Shigellosis

Macleaya cordata protopine total alkaloids as potential treatment for diarrhoea: Mechanistic insights and target identification

Diarrhoea remains a major public health concern, particularly affecting young children and livestock. Macleaya cordata protopine total alkaloids (MPTA), a standardized extract approved in China for poultry diarrhoea, has demonstrated anti-inflammatory properties in intestinal disorders. The study aims to investigate the antidiarrheal mechanism of MPTA using castor oil- and E. coli-induced diarrhoea models in mice. We first tested MPTA for acute oral toxicity. Subsequently, the effect of MPTA on castor oil- and E. coli-induced diarrhoea in mice based on LD50 results. Network pharmacology analysis and target competition assays (inhibitors and antagonists) were integrated to identify targets for MPTA's antidiarrheal effects. Molecular docking was used to verify the binding ability of MPTA components to these receptors. The LD50 of MPTA was determined to be 426.1 mg/kg. The optimal MPTA activity was found at 8 mg/kg in both castor oil and in infectious models. Network pharmacology analysis revealed potential targets and pathways of MPTA against intestinal motility. The impact of MPTA on cholinergic, serotonin, dopaminergic, and adrenergic receptors was assessed using standard inhibitors and agonists to induce intestinal smooth muscle contractions or relaxations. Molecular docking confirmed the binding ability of MPTA components to these receptors. In conclusion, MPTA exhibits significant antidiarrheal effects in both castor oil and E. coli-induced diarrhoea models. Its mechanism may involve modulation of cholinergic, serotonin, dopaminergic, and adrenergic receptors, as well as inhibition of ion channels and anti-inflammatory actions. These findings highlight the potential of MPTA as a novel therapeutic agent for diarrhoea.

Genetic characterization of extensively drug-resistant blaCTX-M-27Shigella sonnei clusters among men who have sex with men in a region of northern Spain

OBJECTIVE

The convergence of globalization with increased sexual risk behaviours has significantly facilitated the dissemination of multidrug-resistant and extensively drug-resistant clusters of Shigella spp. among men who have sex with men, particularly Shigella sonnei and Shigella flexneri. A cluster of S. sonnei carrying blaCTX-M-27 caused a European outbreak in 2020-2021, with more than 30 cases in Spain, including two in our institution. In this study, we conducted a retrospective study from October 2022 to December 2023 that included five additional patients with shigellosis caused by a CTX-M-27-producing S. sonnei.

METHODS

Genetic characterization was assessed by whole-genome sequencing using the MinION Mk1C device (Oxford Nanopore Technologies, Oxford, UK).

RESULTS

All the isolates presented IncB/O/K/Z or IncFII plasmids, which carried genes conferring resistance to second- and third-generation cephalosporins, cotrimoxazole, azithromycin and quinolones. SNP analysis revealed that neither the strains within this study nor the UK cluster were related to each other.

CONCLUSIONS

Different community clusters of extensively drug-resistant S. sonnei strains harbouring blaCTX-M-27 are spreading in our area, mainly associated with sexual transmission among men who have sex with men.

Shigella sonnei: epidemiology, evolution, pathogenesis, resistance and host interactions

Shigella sonnei is a major cause of diarrhoea globally and is increasing in prevalence relative to other Shigella because of multiple demographic and environmental influences. This single-serotype species has traditionally received less attention in comparison to Shigella flexneri and Shigella dysenteriae, which were more common in low-income countries and more tractable in the laboratory. In recent years, we have learned that Shigella are highly complex and highly susceptible to environmental change, as exemplified by epidemiological trends and increasing relevance of S. sonnei. Ultimately, methods, tools and data generated from decades of detailed research into S. flexneri have been used to gain new insights into the epidemiology, microbiology and pathogenesis of S. sonnei. In parallel, widespread adoption of genomic surveillance has yielded insights into antimicrobial resistance, evolution and organism transmission. In this Review, we provide an overview of current knowledge of S. sonnei, highlighting recent insights into this globally disseminated antimicrobial-resistant pathogen and assessing how novel data may impact future vaccine development and implementation.

Protein-specific immune response elicited by the Shigella sonnei 1790GAHB GMMA-based candidate vaccine in adults with varying exposure to Shigella

Shigella is a leading cause of diarrheal morbidity and mortality in young children from low- and middle-income countries. Here, we aimed to verify the ability of the generalized modules for membrane antigens (GMMA)-based Shigella sonnei candidate vaccine 1790GAHB to elicit an anti-protein antibody response. Serum samples from previous clinical trials in adults (a dose-escalation study and its extension in France, a vaccine efficacy study after human challenge in the United States, and a study in Kenya) were investigated using pan-proteome microarrays consisting of 3,150 full-length or fragmented Shigella proteins. Pre-/post-vaccination comparisons identified subsets of proteins that were highly immunoreactive and largely overlapped across all trials; the T3SS lipochaperone family protein (expressed on GMMA) was the most reactive in all studies. Responses to several microarray antigens correlated well with S. sonnei LPS serum IgG antibody levels. Overall, we confirmed the ability of GMMA to elicit an anti-protein IgG/IgA response; however, no association with protection against shigellosis was identified. In the challenge study, IgG response to seven antigens (IpaC, IpaB, IpaA, IpaD, IpaH, IpgC, and MxiD; not expressed on GMMA) was associated with a decreased risk of shigellosis. These antigens were observed to also have high IgG responses at baseline in individuals naturally exposed to Shigella and could constitute targets for future vaccine development.IMPORTANCEShigella remains a major cause of diarrheal disease, especially in children aged under 5 years from low-to-middle-income countries. No vaccine against shigellosis is yet widely available despite the high public health need. An ideal vaccine would provide protection against the most prevalent species, Shigella flexneri and Shigella sonnei; therefore, it could be relevant to identify common antigens. We developed a microarray containing 3,150 full-length or fragmented proteins selected across Shigella species. Sera collected in four clinical trials conducted in three countries of varying endemicity to evaluate a S. sonnei GMMA-based candidate vaccine were tested against these proteins. We identified several Shigella proteins (IpaC, IpaB, IpaA, IpaD, IpaH, IpgC, MxiD) that induced robust antibody response following experimental challenge or natural infection. These proteins correlated with a reduced risk of shigellosis after the S. sonnei challenge. We found no apparent role for anti-GMMA proteins' IgG or IgA response in protection against shigellosis.

Intestinal bacteria aerosols from hospital and municipal wastewater treatment: Seasonal variations, dispersal characteristics and toxic effects

Wastewater contains a rich abundance of intestinal pathogens, which can be released into the air during the wastewater treatment process, posing hazards to occupational workers and surrounding residents. Hospital wastewater contains a higher concentration of pathogens compared to urban wastewater, potentially causing greater harm to human health. In this study, a one-year collection of bioaerosols was conducted at a hospital sewage station (HSS) and a municipal sewage plant (MSP) to investigate the characteristics of intestinal bacteria in bioaerosols from different wastewater sources. The concentration of intestinal bacteria in the biological tank air at HSS ranged from 16 to 42 CFU/m3, while at MSP, the concentration range was from 19 to 30 CFU/m3. The airborne bacterial concentration was highest during the summer season. The average proportions of fine particles (<2.5 μm) in the air of HSS and MSP were 45.48% and 41.59%, respectively. The predominant intestinal bacteria detected in HSS bioaerosols were uncultured_bacterium_f_Enterobacteriaceae, Pantoea, and Serratia. The primary intestinal bacteria in MSP bioaerosols were Brevundimonas, Pseudomonas, and Enterobacteriaceae. Bioaerosols can rapidly diffuse into the surrounding environment. After 1 h of diffusion, the average diffusion areas of bioaerosols from HSS and MSP were 131.79 km2 and 159.01 km2, respectively. Exposure to bioaerosols generated from hospital wastewater can cause damage to the respiratory system of mice. The biological components in the bioaerosols can lead to significant increases in the expression levels of IL-6 and TNF-α in the serum of mice, as well as marked pathological changes in the lungs. This study reveals the potential health hazards of inhaling bioaerosols generated from wastewater and provides a scientific basis for formulating management measures for bioaerosols.

Nitric Oxide Inhibition of Glycyl Radical Enzymes and Their Activases

Innate immune response cells produce high concentrations of the free radical nitric oxide (NO) in response to pathogen infection. The antimicrobial properties of NO include nonspecific damage to essential biomolecules and specific inactivation of enzymes central to aerobic metabolism. However, the molecular targets of NO in anaerobic metabolism are less understood. Here, we demonstrate that the Escherichia coli glycyl radical enzyme pyruvate formate lyase (PFL), which catalyzes the anaerobic metabolism of pyruvate, is irreversibly inhibited by NO. Using electron paramagnetic resonance and site-directed mutagenesis we show that NO destroys the glycyl radical of PFL. The activation of PFL by its cognate radical S-adenosyl-l-methionine-dependent activating enzyme (PFL-AE) is also inhibited by NO, resulting in the conversion of the essential iron-sulfur cluster to dinitrosyl iron complexes. Whole-cell EPR and metabolic flux analyses of anaerobically growing E. coli show that PFL and PFL-AE are inhibited by physiologically relevant levels of NO in bacterial cell cultures, resulting in diminished growth and a metabolic shift to lactate fermentation. The class III ribonucleotide reductase (RNR) glycyl radical enzyme and its corresponding RNR-AE are also inhibited by NO in a mechanism analogous to those observed in PFL and PFL-AE, which likely contributes to the bacteriostatic effect of NO. Based on the similarities in reactivity of the PFL/RNR and PFL-AE/RNR-AE enzymes with NO, the mechanism of inactivation by NO appears to be general to the respective enzyme classes. The results implicate an immunological role of NO in inhibiting glycyl radical enzyme chemistry in the gut.

