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Clonal and horizontal transmission of carbapenem-resistant Enterobacterales strains and genes via flies.

Antimicrobial resistance (AMR) is one of the most pressing global public health challenges; in particular, the rapid dissemination of carbapenem-resistant Enterobacterales (CRE) is emerging as a significant concern worldwide. Flies, serving as carriers of pathogens, pose a potential threat in the transmission of antibiotic-resistant bacteria (ARB) between animals and humans. The aim of this study was to evaluate and reveal the potential risk of AMR spread by flies. A total of 450 flies were collected from four farms, four rural areas, and four urban areas in Dengfeng, Henan, China. To select CRE strains on the surface of flies, three flies sampled from the same geographical location were arbitrarily selected and placed into one tube of brain heart infusion broth (BHI), and the supernatant was screened using CHROMagar™ mSuperCARBA culture medium. Different colors and shapes of colonies were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA sequencing. Antimicrobial susceptibility testing for CRE strains was performed using broth microdilution. All CRE strains were whole-genome sequenced. Short-read sequencing was performed using MGISEQ-2000 and long-read sequencing was conducted using GridION. Totally, 150 BHI tubes were screened for CRE strains, and 33 strains were identified as CRE positive. In 24 mSuperCARBA plates, only one species of CRE strain was isolated from each plate. In three plates, two different species of CRE strains were identified in each plate. In one plate, three different species of CRE strains were simultaneously isolated. Carbapenem resistance genes were detected in 81.8% of CRE strains, and blaNDM-1 was predominant (66.7%). No significant correlations between carbapenem-resistant phenotypes and carbapenem resistance genes were observed. The complete genomes of all 33 strains were obtained. Genome analysis revealed that clonal transmission events may have occurred among different farms and rural areas. Phylogenetic analysis revealed that blaNDM-1 IncFII plasmids could break bacterial species barrier for cross-host transmission in diverse areas. To understand and control the transmission of AMR from the perspective of One Health, it is imperative to enhance surveillance of ARB, antibiotic resistance genes, and antibiotic-resistant plasmids in flies.

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Genomic characterisation of an extended-spectrum β-Lactamase-producing Klebsiella pneumoniae isolate assigned to a novel sequence type (6914).

Cow milk, which is sometimes consumed raw, hosts a plethora of microorganisms, some of which are beneficial, while others raise food safety concerns. In this study, the draft genome of an extended-spectrum β-lactamase-producing Klebsiella pneumoniae subsp. pneumoniae strain Cow102, isolated from raw cow milk used to produce traditional foods in Nigeria, is reported. The genome has a total length of 5,359,907bp, with 70 contigs and a GC content of 57.35%. A total of 5,244 protein coding sequences were detected with 31% mapped to a subsystem, and genes coding for amino acids and derivatives being the most prevalent. Multilocus sequence typing revealed that the strain had new allelic profile assigned to the novel 6914 sequence type possessing capsular and lipopolysaccharide antigen K locus 122 with an unknown K type (KL122) and O locus O1/O2v2 with type O2afg, respectively. A total of 28 resistance-related genes, 98 virulence-related genes, two plasmids and five phages were identified in the genome. The resistance genes oqxA, oqxB and an IS3 belonging to cluster 204 were traced to bacteriophage Escher 500,465. Comparative analysis predicted one strain specific orthologous group comprising three genes. This report of a novel sequence type (ST6914) in K. pneumoniae presents a new allelic profile, indicating ongoing evolution and diversification within the species. Its uniqueness suggests it may represent a locally evolved lineage, although further sampling would be necessary to confirm this hypothesis. The strain's multidrug resistance, virulence gene repertoire, and isolation from animal milk render it a potentially significant public health concern, underscoring the importance of genomic surveillance in non-clinical settings to detect emerging strains. Further research is required to fully characterise the capsular K type of ST6914.

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Occurrence and assemblage distribution of Giardia Duodenalis in symptomatic and asymptomatic patients in southeastern Iran (2019-2022).

