Intensified shigellosis epidemic associated with sexual transmission in men who have sex with men--Shigella flexneri and S. sonnei in England, 2004 to end of February 2015

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.

Escherichia coli killing by epidemiologically successful sublineages of Shigella sonnei is mediated by colicins

BACKGROUND

Shigella sp. are enteric pathogens which causes >125 million cases of shigellosis annually. S. sonnei accounts for about a quarter of those cases and is increasingly prevalent in industrialising nations. Being an enteric pathogen, S. sonnei benefits from outcompeting gut commensals such as Escherichia coli to establish itself and cause disease. There are numerous mechanisms that bacterial pathogens use to outcompete its rivals including molecules called colicins. A Type 6 Secretion System (T6SS) was recently described as contributing to E. coli killing in S. sonnei.

METHODS

We used Bulk Phenotyping of Epidemiological Replicates (BPER) which combined bacterial Genome Wide Association Studies (bGWAS) and high throughput phenotyping on a collection of S. sonnei surveillance isolates to identify the genetic features associated with E. coli killing and explore their relationship with epidemiological behaviour. We further explored the presence of colicins and T6SS components in the isolates using genomics, laboratory experimentation, and proteomics.

FINDINGS

Our bGWAS analysis returned known and novel colicin and colicin related genes as significantly associated with E. coli killing. In silico analyses identified key colicin clusters responsible for the killing phenotype associated with epidemiologically successful sub-lineages. The killing phenotype was not associated with the presence of a T6SS. Laboratory analyses confirmed the presence of the key colicin clusters and that killing was contact-independent.

INTERPRETATION

Colicins are responsible for E. coli killing by S. sonnei, not a T6SS. This phenotype contributes to shaping the observed epidemiology of S. sonnei and may contribute to its increasing prevalence globally. BPER is an epidemiologically relevant approach to phenotypic testing that enables the rapid identification of genetic drivers of phenotypic changes, and assessment of their relevance to epidemiology in natural settings.

FUNDING

Biotechnology and Biological Sciences Research Council, Biotechnology and Biological Sciences Research Council Doctoral Training Partnership studentship, Wellcome Trust, Medical Research Council (UK), French National Research Agency.

Whole-genome sequencing analysis of Klebsiella aerogenes among men who have sex with men in Guangzhou, China

Klebsiella aerogenes is a common infectious bacterium that poses a threat to human health. Nevertheless, there are limited data on the population structure, genetic diversity, and pathogenicity of K. aerogenes, especially among men who have sex with men (MSM). The present study aimed to clarify the sequence types (STs), clonal complexes (CCs), resistance genes, and virulence factors of popular strains. Multilocus sequence typing was used to describe the population structure of K. aerogenes. The Virulence Factor Database and Comprehensive Antibiotic Resistance Database were used to assess the virulence and resistance profiles. In this study, next-generation sequencing was performed on nasal swabs specimens collected in an HIV Voluntary Counseling Testing outpatient department in Guangzhou, China, from April to August 2019. The identification results showed that a total of 258 K. aerogenes isolates were collected from 911 participants. We found that the isolates were most resistant to furantoin (89.53%, 231/258) and ampicillin (89.15%, 230/258), followed by imipenem (24.81%, 64/258) and cefotaxime (18.22%, 47/258). The most common STs in carbapenem-resistant K. aerogenes were ST4, ST93, and ST14. The population has at least 14 CCs, including several novel ones identified in this study (CC11-CC16). The main mechanism of drug resistance genes was antibiotic efflux. Based on the presence of the iron carrier production genes irp and ybt, we identified two clusters according to virulence profiles. In cluster A, CC3 and CC4 carry the clb operator encoding the toxin. Increased monitoring is needed for the three main ST type strains carried by MSM. The main clone group CC4 has a large number of toxin genes, and it spreads among MSM. Caution is needed to prevent further spread of this clone group in this population. In sum, our results may provide a foundation for the development of new therapeutic and surveillance strategies for treating MSM.

British Association of Sexual Health and HIV (BASHH) United Kingdom national guideline for the management of sexually transmitted enteric infections 2023

This is the first British Association of Sexual Health and HIV (BASHH) national guideline for the management of sexually transmitted enteric infections (STEI). This guideline is primarily aimed for level 3 sexual health clinics; however, it may also be applicable to other settings such as primary care or other hospital departments where individuals with STEI may present. This guideline makes recommendations on testing, management, partner notification and public health control of STEI.

The evolution and international spread of extensively drug resistant Shigella sonnei

Shigella sonnei causes shigellosis, a severe gastrointestinal illness that is sexually transmissible among men who have sex with men (MSM). Multidrug resistance in S. sonnei is common including against World Health Organisation recommended treatment options, azithromycin, and ciprofloxacin. Recently, an MSM-associated outbreak of extended-spectrum β-lactamase producing, extensively drug resistant S. sonnei was reported in the United Kingdom. Here, we aimed to identify the genetic basis, evolutionary history, and international dissemination of the outbreak strain. Our genomic epidemiological analyses of 3,304 isolates from the United Kingdom, Australia, Belgium, France, and the United States of America revealed an internationally connected outbreak with a most recent common ancestor in 2018 carrying a low-fitness cost resistance plasmid, previously observed in travel associated sublineages of S. flexneri. Our results highlight the persistent threat of horizontally transmitted antimicrobial resistance and the value of continuing to work towards early and open international sharing of genomic surveillance data.

Prevalence and incidence of HEV among men using HIV pre-exposure prophylaxis: A sub-study of the ANRS IPERGAY trial

BACKGROUND

Men who have sex with men (MSM) have an increased risk of infection by pathogens transmitted by the oro-fecal route. Here, we investigated the seroprevalence and incidence of hepatitis E virus (HEV) infection in 416 MSM included in the ANRS IPERGAY PrEP trial.

RESULTS

Among the 62 (14.9% (95% CI: [11.6%-18.7%]) seropositive for HEV at inclusion, the only factor associated with testing seropositive for HEV was older age. Geographical origin, use of recreational drugs, number of sexual partners, status for HAV and bacterial sexually transmitted infection (STI) at inclusion were not associated. Among the 342 HEV-seronegative patients with available samples, 9 seroconverted after a median of follow-up of 2.1 years (IQR (interquartile range): [1.6; 3.0]).

CONCLUSION

Overall, the HEV incidence was 1.19% per 100 person-years [95% CI: 0.54%; 2.26%]. Sexual transmission does not seem to be a major route of HEV infection in MSM, unlike HAV.

The changing epidemiology of shigellosis in Australia, 2001-2019

Shigellosis is an increasing cause of gastroenteritis in Australia, with prolonged outbreaks reported in remote Aboriginal and Torres Strait Islander (hereafter "First Nations") communities and among men who have sex with men (MSM) in major cities. To determine associations between Shigella species and demographic and geographic factors, we used multivariate negative binomial regression to analyse national case notifications of shigellosis from 2001 to 2019. Between 2001 and 2019, Australian states and territories reported 18,363 shigellosis cases to the National Notifiable Diseases Surveillance System (NNDSS), of which age, sex and organism information were available for >99% (18,327/18,363) of cases. Of the cases included in our analysis, 42% (7,649/18,327) were S. sonnei, 29% (5,267/18,327) were S. flexneri, 1% (214/18,327) were S. boydii, less than 1% (87/18,327) were S. dysenteriae, and species information was unknown for 28% (5,110/18,327) of cases. Males accounted for 54% (9,843/18,327) of cases, and the highest proportion of cases were in children aged 0-4 years (19%; 3,562/18,327). Crude annual notification rates ranged from 2.2 cases per 100,000 in 2003 and 2011 to 12.4 cases per 100,000 in 2019. Nationally, notification rates increased from 2001 to 2019 with yearly notification rate ratios of 1.04 (95% CI 1.02-1.07) for S. boydii and 1.05 (95% CI 1.04-1.06) for S. sonnei. Children aged 0-4 years had the highest burden of infection for S. flexneri, S. sonnei and S. boydii; and males had a higher notification rate for S. sonnei (notification rate ratio 1.24, 95% CI 1.15-1.33). First Nations Australians were disproportionately affected by shigellosis, with the notification rate in this population peaking in 2018 at 92.1 cases per 100,000 population. Over the study period, we also observed a shift in the testing method used to diagnose shigellosis, with culture independent diagnostic testing (CIDT) increasing from 2014; this also coincided with an increase in notifications of untyped Shigella. This change in testing methodology may have contributed to the observed increase in shigellosis notifications since 2014, with CIDT being more sensitive than culture dependent testing methods. The findings of this study provide important insights into the epidemiological characteristics of shigellosis in Australia, including identification of high-risk groups. This can be used to inform public health prevention and control strategies, such as targeted communication programs in First Nations communities and places with high levels of interaction between young children, such as childcare centres. Our study findings also highlight the implications of culture independent testing on shigellosis surveillance, particularly a reduction in the availability of species level information. This emphasises the continued importance of culture dependant testing for national surveillance of shigellosis.