The rise in domestic shigellosis and the genomic characteristics of Shigella clones linked to men who have sex with men in Taiwan, 2015‒2022

Since 2015, Taiwan has experienced a notable rise in domestic shigellosis cases, particularly among young adult males. In this study, we aimed to investigate this epidemiological trend through demographic analysis and genomic characterization of bacterial isolates. We analyzed demographic data on shigellosis cases from 2003-2014 to 2015-2022. For cases from 2015-2022, we conducted genomic analyses of Shigella isolates using pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS). Antimicrobial resistance and plasmid profiles were examined to identify genetic determinants of resistance. From 2015 to 2022, there was a noticeable demographic shift in domestic shigellosis cases from females to males and children to young adults. This trend was driven by three multidrug-resistant Shigella clones associated with men who have sex with men (MSM): ciprofloxacin-resistant S. sonnei (CipR_SSIII), azithromycin-resistant S. flexneri 3a (AziR_SF3), and ciprofloxacin-resistant S. flexneri 2a (CipR_SF2). The CipR_SF2 clone has become the most prevalent since 2018, responsible for 84.9% of cases in 2021. Genomic analysis revealed that CipR_SF2 isolates are genetically distinct from those involved in MSM-related outbreaks in other countries. These MSM-associated clones showed significantly higher resistance to azithromycin, extended-spectrum cephalosporins (ESCs), and ciprofloxacin. Additionally, 14 extensively drug-resistant isolates were identified, carrying resistance genes for azithromycin and ESCs on IncFII or IncB/O/K/Z plasmids. Our findings indicate that the increase in domestic shigellosis cases in Taiwan from 2015 to 2022 is primarily attributed to the spread of highly resistant MSM-associated Shigella clones.

IMPORTANCE

The rise of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Shigella strains poses a growing global health threat, particularly among high-risk groups such as men who have sex with men (MSM). This study highlights the increasing prevalence of domestic shigellosis in Taiwan from 2015 to 2022, driven by the emergence of three MDR Shigella clones. These MSM-associated clones exhibit significantly higher resistance to azithromycin, extended-spectrum cephalosporins (ESCs), and ciprofloxacin compared to non-MSM-associated clones. Additionally, 14 extensively drug-resistant isolates were identified, carrying resistance genes for azithromycin and ESCs on IncFII or IncB/O/K/Z plasmids. Genomic analysis reveals that ciprofloxacin-resistant Shigella flexneri 2a (CipR_SF2) has become the most dominant clone, responsible for the majority of shigellosis cases since 2018, and is genetically distinct from strains observed in MSM-related outbreaks in other countries. By elucidating these clones' genetic characteristics and epidemiological trends, this research offers essential data for public health surveillance, helping to inform strategies for controlling the spread of MDR and XDR Shigella infections.

Development of a Novel mRNA Vaccine Against Shigella Pathotypes Causing Widespread Shigellosis Endemic: An In-Silico Immunoinformatic Approach

Shigellosis remains a major global health concern, particularly in regions with poor sanitation and limited access to clean water. This study used immunoinformatics and reverse vaccinology to design a potential mRNA vaccine targeting Shigella pathotypes out of 4071 proteins from Shigella sonnei str. Ss046, 4 key antigenic candidates were identified: putative outer membrane protein (Q3YZL0), PapC-like porin protein (Q3YZM5), putative fimbrial-like protein (Q3Z3I2), and lipopolysaccharide (LPS)-assembly protein LptD (Q3Z5V5), ensuring broad pathotype coverage. A multitope vaccine was designed incorporating cytotoxic T lymphocyte, helper T lymphocyte, and B-cell epitopes, linked with suitable linkers and adjuvants to enhance immunogenicity. Computational analyses predicted vaccine's favorable antigenicity, solubility, and stability, while molecular docking and dynamic simulations demonstrated strong binding affinity and stability with Toll-like receptor 4 (TLR-4), indicating potential for robust immune activation. Immune simulations predicted strong humoral and cellular immune responses, characterized by significant cytokine production and long-term immune memory. Structural evaluations of the complex, including radius of gyration, root mean square deviation, root mean square fluctuation, and solvent accessibility, confirmed the vaccine's structural integrity, and stability under physiological conditions. This research contributes to the ongoing effort to alleviate the global burden of Shigella infections, providing a foundation for future wet laboratory investigations aimed at vaccine development.

Epidemiology of Shigella species and serotypes in children: a retrospective substudy of the MAL-ED observational birth cohort study

BACKGROUND

Shigellosis is a leading cause of diarrhoea in children globally. We aimed to assess the burden of specific Shigella species and Shigella flexneri serotypes, characterise their clinical syndromes and natural immunity, and evaluate their relevance as causes of diarrhoea and linear growth faltering.

METHODS

In the MAL-ED birth cohort study, children younger than 17 days were enrolled from Nov 3, 2009, to Feb 29, 2012, in Bangladesh, Brazil, India, Nepal, Pakistan, Peru, Tanzania, and South Africa and were followed up for 2 years. In this retrospective substudy, we retested Shigella quantitative PCR-positive diarrhoeal and non-diarrhoeal stool samples with molecular subtyping assays. We estimated the prevalence of specific Shigella species and serotypes, estimated their associations with diarrhoea and clinical characteristics using generalised linear mixed models, estimated their associations with linear growth using linear regression, and used longitudinal infection data to estimate protection due to previous infection using the Andersen and Gill extension of the Cox model.

FINDINGS

1715 children (874 [51·0%] male and 841 [49·0%] female) with complete follow-up to 2 years provided 45 835 stool samples collected between age 0 and 2 years. 1294 (75·5%) children had at least one Shigella detection in a non-diarrhoeal or asymptomatic stool and 507 (29·6%) had at least one Shigella-attributed diarrhoea episode. In this substudy, we were able to type 1202 samples. The most common species and serotypes were Shigella sonnei (366 [30·4%] of 1202), S flexneri 2a (250 [20·8%]), and S flexneri 6 (296 [24·6%]). The associations of S flexneri and S sonnei detection with diarrhoea versus asymptomatic control stools were similar. Compared with diarrhoea episodes attributable to S flexneri, those attributable to S sonnei were less likely to be bloody (prevalence ratio 0·36 [95% CI 0·23 to 0·56]) or severe (prevalence ratio 0·58 [0·35 to 0·96]). The associations between asymptomatic Shigella infections and impaired linear growth at age 2 years were stronger for S flexneri than S sonnei (S flexneri length-for-age Z score difference -0·18 [95% CI -0·29 to -0·07] and S sonnei length-for-age Z score difference -0·07 [-0·21 to 0·07]). Examination of longitudinal infections showed that previous S sonnei infection was associated with a lower hazard of subsequent S sonnei diarrhoea (calibrated hazard ratio 0·41 [95% CI 0·19 to 0·90]). Otherwise, evidence for homotypic or heterotypic natural immunity was not apparent.

INTERPRETATION

This study provides data on prevailing Shigella species and serotypes in settings with a high burden of disease, underscoring the importance of asymptomatic S flexneri infection on growth impairment and the severity of S flexneri diarrhoea. Upcoming Shigella vaccines might need to induce immune responses that improve upon those produced by natural infection.

FUNDING

Bill & Melinda Gates Foundation.

BECC-engineered live-attenuated Shigella vaccine candidates display reduced endotoxicity with robust immunogenicity in mice

Shigella spp. infection contributes significantly to the global disease burden, primarily affecting young children in developing countries. Currently, there are no FDA-approved vaccines against Shigella, and the prevalence of antibiotic resistance is increasing, making therapeutic options limited. Live-attenuated vaccine strains WRSs2 (S. sonnei) and WRSf2G12 (S. flexneri 2a) are highly immunogenic, making them promising vaccine candidates, but possess an inflammatory lipid A structure on their lipopolysaccharide (LPS; also known as endotoxin). Here, we utilized bacterial enzymatic combinatorial chemistry (BECC) to ectopically express lipid A modifying enzymes in WRSs2 and WRSf2G12, as well as their respective wild-type strains, generating targeted lipid A modifications across the Shigella backgrounds. Dephosphorylation of lipid A, rather than deacylation, reduced LPS-induced TLR4 signaling in vitro and dampened endotoxic effects in vivo. These BECC-modified vaccine strains retained the phenotypic traits of their parental strains, such as invasion of epithelial cells and immunogenicity in mice without adverse endotoxicity. Overall, our observations suggest that BECC-engineered live attenuated vaccines are a promising approach to safe and effective Shigella vaccines.

In-Depth Genome-Based Analysis of Shigella spp. and Escherichia spp.: Resolving Ambiguities and Unveiling Phylogenetic Relationships

Although traditionally classified as distinct genera, recent genomic analyses suggest that Shigella species may represent pathogenic clones of Escherichia coli. In this study, we investigated the genetic relationships between Shigella and Escherichia species through comprehensive phylogenomic and taxonomic analyses. Genomic datasets for all validly named species within both genera were retrieved from GenBank. Multiple methods, including 16S rRNA gene sequence analysis, digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), Genome BLAST Distance Phylogeny (GBDP), and percentage of conserved proteins (POCP), were employed. These results reveal a high genetic similarity between Shigella species and E. coli, with ANI values exceeding 96% and dDDH values above 70%, indicating that Shigella species fall within the same species as E. coli. Phylogenomic trees, generated from whole-genome sequences and core genes, further corroborated the close evolutionary relationship between these taxa. Furthermore, these analyses challenge the reclassification of Atlantibacter hermannii and Pseudescherichia vulneris, supporting their retention within the genus Escherichia. Based on these findings, we propose the reclassification of Shigella species as subspecies within E. coli and recommend revisiting the taxonomic status of other related species.

