High rates of quinolone-resistant strains of Shigella sonnei in HIV-infected MSM

Cinnamaldehyde inhibits the NLRP3 inflammasome by preserving mitochondrial integrity and augmenting autophagy in Shigella sonnei-infected macrophages

BACKGROUND

Worldwide, more than 125 million people are infected with Shigella each year and develop shigellosis. In our previous study, we provided evidence that Shigella sonnei infection triggers activation of the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome in macrophages. NLRP3 inflammasome is responsible for regulating the release of the proinflammatory cytokines interleukin (IL)-1β and IL-18 through the protease caspase-1. Researchers and biotech companies have shown great interest in developing inhibitors of the NLRP3 inflammasome, recognizing it as a promising therapeutic target for several diseases. The leaves of Cinnamomum osmophloeum kaneh, an indigenous tree species in Taiwan, are rich in cinnamaldehyde (CA), a compound present in significant amounts. Our aim is to investigate how CA affects the activation of the NLRP3 inflammasome in S. sonnei-infected macrophages.

METHODS

Macrophages were infected with S. sonnei, with or without CA. ELISA and Western blotting were employed to detect protein expression or phosphorylation levels. Flow cytometry was utilized to assess H2O2 production and mitochondrial damage. Fluorescent microscopy was used to detect cathepsin B activity and mitochondrial ROS production. Additionally, colony-forming units were employed to measure macrophage phagocytosis and bactericidal activity.

RESULTS

CA inhibited the NLRP3 inflammasome in S. sonnei-infected macrophages by suppressing caspase-1 activation and reducing IL-1β and IL-18 expression. CA also inhibited pyroptosis by decreasing caspase-11 and Gasdermin D activation. Mechanistically, CA reduced lysosomal damage and enhanced autophagy, while leaving mitochondrial damage, mitogen-activated protein kinase phosphorylation, and NF-κB activation unaffected. Furthermore, CA significantly boosted phagocytosis and the bactericidal activity of macrophages against S. sonnei, while reducing secretion of IL-6 and tumour necrosis factor following infection.

CONCLUSION

CA shows promise as a nutraceutical for mitigating S. sonnei infection by diminishing inflammation and enhancing phagocytosis and the bactericidal activity of macrophages against S. sonnei.

Healthcare providers' knowledge and clinical practice surrounding shigellosis - DocStyles Survey, 2020

BACKGROUND

Shigellosis is an acute diarrheal disease transmitted through contaminated food, water, objects, poor hand hygiene, or sexual activity. Healthcare providers (HCP) may not be aware of the multiple routes of Shigella transmission, populations at increased risk, or importance of antibiotic susceptibility testing (AST). This study assessed HCP knowledge and clinical practices regarding shigellosis and antibiotic resistance.

METHODS

Porter Novelli Public Services administered a web-based survey (Fall DocStyles 2020) to HCP in the United States. Pediatricians, primary care physicians, nurse practitioners, and physician assistants completed questions about knowledge and clinical practice of acute diarrhea and shigellosis.

RESULTS

Of 2196 HCP contacted, 1503 responded (68% response rate). Most identified contaminated food (85%) and water (79%) as routes of Shigella transmission; fewer recognized person-to-person contact (40%) and sexual activity (18%). Men who have sex with men (MSM) were identified as being at risk for shigellosis by 35% of respondents. Most reported counseling patients to wash hands (86%) and avoid food preparation (77%) when ill with shigellosis; 29% reported recommending avoiding sex. Many HCP reported treating shigellosis empirically with ciprofloxacin (62%) and azithromycin (32%), and 29% reported using AST to guide treatment.

CONCLUSIONS

We identified several gaps in shigellosis knowledge among HCP including MSM as a risk group, person-to-person transmission, and appropriate antibiotic use. Improving HCP education could prevent the spread of shigellosis, including drug-resistant infections, among vulnerable populations.