The ubiquitous protozoan parasite Giardia duodenalis is a major contributor to the global burden of diarrhoea, particularly in young children living in poor-resource regions. Although rarely mortal, giardiasis is associated with growth retardation and cognitive impairment in early childhood. Here we investigate the epidemiology of human giardiasis in Iranshahr (south-eastern Iran), a region where this information was previously lacking. Stool samples were collected from 17,455 outpatients and inpatients attended at three major hospital settings during April 2020 and March 2022. Microscopy was used as a screening method for the presence of Giardia cysts, and the identification of G. duodenalis assemblages was carried out using PCR and Sanger sequencing. The overall prevalence of giardiasis was 1.87 (326/17,455; 95% CI: 1.7-2.1). Being female was positively associated with higher odds of giardiasis (p = 0.014). Individuals without diarrhoea were less likely to have giardiasis (p = 0.022). Individuals attending the Iran Hospital were more likely to harbour G. duodenalis infections compared to those attending at the Khatam Hospital and the Clinical Reference Laboratory (p = 0.001). Our sequence analyses revealed the presence of assemblages A (56.5%, 13/23), B (39.1%, 9/23), and A + B (4.4%, 1/23). No association was observed between the occurrence of a given assemblage and the occurrence of diarhroea. Giardia infections were found at relatively low prevalence rates in both symptomatic and asymptomatic individuals seeking medical attention. Being female, having diarrhoea, and being sampled during 2020-21 were predictors of giardiasis. Although limited, our molecular data indicate that some Giardia infections may be zoonotic in nature. These data should be corroborated and expanded in future epidemiological studies targeting simultaneously human, animal, and environmental (water) samples to improve our understanding of the epidemiology of giardiasis in Iran.

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A triad of gut dysbiosis, dysregulated immunity, and 'leaky' gut characterize HCMV associated neonatal cholestasis.

Gut microbiome dysbiosis and related immune dysfunction have been associated with the pathogenesis of Human Cytomegalovirus (HCMV) infection in infants with neonatal cholestasis (NC) as previously reported by us. However, the interaction of a perturbed microbiome, HCMV infection, and dysregulated immunity leading to exacerbation of disease severity has not been investigated so far. In this study, we examined the association of gut microbiome, host inflammatory and homeostatic markers that are likely to govern increased pathogenesis of NC in HCMV infected IgM positive infants (N = 15) compared to IgM negative (N = 15) individuals. Stool samples of HCMV infected infants and age-matched healthy controls (N = 10) were assessed for gut bacteria-derived metabolites like short-chain fatty acids (SCFAs), Lipopolysaccharide (LPS), cytokines and markers of gut barrier integrity. Data were correlated with previously determined gut microbiome composition and frequency of immune cell subsets. Finally, validation of clinical potential was undertaken by principal component analysis (PCA) of integrated data to delineate the spectrum of clinical pathology. Significantly lower levels of SCFAs and elevated fecal levels of soluble inflammatory mediators were observed in IgM positive HCMV infected infants. Further, increased plasma LPS levels and markers of gut permeability, suggestive of microbial translocation due to a 'leaky gut' were observed in HCMV infected IgM positive group. PCA of integrated data revealed clearly disparate profiles representative of IgM positive, IgM negative, and uninfected healthy states. Our results suggest the utility of an integrated approach involving dysregulated microbiome-immune axis for gaining a better understanding of pathogenesis associated with HCMV infection in NC.

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Venous intestinal ischemia of fungal origin as a cause of intestinal obstruction in immunocompromised patients: case report and literature review