Molecular epidemiology of a multidrug-resistant Shigella sonnei outbreak in Tunisia (2022-2023) using whole-genome sequencing

Purpose. The prevalence of multidrug-resistant (MDR) Shigella sonnei is increasing globally, raising concerns for public health. In 2022, an outbreak of MDR S. sonnei was observed in Tunisia. We aimed to evaluate the genetic profile of S. sonnei isolates during the outbreak, including their clonal relationship, antimicrobial determinants and connection to international strains.Methods. In this study, we sequenced the whole genome of 24 S. sonnei strains collected from South Tunisia between July 2022 and November 2023. Bioinformatic analysis was conducted to confirm species identification, assign sequence types, determine core genome sequence types, analyse phylogenetic relationships and identify antimicrobial resistance determinants. Phylodynamic and phylogeographic analyses were performed to trace the spatiotemporal spread of the outbreak genotype.Results. Our investigation revealed that 23 out of 24 isolates were grouped into the HC10-20662 genotype within the 3.6.3 subclade. All isolates carried the blaCTX-M-15 gene associated with extended-spectrum beta-lactamase production, as well as the dfrA1 and qnrS1 genes, along with the D87G mutation in gyrA. Additionally, the sul2, tet(A) and mph(A) resistance genes were present in most isolates (96%, 96 and 83, respectively). Phylogeographic analysis suggested that the outbreak genotype likely spread in Europe before being introduced into Tunisia.Conclusion. To the best of our knowledge, this is the first MDR S. sonnei outbreak in the country. The HC10-20662 genotype appears to be responsible for a multi-country outbreak, affecting both Tunisia and Europe. Continued genomic surveillance efforts, both nationally and internationally, are essential for monitoring the dynamic evolution and global spread of MDR S. sonnei.

Nitric Oxide Inhibition of Glycyl Radical Enzymes and Their Activases

Innate immune response cells produce high concentrations of the free radical nitric oxide (NO) in response to pathogen infection. The antimicrobial properties of NO include non-specific damage to essential biomolecules and specific inactivation of enzymes central to aerobic metabolism. However, the molecular targets of NO in anaerobic metabolism are less understood. Here, we demonstrate that the Escherichia coli glycyl radical enzyme pyruvate formate lyase (PFL), which catalyzes the anaerobic metabolism of pyruvate, is irreversibly inhibited by NO. Using electron paramagnetic resonance and site-directed mutagenesis we show that NO destroys the glycyl radical of PFL. The activation of PFL by its cognate radical S-adenosyl-L-methionine-dependent activating enzyme (PFL-AE) is also inhibited by NO, resulting in the conversion of the essential iron-sulfur cluster to dinitrosyl iron complexes. Whole-cell EPR and metabolic flux analyses of anaerobically growing Escherichia coli show that PFL and PFL-AE are inhibited by physiologically relevant levels of NO in bacterial cell cultures, resulting in diminished growth and a metabolic shift to lactate fermentation. The class III ribonucleotide reductase (RNR) glycyl radical enzyme and its corresponding RNR-AE are also inhibited by NO in a mechanism analogous to those observed in PFL and PFL-AE, which likely contributes to the bacteriostatic effect of NO. Based on the similarities in reactivity of the PFL/RNR and PFL-AE/RNR-AE enzymes with NO, the mechanism of inactivation by NO appears to be general to the respective enzyme classes. The results implicate an immunological role of NO in inhibiting glycyl radical enzyme chemistry in the gut.

Tebipenem pivoxil as an alternative to ceftriaxone for clinically non-responding children with shigellosis: a randomised non-inferiority trial protocol

INTRODUCTION

Shigellosis is the second leading cause of diarrhoeal deaths among children worldwide. Oral azithromycin and intravenous ceftriaxone are the recommended first-line and second-line therapies for shigellosis in Bangladesh, respectively, but growing antibiotic resistance will require new antibiotic options. Tebipenem pivoxil, an orally administered carbapenem antibiotic with activity against many strains of antibiotic-resistant bacteria, may be a viable option.

METHODS

A phase IIb randomised controlled trial was planned to determine the efficacy and safety of oral tebipenem pivoxil, compared with intravenous ceftriaxone, for children with Shigella diarrhoea unresponsive to the first-line antibiotic therapy. We will enrol 132 children in the trial (66 in each arm). Children from Bangladesh aged 24-59 months suspected of having Shigella diarrhoea, with no clinical improvement within 48 hours of starting first-line therapy, will be randomised to a 3-day course of intravenous ceftriaxone (50 mg/kg, once a day) or a 3-day course of oral tebipenem pivoxil (4 mg/kg, three times a day). The children will be evaluated for key clinical, microbiological and safety outcomes during the subsequent 30-day period. Clinically, failure at day 3 will be defined as the presence of fever (axillary temperature ≥38°C), diarrhoea (three or more abnormally loose or watery stools in the last 24 hours), blood in stool, or abdominal pain/tenderness at day 3 of follow-up or death or hospitalisation prior to day 3. It is hypothesised that children treated with tebipenem pivoxil will have no worse clinical and microbiological failure rates compared with ceftriaxone.

ETHICS AND DISSEMINATION

This study protocol was approved by the institutional review board of the International Centre for Diarrhoeal Disease Research, Bangladesh, which comprises a research review committee and an ethics review committee. In addition, the use of tebipenem pivoxil in shigellosis was approved by the Directorate General of Drug Administration of Bangladesh.

TRIAL REGISTRATION NUMBER

NCT05121974.

Increased Severity of Multidrug-Resistant Shigella sonnei Infections in People Experiencing Homelessness

BACKGROUND

Shigella sonnei has caused sexually transmitted enteric infections in men who have sex with men (MSM) in Vancouver. We recently observed a high rate of multidrug-resistant (MDR) S. sonnei bacteremia among persons experiencing homelessness (PEH). We aimed to describe the wider epidemiology, clinical outcomes, and genomics of S. sonnei infections over time.

METHODS

A retrospective review of 163 patients with S. sonnei infections was undertaken from 2015 to 2022. We collected demographic, clinical, and microbiological data over 2 time periods: historical (2015-2020) and recent (2021-2022). Severe shigellosis definition included hospitalization, bacteremia, or death. Whole-genome sequencing was performed to identify genotype, infer relatedness, and predict antimicrobial resistance.

RESULTS

S. sonnei infections increased from 8.3 (historical period) to 56.5 (recent period) cases/year. Over time, the primary population characteristics associated with shigellosis shifted from MSM (45; 98%) to PEH (86; 77%). The population intersection between MSM and PEH historically and recently was similar and occurred in 3 (6%) and 10 (9%) of patients, respectively. Severe shigellosis was significantly higher in the recent versus historical period (69 [61%] vs 7 [14%]; P < .001). A dominant clone of MDR S. sonnei, 3.6.1.1.2 (CipR.MSM5), emerged with resistance to all first- and second-line agents, yet with susceptibility to ceftriaxone.

CONCLUSIONS

We observed a substantial increase in severe shigellosis and shift from sexually transmitted S. sonnei infections in MSM to likely environmental transmission among PEH. More severe disease associated with the 3.6.1.1.2 clone of MDR S. sonnei in PEH could be a result of underlying vulnerabilities of the affected population.

A Candidate Ac3-S-LPS Vaccine Against S. flexneri 1b, 2a, 3a, 6, and Y Activates Long-Lived Systemic and Mucosal Immune Responses in Healthy Volunteers: Results of an Open-Label, Randomized Phase 2 Clinical Trial

OBJECTIVES

Determination of reactogenicity and immunogenicity of a pentavalent candidate vaccine against S. flexneri 1b, 2a, 3a, 6, and Y (PLVF).

METHODS

The study involved 80 healthy adult volunteers aged 18-55 years. Groups were subcutaneously immunized twice at a 30-day interval with 62.5 μg/0.5 mL or 125 μg/0.5 mL of the vaccine.

RESULTS

During the entire 8-month period of post-vaccination observation, the vaccine was well tolerated, with no local or systemic reactions detected objectively. The results of laboratory studies demonstrated no effect on the main indicators of hemogram, biochemical blood test, or urinalysis. IgA, IgG, and IgM levels against LPS S. flexneri 1b, 2a, 3a, 6, and Y were examined before vaccination, a month after each vaccination, and 6 months after booster vaccination. One month after vaccination, IgA and IgG seroconversions were observed in 67.5-82.5% (depending on serotype) and 60-77.5% of volunteers, respectively. Booster immunization did not have a significant effect on vaccine immunogenicity. In two separate groups of 15 and 9 volunteers for mucosal sIgA, IgA, and IgG titer determination after immunization with a 125 μg vaccine dose, paired stool, and saliva samples were taken before and one month after vaccination. In 26.7-40% of volunteers, there was a 2-fold and higher increase in sIgA titer for the studied serotypes in the feces and in 66.7-88.9% in saliva. IgA and IgG 2-fold conversion rates were 26.7-53.3% and 33.3-46.7% in the feces, 33.3-77.9%, and 66.7-77.8% in saliva, respectively.

CONCLUSIONS

the tolerability of PLVF and the pronounced humoral immune response allow us to proceed to the phase 3 clinical trial stage.

Landscape of Bacterial Enteric Disease and Traveler´s Diarrhea in South America

Diarrheal disease is a global public health threat. Cases of enteric disease caused by bacterial enteropathogens result in a significant health burden and can lead to antimicrobial resistance patterns that increase and evolve over time and geography, posing serious health challenges for local populations as well as civilian travelers and military personnel deployed to endemic regions. This review describes the prevalence of the most common bacterial agents of diarrheal disease in South America, as well as the distribution patterns of antibiotic resistance and predominant strains that are present in the region. Furthermore, the development of relevant prevention and treatment strategies are described, and United States Naval Medical Research Unit SOUTH disease surveillance and enteric disease research efforts in this regional context are highlighted.

