Biogenic Preparation and Characterization of Silver Nanoparticles from Seed Kernel of Mangifera indica and Their Antibacterial Potential against Shigella spp.

Shigellosis is a serious foodborne diarrheal disease caused by the Shigella species. It is a critical global health issue. In developing countries, shigellosis causes most of the mortality in children below 5 years of age. Globally, around 165 million cases of diarrhea caused by Shigella are reported, which accounts for almost 1 million deaths, in which the majority are recorded in Third World nations. In this study, silver nanoparticles were synthesized using Mangifera indica kernel (MK-AgNPs) seed extracts. The biosynthesized M. indica silver nanoparticles (MK-AgNPs) were characterized using an array of spectroscopic and microscopic tools, such as UV-Vis, scanning electron microscopy, particle size analyzer, Fourier transform infrared spectroscopy, and X-ray diffractometer. The nanoparticles were spherical in shape and the average size was found to be 42.7 nm. The MK-AgNPs exhibited remarkable antibacterial activity against antibiotic-resistant clinical Shigella sp. The minimum inhibitory concentration (MIC) value of the MK-AgNPs was found to be 20 µg/mL against the multi-drug-resistant strain Shigella flexneri. The results clearly demonstrate that MK-AgNPs prepared using M. indica kernel seed extract exhibited significant bactericidal action against pathogenic Shigella species. The biosynthesized nanoparticles from mango kernel could possibly prove therapeutically useful and effective in combating the threat of shigellosis after careful investigation of its toxicity and in vivo efficacy.

Effect of Plant Systemic Resistance Elicited by Biological and Chemical Inducers on the Colonization of the Lettuce and Basil Leaf Apoplast by Salmonella enterica.

Mitigation strategies to prevent microbial contamination of crops are lacking. We tested the hypothesis that induction of plant systemic resistance by biological (induced systemic resistance [ISR]) and chemical (systemic acquired resistance [SAR]) elicitors reduces endophytic colonization of leaves by Salmonella enterica serovars Senftenberg and Typhimurium. S. Senftenberg had greater endophytic fitness than S. Typhimurium in basil and lettuce. The apoplastic population sizes of serovars Senftenberg and Typhimurium in basil and lettuce, respectively, were significantly reduced approximately 10- to 100-fold by root treatment with microbial inducers of systemic resistance compared to H2O treatment. Rhodotorula glutinis effected the lowest population increases of S. Typhimurium in lettuce and S. Senftenberg in basil leaves, respectively 120- and 60-fold lower than those seen with the H2O treatment over 10 days postinoculation. Trichoderma harzianum and Pichia guilliermondii did not have any significant effect on S. Senftenberg in the basil apoplast. The chemical elicitors acidobenzolar-S-methyl and dl-ß-amino-butyric acid inhibited S. Typhimurium multiplication in the lettuce apoplast 10- and 2-fold, respectively, compared to H2O-treated plants. All ISR and SAR inducers applied to lettuce roots in this study increased leaf expression of the defense gene PR1, as did Salmonella apoplastic colonization in H2O-treated lettuce plants. Remarkably, both acidobenzolar-S-methyl upregulation and R. glutinis upregulation of PR1 were repressed by the presence of Salmonella in the leaves. However, enhanced PR1 expression was sustained longer and at greater levels upon elicitor treatment than by Salmonella induction alone. These results serve as a proof of concept that priming of plant immunity may provide an intrinsic hurdle against the endophytic establishment of enteric pathogens in leafy vegetables. IMPORTANCE Fruit and vegetables consumed raw have become an important vehicle of foodborne illness despite a continuous effort to improve their microbial safety. Salmonella enterica has caused numerous recalls and outbreaks of infection associated with contaminated leafy vegetables. Evidence is increasing that enteric pathogens can reach the leaf apoplast, where they confront plant innate immunity. Plants may be triggered for induction of their defense signaling pathways by exposure to chemical or microbial elicitors. This priming for recognition of microbes by plant defense pathways has been used to inhibit plant pathogens and limit disease. Given that current mitigation strategies are insufficient in preventing microbial contamination of produce and associated outbreaks, we investigated the effect of plant-induced resistance on S. enterica colonization of the lettuce and basil leaf apoplast in order to gain a proof of concept for the use of such an intrinsic approach to inhibit human pathogens in leafy vegetables.

