Sexually Transmitted Infections
Introduction
Sexually transmitted infections (STIs) continue to pose substantial global
public health burdens, with over 1 million new curable STIs acquired daily
worldwide.¹ Although classic pathogens such as Chlamydia trachomatis,
Neisseria gonorrhoeae, and Treponema pallidum are frequently addressed
in public health responses, emerging data indicate the sexual transmission
of enteric pathogens such as Shigella sonnel, particularly among men who
have sex with men (MSM).² The increasing antimicrobial resistance of these
pathogens adds complexity to STI surveillance, prevention, and treatment
efforts. A recent study by Charles et al. investigates a large-scale, extended-
spectrum β-lactamase (ESBL)-producing Shigella sonnel outbreak in
England, offering important insight into pathogen transmission dynamics
and resistance evolution. ³
This review analyzes Charles et al.’s findings in the context of the broader
literature on STIs and antimicrobial resistance. It compares emerging trends
in surveillance, clinical care, and prevention to better understand the
evolving landscape of sexually transmitted enteric infections.
Article Summary
The primary article by Charles et al. documents an investigation into 117
cases of Shigella sonnel infection in England between 2019 and 2023,
primarily among MSM. ³ Genomic sequencing revealed the presence of
blaCTX-M-15 ESBL-producing plasmids in the isolates, rendering standard
antimicrobial treatment ineffective in many cases. Epidemiologic links
Sexually Transmitted Infections
among cases demonstrated sexual transmission through local and
international sexual networks. The authors emphasize the threat of
extensively drug-resistant (XDR) strains and call for enhanced genomic
surveillance, better treatment guidelines, and targeted public health
interventions for high-risk groups.
Epidemiology of Infectious Disease
Globally, sexually transmitted infections affect hundreds of millions of
individuals each year, with the World Health Organization estimating 374
million new cases of four curable STIs in 2020 alone.¹ In recent years, non-
traditional sexually transmitted pathogens like Shigella species have
emerged as significant concerns, particularly within MSM communities.² In
the UK, the Shigella sonnel outbreak described by Charles et al.³ highlights
both the increasing sexual transmission of enteric pathogens and the
concerning trend of antimicrobial resistance. Similar outbreaks in the U.S.,
Canada, and Australia reinforce the global nature of this threat.⁴
Preventive efforts—such as condom use, hygiene education, and regular STI
screening—remain essential but may be insufficient against pathogens like
Shigella, which are highly infectious and can spread via oral–anal contact
and contaminated surfaces.⁵ The impact of such infections extends beyond
individual morbidity, affecting broader public health through strain on
antimicrobial stewardship programs and healthcare resources.
Sexually Transmitted Infections
Best Practices and Standards of Care
Treatment of shigellosis typically involves fluid replacement and, in
moderate to severe cases, antimicrobial therapy.⁶ However, the emergence
of ESBL-producing strains has compromised standard first-line antibiotics
such as ciprofloxacin and azithromycin.³ In Charles et al.’s study, many S.
sonnel isolates were resistant to multiple antibiotic classes, necessitating
updated treatment algorithms and real-time resistance tracking.³
Best practices now include culture-based testing and susceptibility profiling,
especially in patients with travel history, high-risk sexual activity, or
persistent symptoms.⁶ Public health organizations, including the CDC and
WHO, have urged implementation of molecular diagnostics and targeted
interventions in MSM populations.¹,⁴ Culturally appropriate outreach—such
as anonymous contact tracing, multilingual education materials, and
integration with HIV/STI clinics—also plays a critical role in prevention and
management.⁷ In the U.S., updated CDC guidelines recommend rectal
screening for STIs among MSM, which could be adapted to screen for
enteric pathogens.⁸
Compare and Contrast
Charles et al. emphasize genomic surveillance and sexual transmission
networks in their investigation of the English outbreak.³ These findings align
with WHO reports that highlight antimicrobial-resistant STIs as a growing
global health threat, especially in underserved populations.¹ Similarly, a
2022 review in PLOS Medicine describes how Shigella and other enteric
Sexually Transmitted Infections
pathogens have emerged in sexual transmission contexts, predominantly
among MSM, echoing Charles et al.’s observations.²
Where Charles et al. focus on epidemiologic links and genomic resistance
mechanisms, other sources place greater emphasis on clinical treatment and
public health response. For example, Workowski and Bachmann’s JAMA
review stresses the need for integrated, evidence-based treatment protocols
for all STIs, including point-of-care diagnostics and rapid resistance testing.⁶
While Charles et al. raise the alarm about drug resistance, they provide
limited discussion on clinical management, which is addressed more fully in
these broader reviews.