First report of Shigella sonnei carrying a blaCTX-M-15 sexually transmitted among men who have sex with men

Epidemiology of shigellosis has drastically changed in recent years due to globalization and sexual risk behaviors. Here, through whole-genome sequencing, we characterized two ESBL-producing Shigella sonnei strains (ShSoBUH1 and ShSoBUH2) carrying a blaCTX-M-15 among men who have sex with men (MSM), who had not recently traveled and presented sexual risk behaviors. Both strains harbored IncB/O/K/Z and IncFII plasmids, which carry aadA1, aadA5, sul1, sul2, dfrA1, dfrA17, mph(A), erm(B), tet(B), qacE and blaCTX-M-15 genes conferring resistance to 2nd and 3rd generation cephalosporins, cotrimoxazole, erythromycin, azithromycin and quinolones. IncFII plasmids containing blaCTX-M-15 from ShSoBUH1 and ShSoBUH2 presented 99,8-99,9% similarity with plasmids from another five CTX-M-15 S. sonnei strains detected in Belgium and Switzerland. A single-nucleotide polymorphism (SNP) analysis determined that the study strains differed by 361 SNPs, belonging to different clusters. To the best of our knowledge, this is the first report describing two extensively drug-resistant (XDR) CTX-M-15 S. sonnei strains in MSM.

A Perspective on Wastewater and Environmental Surveillance as a Public Health Tool for Low- and Middle-Income Countries

Geographical variations in infectious diseases create differences in public health priorities between high- and low-income countries. Low- and middle-income countries (LMICs) face resource constraints that limit adherence to international monitoring standards for wastewater-based epidemiology (WBE). The development of low-cost WBE programs, such as those to detect SARS-CoV-2, offers LMICs a promising tool for monitoring pathogens of local concern. In this work, we summarize important wastewater biomarkers for LMICs and their associated public health challenges, ranging from pathogens causing gastroenteritis to putative markers for plant diseases linked to food safety, as well as antimicrobial resistance. We raise awareness of the great potential of WBE for LMICs and highlight the critical health markers, research needs, and strategies necessary to establish tailored wastewater surveillance programs.

Macrophages orchestrate elimination of Shigella from the intestinal epithelial cell niche via TLR-induced IL-12 and IFN-γ

Bacteria of the genus Shigella replicate in intestinal epithelial cells and cause shigellosis, a severe diarrheal disease that resolves spontaneously in most healthy individuals. During shigellosis, neutrophils are abundantly recruited to the gut, and have long been thought to be central to Shigella control and pathogenesis. However, how shigellosis resolves remains poorly understood due to the longstanding lack of a tractable and physiological animal model. Here, using our newly developed Nlrc4 -/- Casp11 -/- mouse model of shigellosis, we unexpectedly find no major role for neutrophils in limiting Shigella or in disease pathogenesis. Instead, we uncover an essential role for macrophages in the host control of Shigella . Macrophages respond to Shigella via TLRs to produce IL-12, which then induces IFN-γ, a cytokine that is essential to control Shigella replication in intestinal epithelial cells. Collectively, our findings reshape our understanding of the innate immune response to Shigella .

Molecular epidemiology of extended-spectrum beta-lactamases and carbapenemases-producing Shigella in Africa: a systematic review and meta-analysis

BACKGROUND

The treatment of Shigella infections has become a major challenge due to the emergence of multidrug-resistant Shigella. There is however insufficient knowledge regarding the molecular epidemiology of Shigella strains producing beta-lactamases in Africa. This systematic review investigated the scientific literature on the molecular epidemiology of extended-spectrum beta-lactamase (ESBL) and carbapenemases producing Shigella in Africa.

METHODS

Papers published in English and French from African countries on the molecular epidemiology of ESBL and carbapenemase producing Shigella from January 1999 to July 5, 2024 were reviewed. An extensive literature search was conducted through electronic databases including PubMed, Scopus, Web of Sciences, African Journals Online (AJOL) and Google scholar using specific keywords. The meta-analysis and forest plots of Shigella species, ESBL and carbapenemases genes were done using the comprehensive Meta-Analysis software. All data were analyzed using a binary random-effects model by the DerSimonian-Laird method at a 95% confidence interval.

RESULTS

Out of the 583 research articles, only 18 (3.1%) articles representing eleven countries were included in the meta-analysis. The overall pooled prevalence of ESBL and Carbapenem Resistant (CR)-producing Shigella was estimated as 41.2% (95% CI: 22.8-62.4; I2 = 93.7%, p < 0.05). The leading ESBL and CR-producing Shigella species reported in this review was Shigella flexneri, 34.5% (95% CI: 16.6-58.2; I2 = 94.9%, p < 0.05). ESBL and CR-producing Shigella sonnei was the least reported with estimated prevalence of 6.7% (95% CI: 3.4-13.2; I2 = 80.7%, p < 0.05). In this review, blaTEM, blaOXA-1, and blaCTX-M were the most prevalent genes in Africa with prevalence of 25.9% (95% CI: 13.9-43.2; I2 = 90.9%, p < 0.05), 25.7% (95% CI: 14.9-43.0; I2 = 93.7%, p < 0.05), and 10.8% (95% CI: 4.5-23.4; I2 = 85.6%, p < 0.05) respectively. The prevalence of Carbapenemases genes on the other hand was low, reported as 0.8% (95% CI: 0.2-10.3; I2 = 51.4%; p < 0.05) for blaNDM, 1.1% for blaKPC, and 0.5% for blaIMP.

CONCLUSION

This study highlighted Shigella flexneri as the most prevalent ESBL and CR-producing Shigella species found in various African countries. The findings from this review indicate blaTEM, blaOXA-1 and blaCTX-M as the most prevalent genes in Africa while carbapenemases are least prevalent. The findings from the study suggest that ESBL and CR-producing Shigella pose a significant public health threat in Africa. Effective antimicrobial resistance (AMR) surveillance strategies are needed to improve the management and treatment of Shigella infections in Africa.

Prevalence of Salmonella and Shigella species and their multidrug resistance patterns among pediatric populations in Ethiopia: a systematic review and meta-analysis

BACKGROUND

Salmonella and Shigella are major enteric pathogens that cause diarrhea in children worldwide. They are pathogenic microbes that cause significant diarrheal morbidity and mortality in under five children in resource limited countries. Thus, this systemic review and meta-analysis aimed to investigate the prevalence of Salmonella and Shigella species and their multidrug resistance patterns in pediatric populations in Ethiopia.

METHODS

The articles were searched extensively in the electronic databases and grey literature using entry terms or phrases. Studies meeting the eligibility criteria were extracted in MS Excel and exported for statistical analysis into STATA version 14 software. The overall pooled prevalence of Salmonella and Shigella species was computed using a random-effects model. Heterogeneity was assessed using the Cochrane Q test and I2 statistics with corresponding p-values. Publication bias was assessed using a funnel plot and Egger's test. In addition, sensitivity analysis was performed to determine the impact of individual studies on the pooled effect size.

RESULT

Of a total of 742 identified studies, 89 studies were eligible for full-text analysis. Of 89 studies, 21 were included for meta-analysis involving 5318 study participants. These eligible studies reported a total of 593 bacterial isolates. The overall pooled prevalence of Salmonella and Shigella among pediatrics in Ethiopia was 10.70% (95% CI: 8.96-12.45), with substantial heterogeneity (I2 = 82.1%, p < 0.001) across the studies. The pooled prevalence of Salmonella and Shigella individually among pediatrics in Ethiopia was 15.43% (95% CI: 10.42-20.72) and 15.83% (95% CI: 11.40-20.40), respectively. Moreover, the overall prevalence of multidrug resistance in Salmonella and Shigella isolates was 81.03% (95% CI: 77.39-84.67) with substantial heterogeneity of I2 of 95%, p < 0.0001 between the pooled prevalence of the two species.

CONCLUSION

The pooled prevalence of Salmonella and Shigella and their multidrug resistance were alarmingly high in pediatric. The initial empirical treatment of pediatrics patients remains challenging and results high prevalence of antimicrobial resistance. Thus, appropriate infection prevention and control strategies should be implemented and treatment should be directed based on antimicrobial stewardship protocols.

Safety, Tolerability, and Immunogenicity of the InvaplexAR-DetoxShigella Vaccine Co-Administered with the dmLT Adjuvant in Dutch and Zambian Adults: Study Protocol for a Multi-Center, Randomized, Double-Blind, Placebo-Controlled, Dose-Escalation Phase Ia/b Clinical Trial

BACKGROUND

Shigella infections remain endemic in places with poor sanitation and are a leading cause of diarrheal mortality globally, as well as a major contributor to gut enteropathy and stunting. There are currently no licensed vaccines for shigellosis but it has been estimated that an effective vaccine could avert 590,000 deaths over a 20-year period. A challenge to effective Shigella vaccine development has been the low immunogenicity and protective efficacy of candidate Shigella vaccines in infants and young children. Additionally, a new vaccine might be less immunogenic in a highly endemic setting compared to a low endemic setting ("vaccine hyporesponsiveness"). The use of a potent adjuvant enhancing both mucosal and systemic immunity might overcome these problems. InvaplexAR-Detox is an injectable Shigella vaccine that uses a novel combination of conserved invasion plasmid antigen proteins and a serotype-specific bacterial lipopolysaccharide attenuated for safe intramuscular administration. The adjuvant dmLT has been shown to enhance Shigella immune responses in mice, has safely been administered intramuscularly, and was shown to enhance immune responses in healthy volunteers when given in combination with other antigens in phase I trials. This article describes the protocol of a study that will be the first to assess the safety, tolerability, and immunogenicity of InvaplexAR-Detox co-administered with dmLT in healthy adults in low-endemic and high-endemic settings.