Emergence of extensively drug-resistant and multidrug-resistant Shigella flexneri serotype 2a associated with sexual transmission among gay, bisexual, and other men who have sex with men, in England: a descriptive epidemiological study

BACKGROUND

Shigellosis, also known as bacillary dysentery, is caused by Shigella spp that spread through fecal-oral contact and was traditionally associated with international travel in England. However, sexual transmission of Shigella flexneri and Shigella sonnei among gay, bisexual, and other men who have sex with men (MSM) is now common. In September, 2021, emergence of extensively drug-resistant (XDR) S sonnei harbouring plasmid-encoded bla_CTX-M-27 raised concerns over further spread of this extended-spectrum β-lactamase-producing gene. Using national surveillance in England, we identified and characterised isolates of S flexneri harbouring bla_CTX-M-27.

METHODS

In this epidemiological study, we identified and phylogenetically characterised S flexneri isolates harbouring bla_CTX-M-27 that were referred to the Gastrointestinal Bacterial Reference Unit (GBRU) at the UK Health Security Agency. All isolates referred to the GBRU undergo whole-genome sequencing, enabling antimicrobial resistance determination using genetic markers. Cases were defined as individuals diagnosed with S flexneri harbouring bla_CTX-M-27 in England, with a specimen date between Sept 1, 2015, and June 12, 2022, who were phylogenetically confirmed as part of two t10 (approximately ten single nucleotide polymorphisms) clusters. Long-read sequencing elucidated the genomic location of bla_CTX-M-27. Laboratory data, integrated with available demographic and clinical information from patient questionnaires, were summarised using descriptive statistics.

FINDINGS

A sustained increase in cases of S flexneri harbouring bla_CTX-M-27 (n=26) occurred from September, 2021, having been sporadically reported (n=11) in the preceding 6 years. bla_CTX-M-27 acquisition events within S flexneri 2a established an XDR paraphyletic (n=8) cluster and a multidrug-resistant monophyletic (n=18) cluster. Cases were among adult male individuals (median age 37 years [IQR 31-46]) and, of the 13 individuals who completed a patient questionnaire, ten (77%) identified as MSM. Antimicrobial treatment was received by seven (54%) of 13 individuals, and four (31%) individuals were admitted to hospital. The IncFII plasmids harbouring bla_CTX-M-27 showed high similarity to the XDR S sonnei outbreak plasmid, with 82% and 99% nucleotide similarity between the cluster plasmids and the XDR S sonnei outbreak plasmid.

INTERPRETATION

We report emergence of XDR and multidrug-resistant S flexneri 2a harbouring bla_CTX-M-27 among MSM in England. Epidemiological and plasmid similarities with the XDR S sonnei outbreak support horizontal acquisition events, emphasising the importance of mobilisable antimicrobial resistance and the need for genomic-based surveillance.

FUNDING

National Institute for Health and Care Research Health Protection Research Unit in Gastrointestinal Infections at the University of Liverpool in partnership with the UK Health Security Agency.

Prevalence and risk factors of bacterial enteric pathogens in men who have sex with men: A cross-sectional study at the UK's largest sexual health service

OBJECTIVES

Outbreaks of bacterial enteric pathogens (BEPs) in men who have sex with men (MSM) associated with antimicrobial resistance are a public health concern. We investigated the prevalence and risk factors of BEPs in MSM to inform infection control.

METHODS

We conducted a cross-sectional study at a London sexual health clinic between 20/12/2017 and 06/02/2018. Residual rectal swabs from MSM attending for sexually transmitted infection (STI) testing were anonymously tested for a range of BEPs using real-time PCR. A sub-set of samples were tested for the mphA gene (a marker of azithromycin resistance). Results were linked to electronic health records.

RESULTS

BEPs were detected in 207 of 2116 participants, giving an overall prevalence of 9.8% (95% CI 8.5%-11.1%) ranging from 0.8% (0.4%-1.2%) for Shigella to 4.9% (4.0%-5.9%) for Enteroaggregative E. coli. MSM with BEPs were more likely to have a history of bacterial STIs (p = 0.010), to report more sexual partners (p<0.001), and among HIV-negative MSM, to report current HIV pre-exposure prophylaxis use (p<0.001). Gastrointestinal symptoms were rare (1.7%) and not associated with BEPs. 41.3% of MSM with BEPs and 14.1% of those without BEPs carried mphA (p<0.001). Among the former, this was associated with a history of bacterial STIs (51.5% vs 31.1%, p = 0.003).

CONCLUSIONS

One in ten MSM had a BEP detected and most did not report symptoms. MphA carriage was common, particularly among those with BEPs. Bacterial STI treatment might contribute to selection of resistant gut organisms, emphasising the need for better antimicrobial stewardship.

Epidemiological Characteristics and Spatio-Temporal Distribution of Hepatitis A in Spain in the Context of the 2016/2017 European Outbreak

The aim of our study was to describe the results of the epidemiological surveillance of hepatitis A infections in Spain in the context of the 2016/2017 European outbreak, particularly of hepatitis A outbreaks reported in the MSM population, incorporating the results of a spatio-temporal analysis of cases. Hepatitis A cases and outbreaks reported in 2016-2017 to the National Epidemiological Surveillance Network were reviewed: outbreaks in which some of the cases belonged to the MSM group were described, and clusters of hepatitis A cases in men and women were analysed using a space-time scan statistic. Twenty-six outbreaks were identified, with a median size of two cases per outbreak, with most of the outbreak-related cases belonging to the 15-44 years-old group. Nearly 85% occurred in a household setting, and in all outbreaks, the mode of transmission was direct person-to-person contact. Regarding space-time analysis, twenty statistically significant clusters were identified in the male population and eight in the female population; clusters in men presented a higher number of observed cases and affected municipalities, as well as a higher percentage of municipalities classified as large urban areas. The elevated number of cases detected in clusters of men indicates that the number of MSM-related outbreaks may be higher than reported, showing that spatio-temporal analysis is a complementary, useful tool which may improve the detection of outbreaks in settings where epidemiological investigation may be more challenging.

Epidemiology of Early Monkeypox Virus Transmission in Sexual Networks of Gay and Bisexual Men, England, 2022

After community transmission of monkeypox virus was identified in Europe, interviews of 45 case-patients from England indicated transmission in international sexual networks of gay and bisexual men since April 2022. Interventions targeting sex-on-premises venues, geospatial dating applications, and sexual health services are likely to be critical for outbreak control.

Enteric Infections in Men Who Have Sex With Men

BACKGROUND

Enteric pathogens are often associated with exposure to food, water, animals, and feces from infected individuals. However, in sexual networks of men who have sex with men (MSM), transmission of enteric pathogens may occur during direct or indirect oral-anal contact.

METHODS

We performed a scoping review of the literature for studies prior to July 2019 with key terms for gastrointestinal syndromes ("proctitis," "enteritis," "proctocolitis"), enteric pathogens or sexually transmitted infections (STIs), and outbreaks using multiple electronic databases.

RESULTS

We identified 5861 records through database searches, bibliography reviews, and keyword searches, of which 117 references were included in the pathogen-specific reviews.