Antimicrobial resistance in sexually transmitted Shigella in men who have sex with men: A systematic review

BACKGROUND

Outbreaks of sexually transmitted Shigella flexneri and Shigella sonnei in men who have sex with men (MSM) are a major public health issue. While most cases can be managed conservatively, a minority require antimicrobial treatment. Recent reports have highlighted increasing antimicrobial resistant (AMR) strains of Shigella spp. in men who have sex with men. We aimed to systematically review antimicrobial resistance (and decreased antimicrobial sensitivity) in sexually transmitted shigella in men who have sex with men, focussing on macrolides, quinolones, and third generation cephalosporins.

METHODS

We systematically searched 4 bibliographical databases (EMBASE, medline, EMCARE and CINAHL) from January 2011 to November 2021. We used a 2-stage process to assess eligibility: the primary author conducted an initial screen and then 3 authors conducted independent full-text reviews to determine the final eligible manuscripts. We only included manuscripts in English which included men who have sex with men with sexually transmitted shigella where data on antimicrobial resistance was available.

RESULTS

Thirty-nine manuscripts met the inclusion criteria. A majority of the manuscripts (N = 34) described reduced susceptibility or antimicrobial resistant to macrolides, quinolones and third generation cephalosporins in circulating strains of shigella within sexual networks of men who have sex with men. Extensively drug resistant outbreaks of shigella in men who have sex with men have been reported containing genetic markers of ceftriaxone resistance (e.g. BlaCTX-M27) where isolates also contained markers of reduced susceptibility, and antimicrobial resistant to macrolides and quinolones.

CONCLUSION

There is little role for macrolides, quinolones or third generation cephalosporins in the management of sexually transmitted shigella in men who have sex with men. More research is needed to develop novel strategies for shigella control in men who have sex with men, as antimicrobial options are diminishing.

Antimicrobial-Resistant Shigella spp. in San Diego, California, USA, 2017-2020

Annually, Shigella spp. cause ≈188 million cases of diarrheal disease globally, including 500,000 cases in the United States; rates of antimicrobial resistance are increasing. To determine antimicrobial resistance and risk factors in San Diego, California, USA, we retrospectively reviewed cases of diarrheal disease caused by Shigella flexneri and S. sonnei diagnosed during 2017-2020. Of 128 evaluable cases, S. flexneri was slightly more common than S. sonnei; most cases were in persons who were gay or bisexual cisgender men, were living with HIV, were unhoused, or used methamphetamines. Overall, rates of resistance to azithromycin, fluoroquinolones, ampicillin, and trimethoprim/sulfamethoxazole (TMP/SMX) were comparable to the most recent national data reported from the Centers for Disease Control and Prevention; 55% of isolates were resistant to azithromycin, 23% to fluoroquinolones, 70% to ampicillin, and 83% to TMP/SMX. The rates that we found for TMP/SMX were slightly higher than those in national data.

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.

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.

A Multifactorial Approach for Surveillance of Shigella spp. and Entero-Invasive Escherichia coli Is Important for Detecting (Inter)national Clusters

Shigella spp. and entero-invasive Escherichia coli (EIEC) can cause mild diarrhea to dysentery. In Netherlands, although shigellosis is a notifiable disease, there is no laboratory surveillance for Shigella spp. and EIEC in place. Consequently, the population structure for circulating Shigella spp. and EIEC isolates is not known. This study describes the phenotypic and serological characteristics, the phenotypic and genetic antimicrobial resistance (AMR) profiles, the virulence gene profiles, the classic multi-locus sequence types (MLST) and core genome (cg)MLST types, and the epidemiology of 414 Shigella spp. and EIEC isolates collected during a cross-sectional study in Netherlands in 2016 and 2017. S. sonnei (56%), S. flexneri (25%), and EIEC (15%) were detected predominantly in Netherlands, of which the EIEC isolates were most diverse according to their phenotypical profile, O-types, MLST types, and cgMLST clades. Virulence gene profiling showed that none of the isolates harbored Shiga toxin genes. Most S. flexneri and EIEC isolates possessed nearly all virulence genes examined, while these genes were only detected in approximately half of the S. sonnei isolates, probably due to loss of the large invasion plasmid upon subculturing. Phenotypical resistance correlated well with the resistant genotype, except for the genes involved in resistance to aminoglycosides. A substantial part of the characterized isolates was resistant to antimicrobials advised for treatment, i.e., 73% was phenotypically resistant to co-trimoxazole and 19% to ciprofloxacin. AMR was particularly observed in isolates from male patients who had sex with men (MSM) or from patients that had traveled to Asia. Furthermore, isolates related to international clusters were also circulating in Netherlands. Travel-related isolates formed clusters with isolates from patients without travel history, indicating their emergence into the Dutch population. In conclusion, laboratory surveillance using whole genome sequencing as high-resolution typing technique and for genetic characterization of isolates complements the current epidemiological surveillance, as the latter is not sufficient to detect all (inter)national clusters, emphasizing the importance of multifactorial public health approaches.