METHODS

In a multi-center, randomized, double-blind, and placebo-controlled dose-escalation phase Ia/b trial, the safety, tolerability, and immunogenicity of three intramuscular vaccinations administered 4 weeks apart with 2.5 µg or 10 µg of InvaplexAR-Detox vaccine, alone or in combination with 0.1 µg of the dmLT adjuvant, will first be assessed in a total of 50 healthy Dutch adults (phase Ia) and subsequently in 35 healthy Zambian adults (phase Ib) aged 18-50 years. The primary outcome is safety, and secondary outcomes are humoral and cellular immune responses to the adjuvanted or non-adjuvanted vaccine.

DISCUSSION

This trial is part of the ShigaPlexIM project that aims to advance the early clinical development of an injectable Shigella vaccine and to make the vaccine available for late-stage clinical development. This trial addresses the issue of hyporesponsiveness in an early stage of clinical development by testing the vaccine and adjuvant in an endemic setting (Zambia) after the first-in-human administration and the dose-escalation has proven safe and tolerable in a low-endemic setting (Netherlands). Besides strengthening the vaccine pipeline against a major diarrheal disease, another goal of the ShigaPlexIM project is to stimulate capacity building and strengthen global North-South relations in clinical research.

TRIAL REGISTRATION

EU CT number: 2023-506394-35-02, ClinicalTrials.gov identifier: NCT05961059.

Characterization of Shigella flexneri serotype 6 strains from geographically diverse low- and middle-income countries

Shigella flexneri serotype 6 (Sf6) is one of the most common serotypes recovered from surveillance studies of moderate to severe diarrhea. Despite the clinical significance of Sf6, this serotype is understudied. In this work, we have performed both serotype-specific genomic and phenotypic comparisons of Sf6 isolates to one another and non-S. flexneri serotypes. Comparative genomic analyses identified significant nucleotide homology between Sf6 strains (n = 325), despite a broad range of collection timeframes and geographic locations. We identified Sf6 specific factors, including a potential novel Shigella virulence factor (type II secretion system). Additionally, we identified established Shigella virulence genes (ospG) and metabolic genes (rutABCDEFGR) that were absent in Sf6 strains while present in the majority of 728 non-Sf6 strains. Complete sequencing of 11 clinical Sf6 strains, demonstrated that the Sf6 virulence plasmid (pINV) is ~38 kb smaller than the average non-Sf6 pINV (~228 kb). Comparisons of S. flexneri species level antibiotic susceptibility highlighted that clinical Sf6 isolates from Africa in the Global Enteric Multicenter Study (GEMS) and Vaccine Impact on Diarrhea in Africa (VIDA) study demonstrated geographic, serotype-specific susceptibility pattern. Phenotypic analyses of Sf6 identified reduced intracellular invasion and cytokine induction from HT-29 cells, as well as reduced Ipa protein effector secretion, compared with S. flexneri serotype 2a strain 2457T. Together these data highlight conserved and unique serotype-specific genotypic and phenotypic features for Sf6. This level of conservation has not been noted for other S. flexneri serotypes and is promising for vaccine and diagnostic assays to provide global Sf6-specific coverage.IMPORTANCEShigellosis is an ongoing global public health crisis with >270 million annual episodes among all age groups; however, the greatest disease burden is among children in low- and middle-income countries (LMIC). The lack of a licensed Shigella vaccine and the observed rise in antimicrobial-resistant Shigella spp. highlights the urgency for effective preventative and interventional strategies. The inclusion of S. flexneri serotype 6 (Sf6) is a necessary component of a multivalent vaccine strategies based on its clinical and epidemiological importance. Given the genomic diversity of Sf6 compared with other S. flexneri serotypes and Sf6 unique O-antigen core structure, serotype-specific characterization of Sf6 is a critical step to inform Shigella-directed vaccine and alternative therapeutic designs. Herein, we identified conserved genomic content among a large collection of temporally and geographically diverse Sf6 clinical isolates and characterized genotypic and phenotypic properties that separate Sf6 from non-Sf6 S. flexneri serotypes.

Resistome phylodynamics of multidrug-resistant Shigella isolated from diarrheal patients

Multi-drug resistance (MDR) in Shigella continues to pose a significant public health challenge, particularly in developing countries. Recent advances in genomics strengthen the surveillance of MDR-pathogens and antimicrobial resistance (AMR) mediators. However, genome-based investigations into resistome dynamics in Shigella are limited, specifically in Bangladesh. Therefore, we investigated MDR-Shigella resistomes to evaluate their AMR transmission and phylodynamics. Clinical Shigella strains were screened for MDR phenotypes through susceptibility tests against 28 antibiotics from 10 different classes. Whole-genome sequencing (WGS) and bioinformatics approaches were performed to unveil the resistome dynamics: >500 global plasmid entities and >1,000 plasmid-mediated resistance gene clusters from global databases were included in this study. We identified 28 distinct antimicrobial resistance genes (ARGs) from nine antibiotic classes, with 75% originating from plasmids. Notably, two conjugative MDR plasmids included nearly all potential ARGs, conferring resistance to first-line drugs for shigellosis. Two third-generation cephalosporin-resistant [wubC-blaCTX-M-15-ISEcp1 and blaTEM-1] and two macrolide-resistant mobile genomic islands (GIs) [mphA-mrx-mph(R)A-IS6100 and mphE-msrE-IS482-IS6] had emerged in Shigella in Bangladesh. In addition, trimethoprim-aminoglycoside-streptothricin-sulfonamide-resistant dfrA1-sat1-aadA1 and aph3-dfrA14-aph6-sul2 were in conjugative plasmids in Bangladesh. The MDR plasmids and resistant GIs were phylogenetically relevant to Europe, USA, or China-derived isolates, indicating carry-over of the emerging ARGs from heavily industrialized countries and MSM-burdened (men who have sex with men) populations. The global burden of resistance GIs has increased sharply, especially after 2014. Emerging resistance mediators were most frequent (>80%) in human-associated Escherichia coli and Klebsiella pneumoniae. We infer ARGs horizontally propagate among Enteropathogens: informing treatment strategies and supporting policymakers in strengthening AMR-containment efforts utilizing the phylodynamics network.IMPORTANCEThe world is suffering from a high burden of MDR enteropathogens. Healthcare providers in low- and middle-income countries (LMICs) often face trouble finding effective drugs among the many antibiotics introduced in diarrheal treatment. Resistance-mediated drug inactivation is more rapid than the advent of new antimicrobials, leaving enteritis treatment on the edge. In Bangladesh, where one-third of users are self-prescribing antibiotics and thousands are dying due to resistance-related treatment failure, phylogenomic evidence of AMR transmission root is scarce. Therefore, investigating the resistomes of MDR-Shigella, the leading cause of diarrheal deaths in Bangladesh, is crucial. We identified several emerging resistance mediators and their phylogenetic links to global entities, which is significant for improving shigellosis treatment and enhancing AMR containment strategies. Understanding the MDR mechanism in Shigella will help physicians choose effective drugs and anticipate resistance-mediated changes in treatment approaches; the spatiotemporal phylodynamics of AMR mediators aid policymakers in setting effective checkpoints in the AMR transmission network.

Lagged effects of climate factors on bacillary dysentery in western China

BACKGROUND

Evidence has shown that the incidence of bacillary dysentery (BD) is associated with climatic factors. However, the lagged effects of climatic factors on BD are still unclear, especially lacking research evidence from arid and semi-arid regions. Therefore, this study aims to add new insights into this research field.

METHODS

Spatial autocorrelation, time series analysis and spatiotemporal scans were used to perform descriptive analyses of BD cases from 2009 to 2019. On the basis of monthly data from 2015 to 2019, multivariable distributed lag non-linear models were used to investigate the lagged effects of climatic factors on BD.

RESULTS

The hot spots for BD incidence are gradually decreasing and becoming increasingly concentrated in the southern part of Gansu Province. The maximum cumulative relative risks for monthly average temperature, sunshine duration, average relative humidity and precipitation were 3.21, 1.64, 1.55 and 1.41, respectively. The lagged effects peaked either in the current month or with a 1-month lag, and the shape of the exposure-response curve changed with the increase in maximum lag time. After stratification by per capita gross domestic product, there were differences in the effects.

CONCLUSIONS

Climatic factors can influence the incidence of BD, with effects varying across different lag times. It is imperative to vigilantly track the disparities in the incidence of BD attributable to economic factors.

A case of intercurrent shigellosis and rectal gonorrhea in an acutely unwell febrile returned traveler

Both acute traveler's diarrhea and sexually transmitted infections are common causes of fever in the returned traveler, with the male sex corresponding to two-fold increased odds of a sexually transmitted infection (STI) diagnosis related to travel. Shigella flexneri is the most common cause of shigellosis in low- and middle-income countries, while within the men who have sex with men (MSM) population, outbreaks of S. flexneri 3a, S. flexneri 2a, and S. sonnei have been reported. We herein present a case of a febrile returned MSM traveler with a predominantly gastrointestinal presentation and proctocolitis whose microbiological work-up confirmed coinfection with S. flexneri and rectal gonorrhea. Based on his travel history and epidemiologic risk factors, it is unclear if food- and waterborne shigellosis versus transmission via sexual contact was the major route of acquisition. This case highlights the broad differential for proctocolitis and the importance of consideration of intercurrent infections.

