of the STEIM study is being conducted in partnership with University Hospitals Sussex NHS Foundation Trust.

This study has been reviewed and approved by the London - South East NHS Research Ethics Committee (Reference 21/LO/0891)




For further information or to get in touch with the study team, please email:

If you are interested in taking part, please speak to a member of staff at your local participating clinic.


For more information, please read the study protocol and the participant information sheet.

Please check back at a later date for study updates and summary results.