Association of Household Pets, Common Dietary Factors, and Lifestyle Factors with Clostridium difficile Infection.

BACKGROUND: Clostridium difficile infection (CDI) is one of the most common hospital-acquired infections and is associated with significant morbidity and mortality. Since owning a cat or dog could enrich the gut microbiome, we hypothesized that it would be protective against CDI. AIMS: We conducted a survey study on patients tested for CDI in order to assess whether living in the presence of a pet is associated with a decreased risk of CDI. METHODS: We surveyed subjects aged 18-90 over a 14-month period using a retrospective case-control design. Subjects with CDI were matched by gender and age to patients who tested negative and had no prior history of CDI. A web-based survey was provided to subjects by mail or assisted by phone. Conditional logistic regression was used to assess for associations between CDI and the various risk factors. RESULTS: 205 CDI positive and 205 CDI negative subjects (response rate of 50.2%) were included. After matching for age and sex, living with a cat or dog was not associated with negative CDI testing. Exploratory multivariable modeling identified an unexpected association between positive CDI testing and high meat intake (OR 2.13, 95% CI 1.21-3.77) as well as between positive CDI testing and cat allergies (OR 1.88, 95% CI 1.02-3.46). CONCLUSION: Living with a cat or dog was not associated with negative CDI testing. Several novel risk factors for CDI have been identified including high meat intake and cat allergies.

Characterization of an Endolysin Targeting Clostridioides difficile That Affects Spore Outgrowth.

Clostridioides difficile is a spore-forming enteric pathogen causing life-threatening diarrhoea and colitis. Microbial disruption caused by antibiotics has been linked with susceptibility to, and transmission and relapse of, C. difficile infection. Therefore, there is an urgent need for novel therapeutics that are effective in preventing C. difficile growth, spore germination, and outgrowth. In recent years bacteriophage-derived endolysins and their derivatives show promise as a novel class of antibacterial agents. In this study, we recombinantly expressed and characterized a cell wall hydrolase (CWH) lysin from C. difficile phage, phiMMP01. The full-length CWH displayed lytic activity against selected C. difficile strains. However, removing the N-terminal cell wall binding domain, creating CWH351-656, resulted in increased and/or an expanded lytic spectrum of activity. C. difficile specificity was retained versus commensal clostridia and other bacterial species. As expected, the putative cell wall binding domain, CWH1-350, was completely inactive. We also observe the effect of CWH351-656 on preventing C. difficile spore outgrowth. Our results suggest that CWH351-656 has therapeutic potential as an antimicrobial agent against C. difficile infection.

Antimicrobial peptides as an alternative to relieve antimicrobial growth promoters in poultry.

1. This review describes different classes of antimicrobial peptides (AMP) found in the gastrointestinal (GI) tract of avian species, and their antimicrobial and immunomodulatory activities. The potential benefits of synthetic AMP in poultry production are examined, in the context of the use of AMP as alternatives to antimicrobial growth promoters (AGP).2. Since the mid-1950s, antibiotic growth promoters (AGP) have been used in feed at low prophylactic doses to modulate the homoeostasis of intestinal microbiota, decreasing the risk of intestinal dysbacteriosis and the growth of pathogens within the avian gut. Over the last three decades, AGP have faced major regulatory restrictions due to concerns of generating antimicrobial resistance (AMR). It is now well documented that the rate of infectious disease outbreaks is higher in flocks that are not fed prophylactic antibiotics, resulting in a compensatory increase in antimicrobial use for therapeutic purposes.3. Endogenous natural AMP production is associated with the presence of microbiota and their interaction with the intestinal epithelial and lamina propria lymphoid cells. Their antimicrobial activity shapes the beneficial microbiota population and controls intestinal pathogens such Clostridium and Salmonella spp., and stimulates the development and maturation of the local immune system.4. Similar to AGP, AMP can establish a well-balanced gut beneficial microbiota for adequate immune-competence, animal health and high growth performance parameters such as feed intake, daily weight, feed conversion and accumulated mortality.5. Antimicrobial proteins and peptides constitute an essential part of the innate immune system of all organisms and protect the host from invading pathogenic bacteria, viruses, fungi, and parasites by interacting with the negatively charged pathogen membranes.