SPATEs promote the survival of Shigella to the plasma complement system upon local hemorrhage and bacteremia

Shigella spp. are the causative agents of shigellosis, which remains a leading cause of death in children under the age of 5. Symptoms of shigellosis include bloody diarrhea, associated to colon hemorrhage; in more severe cases, Shigella bacteremia is induced. These clinical features indicate that Shigella are exposed and survive exposure to plasma, locally and systemically, although this has not yet been studied at a molecular level. In this report, we confirmed in a guinea pig model of shigellosis that both S. flexneri 5a and S. sonnei induced local hemorrhages and we demonstrated that Shigella reached CD31+/CD34+ blood vessels located in the mucosa during the late stages of infection, and further disseminated in the bloodstream. These results confirmed the exposure of Shigella to plasma components during its virulence cycle. We demonstrated that all the tested Shigella strains survived plasma exposure in vitro, and we showed that Serine Protease Autotransporters of Enterobacteriaceae (SPATEs) contribute to Shigella dissemination within the colonic mucosa and in the bloodstream. We have confirmed that SPATEs are expressed and secreted in poorly oxygenated environments encountered by Shigella during late infection stages. We further demonstrated that SPATEs promoted Shigella survival in plasma, by cleaving complement component 3 (C3), thereby impairing the complement system activation. We have shown here that the ability of Shigella to survive plasma exposure is a key factor in its virulence, both within primary foci and systemically.

Genome and antibiotic resistance characteristics of Shigella clinical isolates in Fujian Province, Southeast China, 2005-2019

Shigellosis is a serious public health issue in many developing countries. The emergence of multidrug-resistant (MDR) Shigella isolates has deepened the treatment difficulty and health burden of shigellosis. China is the largest developing country in the world, but so far, the genome of MDR Shigella isolates has not been well characterized. In this study, 60 clinical isolates of Shigella spp. in Fujian Province, southeast China, from 2005 to 2019 were characterized for drug resistance phenotype, whole-genome sequencing and bioinformatics analysis. The results showed that the MDR rate of Shigella isolates was 100%, among which the resistance rates of cefotaxime, ciprofloxacin and azithromycin were 36.67, 21.67 and 10.00 %, respectively. The positive rate of extended-spectrum beta-lactamase (ESBL)-producing strains was 23.33%. The resistance profiles of Shigella flexneri and Shigella sonnei to some antimicrobials differed. The MDR isolates carried multiple antimicrobial resistance genes, among which blaCTX-M-14 and blaCTX-M-15 mediated ESBL resistance. 'ISEcp1 -blaCTX-M -IS903' (type I) and 'ISEcp1 -blaCTX-M' (type II) were the most common genetic environments around the blaCTX-M genes, and plasmids containing these structures included IncFII, IncI1, IncI2 and IncN. The double gene mutation pattern of gyrA and parC resulted in a significant decrease in the sensitivity of S. flexneri to ciprofloxacin. The overall resistance phenotype and genotype concordance rate was 88.50%, and the sensitivity and specificity of the genotype antimicrobial susceptibility test (AST) were 93.35 and 82.53 %, respectively. However, inconsistency occurred between phenotypic and genotype profiles for a few antibiotics. Phylogenomic investigation with core genome multi-locus sequence typing (cgMLST) and SNPs were used to characterize the endemic transmission of these infections in Fujian and their evolutionary origin within the global context. For S. flexneri, Fujian isolates were all limited to PG3 and could be divided into three phylogenetic clusters. The ciprofloxacin-resistant strains were mainly F2a and FXv and assigned to the three clusters with different quinolone resistance-determining region mutation patterns. For S. sonnei, most Fujian strains belonged to Lineage III with genotype 3.7.6, except three isolates of Lineage I with genotype 1.3. The strains carrying the blaCTX-M genes were dispersed, indicating different origins of gene acquisition. Most of the circulating isolates in Fujian Province were not related to major international outbreak lineages and were only endemic to the country. In conclusion, multi-drug resistance of Shigella isolates in Fujian Province was serious, and genome-based laboratory surveillance will be crucial to the clinical treatment and public health measures for shigellosis.

An Emerging Way for Bacteria to Engage with Host Cells via Protein ADP-riboxanation

Post-translational modifications (PTMs) are increasingly recognized as important strategies used by bacterial pathogens to modulate host cellular functions. Protein ADP-riboxanation, a derivative of ADP-ribosylation, has recently emerged as a new biochemical way by which bacterial pathogens interact with host cells. Recent studies have revealed that this modification has broad regulatory roles in host processes including cell death, protein translation, and stress granule formation. Given that the vast majority of bacterial ADP-riboxanases are still uncharacterized, in this review we also highlight the utility of advanced proteomic tools in the functional dissection of ADP-riboxanation events during bacterial infections.

Prevalence of Shigella species and antimicrobial resistance patterns in Africa: systematic review and meta-analysis

BACKGROUND

Shigellosis continues to pose a significant public health problem in Africa; however, there is a lack of comprehensive knowledge regarding its prevalence, serogroup distribution, and antimicrobial resistance profiles. Therefore, the objective of this systematic review and meta-analysis was to determine the overall prevalence of Shigella, the distribution of species, and the patterns of antimicrobial resistance across Africa.

METHODS

Following PRISMA guidelines, a systematic search strategy was conducted using the PubMed, Web of Science and Scopus databases from January 31, 2024 to February 10, 2024. The study quality was assessed using the Joanna Briggs Institute checklist, and data were analyzed using the R statistical language and the R package 'meta'. The random effects model was employed to estimate the pooled prevalence, while heterogeneity was assessed using the I2 statistic and prediction interval.

RESULTS

A total of 116 studies from 29 African countries were included in this meta-analysis, involving the examination of 99,510 samples. The overall pooled estimate of Shigella prevalence was determined to be 5.9% (95% CI: 4.9 - 7.0%). Regional prevalence showed prevalences of Southern Africa (6.9 [95% CI: 3.0 - 12.2%]), Northern Africa (6.7% [95% CI: 4.1 - 9.8%]), Eastern Africa (6.2% [95% CI: 4.9 - 7.6%]), Central Africa (4.5% [95% CI: 2.6 - 6.8%]) and Western Africa (4.0% [95% CI: 2.5 - 5.9%]). Shigella prevalence was found to be higher in children (6.6%, 95% CI: 3.2 - 11.1%) than in adults (3.6%, 95% CI: 1.6 - 6.3%). The most prevalent species was S. flexneri (53.6%, 95% CI: 46.1%-61.0%), followed by S. sonnei (11.5%, 95% CI: 7.7%-15.7%), S. dysenteriae (10.1%, 95% CI: 6.2 - 14.5%) and S. boydii (7.7%, 95% CI: 4.7 - 11.1%). Among the currently recommended first-line antibiotics, ciprofloxacin and ceftriaxone showed resistance prevalences of 10.0% (95% CI: 4.5%-16.9%) and 8.5% (95% CI: 2.4-16.9%) respectively.

CONCLUSION

This review highlights the burden of shigellosis in Africa. S. flexneri remains the most prevalent species associated with shigellosis cases with S. sonnei being the second most dominant. The antimicrobial resistance patterns observed in the study suggest local antimicrobial patterns in choosing antibiotics for the treatment of Shigellosis.

RECOMMENDATION

There is the need to explore alternative treatments for shigellosis with particular focus on vaccine development. There is also the need for more genomic epidemiology studies exploring the dissemination and risk of drug-resistant S. sonnei clones in Africa.

High-Throughput Luminescence-Based Serum Bactericidal Assay Optimization and Characterization to Assess Human Sera Functionality Against Multiple Shigella flexneri Serotypes

Shigellosis represents a significant global health concern particularly affecting children under 5 years in low- and middle-income countries (LMICs) and is associated with stunting and antimicrobial resistance. There is a critical need for an effective vaccine offering broad protection against the different Shigella serotypes. A correlate of protection has not yet been established but there is a general consensus about the relevant role of anti-O-Antigen-specific IgG and its functionality evaluated by the Serum Bactericidal Assay (SBA). This study aims to characterize a high-throughput luminescence-based SBA (L-SBA) against seven widespread Shigella serotypes. The assay was previously developed and characterized for S. sonnei and S. flexneri 1b, 2a, and 3a and has now been refined and extended to an additional five serotypes (S. flexneri 4a, 5b, 6, X, and Y). The characterization of the assay with human sera confirmed the repeatability, intermediate precision, and linearity of the assays; both homologous and heterologous specificity were verified as well; finally, limit of detection and quantification were established for all assays. Moreover, different sources of baby rabbit complement showed to have no impact on L-SBA output. The results obtained confirm the possibility of extending the L-SBA to multiple Shigella serotypes, thus enabling analysis of the functional response induced by natural exposure to Shigella in epidemiological studies and the ability of candidate vaccines to elicit cross-functional antibodies able to kill a broad panel of prevalent Shigella serotypes in a complement-mediated fashion.

An RPA-Based CRISPR/Cas12a Assay in Combination with a Lateral Flow Assay for the Rapid Detection of Shigella flexneri in Food Samples

Among the pathogens that cause infectious diarrhea in China, Shigella is the most prominent. Shigellosis affects both adults and children, particularly those in developing nations, with nearly 190 million annual cases and a third resulting in fatalities. The recently emerged CRISPR/Cas system has also been increasingly applied for the detection of different biological targets. The lateral flow assay (LFA) has the advantages of short detection time, simple operation, high sensitivity, and low cost, and it provides an ideal platform for on-site detection. In this study, a recombinase polymerase amplification-CRISPR/Cas12a-LFA test for Shigella flexneri was constructed. The established method had good specificity and sensitivity, and the qualitative accuracy of 32 tested strains reached 100%. The detection limit of genomic DNA reached 8.3 copies/μL. With the advantages of high accuracy and portability, this diagnostic apparatus represents a novel method of identification and detection of Shigella flexneri, particularly in settings that lack complex laboratory infrastructure.

