P318 Frequent detection of Shigella in MSM also in the absence of clinical symptoms

Introduction Shigellosis can present as a severe infection, including bloody diarrhea. About 22% of reported shigellosis cases in the Netherlands occur in men who have sex with men (MSM). Not all infections result in clinical symptoms and not all persons with clinical symptoms are diagnosed. We performed a study among MSM visiting the STI clinic in Amsterdam to assess the prevalence of Shigella. Methods From March to June, 2020, Anal swab samples taken from MSM routinely visiting the STI clinic to detect Chlamydia trachomatis and Neisseria gonorrhoeae were additionally tested pseudonymously for the presence of Shigella by PCR on the ipaH gene. Consecutive samples from MSM who reported no diarrhea, or diarrhea during last month, or diarrhea at visit of clinic were included. Predefined minimal numbers of inclusion of these groups were 150, 100 and 50, respectively. During the same months the frequency of Shigella as assessed by PCR in routinely tested samples sent by general physicians was assessed. Results We included samples from 214 MSM without diarrhea, 109 MSM who recently had diarrhea and 68 MSM who reported diarrhea at visit of the clinic. The total number of samples positive for Shigella was 13/389 (3.3%), of whom 6/212 (2.8%) had no diarrhea, 4/107 (3.7%) recently had diarrhea and 3/68 (4.4%) had diarrhea at clinic visit. Positive samples were more frequently found in persons using or recently having used PREP (10/152), compared to no PREP (2/163) or being HIV-positive (1/74) (p=0.02, chi square test). In comparison, only 11/774 (1.4%) routinely tested fecal samples sent by general physicians during the study period were positive for Shigella. Conclusion Shigella infections without symptoms or with minor symptoms are relatively common in MSM. More detailed studies should focus on the risk of transmission from these persons to others, leading to symptomatic infections.