On the other hand, WHO's 2024 report calls for improved access to STI
screening and treatment globally, particularly among key populations such
as MSM and sex workers.¹ This aligns with the culturally appropriate
outreach strategies discussed by Charles et al., though WHO extends these
considerations to regions with fewer resources.¹ Finally, while Charles et al.
focus on a UK-specific outbreak, global studies reinforce that sexual
transmission of multidrug-resistant Shigella is increasingly recognized
across continents.⁴⁻⁵ Together, these articles underscore the need for
enhanced surveillance, integrated care, and culturally responsive
interventions.
Evaluation and Critique
The Charles et al. article makes a significant contribution to the literature on
sexually transmitted enteric pathogens by combining epidemiologic analysis
with genomic sequencing to track resistance evolution. ³ Its strengths
Sexually Transmitted Infections
include its rigorous methodology, identification of resistance mechanisms,
and relevance to sexual health interventions. However, the article has
limitations. First, it is geographically limited to the UK and primarily focused
on MSM populations, leaving gaps regarding other transmission routes or
affected groups. Additionally, while the article calls for improved
surveillance and awareness, it does not fully address best practices in
clinical management, leaving readers to consult external guidelines. ⁶
Nonetheless, this article expanded my understanding of how enteric
infections intersect with sexual health and antimicrobial resistance. It
illustrates the importance of genomics in infectious disease surveillance and
the public health risks posed by XDR organisms.
Conclusion
Sexually transmitted infections continue to evolve in complexity, particularly
with the emergence of nontraditional pathogens like Shigella sonnel. The
article by Charles et al. highlights the intersection of antimicrobial
resistance, sexual networks, and public health surveillance. ³ When
compared to global literature, it reinforces the need for integrative
approaches combining molecular diagnostics, treatment guidelines, and
culturally competent outreach. Ongoing investment in STI research,
surveillance, and care is essential to contain the spread of drug-resistant
infections and protect vulnerable populations worldwide.
Sexually Transmitted Infections
References
1. World Health Organization. Sexually transmitted infections (STIs).
Updated 2024. Accessed July 15, 2025. https://www.who.int/news-room/fact-
sheets/detail/sexually-transmitted-infections-(stis)
2. Kenyon C. Re-emergence of sexually transmitted enteric infections among
MSM. PLoS Med. 2022;19(3):e1002474.
3. Charles H, Greig DR, Swift C, et al. Epidemiologic and Genomic
Investigation of Sexually Transmitted Shigella sonnel, England. Emerg Infect
Dis. 2025;31(7). https://wwwnc.cdc.gov/eid/article/31/7/23-2050_article
4. Centers for Disease Control and Prevention. Antibiotic-Resistant Shigella:
Protecting People from an Emerging Threat. Updated 2023. Accessed July
15, 2025. https://www.cdc.gov/shigella/antibiotic-resistance.html
Sexually Transmitted Infections
5. Simms I, Field N. Sexual transmission of enteric infections. Curr Opin
Infect Dis. 2020;33(1):31–36.
6. Workowski KA, Bachmann LH, et al. Sexually transmitted infections
treatment guidelines, 2021. JAMA. 2022;327(2):132–144.
7. Beyrer C, Baral SD, et al. The Global Response to HIV in Men Who Have
Sex with Men. Lancet. 2020;385(9981):448–464.
8. CDC. 2021 STD Treatment Guidelines. Centers for Disease Control and
Prevention. Accessed July 15, 2025. https://www.cdc.gov/std/treatment-
guidelines/default.htm
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