CONCLUSIONS

The strength of observational data describing enteric pathogens in MSM and possible sexual transmission of enteric pathogens varies by pathogen; however, a robust body of literature describes the sexual transmission of Campylobacter, Giardia lamblia, and Shigella (particularly antimicrobial-resistant strains) in sexual networks of MSM. Providers are encouraged to consider enteritis or proctocolitis in MSM as possibly having been sexually transmitted and encourage targeted STI testing. Risk/harm reduction and prevention messages should also be incorporated, though there is an acknowledged paucity of evidence with regards to effective strategies. Further research is needed to understand the transmission and prevention of enteric pathogens in MSM.

Linkage of Whole Genome Sequencing, Epidemiological, and Clinical Data to Understand the Genetic Diversity and Clinical Outcomes of Shigella flexneri among Men Who Have Sex with Men in England

The public health value of whole genome sequencing (WGS) for Shigella spp. in England has been limited by a lack of information on sexual identity and behavior. We combined WGS data with other data sources to better understand Shigella flexneri transmission in men who have sex with men (MSM). WGS data for all S. flexneri isolates referred to the national reference laboratory were linked to i) clinical and behavioral data collected in seven of 21 health regions in England using a standardized exposure questionnaire and, ii) national HIV surveillance data. We included 926 S. flexneri isolates, of which 43.0% (n = 398) fell phylogenetically within two domestically circulating clades associated with genotypic markers of azithromycin resistance. Approximately one third of isolates in these clades were from people living with HIV, primarily acquired through sex between men. 182 (19.7%) isolates had linked questionnaire data; 88% (84/95) of MSM isolates fell phylogenetically within the domestically circulating clades, while 92% (72/78) of isolates from other cases fell within lineages linked with travel to high-risk regions. There was no evidence of sustained transmission between networks of MSM and the wider community. MSM were more likely to be admitted to hospital and receive antimicrobials. Our study emphasizes the importance of sex between men as a major route of transmission for S. flexneri. Combined WGS, epidemiological and clinical data provide unique insights that can inform contact tracing, clinical management and the delivery of targeted prevention activities. Future studies should investigate why MSM experience more severe clinical outcomes. IMPORTANCE Within the last 2 decades there have been an increasing number of Shigella spp. outbreaks among men who have sex with men (MSM) worldwide. In 2015, Public Health England (PHE) introduced routine whole genome sequencing (WGS) for the national surveillance of Shigella spp. However, the lack of information on sexual identity and behavior has hindered interpretation. Our study illustrates the power of linking WGS data with epidemiological, behavioral, and clinical data. We provide unique population-level insights into different transmission networks that can inform the delivery of appropriate public health interventions and patient management. Furthermore, we describe and compare clinical characteristics and outcomes of S. flexneri infection in MSM and other exposure groups. We found that MSM were more likely to be admitted to hospital and receive antimicrobials, indicating that their infections were potentially more severe. The exact reasons for this are unclear and require further exploration.

Evaluation of whole-genome sequencing-based subtyping methods for the surveillance of Shigella spp. and the confounding effect of mobile genetic elements in long-term outbreaks

Many public health laboratories across the world have implemented whole-genome sequencing (WGS) for the surveillance and outbreak detection of foodborne pathogens. PulseNet-affiliated laboratories have determined that most single-strain foodborne outbreaks are contained within 0–10 multi-locus sequence typing (MLST)-based allele differences and/or core genome single-nucleotide variants (SNVs). In addition to being a food- and travel-associated outbreak pathogen, most Shigella spp. cases occur through continuous person-to-person transmission, predominantly involving men who have sex with men (MSM), leading to long-term and recurrent outbreaks. Continuous transmission patterns coupled to genetic evolution under antibiotic treatment pressure require an assessment of existing WGS-based subtyping methods and interpretation criteria for cluster inclusion/exclusion. An evaluation of 4 WGS-based subtyping methods [SNVPhyl, coreMLST, core genome MLST (cgMLST) and whole-genome MLST (wgMLST)] was performed on 9 foodborne-, travel- and MSM-related retrospective outbreaks from a collection of 91 Shigella flexneri and 232  Shigella sonnei isolates to determine the methods’ epidemiological concordance, discriminatory power, robustness and ability to generate stable interpretation criteria. The discriminatory powers were ranked as follows: coreMLST<SNVPhyl<cgMLST<wgMLST (range: 0.970–1.000). The genetic differences observed for non-MSM-related Shigella spp. outbreaks respect the standard 0–10 allele/SNV guideline; however, mobile genetic element (MGE)-encoded loci caused inflated genetic variation and discrepant phylogenies for prolonged MSM-related S. sonnei outbreaks via wgMLST. The S. sonnei correlation coefficients of wgMLST were also the lowest at 0.680, 0.703 and 0.712 for SNVPhyl, coreMLST and cgMLST, respectively. Plasmid maintenance, mobilization and conjugation-associated genes were found to be the main source of genetic distance inflation in addition to prophage-related genes. Duplicated alleles arising from the repeated nature of IS elements were also responsible for many false cg/wgMLST differences. The coreMLST approach was shown to be the most robust, followed by SNVPhyl and wgMLST for inter-laboratory comparability. Our results highlight the need for validating species-specific subtyping methods based on microbial genome plasticity and outbreak dynamics in addition to the importance of filtering confounding MGEs for cluster detection.

Emergence of novel strains of Shigella flexneri associated with sexual transmission in adult men in England, 2019-2020

National surveillance of shigellosis in England revealed an increase in sexually transmitted Shigella flexneri in adult males in 2019 that persisted throughout 2020. We observed a resurgence of azithromycin-resistant S. flexneri serotype 3a, and the emergence of two novel multidrug-resistant clades of S. flexneri 2a and S. flexneri 1b.

Acquisition and loss of CTX-M plasmids in Shigella species associated with MSM transmission in the UK

Shigellosis in men who have sex with men (MSM) is caused by multidrug resistant Shigellae, exhibiting resistance to antimicrobials including azithromycin, ciprofloxacin and more recently the third-generation cephalosporins. We sequenced four bla_CTX-M-27-positive MSM Shigella isolates (2018–20) using Oxford Nanopore Technologies; three S. sonnei (identified as two MSM clade 2, one MSM clade 5) and one S. flexneri 3a, to explore AMR context. All S. sonnei isolates harboured Tn7/Int2 chromosomal integrons, whereas S. flexneri 3a contained the Shigella Resistance Locus. All strains harboured IncFII pKSR100-like plasmids (67-83kbp); where present bla_CTX-M-27 was located on these plasmids flanked by IS26 and IS903B, however bla_CTX-M-27 was lost in S. flexneri 3a during storage between Illumina and Nanopore sequencing. IncFII AMR regions were mosaic and likely reorganised by IS26; three of the four plasmids contained azithromycin-resistance genes erm(B) and mph(A) and one harboured the pKSR100 integron. Additionally, all S. sonnei isolates possessed a large IncB/O/K/Z plasmid, two of which carried aph(3’)-Ib/aph(6)-Id/sul2 and tet(A). Monitoring the transmission of mobile genetic elements with co-located AMR determinants is necessary to inform empirical treatment guidance and clinical management of MSM-associated shigellosis.