Multiplex real-time SYBR Green I PCR assays for simultaneous detection of 15 common enteric pathogens in stool samples.

Diarrheal diseases account for more than 50% of foodborne diseases worldwide, the majority of which occur in infants and young children. The traditional bacterial detection method is complex and time-consuming; therefore, it is necessary to establish a rapid and convenient detection method that can detect multiple pathogens simultaneously. In this study, we developed a set of five multiplex real-time SYBR Green I PCR assays to simultaneously detect 15 common enteric pathogens based on the Homo-Tag Assisted Non-Dimer system. These assays effectively reduced primer-dimer formation and improved the stability, uniformity, and amplification efficiency of multiplex PCR. The detection limit of the multiplex SYBR Green I PCR system was approximately 104-106 CFU/mL for stool specimens. Furthermore, we vitrified heat-unstable components on the cap of a reaction tube, showing that Taq DNA polymerase, dNTPs, primers, and SYBR Green I remained stable at 25 °C. In summary, we developed multiplex SYBR Green I PCR assays that can simultaneously detect 15 enteric pathogens. This method is comprehensive, rapid, inexpensive, accurate, and simple and displays high specificity.

Detecting national human enteric disease outbreaks linked to animal contact in the United States of America.

Enteric pathogens, such as non-typhoidal Salmonella, Campylobacter and Escherichia coli, can reside in the intestinal tract of many animals, including livestock, companion animals, small mammals and reptiles. Often, these animals can appear healthy; nonetheless, humans can become infected after direct or indirect contact, resulting in a substantial illness burden. An estimated 14% of the 3.2 million illnesses that occur in the United States of America (USA) each year from such enteric pathogens are attributable to animal contact. Surveillance for enteric pathogens in the USA includes the compilation and interpretation of both laboratory and epidemiologic data. However, the authors feel that a collaborative, multisectoral and transdisciplinary - or One Health - approach is needed for data collection and analysis, at every level. In addition, they suggest that the future of enteric illness surveillance lies in the development of improved technologies for pathogen detection and characterisation, such as genomic sequencing and metagenomics. In particular, using whole-genome sequencing to compare genetic sequences of enteric pathogens from humans, food, animals and the environment, can help to predict antimicrobial resistance among these pathogens, determine their genetic relatedness and identify outbreaks linked to a common source. In this paper, the authors describe three recent, multi-state human enteric illness outbreaks linked to animal contact in the USA and discuss how integrated disease surveillance was essential to outbreak detection and response. Additional datasharing between public health and animal health laboratories and epidemiologists at the local, national, regional and international level may help to improve surveillance for emerging animal and human health threats and lead to new opportunities for prevention.

Les agents pathogènes entériques tels que les Salmonella non typhiques, Campylobacter et Escherichia coli peuvent coloniser le tractus intestinal d'un grand nombre d'animaux y compris les espèces d'élevage, les animaux de compagnie, les petits mammifères et les reptiles. Les animaux porteurs sont souvent sains en apparence ; néanmoins, les humains peuvent contracter l'infection après un contact direct ou indirect avec un animal atteint, ce qui induit un fardeau significatif associé à ces maladies. D'après les estimations, environ 14 % des 3,2 millions de cas annuels d'infections par des agents pathogènes entériques aux États-Unis d'Amérique ont pour origine un contact avec des animaux. Aux États-Unis, la surveillance des agents pathogènes entériques est basée sur la collecte et l'interprétation des résultats de laboratoire et des données épidémiologiques. Les auteurs sont néanmoins convaincus de la nécessité de recourir à une approche collaborative, multisectorielle et transdisciplinaire (en d'autres termes, une approche Une seule santé) pour la collecte et l'analyse des données, à tous les niveaux. Ils considèrent également que la surveillance des infections entériques reposera à l'avenir sur le développement de technologies avancées dans le domaine de la détection et de la caractérisation des agents pathogènes, notamment le séquençage génomique et la métagénomique. En particulier, le recours au séquençage du génome entier afin de comparer les séquences d'agents pathogènes d'origine humaine, alimentaire, animale et environnementale permettra d'anticiper l'apparition d'antibiorésistances, de déterminer le degré de parenté génétique de ces agents et d'identifier les foyers provenant d'une même source. Les auteurs décrivent trois foyers récents d'infections entériques humaines survenus dans plusieurs états des États-Unis et soulignent à quel point l'exercice d'une surveillance sanitaire intégrée a été déterminant pour la détection de ces foyers et la mise en œuvre d'une réponse appropriée. Un partage accru d'informations entre les laboratoires et les épidémiologistes de santé publique et animale aux niveaux local, national, régional et international pourrait contribuer à améliorer la surveillance des menaces émergentes pesant sur la santé animale et humaine et à mettre en œuvre de nouvelles modalités de prévention.