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.

Antibiotic treatment of gastroenteritis in primary care

Background

Gastroenteritis (GE) is a frequent reason for consultating a general practitioner. Yet little is known about antibiotic prescribing in primary care patients with GE. In this study, we quantified empirical and targeted antibiotic treatment of GE, compliance with recommendations from primary care clinical practice guidelines (CPGs) and the degree of antimicrobial resistance in patients receiving diagnostic faeces testing (DFT).

Methods

We performed a cohort study using routine care data of 160 general practitioners, including electronic patient records from 2013 to 2014. GE episodes were extracted and linked to microbiological laboratory records to retrieve results of DFT. For each episode, data on patient characteristics, DFT results including antimicrobial resistance testing, and antibiotic prescriptions were collected.

Results

We identified 13217 GE episodes. Antibiotic treatment was prescribed in 1163 (8.8%) episodes, most frequently with metronidazole (n = 646, 4.9%), azithromycin (n = 254, 1.9%) or ciprofloxacin (n = 184, 1.4%). Treatment was empirical for 641 (5%) GE episodes, of which 30% (n = 191) followed the CPG-recommended antibiotic choice. Targeted treatment following DFT results was prescribed for 537 GE episodes (4%), of which 99% (n = 529) followed CPG recommendations. Non-susceptibility to first- or second-choice antibiotics was demonstrated in three Salmonella isolates (9%-13% of all isolates) and one Campylobacter isolate (1%).

Conclusions

Antibiotic treatment of GE in primary care is relatively infrequent, with 1 in 11 episodes treated. Empirical treatment was more frequent compared with targeted treatment and mostly with non-CPG-recommended antibiotics. However, treatment based upon DFT results followed CPG recommendations.

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.

Dominant serotype distribution and antimicrobial resistance profile of Shigella spp. in Xinjiang, China

Shigella represents one of the major diarrhea-inducing pathogens threatening public health, but its prevalence and antimicrobial resistance profile in Xinjiang Uygur Autonomous region, China, remains unclear. We conducted comprehensive investigation of Shigella serotype distribution and antimicrobial resistance pattern in Xinjiang, identifying 458 Shigella isolates between 2008 to 2014. Shigella flexneri was identified as predominant species, and several S. flexneri serotypes were isolated, including atypical serotypes 1c, 2c, and 4s. Dominant S. flexneri serotypes were 2a, 1b, 2b, and Xv, different from those generally dominant in China. A hybrid serotype pattern was observed, which included the major Chinese serotypes (2a, Xv) and those predominant in Pakistan (1b, 2b). Shigella sonnei was shown to have a lower frequency compared with that generally observed in China, but an increasing trend of infections associated with this pathogen was observed. Furthermore, a high frequency of drug resistance and different Shigella antimicrobial resistance patterns were demonstrated as well, including very severe resistance phenotypes, such as multidrug resistance and resistance to frontline antibiotics. Seventy-five cephalosporin-resistant Shigella isolates were frequently identified with the resistance determinants that can undergo horizontal transfer, such as bla_OXA, bla_TEM, bla_CTX-M, and integrons, facilitating the development of cephalosporin resistance among Shigella subtypes. Additionally, genetic analyses demonstrated that all 86 quinolone-resistant S. flexneri isolates possess 3–4 mutation sites in quinolone resistance-determining regions, primarily contributing to their resistance to quinolone. However, S. sonnei isolates were not shown to be quinolone resistant. Co-resistance to cephalosporins and quinolones was detected in 17 S. flexneri isolates, and these isolates were additionally multidrug resistant and carried β-lactamase genes and quinolone-resistance determinants. As is demonstrated in this study, dominant serotypes of Shigella were distributed in unique trend with dangerous drug resistance patterns. Novel strategies are urgently required to prevent the development of drug resistance among diarrhea-inducing pathogens.