Potential for Phages in the Treatment of Bacterial Sexually Transmitted Infections

Bacterial sexually transmitted infections (BSTIs) are becoming increasingly significant with the approach of a post-antibiotic era. While treatment options dwindle, the transmission of many notable BSTIs, including Neisseria gonorrhoeae, Chlamydia trachomatis, and Treponema pallidum, continues to increase. Bacteriophage therapy has been utilized in Poland, Russia and Georgia in the treatment of bacterial illnesses, but not in the treatment of bacterial sexually transmitted infections. With the ever-increasing likelihood of antibiotic resistance prevailing and the continuous transmission of BSTIs, alternative treatments must be explored. This paper discusses the potentiality and practicality of phage therapy to treat BSTIs, including Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, Streptococcus agalactiae, Haemophilus ducreyi, Calymmatobacterium granulomatis, Mycoplasma genitalium, Ureaplasma parvum, Ureaplasma urealyticum, Shigella flexneri and Shigella sonnei. The challenges associated with the potential for phage in treatments vary for each bacterial sexually transmitted infection. Phage availability, bacterial structure and bacterial growth may impact the potential success of future phage treatments. Additional research is needed before BSTIs can be successfully clinically treated with phage therapy or phage-derived enzymes.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Circulation of multi-drug-resistant Shigella sonnei and Shigella flexneri among men who have sex with men in Barcelona, Spain, 2015-2019

BACKGROUND

In high-income countries, shigellosis is mainly found in travellers to high-risk regions or in men who have sex with men (MSM). This study investigated the genomic characteristics and the features of antimicrobial resistance of MSM-associated Shigella flexneri and Shigella sonnei circulating in Barcelona, Spain, elucidating their connectivity with contemporaneous Shigella spp. from other countries.

METHODS

Antimicrobial susceptibility, whole-genome sequencing, genomic characterization and phylogenetic analysis were performed in MSM-associated Shigella spp. recovered from 2015 to 2019. Reference genomes of MSM-associated Shigella spp. were included for contextualization and to determine their connection with international outbreaks.

RESULTS

In total, 44 S. flexneri and 26 S. sonnei were identified among MSM. Overall, 80% showed resistance to azithromycin, 65.7% showed resistance to trimethoprim-sulphamethoxazole and 32.8% showed resistance to ciprofloxacin; 27.1% were resistant to all three antimicrobials. mphA and/or ermB, and qnrS and mutations in the quinolone resistance determining regions were found in the azithromycin- and ciprofloxacin-resistant isolates, respectively. Additionally, two isolates carried bla_CTX-M-27. Single-nucleotide-polymorphism-based analysis revealed that the isolates were organized into different lineages, most of which were closely related to dominant MSM-associated lineages described previously in the UK and Australia.

CONCLUSIONS

This study investigated the circulation of lineages of S. flexneri and S. sonnei among MSM in Spain that were mainly resistant to first-/second-line oral treatments, and closely related to dominant MSM-associated lineages described previously in the UK and Australia. These data reinforce the urgent need for the implementation of public health measures focusing on the early detection and prevention of transmission of this emerging pathogen, which is contributing to the antimicrobial resistance crisis in sexually transmitted infections.

Accessory Genome Dynamics and Structural Variation of Shigella from Persistent Infections

Shigellosis is a diarrheal disease caused mainly by Shigella flexneri and Shigella sonnei Infection is thought to be largely self-limiting, with short- to medium-term and serotype-specific immunity provided following clearance. However, cases of men who have sex with men (MSM)-associated shigellosis have been reported where Shigella of the same serotype were serially sampled from individuals between 1 and 1,862 days apart, possibly due to persistent carriage or reinfection with the same serotype. Here, we investigate the accessory genome dynamics of MSM-associated S. flexneri and S. sonnei isolates serially sampled from individual patients at various days apart to shed light on the adaptation of these important pathogens during infection. We find that pairs likely associated with persistent infection/carriage and with a smaller single nucleotide polymorphism (SNP) distance, demonstrated significantly less variation in accessory genome content than pairs likely associated with reinfection, and with a greater SNP distance. We observed antimicrobial resistance acquisition during Shigella carriage, including the gain of an extended-spectrum beta-lactamase gene during carriage. Finally, we explored large chromosomal structural variations and rearrangements in seven (five chronic and two reinfection associated) pairs of S. flexneri 3a isolates from an MSM-associated epidemic sublineage, which revealed variations at several common regions across isolate pairs, mediated by insertion sequence elements and comprising a distinct predicted functional profile. This study provides insight on the variation of accessory genome dynamics and large structural genomic changes in Shigella during persistent infection/carriage. In addition, we have also created a complete reference genome and biobanked isolate of the globally important pathogen, S. flexneri 3a.IMPORTANCEShigella spp. are Gram-negative bacteria that are the etiological agent of shigellosis, the second most common cause of diarrheal illness among children under the age of five in low-income countries. In high-income countries, shigellosis is also a sexually transmissible disease among men who have sex with men. Within the latter setting, we have captured prolonged and/or recurrent infection with shigellae of the same serotype, challenging the belief that Shigella infection is short lived and providing an early opportunity to study the evolution of the pathogen over the course of infection. Using this recently emerged transmission scenario, we comprehensively characterize the genomic changes that occur over the course of individual infection with Shigella and uncover a distinct functional profile of variable genomic regions, findings that have relevance for other Enterobacteriaceae.

Utility of whole-genome sequencing during an investigation of multiple foodborne outbreaks of Shigella sonnei

In April 2018, Public Health England was notified of cases of Shigella sonnei who had eaten food from three different catering outlets in England. The outbreaks were initially investigated as separate events, but whole-genome sequencing (WGS) showed they were caused by the same strain. The investigation included analyses of epidemiological data, the food chain and microbiological examination of food samples. WGS was used to determine the phylogenetic relatedness and antimicrobial resistance profile of the outbreak strain. Ultimately, 33 cases were linked to this outbreak; the majority had eaten food from seven outlets specialising in Indian or Middle Eastern cuisine. Five outlets were linked to two or more cases, all of which used fresh coriander although a shared supplier was not identified. An investigation at one of the venues recorded that 86% of cases reported eating dishes with coriander as an ingredient or garnish. Four cases were admitted to hospital and one had evidence of treatment failure with ciprofloxacin. Phylogenetic analysis showed that the outbreak strain was part of a wider multidrug-resistant clade associated with travel to Pakistan. Poor hygiene practices during cultivation, distribution or preparation of fresh produce are likely contributing factors.

Zakażenia przewodu pokarmowego w XXI wieku w Polsce i na świecie

Na początku XXI wieku wciąż istnieje ogólnoświatowy problem zakażeń przewodu pokarmowego we wszystkich grupach wiekowych ludności. Za najpowszechniejszy czynnik etiologiczny chorób biegunkowych na świecie przenoszony przez skażoną żywność uważany jest Norovirus oraz bakterie z rodzaju Salmonella i Campylobacter, jednak za największą liczbę nieżytów żołądkowo-jelitowych odpowiadają rotawirusy. Ciągle terenami endemicznymi ciężkich zakażeń pokarmowych jest Afryka, Azja Południowo-Wschodnia, Ameryka Łacińska oraz wschodnia część Basenu Morza Śródziemnego. Na tych terenach utrzymują się „stare” czynniki etiologiczne biegunek, takie jak np.: Vibrio cholerae, Salmonella Typhi, Salmonella Paratyphi. Grupą szczególnie narażoną na infekcje pokarmowe pozostają dzieci <5. roku życia. Głównym czynnikiem etiologicznym biegunek w tej grupie wiekowej – zarówno w krajach rozwiniętych, jak i rozwijających się – są rotawirusy. Odpowiadają one za 500 tys. zgonów rocznie. Polska ze względu na ograniczone standardy diagnostyczne, epidemiologicznie różni się częstotliwością występowania poszczególnych patogenów biegunkowych od pozostałych krajów. Dotyczy to niższej zapadalności na zakażenia o etiologiach: Campylobacter, Norovirus, Shigella. Dominującym czynnikiem zakażeń pokarmowych o podłożu bakteryjnym w kraju są pałeczki Salmonella, natomiast wirusowym rotawirusy. Wiedza na temat chorób infekcyjnych układu pokarmowego może być w XXI w. na nowo sformułowana, a lista czynników etiologicznych poszerzona, sprzyjają temu zaś badania mikrobioty jelit oraz powszechne stosowanie nowych technik diagnostycznych m.in. spektometrii mas i real-time PCR.

High carriage of ESBL-producing Enterobacteriaceae associated with sexual activity among men who have sex with men

BACKGROUND

Extended-spectrum β-lactamase Enterobacteriaceae (ESBL-E) may be sexually transmitted. Men who have sex with men (MSM) have different sexual behaviour than the general population, and thus may be at risk for ESBL-E carriage. This study determined the prevalence of ESBL-E carriage and its association with sexual behaviour among MSM in Amsterdam, The Netherlands.