BackgroundMucormycosis is a highly lethal opportunistic fungal disease caused by ubiquitous molds of the order Mucorales, with Rhizopus, Lichtheimia and Mucor being the most common genera. This rare disease primarily affects immunocompromised patients, with presentations ranging from rhino-orbito-cerebral infections to disseminated mucormycosis with angioinvasion, leading to thrombosis and tissue infarction. Gastrointestinal mucormycosis is the least common clinical presentation and is believed to be secondary to spore ingestion. It can involve multiple components of the gastrointestinal tract, such as the stomach, liver, ileum, and colon, with nonspecific manifestations, including pain, nausea, vomiting, and abdominal distension. The initial clinical presentation may even manifest as gastrointestinal bleeding due to gastric ulceration or intestinal perforation.Case presentationHere we present the case of a 48-year-old male patient with a 9-year history of human immunodeficiency virus (HIV) infection who was hospitalized in the context of febrile neutropenia and whose acute respiratory infection was documented; therefore, antibiotic treatment was initiated. However, due to persistent febrile peaks and peripheral blood showing documentation of multilineage cytopenias, a bone marrow biopsy was performed, compatible with presenting features of marrow myelodysplasia. During hospitalization, the patient presented left flank abdominal pain, and an abdominal computed tomography (CT) scan revealed signs of intussusception of a small bowel loop at the distal jejunum level, leading to intestinal obstruction with ischemic progression, requiring ileectomy (60 cm). Histopathological analysis of the resected intestine revealed severe transmural ischemic changes associated with venous thrombosis due to fungal structures, with histochemical studies demonstrating the presence of zygomycete (Mucor) fungal structures, leading to the initiation of treatment with amphotericin B. However, despite treatment, the patient experienced progressive clinical deterioration with persistent fever and ventilatory failure, with follow-up tests showing absolute neutropenia and blood cultures positive for yeast, leading to death 52 days after admission.ConclusionsThe diagnosis of intestinal mucormycosis may be delayed due to the lack of specificity of the signs and symptoms. Pathologists as well as histopathological studies are essential for timely treatment.

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Depletion of core microbiome forms the shared background against diverging dysbiosis patterns in Crohn’s disease and intestinal tuberculosis: insights from an integrated multi-cohort analysis

Background/aimsCrohn’s disease (CD) and intestinal tuberculosis (ITB) are gastrointestinal (GI) inflammatory disorders with overlapping clinical presentations but diverging etiologies. The study aims to decipher CD and ITB-associated gut dysbiosis signatures and identify disease-associated co-occurring modules to evaluate whether this dysbiosis signature is a disease-specific trait or is a shared feature across diseases of diverging etiologies.MethodsDisease-associated gut microbial modules were identified using statistical machine learning and co-abundance network analysis in controls, CD and ITB patients recruited as part of this study. Module reproducibility was reinvestigated through meta-network analysis encompassing >5400 bacteriomes and ~900 mycobiomes. Subsequently, >1600 Indian gut microbiomes were analyzed to identify a central-core gut microbiome of 46 taxa, whose abundances aided in the formulation of an India-specific Core Gut Microbiome Score (CGMS) to measure the degree of core retention.ResultsBoth diseases witness similar patterns of alterations in [alpha]-diversity, characterized by a significant reduction in gut bacterial (i.e., bacterial/archaeal) diversity and a concomitant increase in the fungal [alpha]-diversity. Specific bacterial taxa, along with the diverging mycobiome enabled distinction between the diseases. Co-abundance network analysis of these taxa, validated by integrated meta-network analysis, revealed a ‘disease-depleted’ module, consistent across multiple cohorts, with >75% of this module constituting the central-core Indian gut microbiome. CGMS robustly assessed the core-microbiome loss across different stages of gut inflammatory disorders, in Indian and international cohorts.ConclusionsWhile the disease-specific gain of detrimental bacteria forms an important component of gut dysbiosis, loss of the core microbiome is a shared phenomenon contributing to various GI disorders.

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CRISPR-Cas system positively regulates virulence of Salmonella enterica serovar Typhimurium

BackgroundSalmonella, a foodborne pathogen, possesses a type I-E clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated (Cas) system. We investigated the system’s role in regulating Salmonella virulence by deleting the CRISPR arrays and Cas operon.ResultsOur study demonstrates invasion and proliferation defects of CRISPR-Cas knockout strains in intestinal epithelial cells and macrophages owing to the repression of invasion and virulence genes. However, proliferation defects were not observed in the Gp91phox−/− macrophages, suggesting the system’s role in the pathogens’ antioxidant defense. We deduced that the CRISPR-Cas system positively regulates H2O2 importer (OmpW), catalase (katG), peroxidase (ahpC), and superoxide dismutase (soda and sodCI), thereby protecting the cells from oxidative radicals. The knockout strains were attenuated in in-vivo infection models (Caenorhabditis elegans and BALB/c mice) due to hypersensitivity against antimicrobial peptides, complement proteins, and oxidative stress. The attenuation in virulence was attributed to the suppression of LPS modifying (pmr) genes, antioxidant genes, master regulators, and effectors of the SPI-1 (invasion) and SPI-2 (proliferation) islands in knockout strains. The regulation could be attributed to the partial complementarity of the CRISPR spacers with these genes.ConclusionsOverall, our study extends our understanding of the role of the CRISPR-Cas system in Salmonella pathogenesis and its virulence determinants.