En el tracto intestinal de muchos animales, entre ellos ganado, mascotas, pequeños mamíferos o reptiles, puede haber patógenos intestinales como salmonelas no tifoideas, Campylobacter o Escherichia coli. A menudo los animales parecen sanos, pese a lo cual las personas pueden infectarse por contacto directo o indirecto con ellos, lo que da lugar a una considerable carga de morbilidad. Se calcula que, de los 3,2 millones de casos de enfermedad que estos patógenos intestinales causan al año en los EE. UU., un 14% es atribuible al contacto con animales. La vigilancia de patógenos intestinales que se practica en los EE. UU. incluye la compilación e interpretación de datos tanto epidemiológicos como de laboratorio. En opinión de los autores, sin embargo, es preciso que la obtención y el análisis de datos respondan a un planteamiento de colaboración multisectorial y transdisciplinar ­ esto es, a la lógica de Una sola salud ­ que abarque todos los niveles. Los autores apuntan además que el futuro de la vigilancia de las enfermedades intestinales pasa por el desarrollo de tecnologías más eficaces de detección y caracterización de patógenos, como la secuenciación genómica o la metagenómica. En particular, el uso de la secuenciación de genomas completos para comparar entre sí las secuencias genéticas de patógenos intestinales presentes en personas, alimentos, animales y el medio ambiente puede ayudar a predecir la aparición de resistencias a los antimicrobianos en estos patógenos, determinar su parentesco genético e identificar brotes vinculados con un origen común. Los autores, tras describir tres recientes brotes de enfermedad intestinal humana ligados al contacto con animales que afectaron a varios estados de los EE. UU., explican la función esencial que cumplió la vigilancia integrada de enfermedades para detectar esos brotes y responder a ellos. El intercambio de más datos entre los laboratorios de salud pública y sanidad animal y los epidemiólogos a escala local, nacional, regional e internacional puede ser de ayuda para mejorar la vigilancia de amenazas sanitarias y zoosanitarias emergentes y abrir nuevas posibilidades de prevención.

Risk factors for sporadic Giardia infection in the USA: a case-control study in Colorado and Minnesota.

Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9-39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0-20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5-7.0), male-male sexual behaviour (aOR = 45.7; 95% CI 5.8-362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01-2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2-5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1-3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1-0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.

Construction of a Dose-Illness Relationship via Modeling Morbidity and Application to Risk Assessment of Wastewater Reuse.

A disease burden (DB) evaluation for environmental pathogens is generally performed using disability-adjusted life years with the aim of providing a quantitative assessment of the health hazard caused by pathogens. A critical step in the preparation for this evaluation is the estimation of morbidity between exposure and disease occurrence. In this study, the method of a traditional dose-response analysis was first reviewed, and then a combination of the theoretical basis of a "single-hit" and an "infection-illness" model was performed by incorporating two critical factors: the "infective coefficient" and "infection duration." This allowed a dose-morbidity model to be built for direct use in DB calculations. In addition, human experimental data for typical intestinal pathogens were obtained for model validation, and the results indicated that the model was well fitted and could be further used for morbidity estimation. On this basis, a real case of a water reuse project was selected for model application, and the morbidity as well as the DB caused by intestinal pathogens during water reuse was evaluated. The results show that the DB attributed to Enteroviruses was significant, while that for enteric bacteria was negligible. Therefore, water treatment technology should be further improved to reduce the exposure risk of Enteroviruses. Since road flushing was identified as the major exposure route, human contact with reclaimed water through this pathway should be limited. The methodology proposed for model construction not only makes up for missing data of morbidity during risk evaluation, but is also necessary to quantify the maximum possible DB.

Surface hypothermia predicts murine mortality in the intragastric Vibrio vulnificus infection model.