MATERIALS AND METHODS

In total, 583 HIV-positive and HIV-negative MSM from the Amsterdam Cohort Study were screened for rectal ESBL-E carriage between April and December 2018. Participants completed a self-administered questionnaire on (sexual) behaviour and risk factors for antimicrobial resistance. The proportion of the study population with ESBL-E carriage was compared by number of sexual partners using logistic regression, and across clusters of sexual behaviours with steady and casual partners, separately, using latent class analyses; all results were adjusted for recent use of antibiotics, travel and hospitalization.

RESULTS

Overall, 16.3% [95% confidence interval (CI) 13.4-19.5] of the study population tested positive for ESBL-E. The odds of ESBL-E carriage increased as number of sexual partners increased [adjusted odds ratio per ln(partner+1), 1.57, 95% CI 1.26-1.94; P<0.001]. There was no association between ESBL-E carriage and sexual behaviour with steady partner(s). Compared with participants in the 'no sex with casual partner(s)' cluster, adjusted odds of being ESBL-E positive were 2.95-fold higher (95% CI 1.52-5.80) for participants in the 'rimming and frottage' cluster (P=0.001) and 2.28-fold higher (95% CI 0.98-5.31) for participants in the 'toy use and fisting' cluster (P=0.056).

CONCLUSIONS

The prevalence of ESBL-E in MSM is higher compared with the overall Dutch population, likely due to sexual transmission with casual partners. This implies that sexually active MSM should be considered a risk group for ESBL-E carriage.

Human intestinal spirochetosis, a sexually transmissible infection? Review of six cases from two sexually transmitted infection centres in Barcelona

Human intestinal spirochetosis (HIS) is a possible cause of chronic diarrhoea and affects mainly men who have sex with men (MSM) and people living with HIV. Diagnosis is based on colon biopsy, where spirochetes can be observed on the luminal surface, especially with the Warthin-Starry stain or similar silver stains. We conducted a retrospective descriptive study of all HIS cases diagnosed in two sexually transmitted infections (STI) centres in Barcelona from 2009 until 2018. The medical histories were reviewed to gather epidemiological, clinical, and diagnostic variables. Six patients were diagnosed with HIS. All the individuals were MSM, with a median age of 31.5 years (interquartile range [IQR] 29.5;49.25) and half of them were living with HIV. Five patients reported condomless anal intercourse and 4 patients had practised oro-anal sex previously. Concomitantly, two of them had rectal gonorrhoea, one had rectal Chlamydia trachomatis and none of them had syphilis. The predominant clinical symptom was diarrhoea (5 patients). All cases were diagnosed by a Warthin-Starry stain on a colon biopsy specimen, and mild inflammatory changes were found in 5 cases. Five patients were treated with metronidazole and one with benzathine penicillin G. Treatment was successful in all the patients. HIS should be considered in patients with chronic diarrhoea who report risky sexual practices and/or concomitant STI. HIS may also be sexually transmitted according to the context.

Shigella sonnei: virulence and antibiotic resistance

Shigella sonnei is the emerging pathogen globally, as it is the second common infectious species of shigellosis (bloody diarrhoea) in low- and middle-income countries (LMICs) and the leading one in developed world. The multifactorial processes and novel mechanisms have been identified in S. sonnei, that are collectively playing apart a substantial role in increasing its prevalence, while replacing the S. flexneri and other Gram-negative gut pathogens niche occupancy. Recently, studies suggest that due to improvement in sanitation S. sonnei has reduced cross-immunization from Plesiomonas shigelliodes (having same O-antigen as S. sonnei) and also found to outcompete the two major species of Enterobacteriaceae family (Shigella flexneri and Escherichia coli), due to encoding of type VI secretion system (T6SS). This review aimed to highlight S. sonnei as an emerging pathogen in the light of recent research with pondering aspects on its epidemiology, transmission, and pathogenic mechanisms. Additionally, this paper aimed to review S. sonnei disease pattern and related complications, symptoms, and laboratory diagnostic techniques. Furthermore, the available treatment reigns and antibiotic-resistance patterns of S. sonnei are also discussed, as the ciprofloxacin and fluoroquinolone-resistant S. sonnei has already intensified the global spread and burden of antimicrobial resistance. In last, prevention and controlling strategies are briefed to limit and tackle S. sonnei and possible future areas are also explored that needed more research to unravel the hidden mysteries surrounding S. sonnei.

Co-circulation of Multidrug-resistant Shigella Among Men Who Have Sex With Men in Australia

BACKGROUND

In urban Australia, the burden of shigellosis is either in returning travelers from shigellosis-endemic regions or in men who have sex with men (MSM). Here, we combine genomic data with comprehensive epidemiological data on sexual exposure and travel to describe the spread of multidrug-resistant Shigella lineages.

METHODS

A population-level study of all cultured Shigella isolates in the state of Victoria, Australia, was undertaken from 1 January 2016 through 31 March 2018. Antimicrobial susceptibility testing, whole-genome sequencing, and bioinformatic analyses of 545 Shigella isolates were performed at the Microbiological Diagnostic Unit Public Health Laboratory. Risk factor data on travel and sexual exposure were collected through enhanced surveillance forms or by interviews.

RESULTS

Rates of antimicrobial resistance were high, with 17.6% (95/541) and 50.6% (274/541) resistance to ciprofloxacin and azithromycin, respectively. There were strong associations between antimicrobial resistance, phylogeny, and epidemiology. Specifically, 2 major MSM-associated lineages were identified: a Shigellasonnei lineage (n = 159) and a Shigella flexneri 2a lineage (n = 105). Of concern, 147/159 (92.4%) of isolates within the S. sonnei MSM-associated lineage harbored mutations associated with reduced susceptibility to recommended oral antimicrobials: namely, azithromycin, trimethoprim-sulfamethoxazole, and ciprofloxacin. Long-read sequencing demonstrated global dissemination of multidrug-resistant plasmids across Shigella species and lineages, but predominantly associated with MSM isolates.

CONCLUSIONS

Our contemporary data highlight the ongoing public health threat posed by resistant Shigella, both in Australia and globally. Urgent multidisciplinary public health measures are required to interrupt transmission and prevent infection.

Use of whole-genome sequencing to identify clusters of Shigella flexneri associated with sexual transmission in men who have sex with men in England: a validation study using linked behavioural data

Since the 1970s, shigellosis has been reported as a sexually transmissible infection, and in recent years, genomic data have revealed the breadth of Shigella spp. transmission among global networks of men who have sex with men (MSM). In 2015, Public Health England (PHE) introduced routine whole-genome sequencing (WGS) of Shigella spp. to identify transmission clusters. However, limited behavioural information for the cases hampers interpretation. We investigated whether WGS can distinguish between clusters representing sexual transmission in MSM and clusters representing community (non-sexual) transmission to inform infection control. WGS data for Shigella flexneri from August 2015 to July 2017 were aggregated into single linkage clusters based on SNP typing using a range of SNP distances (the standard for Shigella surveillance at PHE is 10 SNPs). Clusters were classified as ‘adult male’, ‘household’, ‘travel-associated’ or ‘community’ using routine demographic data submitted alongside laboratory cultures. From August 2015 to March 2017, PHE contacted those with shigellosis as part of routine public-health follow-up and collected exposure data on a structured questionnaire, which for the first time included questions about sexual identity and behaviour. The questionnaire data were used to determine whether clusters classified as ‘adult male’ represented likely sexual transmission between men, thereby validating the use of the SNP clustering tool for informing appropriate public-health responses. Overall, 1006 S. flexneri cases were reported, of which 563 clustered with at least one other case (10-SNP threshold). Linked questionnaire data were available for 106 clustered cases, of which 84.0 % belonged to an ‘adult male’ cluster. At the 10-SNP threshold, 95.1 % [95 % confidence interval (CI) 88.0–98.1%] of MSM belonged to an ‘adult male’ cluster, while 73.2 % (95 % CI 49.1–87.5%) of non-MSM belonged to a ‘community’ or ‘travel-associated’ cluster. At the 25-SNP threshold, all MSM (95 % CI 96.0–100%) belonged to an ‘adult male’ cluster and 77.8 % (95 % CI 59.2–89.4%) of non-MSM belonged to a ‘community’ or ‘travel-associated’ cluster. Within one phylogenetic clade of S. flexneri, 9 clusters were identified (7 ‘adult male’; 2 ‘community’) using a 10-SNP threshold, while a single ‘adult male’ cluster was identified using a 25-SNP threshold. Genotypic markers of azithromycin resistance were detected in 84.5 % (294/348) of ‘adult male’ cases and 20.9 % (9/43) of cases in other clusters (10-SNP threshold), the latter of which contained gay-identifying men who reported recent same-sex sexual contact. Our study suggests that SNP clustering can be used to identify Shigella clusters representing likely sexual transmission in MSM to inform infection control. Defining clusters requires a flexible approach in terms of genetic relatedness to ensure a clear understanding of underlying transmission networks.