Disparities in severe shigellosis among adults - Foodborne diseases active surveillance network, 2002-2014

BACKGROUND

Shigella causes approximately 500,000 illnesses, 6000 hospitalizations, and 40 deaths in the United States annually, but incidence and populations at risk for severe shigellosis among adults are unclear. This study describes severe shigellosis among US adults.

METHODS

We analyzed Foodborne Diseases Active Surveillance Network data for infections caused by Shigella among adults ≥18 years old during 2002-2014. Criteria to define severe shigellosis included hospitalization, bacteremia, or death. We estimated annual incidence of shigellosis per 100,000 among adult populations, and conducted multivariable mixed-effects logistic regression to assess associations between severe shigellosis, demographic factors and Shigella species among adults with shigellosis.

RESULTS

Among 9968 shigellosis cases, 2764 (28%) were severe. Restricting to cases due to S. sonnei and S. flexneri, median annual incidence of severe shigellosis among adults was 0.56 and highest overall incidence was among black males 18-49 years old (1.58). Among adults with shigellosis, odds of severe disease were higher among males than females aged 18-49 years old (OR [95% CI] = 1.32 [1.15-1.52], p < 0.001) and among males than females with S. flexneri infections (OR [95% CI] =1.39 [1.10-1.75], p = 0.005). The odds of severe shigellosis were higher among blacks than whites (OR [95% CI] = 1.36 [1.22-1.52], p < 0.001).

CONCLUSIONS

Among adults, men 18-49 years old, particularly blacks, have the highest incidence of severe shigellosis. Among adults with shigellosis, severe shigellosis was associated with being male in age group 18-49 years, with infections caused by S. flexneri, and with black race. Future research should assess associations between severe shigellosis and sexual practices, antimicrobial resistance, comorbidities, and access to care.

ESBL-Producing and Macrolide-Resistant Shigella sonnei Infections among Men Who Have Sex with Men, England, 2015

In England in 2015, Shigella sonnei isolates from men who have sex with men produced extended-spectrum β-lactamases and exhibited macrolide resistance. Whole-genome sequencing showed a close relationship among the isolates, which harbored a plasmid that was previously identified in a shigellosis outbreak among this population but has acquired a mobile element.