BACKGROUND: The Gram-negative bacterium Vibrio vulnificus can cause severe disease in humans who consume undercooked, contaminated seafood. To study food-borne V. vulnificus disease in the laboratory, mouse virulence studies predominantly use death as the primary experimental endpoint because behaviorally based moribund status does not consistently predict lethality. This study assessed ventral surface temperature (VST) and its association with mouse survival during V. vulnificus virulence studies as an efficacious, humane alternative. METHODS: VST of mice intragastrically inoculated with V. vulnificus was measured every 2-h for 24 h and data for minimal VST analyzed for prediction of lethal outcome. RESULTS: In contrast to the relatively stable VST of mock-infected control animals, mice infected with V. vulnificus exhibited hypothermia with minima occurring 8 to 12 h post-inoculation. The minimum VST of mice that proceeded to death was significantly lower than that of surviving mice. VST ≤ 23.5 °C was predictive of subsequent death with a sensitivity of 68% and specificity of 95%. CONCLUSIONS: Use of VST ≤ 23.5 °C as an experimental endpoint during V. vulnificus infection has potential to reduce suffering of nearly 70% of mice for a mean of 10 h per mouse, without compromising experimental efficacy. Temperature cutoff of 23.5 °C exhibited 93% positive and 77% negative predictive value. For future V. vulnificus virulence studies requiring only binary comparison (e.g., LD50 assays), we find that VST can be applied as a humane endpoint. However, use of VST is not recommended when detailed survival kinetics are desired.

Report of the first clinical case of intestinal trichomoniasis caused by Tritrichomonas foetus in a cat with chronic diarrhoea in Brazil.

BACKGROUND: Tritrichomonas foetus is an emergent and important enteric pathogen of cats, which causes prolonged diarrhoea in cats. CASE PRESENTATION: This study describes a T. foetus infection in a seven-month-old, entire male domestic shorthair kitten with a six-month history of persistent large intestinal diarrhoea, faecal incontinence, prostration, apathy and weight loss. Parasites were microscopically observed and confirmed by PCR and DNA sequencing. Molecular analyses were carried out comparing the sequence obtained in this study with T. foetus and T. suis. Retrieved from GenBank. After treatment with ronidazole, the cat showed resolution of clinical signs. CONCLUSIONS: This is the first clinical case of T. foetus infection in a chronic diarrheic cat in Brazil and South America, confirming the presence of this pathogen in this part of the world and highlighting the importance of this protozoa being considered in the differential diagnosis of cats presenting diarrhoea of the large intestine. Our case report enriches our knowledge on the geographical distribution of T. foetus in cats in Brazil and provides further understanding of the clinical significance of feline intestinal trichomoniasis in this country.

Intracellular Shigella remodels its LPS to dampen the innate immune recognition and evade inflammasome activation.

LPS is a potent bacterial effector triggering the activation of the innate immune system following binding with the complex CD14, myeloid differentiation protein 2, and Toll-like receptor 4. The LPS of the enteropathogen Shigella flexneri is a hexa-acylated isoform possessing an optimal inflammatory activity. Symptoms of shigellosis are produced by severe inflammation caused by the invasion process of Shigella in colonic and rectal mucosa. Here we addressed the question of the role played by the Shigella LPS in eliciting a dysregulated inflammatory response of the host. We unveil that (i) Shigella is able to modify the LPS composition, e.g., the lipid A and core domains, during proliferation within epithelial cells; (ii) the LPS of intracellular bacteria (iLPS) and that of bacteria grown in laboratory medium differ in the number of acyl chains in lipid A, with iLPS being the hypoacylated; (iii) the immunopotential of iLPS is dramatically lower than that of bacteria grown in laboratory medium; (iv) both LPS forms mainly signal through the Toll-like receptor 4/myeloid differentiation primary response gene 88 pathway; (v) iLPS down-regulates the inflammasome-mediated release of IL-1ß in Shigella-infected macrophages; and (vi) iLPS exhibits a reduced capacity to prime polymorfonuclear cells for an oxidative burst. We propose a working model whereby the two forms of LPS might govern different steps of the invasive process of Shigella. In the first phases, the bacteria, decorated with hypoacylated LPS, are able to lower the immune system surveillance, whereas, in the late phases, shigellae harboring immunopotent LPS are fully recognized by the immune system, which can then successfully resolve the infection.