Persistent Transmission of Shigellosis in England Is Associated with a Recently Emerged Multidrug-Resistant Strain of Shigella sonnei

Whole-genome sequencing has enhanced surveillance and facilitated detailed monitoring of the transmission of Shigella species in England. We undertook an epidemiological and phylogenetic analysis of isolates from all cases of shigellosis referred to Public Health England between 2015 and 2018 to explore recent strain characteristics and the transmission dynamics of Shigella species. Of the 4,950 confirmed cases of shigellosis identified during this period, the highest proportion of isolates was Shigella sonnei (54.4%), followed by S. flexneri (39.2%), S. boydii (4.1%), and S. dysenteriae (2.2%). Most cases were adults (82.9%) and male (59.5%), and 34.9% cases reported recent travel outside the United Kingdom. Throughout the study period, diagnoses of S. flexneri and S. sonnei infections were most common in men with no history of recent travel abroad. The species prevalence was not static, with cases of S. flexneri infection in men decreasing between 2015 and 2016 and the number of cases of S. sonnei infection increasing from 2017. Phylogenetic analysis showed this recent increase in S. sonnei infections was attributed to a novel clade that emerged from a Central Asia sublineage exhibiting resistance to ciprofloxacin and azithromycin. Despite changes in species prevalence, diagnoses of Shigella infections in England are persistently most common in adult males without a reported travel history, consistent with sexual transmission among men who have sex with men. The trend toward increasing rates of ciprofloxacin resistance in S. sonnei, in addition to plasmid-mediated azithromycin resistance, is of significant public health concern with respect to the transmission of multidrug-resistant gastrointestinal pathogens and the risk of treatment failures.

Shigellosis in adults: A retrospective study of clinical and epidemiological features in East London

Shigella is a leading cause of gastroenteritis worldwide; however, data on clinical outcomes amongst adults are lacking. All adult cases (>16 years) of Shigella gastroenteritis diagnosed between January 2014 to December 2017 at an East London NHS Trust in the United Kingdom were included. Demographic, clinical, microbiological and whole genome sequencing (WGS) data were retrospectively collected. Shigella spp isolates from 169 cases were identified: S. flexneri 90 (53.3%), S. sonnei 75 (44.9%) and S. boydii 4 (2.0%). The median age was 34 years (IQR 29–45), and 127 (75.1%) were male. S. flexneri cases were more likely to attend accident and emergency (46.7% vs. 25.3%, p = 0.005), be admitted to hospital (26.7% vs. 10.7%, p = 0.01), and receive antibiotics (51.1% vs. 28.0%, p = 0.003) compared to S. sonnei cases. Thirty-two (18.9%) patients were admitted to hospital for a median of five days (IQR 3–8). Where recorded 42/84 (50.0%) reported recent travel. Seventeen (10.1%) patients experienced complications. There were no deaths within one year of diagnosis. Seventy-nine isolates were characterised by WGS. Fifty-seven (72.2%) belonged to known national clusters; 44 (55.7%) involving adult males and 11 (13.9%) travel-associated clusters. We demonstrate the development of severe complications of shigellosis among adults and highlight the changing epidemiology and antibiotic resistance patterns.

Recent epidemiology of sexually transmissible enteric infections in men who have sex with men

PURPOSE OF REVIEW

Sexual transmission of enteric pathogens in men who have sex with men (MSM) has been described since the 1970s. Recently, an increasing number of enteric infection outbreaks have been reported in MSM. This article summarizes recent outbreaks and discusses the key issues for prevention and control.

RECENT FINDINGS

Sexually transmissible enteric infections (STEIs) can spread rapidly and internationally within highly connected MSM populations and are often associated with antimicrobial resistance (AMR). The infections often cluster in high-risk groups of HIV-positive MSM who are more likely to engage in diverse sexual practices and chemsex, and to have multiple other sexually transmitted infections (STIs).

SUMMARY

The roles of asymptomatic and/or persistent infection and other contextual factors in STEI transmission are not well described. STEI-associated AMR is increasing and has potential to spread rapidly in MSM, warranting further public health attention. A better understanding of the factors associated with sexual transmission will enable the development of more effective control measures. A holistic approach that promotes health and wellbeing as well as infection prevention and management is needed.

Risk Factors for Asymptomatic Enteric Pathogen Detection Among Men Who Have Sex With Men

Improved knowledge of factors that promote outbreaks of enteric pathogens among men who have sex with men (MSM) could enable targeted public health interventions. We detected enteric pathogens in 57 of 519 (11%) asymptomatic MSM, and we found that enteric pathogen detection was associated with both oroanal sex (rimming) and group sex.

Diarrhea caused by Shigella flexneri in patients with primary HIV infection

Acute bacterial diarrhea due to Shigella spp. infection is a common disease in low-income settings. In developed countries, these are usually cases of patients with recent travel history to tropical countries. In recent years, there has been a noticeable increase of cases of Shigella infection amongst men having sex with men in developed countries with no recent travel history. We present a report of two cases of patients hospitalized due to diarrhea of Shigella flexneri origin. During hospitalization, both of them were diagnosed also with primary HIV infection and one patient also had acute hepatitis A. The course of the disease was complicated in both cases and symptoms were severe. In both cases, Shigella was most likely transmitted through sexual contact. Shigella infection should also be considered as one of the sexually transmitted infections.

Epidemiology and prevention of sexually transmitted infections in men who have sex with men at risk of HIV

Since 2012, the increasingly widespread promotion and uptake of HIV treatment as prevention and pre-exposure prophylaxis in men who have sex with men has been associated with increased sexually transmitted infections (STIs). However, numbers of STI cases have been rising for more than 20 years and the introduction of biomedical HIV interventions cannot explain the majority of the rises in STIs. The increases appear to have occurred mostly because of gradual changes in behaviour over many years, coupled in some settings with more condomless anal intercourse, and as a result of the increased screening for previously undetected asymptomatic infections. If control of STIs is to be improved, then a far greater emphasis on increased use of existing effective STI control strategies will be required, in addition to the investigation of new interventions. Central to effective STI control is accessible clinical care and screening services, which are currently inadequate in most settings. Insufficient action carries a risk of increased STI epidemics, including of newly resistant organisms.

Awareness of and attitudes to sexually transmissible infections among gay men and other men who have sex with men in England: a qualitative study

Background Rates of sexually transmissible infections (STIs) have increased over recent years among gay men and other men who have sex with men (MSM) in England and Wales. HIV diagnoses remain high in this group and men with diagnosed HIV are disproportionally affected by STIs. MSM are therefore a priority for health promotion efforts to reduce STIs. Understanding awareness of and attitudes towards STIs is essential in developing health promotion interventions to reduce prevalence. Methods: Eight focus group discussions (FGDs) with a total of 61 MSM in four English cities included a ranking exercise to gauge how ‘scary’ participants thought 11 STIs are. The exercise sought insights into participants’ awareness of, knowledge about and attitudes towards STIs and blood-borne viruses (BBVs). FGDs were audio-recorded, transcribed and data analysed thematically. Results: All groups ranked HIV and Hepatitis C virus (HCV) as the scariest infections, and the majority ranked syphilis and herpes as highly scary. Scabies was ranked as the least scary by most groups. Rankings were dependent on how well informed participants felt about an infection, its transmission mechanisms, health affect and the availability of vaccines and treatment. Personal experience or that of friends influenced perceptions of particular infections, as did their prevalence, treatment options, visibility of symptoms and whether an STI could be cleared from the body. Conclusions: The study findings suggest that, although some MSM are well informed, there is widespread lack of knowledge about the prevalence, modes of transmission, health implications and treatment regimens of particular STIs.