Trends in shigellosis notifications in England, January 2016 to March 2023

We reviewed all diagnoses of Shigella species notified to the UK Health Security Agency from January 2016 to March 2023. An overall increase in notifications of shigellosis was seen between 2016 (n = 415/quarter) and 2023 (n = 1 029/quarter). However, notifications dramatically declined between March 2020 and September 2021 during the COVID-19 pandemic (n = 208/quarter) highlighting the impact of travel and social distancing restrictions on transmission. S. sonnei diagnoses were more affected by lockdown restrictions than S. flexneri, most likely due to a combination of species-specific characteristics and host attributes. Azithromycin resistance continued to be associated with epidemics of sexually transmissible S. flexneri (adult males = 45.6% vs. adult females = 8.7%) and S. sonnei (adult males = 59.5% vs. adult females = 14.6%). We detected resistance to ciprofloxacin in S. sonnei from adult male cases not reporting travel at a higher frequency (79.4%) than in travel-associated cases (61.7%). Extensively drug-resistant Shigella species associated with sexual transmission among men almost exclusively had ESBL encoded by blaCTX-M-27, whereas those associated with returning travellers had blaCTX-M-15. Given the increasing incidence of infections and AMR, we recommend that enhanced surveillance is used to better understand the impact of travel and sexual transmission on the acquisition and spread of MDR and XDR Shigella species.

Characterization of azithromycin-resistant Shigella flexneri serotype 2a isolates using whole genome sequencing in Ontario from 2016 to 2018

Azithromycin-resistant shigellosis is increasing globally. This retrospective analysis of Shigella flexneri serotype 2a isolates from 2016 to 2018 in Ontario found nearly half were azithromycin (47.7%, 72/151) and ciprofloxacin (50.7%, 77/152) resistant. Moreover, 34.7% (25/72) of azithromycin-resistant isolates were also ciprofloxacin-resistant. Four isolates were ceftriaxone-resistant, although all azithromycin-resistant isolates were ceftriaxone-susceptible. Overall, 83.6% (127/152) of all S. flexneri 2a isolates were recovered from males and 97.2% (70/72) of the azithromycin-resistant cases were males. Among the azithromycin-resistant cases, some (8/72) reported international travel. Phylogenetic analysis of azithromycin-resistant isolates revealed two large male-dominated clusters, and one cluster may have been due to importation of resistant strain. Comparison of plasmids isolated from the clusters in Ontario revealed the presence of incFII plasmid with high percentage of similarity to plasmids present in global outbreaks affecting mostly males including men who have sex with men (MSM). These two large azithromycin-resistant clusters are suggestive of an outbreak among MSM, though disease exposure or sexual orientation of patients was unknown. The presence of plasmid-borne azithromycin resistance in ciprofloxacin-resistant isolates is a public health concern. Antimicrobial surveillance is important for patient management, understanding the spread of novel resistance types in local communities which sometimes is introduced by travel. We found ongoing multidrug-resistant outbreaks spanning multiple years affecting males. Reduction of future outbreaks in high-risk communities like MSM requires consorted information flow between laboratory, public health, and physicians. We impart genomic and antimicrobial characteristics of multidrug S. flexneri 2a which may serve as reference by clinicians and public health.IMPORTANCEOral ciprofloxacin and azithromycin are generally considered as the first-line therapy of shigellosis. Here, we report the emergence and transmission of azithromycin and ciprofloxacin-resistant S. flexneri serotype 2a among male adults in Ontario during 2016-2018. The percentage of azithromycin and ciprofloxacin resistance among S. flexneri 2a is higher compared to previous reports from Canada and United States. Here, we show the genetic basis of the antimicrobial resistance among these unique groups of S. flexneri 2a isolates. We describe a domestically acquired azithromycin-resistant and ciprofloxacin-resistant S. flexneri 2a lineage in Ontario. Combining whole-genome sequencing (WGS) data with travel-associated data helped in understanding dissemination and transmission. We employed WGS, which not only helped us in understanding the genetic-relationship between isolates but also mine information regarding plasmids. In the future, linking WGS, travel-related data, and clinical data can provide enhanced contact tracing and improve public-health management.

A multi-epitope protein vaccine encapsulated in alginate nanoparticles as a candidate vaccine against Shigella sonnei

Shigellosis, caused by the Gram-negative bacterium Shigella, is a major global health challenge. Despite extensive research over the past two decades, no commercial vaccine is available to prevent Shigella infection. Developing multi-epitope vaccines offers a promising and innovative approach to tackling infectious diseases. In this study, we produced a multi-epitope vaccine candidate using E. coli BL21 (DE3) plysS bacteria and purified the vaccine protein with Ni-NTA affinity chromatography. We then prepared alginate nanoparticles containing the vaccine protein, with a particle size of 122 ± 6 nm, PDI 0.17, SPAN 0.83, and zeta potential of -27 ± 2 mV. Successful protein loading was confirmed through nanodrop and ATR-FTIR analyses. To evaluate the immunogenicity of the encapsulated vaccine, mice were orally vaccinated, and their serum was analyzed for IgG, IL-4, and IFN-γ levels cytokines. The results showed a significant increase in IgG level in the vaccinated group compared to controls. Additionally, the vaccinated group exhibited a notable increase in IL-4 and IFN-γ cytokines, indicating a robust Th-cell-mediated immune response essential for combating Shigella. Our nano-vaccine demonstrated high efficacy in activating both humoral and cellular immunity, effectively protecting against the bacteria. The alginate-based oral vaccine candidate thus emerges as a promising strategy for developing a multi-epitope vaccine candidate against Shigella.

Safety and Tolerability of ShigActive™, a Shigella spp. Targeting Bacteriophage Preparation, in a Phase 1 Randomized, Double-Blind, Controlled Clinical Trial

Bacterial diseases of the gastrointestinal (GI) tract continue to be a major worldwide cause of human morbidity and mortality. Among various enteric pathogens, Shigella spp. are some of the most common and deadly bacterial pathogens. They are responsible for ~125 million worldwide cases of shigellosis, and ~14,000 deaths annually, the majority in children under the age of 5 and occurring in developing countries. Preventing and treating shigellosis with conventional drugs (e.g., vaccines and antibiotics) has proven to be very difficult. Here, we assessed the safety and tolerability of ShigActive™, a lytic bacteriophage preparation targeting Shigella spp., in a randomized, placebo-controlled, double-blind Phase 1 clinical trial. Ten participants randomized 4:1 received ShigActive™ or placebo co-administered with sodium bicarbonate orally three times daily for 7 days. Solicited and unsolicited adverse events (AEs) were observed for 29 days. Fifty percent of the subjects receiving ShigActive™ reported mild GI-related symptoms, while one participant experienced moderate fatigue. No serious or medically attended AEs occurred through day 90. Additionally, no significant differences in GI-associated inflammatory mediators or fecal microbiome changes were observed between placebo- and ShigActive™-treated subjects, or from a participants' baseline value. The results of this first-in-human (FIH) randomized, controlled Phase 1 trial of ShigActive™ demonstrate that it is safe and well tolerated when orally administered with no significant differences compared to placebo controls.

Recent advances in modelling Shigella infection

Shigella is an important human-adapted pathogen which contributes to a large global burden of diarrhoeal disease. Together with the increasing threat of antimicrobial resistance and lack of an effective vaccine, there is great urgency to identify novel therapeutics and preventatives to combat Shigella infection. In this review, we discuss the development of innovative technologies and animal models to study mechanisms underlying Shigella infection of humans. We examine recent literature introducing (i) the organ-on-chip model, and its substantial contribution towards understanding the biomechanics of Shigella infection, (ii) the zebrafish infection model, which has delivered transformative insights into the epidemiological success of clinical isolates and the innate immune response to Shigella, (iii) a pioneering oral mouse model of shigellosis, which has helped to discover new inflammasome biology and protective mechanisms against shigellosis, and (iv) the controlled human infection model, which has been effective in translating basic research into human health impact and assessing suitability of novel vaccine candidates. We consider the recent contributions of each model and discuss where the future of modelling Shigella infection lies.

Pathogen detection via inductively coupled plasma mass spectrometry analysis with nanoparticles

Infections caused by viruses and bacteria pose a significant threat to global public health, emphasizing the critical importance of timely and precise detection methods. Inductively coupled plasma mass spectrometry (ICP-MS), a contemporary approach for pathogen detection, offers distinct advantages such as high sensitivity, a wide linear range, and multi-index capabilities. This review elucidates the underexplored application of ICP-MS in conjunction with functional nanoparticles (NPs) for the identification of viruses and bacteria. The review commences with an elucidation of the underlying principles, procedures, target pathogens, and NP requirements for this innovative approach. Subsequently, a thorough analysis of the advantages and limitations associated with these techniques is provided. Furthermore, the review delves into a comprehensive examination of the challenges encountered when utilizing NPs and ICP-MS for pathogen detection, culminating in a forward-looking assessment of the potential pathways for advancement in this domain. Thus, this review contributes novel perspectives to the field of pathogen detection in biomedicine by showcasing the promising synergy of ICP-MS and NPs.

The Impact of Non-Dysentery Shigella Infection on the Growth and Health of Children over Time (INSIGHT)-A Prospective Case-Control Study Protocol

(1) Shigella spp. (Shigella) is known for causing dysentery with blood in stool, but most children infected with Shigella have non-dysentery Shigella-associated diarrhea (NDSD). The World Health Organization recommends the use of antibiotics when diarrhea is bloody, leaving most NDSD cases untreated. The absence of dysentery may not indicate a low risk of death and severe morbidity. Rapid diagnosis and treatment of shigellosis in vulnerable, young children may be lifesaving. INSIGHT aims to determine the potential benefit of identifying NDSD cases (n = 296) and their outcomes compared to cases of Shigella dysentery [DS (n = 148)] and non-Shigella watery diarrhea [WD (n = 148)]. (2) Children seeking care at hospitals in Bangladesh will be enrolled and followed for 1 year (NDSD and DS) or 90 days (WD). We will determine the impact of NDSD on morbidity, mortality, gut health, nutritional status, and cognitive development compared to DS and WD in children and whether the simple "Rapid LAMP-based Diagnostic Test (RLDT)" can accelerate the detection and treatment of shigellosis in the clinical settings of rural Bangladesh. (3) INSIGHT will determine the impact of NDSD in children and determine if the treatment guidelines of shigellosis need to be revisited to improve clinical outcomes and the development of these children.