2016 United Kingdom national guideline on the sexual health care of men who have sex with men

This guideline is intended for use in UK Genitourinary medicine clinics and sexual health services but is likely to be of relevance in all sexual health settings, including general practice and Contraception and Sexual Health (CASH) services, where men who have sex with men (MSM) seek sexual health care or where addressing the sexual health needs of MSM may have public health benefits. For the purposes of this document, MSM includes all gay, bisexual and all other males who have sex with other males and both cis and trans men. This document does not provide guidance on the treatment of particular conditions where this is covered in other British Association for Sexual Health and HIV (BASHH) Guidelines but outlines best practice in multiple aspects of the sexual health care of MSM. Where prevention of sexually transmitted infections including HIV can be addressed as an integral part of clinical care, this is consistent with the concept of combination prevention and is included. The document is designed primarily to provide guidance on the direct clinical care of MSM but also makes reference to the design and delivery of services with the aim of supporting clinicians and commissioners in providing effective services. Methodology This document was produced in accordance with the guidance set out in the BASHH CEG's document 'Framework for guideline development and assessment' published in 2010 at http://www.bashh.org/guidelines and with reference to the Agree II instrument. Following the production of the updated framework in April 2015, the GRADE system for assessing evidence was adopted and the draft recommendations were regraded. Search strategy (see also Appendix 1) Ovid Medline 1946 to December 2014, Medline daily update, Embase 1974 to December 2014, Pubmed NeLH Guidelines Database, Cochrane library from 2000 to December 2014. Search language English only. The search for Section 3 was conducted on PubMed to December 2014. Priority was given to peer-reviewed papers published in scientific journals, although for many issues evidence includes conference abstracts listed on the Embase database. In addition, for 'Identification of problematic recreational drug and alcohol use' section and 'Sexual problems and dysfunctions in MSM' section, searches included PsycINFO. Methods Article titles and abstracts were reviewed and if relevant the full text article was obtained. Priority was given to randomised controlled trial and systematic review evidence, and recommendations made and graded on the basis of best available evidence. Piloting and feedback The first draft of the guideline was circulated to the writing group and to a small group of relevant experts, third sector partners and patient representatives who were invited to comment on the whole document and specifically on particular sections. The revised draft was reviewed by the CEG and then reviewed by the BASHH patient/public panel and posted on the BASHH website for public consultation. The final draft was piloted before publication. Guideline update The guidelines will be reviewed and revised in five years' time, 2022.

Antibiotic-Resistant Infections and Treatment Challenges in the Immunocompromised Host

This article reviews antibiotic resistance and treatment of bacterial infections in the growing number of patients who are immunocompromised: solid organ transplant recipients, the neutropenic host, and persons with human immunodeficiency virus and AIDS. Specific mechanisms of resistance in both gram-negative and gram-positive bacteria, as well as newer treatment options are addressed elsewhere, and are only briefly discussed in the context of the immunocompromised host.

Elevated prevalence of multidrug-resistant gram-negative organisms in HIV positive men

BACKGROUND

Routes of transmission of multidrug-resistant gram-negative organisms (MDRGN) are not completely understood. Since sexual transmission of MDRGN might represent a potential mode that has not been noticed so far, this study evaluated transmission of MDRGN in HIV positive men.

METHODS

Between November 2014 and March 2016, we retrospectively investigated the MDRGN prevalence in rectal swabs of n = 109 males tested positive for HIV (HP). These findings were compared to the MDRGN prevalence in n = 109 rectal swabs in age-matched males tested negative for HIV (HN) within the same period. According to the infection control protocol of University Hospital Frankfurt, Germany (UHF), patients admitted to intensive/intermediate care units have to be screened for MDRGN on day of admittance. Patients without HIV testing or MDRGN screening were excluded.

RESULTS

MDRGN prevalence in rectal swabs was significantly higher (p = 0.002) in male HP (23.9%; 95% confidence interval 16.2-32.9%) than in age-matched male HN (8.3%; 3.8-15.1%). In total, 35 MDRGN species were detected. The most frequent MDRGN species was Escherichia coli with resistance due to ESBL expression and additional resistance to fluoroquinolones with n = 25/35 (71.4%; 53.7-85.4%). Thereof, n = 19/26 (73.1%; 52.2-88.4%) were detected in HP and n = 6/9 (66.7%; 29.9-92.5%) in HN, respectively.

CONCLUSIONS

Prevalence of MDRGN is significantly higher in male HIV positive than in male HIV negative individuals. This might indicate sexual transmission of MDRGN within the male HIV positive population. As treatment options in case of MRGN infections are limited, prevention of MDRGN transmission is strongly emphasized.

Elevated Risk for Antimicrobial Drug-Resistant Shigella Infection among Men Who Have Sex with Men, United States, 2011-2015

Shigella spp. cause ≈500,000 illnesses in the United States annually, and resistance to ciprofloxacin, ceftriaxone, and azithromycin is emerging. We investigated associations between transmission route and antimicrobial resistance among US shigellosis clusters reported during 2011-2015. Of 32 clusters, 9 were caused by shigellae resistant to ciprofloxacin (3 clusters), ceftriaxone (2 clusters), or azithromycin (7 clusters); 3 clusters were resistant to >1 of these drugs. We observed resistance to any of these drugs in all 7 clusters among men who have sex with men (MSM) but in only 2 of the other 25 clusters (p<0.001). Azithromycin resistance was more common among MSM-associated clusters than other clusters (86% vs. 4% of clusters; p<0.001). For adults with suspected shigellosis, clinicians should culture feces; obtain sex histories; discuss shigellosis prevention; and choose treatment, when needed, according to antimicrobial drug susceptibility. Public health interviews for enteric illnesses should encompass sex practices; health messaging for MSM must include shigellosis prevention.