Use of gender distribution in routine surveillance data to detect potential transmission of gastrointestinal infections among men who have sex with men in England

Detecting gastrointestinal (GI) infection transmission among men who have sex with men (MSM) in England is complicated by a lack of routine sexual behavioural data. We investigated whether gender distributions might generate signals for increased transmission of GI pathogens among MSM. We examined the percentage male of laboratory-confirmed patient-episodes for patients with no known travel history for 10 GI infections of public health interest in England between 2003 and 2013, stratified by age and region. An adult male excess was observed for Shigella spp. (annual maximum 71% male); most pronounced for those aged 25-49 years and living in London, Brighton and Manchester. An adult male excess was observed every year for Entamoeba histolytica (range 59.8-76.1% male), Giardia (53.1-57.6%) and Campylobacter (52.1-53.5%) and for a minority of years for hepatitis A (max. 69.8%) and typhoidal salmonella (max. 65.7%). This approach generated a signal for excess male episodes for six GI pathogens, including a characterised outbreak of Shigella among MSM. Stratified analyses by geography and age group were consistent with MSM transmission for Shigella. Optimisation and routine application of this technique by public health authorities elsewhere might help identify potential GI infection outbreaks due to sexual transmission among MSM, for further investigation.

An outbreak of a rare Shiga-toxin-producing Escherichia coli serotype (O117:H7) among men who have sex with men

Sexually transmissible enteric infections (STEIs) are commonly associated with transmission among men who have sex with men (MSM). In the past decade, the UK has experienced multiple parallel STEI emergences in MSM caused by a range of bacterial species of the genus Shigella, and an outbreak of an uncommon serotype (O117 : H7) of Shiga-toxin-producing Escherichia coli (STEC). Here, we used microbial genomics on 6 outbreak and 30 sporadic STEC O117 : H7 isolates to explore the origins and pathogenic drivers of the STEC O117 : H7 emergence in MSM. Using genomic epidemiology, we found that the STEC O117 : H7 outbreak lineage was potentially imported from Latin America and likely continues to circulate both in the UK MSM population and in Latin America. We found genomic relationships consistent with existing symptomatic evidence for chronic infection with this STEC serotype. Comparative genomic analysis indicated the existence of a novel Shiga toxin 1-encoding prophage in the outbreak isolates, and evidence of horizontal gene exchange among the STEC O117 : H7 outbreak lineage and other enteric pathogens. There was no evidence of increased virulence in the outbreak strains relative to contextual isolates, but the outbreak lineage was associated with azithromycin resistance. Comparing these findings with similar genomic investigations of emerging MSM-associated Shigella in the UK highlighted many parallels, the most striking of which was the importance of the azithromycin phenotype for STEI emergence in this patient group.

Emergence of quinolone-resistant Shigella flexneri in Italy (March 2017)

In March 2017, a 45-year-old Italian man who has sex with men was admitted to the Infectious Diseases Department of Trieste Hospital (northeast Italy), because of fever, abdominal pain and dysentery. The patient had neither foreign travel history nor sexual contact with non-Italian partners. Stool cultures grew multidrug-resistant Shigella flexneri (resistant to ampicillin, chloramphenicol, streptomycin, tetracycline, trimethoprim, amoxicillin/clavulanic acid and ciprofloxacin) and whole genome sequencing detailed the resistance features. The phylogenetic analysis showed that the strain was unrelated to any previously reported strain. The patient was treated successfully with ceftriaxone. We hereby report the first case of locally-acquired, multidrug-resistant S. flexneri infection in Italy and also the emergence of a new clone.

Genomic epidemiology of Shigella in the United Kingdom shows transmission of pathogen sublineages and determinants of antimicrobial resistance

Shigella are globally important diarrhoeal pathogens that are endemic in low-to-middle income nations and also occur in high income nations, typically in travellers or community-based risk-groups. Shigella phylogenetics reveals population structures that are more reliable than those built with traditional typing methods, and has identified sublineages associated with specific geographical regions or patient groups. Genomic analyses reveal temporal increases in Shigella antimicrobial resistance (AMR) gene content, which is frequently encoded on mobile genetic elements. Here, we whole genome sequenced representative subsamples of S. flexneri 2a and S. sonnei (n = 366) from the United Kingdom from 2008 to 2014, and analysed these alongside publicly available data to make qualitative insights on the genomic epidemiology of shigellosis and its AMR within the broader global context. Combined phylogenetic, epidemiological and genomic anlayses revealed the presence of domestically-circulating sublineages in patient risk-groups and the importation of travel-related sublineages from both Africa and Asia, including ciprofloxacin-resistant sublineages of both species from Asia. Genomic analyses revealed common AMR determinants among travel-related and domestically-acquired isolates, and the evolution of mutations associated with reduced quinolone susceptibility in domestically-circulating sublineages. Collectively, this study provides unprecedented insights on the contribution and mobility of endemic and travel-imported sublineages and AMR determinants responsible for disease in a high-income nation.

100 years of STIs in the UK: a review of national surveillance data

Objectives

The 1916 Royal Commission on Venereal Diseases was established in response to epidemics of syphilis and gonorrhoea in the UK. In the 100 years since the Venereal Diseases Act (1917), the UK has experienced substantial scientific, economic and demographic changes. We describe historical and recent trends in STIs in the UK.

Methods

We analysed surveillance data derived from STI clinics’ statistical returns from 1917 to 2016.

Results

Since 1918, gonorrhoea and syphilis diagnoses have fluctuated, reflecting social, economic and technological trends. Following spikes after World Wars I and II, rates declined before re-emerging during the 1960s. At that time, syphilis was more common in men, suggestive of transmission within the men who have sex with men (MSM) population. Behaviour change following the emergence of HIV/AIDS in the 1980s is thought to have facilitated a precipitous decline in diagnoses of both STIs in the mid-1980s. Since the early 2000s, gonorrhoea and syphilis have re-emerged as major public health concerns due to increased transmission among MSM and the spread of antimicrobial-resistant gonorrhoea. Chlamydia and genital warts are now the most commonly diagnosed STIs in the UK and have been the focus of public health interventions, including the national human papillomavirus vaccination programme, which has led to substantial declines in genital warts in young people, and the National Chlamydia Screening Programme in England. Since the 1980s, MSM, black ethnic minorities and young people have experienced the highest STI rates.

Conclusion

Although diagnoses have fluctuated over the last century, STIs continue to be an important public health concern, often affecting more marginalised groups in society. Prevention must remain a public health priority and, as we enter a new era of sexual healthcare provision including online services, priority must be placed on maintaining prompt access for those at greatest risk of STIs.

Horizontal antimicrobial resistance transfer drives epidemics of multiple Shigella species

Horizontal gene transfer has played a role in developing the global public health crisis of antimicrobial resistance (AMR). However, the dynamics of AMR transfer through bacterial populations and its direct impact on human disease is poorly elucidated. Here, we study parallel epidemic emergences of multiple Shigella species, a priority AMR organism, in men who have sex with men to gain insight into AMR emergence and spread. Using genomic epidemiology, we show that repeated horizontal transfer of a single AMR plasmid among Shigella enhanced existing and facilitated new epidemics. These epidemic patterns contrasted with slighter, slower increases in disease caused by organisms with vertically inherited (chromosomally encoded) AMR. This demonstrates that horizontal transfer of AMR directly affects epidemiological outcomes of globally important AMR pathogens and highlights the need for integration of genomic analyses into all areas of AMR research, surveillance and management.