Disarming bacterial virulence through chemical inhibition of the DNA binding domain of an AraC-like transcriptional activator protein.

The misuse of antibiotics during past decades has led to pervasive antibiotic resistance in bacteria. Hence, there is an urgent need for the development of new and alternative approaches to combat bacterial infections. In most bacterial pathogens the expression of virulence is tightly regulated at the transcriptional level. Therefore, targeting pathogens with drugs that interfere with virulence gene expression offers an effective alternative to conventional antimicrobial chemotherapy. Many Gram-negative intestinal pathogens produce AraC-like proteins that control the expression of genes required for infection. In this study we investigated the prototypical AraC-like virulence regulator, RegA, from the mouse attaching and effacing pathogen, Citrobacter rodentium, as a potential drug target. By screening a small molecule chemical library and chemical optimization, we identified two compounds that specifically inhibited the ability of RegA to activate its target promoters and thus reduced expression of a number of proteins required for virulence. Biophysical, biochemical, genetic, and computational analyses indicated that the more potent of these two compounds, which we named regacin, disrupts the DNA binding capacity of RegA by interacting with amino acid residues within a conserved region of the DNA binding domain. Oral administration of regacin to mice, commencing 15 min before or 12 h after oral inoculation with C. rodentium, caused highly significant attenuation of intestinal colonization by the mouse pathogen comparable to that of an isogenic regA-deletion mutant. These findings demonstrate that chemical inhibition of the DNA binding domains of transcriptional regulators is a viable strategy for the development of antimicrobial agents that target bacterial pathogens.

A scoping review of modifiable and behavioural drivers of infectious gastroenteritis among children in high-income countries.

BACKGROUND: Globally, gastroenteritis (GE) significantly impacts children's health and contributes to societal, economic, and health burdens. Previous studies reporting risk factors of GE in children in high-income settings mainly rely on outbreak investigations, which inherently capture only a fractional representation of the overall spectrum of GE occurrences. In addition, there is paucity of comprehensive information pertaining to modifiable risk factors of GE. This scoping review aims to synthesize existing evidence concerning modifiable and behavioural risk factors associated with GE among children in high-income countries. METHODS: PubMed, Embase, CINAHL, and Scopus were the databases from which articles were retrieved. A descriptive synthesis of the evidence was performed, following the Arksey and O'Malley scoping studies framework and enhanced by the Preferred Reporting Items for Systematic Reviews and Meta-analysis extension for Scoping Reviews checklist (PRISMA-ScR). RESULTS: The systematic search identified 13,395 journal articles, which were subsequently screened, and duplicates removed, resulting in 19 articles for inclusion in the review. The majority of these studies (63.2%) employed a case-control design and were predominantly conducted in community settings (68.4%). Factors such as parental literacy, contact with individuals exhibiting gastrointestinal symptoms, and nappy-wearing were identified as significantly associated with childhood GE within domestic environments. Childcare-related variables, including enrolment size, mixing of personnel between child groups, the presence of central cleaning stations, and the implementation of hygiene and disease prevention policies, showed significant association with GE. In addition, the presence of sand pits, paddling pools, and animals in childcare centers correlated with increased incidences of GE among attending children. CONCLUSIONS: The scoping review reveals a complex and varied research landscape on factors influencing gastroenteritis (GE) for children in high-income countries. The findings suggest that while some variables are closely linked to specific pathogens, others may not be, highlighting variability across GE aetiology. The significant association between various household level and childcare-related factors and childhood GE points to a valuable direction for future research and public health intervention.

Identification of Enteric Pathogen Reservoirs and Transmission Pathways Associated with Short Childhood Stature in the Kolkata Indian Site of the Global Enteric Multicenter Study.