The re-emergence of sexually transmissible multidrug resistant Shigella flexneri 3a, England, United Kingdom

Shigellosis is an enteric infection that transmits through the faecal-oral route, which can occur during sex between men who have sex with men (MSM). Between 2009 and 2014, an epidemic of sexually transmissible Shigella flexneri 3a occurred in England that subsequently declined. However, from 2019 to 2021, despite SARS-CoV-2 restrictions, S. flexneri 3a continued to re-emerge. We explored possible drivers of re-emergence by comparing host demography and pathogen genomics. Cases were primarily among 35-64 year old men in London. Genomic analyses of 502 bacterial isolates showed that the majority (58%) of re-emerging MSM strains were a clonal replacement of the original, with reduced antimicrobial resistance, conservation of plasmid col156_1, and two SNPs with 19 predicted effects. The absence of major changes in the pathogen or host demographics suggest that other factors may have driven the re-emergence of S. flexneri 3a and highlight the need for further work in the area.

Twenty-five years of sentinel laboratory-based surveillance of shigellosis in a high-income country endemic for the disease, Israel, 1998 to 2022

BackgroundShigella is a leading cause of moderate-to-severe diarrhoea worldwide and diarrhoeal deaths in children in low- and-middle-income countries.AimWe investigated trends and characteristics of shigellosis and antimicrobial resistance of Shigella sonnei in Israel.MethodsWe analysed data generated by the Sentinel Laboratory-Based Surveillance Network for Enteric Pathogens that systematically collects data on detection of Shigella at sentinel laboratories, along with the characterisation of the isolates at the Shigella National Reference Laboratory. Trends in the shigellosis incidence were assessed using Joinpoint regression and interrupted time-series analyses.ResultsThe average incidence of culture-confirmed shigellosis in Israel declined from 114 per 100,000 population (95% confidence interval (CI): 112-115) 1998-2004 to 80 per 100,000 population (95% CI: 79-82) 2005-2011. This rate remained stable 2012-2019, being 18-32 times higher than that reported from the United States or European high-income countries. After decreasing to its lowest values during the COVID-19 pandemic years (19/100,000 in 2020 and 5/100,000 in 2021), the incidence of culture-confirmed shigellosis increased to 39 per 100,000 population in 2022. Shigella sonnei is the most common serogroup, responsible for a cyclic occurrence of propagated epidemics, and the proportion of Shigella flexneri has decreased. Simultaneous resistance of S. sonnei to ceftriaxone, ampicillin and sulphamethoxazole-trimethoprim increased from 8.5% (34/402) in 2020 to 92.0% (801/876) in 2022.ConclusionsThese findings reinforce the need for continuous laboratory-based surveillance and inform the primary and secondary prevention strategies for shigellosis in Israel and other endemic high-income countries or communities.

A Qualitative Evaluation of the Acceptability of Shigellosis Prevention Recommendations Among Gay, Bisexual, and Other Men Who Have Sex With Men

BACKGROUND

Shigellosis is diarrheal disease caused by highly infectious Shigella bacteria. Shigella can spread in multiple ways, including sexual contact. Gay, bisexual, and other men who have sex with men are particularly at risk for shigellosis.

METHODS

To evaluate the acceptability of 3 Centers for Disease Control and Prevention-developed behavioral recommendations for the prevention of sexually transmitted shigellosis, virtual in-depth interviews were conducted among 26 gay or bisexual men in March to May 2021.

RESULTS

Participants had a median age of 25 years; 65% were non-Hispanic White, 12% were Hispanic White, 12% Asian, 4% Hispanic Black, and 8% multiracial/other. Respondents indicated willingness to engage in certain prevention behaviors (e.g., washing hands, genitals, and anus before and after sex), but were less willing to engage in behaviors that were viewed as outside social norms or difficult to practice (e.g., dental dams for oral-anal contact; latex gloves for fingering or fisting). Respondents thought recommendations may be more feasible if knowledge of shigellosis was greater; however, some perceived that the severity of shigellosis is low and did not warrant the effort of engaging in prevention behaviors.

CONCLUSIONS

Educational efforts to increase awareness of shigellosis and other enteric diseases spread through sexual contact are needed and public health practitioners should consider the acceptability of how realistic it is for individuals to engage in certain prevention behaviors. Rather than recommending behaviors that do not have buy-in, it may be more efficacious to focus recommendations on adopting behaviors reported as acceptable to the target audience.

Multidrug-resistant Shigella flexneri outbreak associated with a high-mortality spillover event into nonhuman primates

Shigellosis is a gastrointestinal infection caused by species of Shigella. A large outbreak of Shigella flexneri serotype 2a occurred in Albuquerque, New Mexico (NM) between May 2021 and November 2023 that involved humans and nonhuman primates (NHP) from a local zoo. We analyzed the genomes of 202 New Mexico isolates as well as 15 closely related isolates from other states, and four from NHP. The outbreak was initially detected within men who have sex with men (MSM) but then predominantly affected people experiencing homelessness (PEH). Nearly 70% of cases were hospitalized and there was one human death. The outbreak extended into Albuquerque's BioPark Zoo, causing high morbidity and six deaths in NHPs. The NHP isolates were identical to those in the human outbreak. All isolates were multidrug-resistant, including towards fluoroquinolones, a first line treatment option which led to treatment failures in human and NHP populations. We demonstrate the transmission of this S. flexneri strain between humans and NHPs, causing fatalities in both populations. This study demonstrates the threat of antimicrobial resistant organisms to vulnerable human and primate populations and emphasizes the value of vigilant genomic surveillance within a One Health framework.

A Case of Co-infection Due to Shigella flexneri Colitis Resulting in Bacillus Septic Shock in an Immunocompetent Patient

Shigella flexneri (S. flexneri) is a facultatively anaerobic gram-negative bacterium that is a member of Enterobacteriaceae. The bacterium has been known to cause mild symptoms, such as diarrhea, to more severe diseases such as hemorrhagic colitis. Fortunately, such instances of severe diseases are rare. Nevertheless, even though S. flexneri is a more benign bacterium of the Shigella genus when compared to Shigella dysenteriae, this doesn't mean that it should be neglected. In fact, the ability of this microorganism to cause inflammation of the colon or colitis and disrupt tissue architecture can allow other organisms that would otherwise be benign to cause severe complications, hence allowing said organisms to be opportunistic. Here, we would like to present a case of S. flexneri colitis resulting in bacillus bacteremia and eventually causing an inappropriate physiological host response leading to hypotension, systematic organ failure, etc., also known as septic shock. The pathogenesis and treatment of this patient will also be discussed.

Emergence of lineage III of Shigella sonnei ST152 belonging to a high-risk clone harboring the blaCTX-M-15 gene in Peru

Multidrug-resistant Shigella sonnei ST152, global lineage III, is a high-risk clone, whose dissemination has limited therapeutic options for shigellosis. This study aimed to characterize two isolates of S. sonnei, which were recovered in Lima, Peru, during November 2019, exhibiting resistance to extended-spectrum cephalosporins and quinolones, and concurrently harboring blaCTX-M-15 and qnrS1 genes, in addition to mutations in gyrA-S83L. These isolates were resistant to ceftriaxone, ciprofloxacin and trimethoprim/sulfamethoxazole. The molecular analysis showed that both isolates belonged to lineage III, sublineages IIIa and IIIb. The blaCTX-M-15 gene was located in the same genetic platform as qnrS1, flanked upstream by ISKpn19, on a conjugative plasmid belonging to the IncI-γ group. To the best of our knowledge, this would be the first report on S. sonnei isolates carrying the blaCTX-M-15 gene in Peru. The global dissemination of S. sonnei ST152, co-resistant to β-lactams and quinolones, could lead to a worrisome scenario in the event of potential acquisition of genetic resistance mechanisms to azithromycin.

Collecting a Sexual History During Shigellosis Case Investigations: Nationwide Practices and an Assessment of Data Quality

Shigellosis is spread through the fecal-oral route, including sexual activity. The Centers for Disease Control and Prevention recommends collecting a sexual history from people diagnosed with shigellosis to enhance the understanding of its epidemiology and outbreak detection and the design of disease prevention messaging, although individual jurisdictions decide if and how this is done. Moreover, enteric disease interviewers typically receive in-depth general interviewing training, but often not sexual history question training. The goal of this project was to inform national practices around sexual history questions asked during shigellosis interviews by collecting information from U.S. state health agencies and evaluating sexual history data from people diagnosed with shigellosis in Colorado. From November 2021 to January 2022, information on sexual history questions asked of persons with reported shigellosis and accompanying training resources were collected from U.S. state health departments. Data completeness and quality of shigellosis sexual history questions from Colorado's notifiable disease database from 2018 to 2022 were also evaluated. Of 48 states, 54% reported routinely asking all adults about their sexual history during shigellosis interviews. Of 44 states, 18% indicated having accompanying training materials for interviewers. In Colorado, the proportion of unknown/missing responses to questions about recent sexual contact with male and female partners was lower for males (3.3% unknown and 3.3% missing) than females (5.4% and 6.2%) and highest among those 66 years and older (6.7% and 10%). Among those reporting new sexual partners, 93.5% indicated how they met. The evaluation of Colorado data demonstrates that routine collection of complete, high-quality, actionable sexual history data from all adults with reported shigellosis is feasible. Nearly half of the responding states indicated not doing so, and few had training resources. We recommend training enteric disease interviewers to routinely ask all adults with reported shigellosis about their sexual history, including new partner meeting location.