Shigellosis outbreak among MSM living with HIV: a case-control study in Taiwan, 2015-2016

OBJECTIVES

Outbreaks of shigellosis among men who have sex with men (MSM) have been reported since the late 1990s. HIV infection is an important risk factor. Since 2014, the global shigellosis epidemic has intensified. Whether chemsex (the use of crystal methamphetamine, γ-hydroxybutyrate or mephedrone to enhance sex) is a new risk factor has not been previously examined.

METHODS

We conducted a population-based, case-control study in Taiwan. Acute shigellosis cases diagnosed during the 2015 outbreak among MSM living with HIV were compared with those without shigellosis. CD4⁺ counts, plasma viral load (pVL), gonorrhoea, syphilis and amoebiasis records were obtained from the Notifiable Disease Surveillance System database. We invited cases/controls to provide information on illicit drug use and sexual behaviours, using a structured questionnaire.

RESULTS

Seventy-five shigellosis cases were compared with 225 controls. High pVL (>100 000 copies/mL; adjusted OR (aOR): 4.9, 95% CI 1.4 to 16.9), gonorrhoea (aOR: 29.4, 95% CI 2.3 to 340.2) and syphilis (aOR: 4.3, 95% CI 1.6 to 11.6) were independent risk factors of shigellosis. Twenty shigellosis cases and 59 controls completed the questionnaire. Oral-to-anal sex (aOR: 15.5, 95% CI 3.6 to 66.7), chemsex (aOR: 5.6, 95% CI 1.4 to 22.7) and poppers use (aOR: 10.9, 95% CI 1.9 to 64.2) within 12 months were independent behavioural risk factors of shigellosis.

CONCLUSIONS

Chemsex is a new risk factor for shigellosis among MSM living with HIV, as identified in the 2015-2016 outbreak. Additional risk factors include poppers use, sexual risk behaviours and high pVL. Further studies on chemsex among MSM, which is a rising public health concern, are urgently required.

Outbreak of intestinal amoebiasis among men who have sex with men, Barcelona (Spain), October 2016 and January 2017

Entamoeba histolytica has been recently recognised as an emerging sexually transmissible pathogen in men who have sex with men (MSM), causing sporadic outbreaks in countries where it is not endemic. Here we report two closed clusters of invasive amoebiasis occurring in Barcelona, Spain, in October 2016 (four cases) and in January 2017 (four cases).

The clinical effectiveness of individual behaviour change interventions to reduce risky sexual behaviour after a negative human immunodeficiency virus test in men who have sex with men: systematic and realist reviews and intervention development

BACKGROUND

Men who have sex with men (MSM) experience significant inequalities in health and well-being. They are the group in the UK at the highest risk of acquiring a human immunodeficiency virus (HIV) infection. Guidance relating to both HIV infection prevention, in general, and individual-level behaviour change interventions, in particular, is very limited.

OBJECTIVES

To conduct an evidence synthesis of the clinical effectiveness of behaviour change interventions to reduce risky sexual behaviour among MSM after a negative HIV infection test. To identify effective components within interventions in reducing HIV risk-related behaviours and develop a candidate intervention. To host expert events addressing the implementation and optimisation of a candidate intervention.

DATA SOURCES

All major electronic databases (British Education Index, BioMed Central, Cumulative Index to Nursing and Allied Health Literature, EMBASE, Educational Resource Index and Abstracts, Health and Medical Complete, MEDLINE, PsycARTICLES, PsycINFO, PubMed and Social Science Citation Index) were searched between January 2000 and December 2014.

REVIEW METHODS

A systematic review of the clinical effectiveness of individual behaviour change interventions was conducted. Interventions were examined using the behaviour change technique (BCT) taxonomy, theory coding assessment, mode of delivery and proximity to HIV infection testing. Data were summarised in narrative review and, when appropriate, meta-analysis was carried out. Supplemental analyses for the development of the candidate intervention focused on post hoc realist review method, the assessment of the sequential delivery and content of intervention components, and the social and historical context of primary studies. Expert panels reviewed the candidate intervention for issues of implementation and optimisation.

RESULTS

Overall, trials included in this review (n = 10) demonstrated that individual-level behaviour change interventions are effective in reducing key HIV infection risk-related behaviours. However, there was considerable clinical and methodological heterogeneity among the trials. Exploratory meta-analysis showed a statistically significant reduction in behaviours associated with high risk of HIV transmission (risk ratio 0.75, 95% confidence interval 0.62 to 0.91). Additional stratified analyses suggested that effectiveness may be enhanced through face-to-face contact immediately after testing, and that theory-based content and BCTs drawn from 'goals and planning' and 'identity' groups are important. All evidence collated in the review was synthesised to develop a candidate intervention. Experts highlighted overall acceptability of the intervention and outlined key ways that the candidate intervention could be optimised to enhance UK implementation.

LIMITATIONS

There was a limited number of primary studies. All were from outside the UK and were subject to considerable clinical, methodological and statistical heterogeneity. The findings of the meta-analysis must therefore be treated with caution. The lack of detailed intervention manuals limited the assessment of intervention content, delivery and fidelity.

CONCLUSIONS

Evidence regarding the effectiveness of behaviour change interventions suggests that they are effective in changing behaviour associated with HIV transmission. Exploratory stratified meta-analyses suggested that interventions should be delivered face to face and immediately after testing. There are uncertainties around the generalisability of these findings to the UK setting. However, UK experts found the intervention acceptable and provided ways of optimising the candidate intervention.

FUTURE WORK

There is a need for well-designed, UK-based trials of individual behaviour change interventions that clearly articulate intervention content and demonstrate intervention fidelity.

STUDY REGISTRATION

The study is registered as PROSPERO CRD42014009500.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Concordance of gonorrhoea of the rectum, pharynx and urethra in same-sex male partnerships attending a sexual health service in Melbourne, Australia

BACKGROUND

We aimed to describe anatomic site-specific concordance of gonococcal infections in partnerships of men who have sex with men (MSM).

METHODS

We conducted a cross-sectional analysis of data from MSM partnerships attending Melbourne Sexual Health Centre between March 2011 and February 2015. Logistic regression models (random effect) were used to examine the association between gonococcal infections of the urethra, rectum and pharynx. Gonococci were detected by culture at all anatomic sites.

RESULTS

The analysis included 495 partnerships. Of the men with urethral gonorrhoea, 33% (95% CI 18-52) had partners with pharyngeal gonorrhoea and 67% (95% CI 48-82) had partners with rectal gonorrhoea. The adjusted odds of having urethral gonorrhoea was 4.6 (95% CI 1.2-17.1) for a man whose partner had pharyngeal gonorrhoea, and 48.1 (95% CI 18.3-126.7) for a man whose partner had rectal gonorrhoea. Of the men with rectal gonorrhoea, 46% (95% CI 31-61) had a partner with urethral gonorrhoea and 23% (95% CI 12-37) had a partner with pharyngeal gonorrhoea. The adjusted odds of having rectal gonorrhoea was 63.9 (95% CI 24.7-165.6) for a man whose partner had urethral gonorrhoea. Of the men with pharyngeal gonorrhoea, 42% (95% CI 23-63) had a partner with rectal gonorrhoea and 23% (95% CI 9-44) had a partner with had a partner with pharyngeal gonorrhoea. The adjusted odds of having pharyngeal gonorrhoea was 8.9 (95% CI 3.2-24.6) for a man whose partner had rectal gonorrhoea. The crude odds of having pharyngeal gonorrhoea was 14.2 (95% CI 5.1-39.0) for a man whose partner had pharyngeal gonorrhoea.

CONCLUSIONS

These data provide the first estimates of concordance of anatomic site-specific gonococcal infections in MSM partnerships, and confirm that urethral gonorrhoea is contracted from both rectal and pharyngeal sites, and suggest that gonococci transmit between the rectum and pharynx. However, due to use of culture rather than NAAT, our analysis was not adequately powered to assess pharynx-to-pharynx transmission of gonococci.