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Whole-genome sequencing analyses and antibiotic resistance situation of 48 Helicobacter pylori strains isolated in Zhejiang, China

PurposeIn the Zhejiang region, research on Helicobacter pylori is lacking. The purpose of this study was to assess the extent of antibiotic resistance in H. pylori in this region, explore alternative methods for predicting the resistance patterns of H. pylori, and investigate the colonization of native gastric mucosa by other clades of H. pylori in the structure population of this bacterium.MethodsStrains were cultured under microaerobic conditions, and antimicrobial susceptibility testing (AST) was performed via agar dilution. Whole-genome sequencing (WGS) was performed via next-generation sequencing (NGS) technology. Epidemiological data including data from this study and reported articles from Zhejiang, China, were included. Further analyses based on AST, WGS, and epidemiological date include virulence genes, antibiotic resistance-related mutations, and phylogenetic trees based on 7 housekeeping genes and core-genome single nucleotide polymorphisms (SNPs).ResultsThe bacterial isolates in this study presented higher antibiotic resistance rates than previously reported, especially against levofloxacin and clarithromycin. The point mutation A2147G in 23 S rRNA is specific to clarithromycin resistance. Mutations at position/s 87 and/or 91 of the gyrA gene amino acid sequence are highly consistent with levofloxacin resistance highly. The point mutations C1707T in 23 S rRNA and E463K in the gyrB gene have not been previously documented in China. All the bacterial isolates belong to Asian branches in the structure population. The resistance rate to clarithromycin of isolates from hosts born after January 1, 1977 is statistically higher than that of hosts born before 1977.ConclusionEradication therapy based on AST results is urgently needed in Zhejiang. The point mutation A2147G in 23 S rRNA and point mutations in the gyrA gene at amino acid/s 87 and/or 91 are sufficient for predicting resistance to clarithromycin and levofloxacin, respectively. The isolate with the mutation E463K in the gyrB gene represents a significant contribution to the field. Mutations in 23 S rRNA may offer valuable insights into the dynamics of H. pylori transmission among hosts.

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Infectious etiology of intussusception in Indian children less than 2 years old: a matched case-control analysis

BackgroundEnteric infections are hypothesized to be associated with intussusception in children. A small increase in intussusception following rotavirus vaccination has been seen in some settings. We conducted post-marketing surveillance for intussusception following rotavirus vaccine, Rotavac introduction in India and evaluated association of intussusception with enteric pathogens.MethodsIn a case-control study nested within a large sentinel hospital-based surveillance program in India, stool samples from 272 children aged less than 2 years admitted for intussusception and 272 age-, gender- and location-matched controls were evaluated with Taqman array card based molecular assays to detect enteric viruses, bacterial enteropathogens and parasites. Matched case-control analysis with conditional logistic regression evaluated association of enteropathogens with intussusception. Population attributable fractions (PAF) were calculated for enteropathogens significantly associated with intussusception.ResultsThe most prevalent enteropathogens in cases and controls were enteroaggregative Escherichia coli, adenovirus 40/41, adenovirus C serotypes and enteroviruses. Children with intussusception were more likely to harbor adenovirus C serotypes (adjusted odds-ratio (aOR) = 1.74; 95% confidence interval (CI) 1.06–2.87) and enteroviruses (aOR = 1.77; 95% CI 1.05–2.97) than controls. Rotavirus was not associated with increased intussusception risk. Adenovirus C (PAF = 16.9%; 95% CI 4.7% − 27.6%) and enteroviruses (PAF = 14.7%; 95% CI 4.2% − 24.1%) had the highest population attributable fraction for intussusception.ConclusionAdenovirus C serotypes and enteroviruses were significantly associated with intussusception in Indian children. Rotavirus was not associated with risk of intussusception.

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