Shigellosis in men who have sex with men: an overlooked opportunity to counsel with pre-exposure prophylaxis for HIV

In the absence of other epidemiological exposures, shigellosis in men who have sex with men (MSM) suggests engagement in high-risk sexual encounters. Infection and diagnosis of shigellosis in MSM presents a potentially overlooked opportunity to discuss the availability of pre-exposure prophylaxis medications to prevent incident HIV infections.

Shigellosis in Subjects with Traveler's Diarrhea Versus Domestically Acquired Diarrhea: Implications for Antimicrobial Therapy and Human Immunodeficiency Virus Surveillance

An increase of sexually transmitted shigellosis is currently being reported in developed countries. In addition, travel-related shigellosis can introduce resistant strains that could be disseminated within this new scenario. Epidemiological features and antimicrobial susceptibility of shigellosis depending on where infection was acquired were investigated. From 2008 to 2013, subjects with shigellosis were studied. Patients were classified according to acquisition of Shigella as traveler's diarrhea (TD) or domestically acquired diarrhea (DAD). Ninety cases of shigellosis were identified: 76 corresponding to the TD group and 14 to the DAD group. In the DAD group, most of patients were human immunodeficiency virus (HIV)-positive men who have sex with men (MSM), being shigellosis associated to male sex (P = 0.007) and HIV infection (P < 0.0001). S. sonnei (47.8%) and S. flexneri (42.2%) were the predominant species. The highest resistance was detected for trimethoprim/sulfamethoxazole (SXT) (81.8%), followed by ampicillin (AMP) (37.8%) and ciprofloxacin (CIP) (23.3%). Resistant Shigella strains were more frequent in subjects with TD than those with DAD, although only for CIP the difference was significant (P = 0.034). Continuous monitoring of patients with shigellosis is necessary to control the spread of resistant Shigella strains and for effective therapy. Men with shigellosis who have not traveled to an endemic area should be screened for HIV infection.

Enteropathogens and antibiotics

Infectious gastroenteritis remains a public health problem. The most severe cases are of bacterial origin. In Spain, Campylobacter and Salmonella are the most prevalent bacterial genus, while Yersinia and Shigella are much less frequent. Most cases are usually self-limiting and antibiotic therapy is not generally indicated, unless patients have risk factors for severe infection and shigellosis. Ciprofloxacin, third generation cephalosporins, azithromycin, ampicillin, cotrimoxazole and doxycycline are the most recommended drugs. The susceptibility pattern of the different bacteria determines the choice of the most appropriate treatment. The aim of this review is to analyse the current situation, developments, and evolution of resistance and multidrug resistance in these 4 enteric pathogens.

'Gay bowel syndrome': relic or real (and returning) phenomenon?

PURPOSE OF REVIEW

This article aims to review the term 'gay bowel syndrome', including the recent research looking at increased rates of bowel infections in men who have sex with men (MSM), particularly in light of the recent Shigella outbreaks in MSM in London and New York, and considers whether 'gay bowel syndrome' is a syndrome that really exists and is worthy of further research and specific treatment, or whether the term continues to be obsolete and not useful.

RECENT FINDINGS

Little or no recent research exists around the concept of a specific syndrome affecting the bowels of MSM. Rather, there seems to be a clustering of diseases in certain high-risk groups, especially those in urban areas with multiple sexual partners, recreational drug use, and possible concomitant HIV infection.

SUMMARY

All healthcare practitioners (including non-sexual health/HIV specialists) need to consider careful and thorough history taking (including sexual history) to identify those at risk.