Age-stratified path analyses modeled associations between enteric pathogen reservoirs, transmission pathways and height-for-age z-scores (HAZ) to identify determinants of childhood growth in the Kolkata, India site of the Global Enteric Multicenter Study (GEMS). Models tested direct associations of potential pathogen reservoirs with HAZ at 60-day follow-up in separate moderate and severe diarrhea (MSD) case and control cohorts or indirectly when mediated by enteric infections. In the MSD cohort, rotavirus and typical EPEC (tEPEC) infections among children 0-11 months of age and ST-ETEC infections among children 12-23 months of age were associated with lower HAZ. Handwashing after defecating and before cooking reduced impaired growth through reductions in rotavirus and tEPEC infections. Water storage increased rotavirus and ST-ETEC infection risks, resulting in increased impaired growth, but was reduced with reported child feces disposal. The GII norovirus variant was inversely associated with HAZ among children 12-59 months of age in the control cohort. Reported handwashing before the handling of children reduced GII infections and impaired growth. Boiling water and the disposal of children's feces mediated by stored water were positively associated with HAZ. The targeting of pathogen-specific reservoirs and transmission pathways may more effectively improve childhood linear growth in South Asian urban communities.

Comparative evaluation of two molecular multiplex syndromic panels with acute gastroenteritis.

We compared the Allplex Gastrointestinal V/B1/B2 Assays and Seeplex Diarrhea V/B1/B2 ACE Detection Assays in patients with acute gastroenteritis (AGE). Of the total 432 specimens, 48.8% and 54.9% samples were positive for any bacterial or viral target using Seeplex and Allplex, respectively (P = 0.002). The overall percent agreement (OPA) between the two panels was >95% and the lowest OPA was 95.4% for CdB. Allplex identified 40 samples positive for Salmonella spp., while Seeplex and OBC identified only 27 (67.5%) and 8 (20%), respectively. Shigella spp. were detected by assays in six samples, but none were identified using culture. Clostridium perfringens with Seeplex was detected in 70 (16.2%). It remained an informative species in identifying AGE although cpe gene showed only 9.8% positivity. Pathogenic Escherichia coli with Allplex could be detected in 40 (9.3%) samples, which could provide valuable information for the diagnosis of AGE.

Cultivar was more influential than bacterial strain and other experimental factors in recovery of Escherichia coli O157:H7 populations from inoculated live Romaine lettuce plants.

The varied choice of bacterial strain, plant cultivar, and method used to inoculate, retrieve, and enumerate Escherichia coli O157:H7 from live plants could affect comparability among studies evaluating lettuce-enterobacterial interactions. Cultivar, bacterial strain, incubation time, leaf side inoculated, and sample processing method were assessed for their influence in recovering and quantifying E. coli O157:H7 from live Romaine lettuce. Cultivar exerted the strongest effect on E. coli O157:H7 counts, which held up even when cultivar was considered in interactions with other factors. Recovery from the popularly grown green Romaine "Rio Bravo" was higher than from the red variety "Outredgeous." Other modulating variables were incubation time, strain, and leaf side inoculated. Sample processing method was not significant. Incubation for 24 hours post-lettuce inoculation yielded greater counts than 48 hours, but was affected by lettuce cultivar, bacterial strain, and leaf side inoculated. Higher counts obtained for strain EDL933 compared to a lettuce outbreak strain 2705C emphasized the importance of selecting relevant strains for the system being studied. Inoculating the abaxial side of leaves gave higher counts than adaxial surface inoculation, although this factor interacted with strain and incubation period. Our findings highlight the importance of studying interactions between appropriate bacterial strains and plant cultivars for more relevant research results, and of standardizing inoculation and incubation procedures. The strong effect of cultivar exerted on the E. coli O157:H7-lettuce association supports the need to start reporting cultivar information for illness outbreaks to facilitate the identification and study of plant traits that impact food safety risk.IMPORTANCEThe contamination of Romaine lettuce with Escherichia coli O157:H7 has been linked to multiple foodborne disease outbreaks, but variability in the methods used to evaluate E. coli O157:H7 association with live lettuce plants complicates the comparability of different studies. In this study, various experimental variables and sample processing methods for recovering and quantifying E. coli O157:H7 from live Romaine lettuce were assessed. Cultivar was found to exert the strongest influence on E. coli O157:H7 retrieval from lettuce. Other modulating factors were bacterial incubation time on plants, strain, and leaf side inoculated, while sample processing method had no impact. Our findings highlight the importance of selecting relevant cultivars and strains, and of standardizing inoculation and incubation procedures, in these types of assessments. Moreover, results support the need to start reporting cultivars implicated in foodborne illness outbreaks to facilitate the identification and study of plant traits that impact food safety risk.

Prevalence, Antibiotic Susceptibility Pattern, and Associated Factors of Enteric Bacterial Pathogens Among HIV Infected Patients with Diarrhea Attending the ART Clinic of Dilla University Referral Hospital, Southern Ethiopia.

Background: In people with human immunodeficiency virus infection, diarrhea is reportedly associated with significant morbidity and mortality. Therefore, the aim of this study was to determine the prevalence, antibiotic susceptibility pattern, and associated factors of enteric bacterial pathogens among HIV infected patients with diarrhea attending the antiretroviral treatment (ART) clinic of Dilla University Referral Hospital, southern Ethiopia. Methods: This institutional-based cross-sectional study was conducted on 422 study participants attending at ART clinic of Dilla University Referral Hospital from March to August 2022. Demographic and clinical data were collected by using a semi-structured questionnaire. Stool specimens were inoculated on selective media like Butzller's medium and Xylose Lysine Deoxycholate (XLD) agar. Antimicrobial resistance pattern was assessed by using Kirby-Bauer disk diffusion techniques. Adjusted odds ratio (AOR) and 95% Confidence Interval (CI) was used to determine the presence of association. Results: A total of 422 adult patients were enrolled in this study, 51.7% were females. The mean age of the study participants was 27.4 (±15.6 SD) years. The overall prevalence of enteric pathogens was 14.7% (95% CI=11.4-18.2). Shigella spp was the most prevalent organism. Being a farmer (AOR=5.1; 95% CI=1.4-19.1; p<0.015), the habit of hand washing after toilet (AOR=1.9; 95% CI=1.02-3.47; p<0.04), low CD4 cell count of <200 cells (AOR=2.22; 95% CI=1.15-4.27; p<0.02), and longer duration of diarrhea (AOR=2.68; 95% CI=1.23-5.85; p<0.01) were statistically associated. In total, 98.4% of enteric bacterial isolates were sensitive for Meropenem, whereas 82.5% were resistant against Ampicillin. Multidrug resistance was detected in 49.2% of enteric bacteria. Conclusion: We found that enteric bacteria are common causative agents of diarrhea in immune-compromised patients. The high rate of drug resistance calls for escalating antimicrobial susceptibility testing before prescribing antimicrobial agent.

Intestinal colonization against Vibrio cholerae: host and microbial resistance mechanisms.

Vibrio cholerae is a non-invasive enteric pathogen known to cause a major public health problem called cholera. The pathogen inhabits the aquatic environment while outside the human host, it is transmitted into the host easily through ingesting contaminated food and water containing the vibrios, thus causing diarrhoea and vomiting. V. cholerae must resist several layers of colonization resistance mechanisms derived from the host or the gut commensals to successfully survive, grow, and colonize the distal intestinal epithelium, thus causing an infection. The colonization resistance mechanisms derived from the host are not specific to V. cholerae but to all invading pathogens. However, some of the gut commensal-derived colonization resistance may be more specific to the pathogen, making it more challenging to overcome. Consequently, the pathogen has evolved well-coordinated mechanisms that sense and utilize the anti-colonization factors to modulate events that promote its survival and colonization in the gut. This review is aimed at discussing how V. cholerae interacts and resists both host- and microbe-specific colonization resistance mechanisms to cause infection.

Salmonella-liberated dietary L-arabinose promotes expansion in superspreaders.

The molecular understanding of host-pathogen interactions in the gastrointestinal (GI) tract of superspreader hosts is incomplete. In a mouse model of chronic, asymptomatic Salmonella enterica serovar Typhimurium (S. Tm) infection, we performed untargeted metabolomics on the feces of mice and found that superspreader hosts possess distinct metabolic signatures compared with non-superspreaders, including differential levels of L-arabinose. RNA-seq on S. Tm from superspreader fecal samples showed increased expression of the L-arabinose catabolism pathway in vivo. By combining bacterial genetics and diet manipulation, we demonstrate that diet-derived L-arabinose provides S. Tm a competitive advantage in the GI tract, and expansion of S. Tm in the GI tract requires an alpha-N-arabinofuranosidase that liberates L-arabinose from dietary polysaccharides. Ultimately, our work shows that pathogen-liberated L-arabinose from the diet provides a competitive advantage to S. Tm in vivo. These findings propose L-arabinose as a critical driver of S. Tm expansion in the GI tracts of superspreader hosts.