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National Science Review Oct 2023Understanding changes in pathogen behavior (e.g. increased virulence, a shift in transmission channel) is critical for the public health management of emerging...
Understanding changes in pathogen behavior (e.g. increased virulence, a shift in transmission channel) is critical for the public health management of emerging infectious diseases. Genome degradation via gene depletion or inactivation is recognized as a pathoadaptive feature of the pathogen evolving with the host. However, little is known about the exact role of genome degradation in affecting pathogenic behavior, and the underlying molecular detail has yet to be examined. Using large-scale global avian-restricted genomes spanning more than a century, we projected the genetic diversity of Pullorum (bvSP) by showing increasingly antimicrobial-resistant ST92 prevalent in Chinese flocks. The phylogenomic analysis identified three lineages in bvSP, with an enhancement of virulence in the two recently emerged lineages (L2/L3), as evidenced in chicken and embryo infection assays. Notably, the ancestor L1 lineage resembles the serovars with higher metabolic flexibilities and more robust environmental tolerance, indicating stepwise evolutionary trajectories towards avian-restricted lineages. Pan-genome analysis pinpointed fimbrial degradation from a virulent lineage. The later engineered -deletion mutant, and all other five fimbrial systems, revealed behavior switching that restricted horizontal fecal-oral transmission but boosted virulence in chicks. By depleting fimbrial appendages, bvSP established persistent replication with less proinflammation in chick macrophages and adopted vertical transovarial transmission, accompanied by ever-increasing intensification in the poultry industry. Together, we uncovered a previously unseen paradigm for remodeling bacterial surface appendages that supplements virulence-enhanced evolution with increased vertical transmission.
PubMed: 37965675
DOI: 10.1093/nsr/nwad228 -
Journal of Epidemiology and Global... Dec 2023Salmonella is a foodborne zoonotic bacterium, and the antimicrobial-resistant strains of Salmonella are a worldwide health concern. Herein, we employed a meta-analysis... (Meta-Analysis)
Meta-Analysis Review
Salmonella is a foodborne zoonotic bacterium, and the antimicrobial-resistant strains of Salmonella are a worldwide health concern. Herein, we employed a meta-analysis to determine the pooled prevalence of Salmonella and its antimicrobial resistance status in human, animal, and environmental isolates in South Asia. To this end, we followed the standard guideline of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statements for searching literature in three databases namely PubMed, Google Scholar, and CAB abstracts, and a total of 100 eligible datasets were finally included which were published from January 2010 to June 2021. In the pooled prevalence of Salmonella in South Asia, the random model effect was 14.47% (95% CI: 10.17-20.19) with a high degree of heterogeneity (I, 99.8%) and overall antimicrobial resistance was 70% (95% CI: 63.0-76.0) with a heterogeneity of 23.6%. The temporal distribution of the overall antimicrobial resistance (%) against Salmonella was increased from 53 to 77% within 10 years. Out of 18 distinct Salmonella serotypes, S. enterica was highly prevalent (14.22%, 95% CI: 4.02-39.64) followed by S. pullorum (13.50%, 95% CI: 5.64-29.93) with antimicrobial resistance (%) were 86.26 and 90.06, respectively. Noteworthy, nalidixic acid (74.25%) and tetracycline (37.64%) were found mostly resistant to Salmonella whereas ceftriaxone (1.07%) and cefixime (1.24%) were sensitive. This systematic review demonstrated that overall antibiotic resistance profiles of Salmonella are increasing over time in South Asia. Thus, adequate hygienic practices, proper use of antimicrobials, and implementation of antibiotic stewardship are imperative for halting the Salmonella spread and its antimicrobial resistance.
Topics: Animals; Humans; Anti-Bacterial Agents; Prevalence; Asia, Southern; Drug Resistance, Bacterial; Salmonella; Microbial Sensitivity Tests
PubMed: 37883006
DOI: 10.1007/s44197-023-00160-x -
Frontiers in Microbiology 2023spp. have been widely used as probiotic supplements in animal feed as alternatives to antibiotics. In the present study, we screened a strain named BS21 from pig...
spp. have been widely used as probiotic supplements in animal feed as alternatives to antibiotics. In the present study, we screened a strain named BS21 from pig feces. Antimicrobial activities, whole genome mining and UHPLC-MS/MS analysis were used to explore its antimicrobial mechanism. Strain BS21 showed Significant growth inhibition against a variety of animal pathogens, including , , , , and . Seven gene clusters involved in antimicrobial biosynthesis of secondary metabolites were encoded by strain BS21 genome, including four non-ribosomal peptides (bacillibactin, fengycin, surfactin and zwittermicin A), one ribosomal peptide (subtilosin A), one dipeptide (bacilysin) and one polyketide (bacillaene). Among them, production of surfactin, fengycin, bacillibactin, bacilysin and bacillaene was detected in the supernatant of strain BS21. To develop the potential application of BS21 in animal production, medium components and fermentation parameters optimization was carried out using response surface methodology (RSM). Production of antimicrobial secondary metabolites of strain BS21 was increased by 43.4%, and the best medium formula after optimization was corn flour 2%, soybean meal 1.7% and NaCl 0.5% with optimum culture parameters of initial pH 7.0, temperature 30°C, rotating speed at 220 rpm for 26 h. Our results suggested that strain BS21 has the potential for large-scale production and application as a potential source of probiotics and alternative to antibiotics for animal production.
PubMed: 37840708
DOI: 10.3389/fmicb.2023.1239837 -
Frontiers in Veterinary Science 2023The study explored the biofilm (BF) formation capacity, BF-related gene profiles, and the trends in antimicrobial resistance (AMR) of (SP) strains over several years. A...
The study explored the biofilm (BF) formation capacity, BF-related gene profiles, and the trends in antimicrobial resistance (AMR) of (SP) strains over several years. A total of 627 SP strains were isolated from 4,540 samples collected from chicken farms in Guangxi, China during 2018-2022. The BF-forming capacity of these isolates was assessed using crystal violet staining, and the presence of eight BF-related genes (, and ) in BF formation-positive strains was determined through Polymerase Chain Reaction (PCR) analysis. Antimicrobial susceptibility test was conducted to investigate the AMR of the isolates. Minimum Inhibitory Concentration (MIC) and Minimal Biofilm Eradication Concentration (MBEC) of nine SP-BF strains were determined using the broth microdilution method to assess the impact of BF formation on AMR. Additionally, the Optimal Biofilm Formation Conditions (OBFC) were investigated. The results indicated that 36.8% (231/627) of the strains exhibited a positive BF-formation capacity. Among these, 24.7% (57/231) were strong BF producers, 23.4% (54/231) were moderate BF producers, and 51.9% (120/231) were weak BF producers. Analysis of the eight BF-related genes in SP-BF strains revealed that over 90% of them were positive for all the genes. Antimicrobial susceptibility test conducted on the isolates showed that 100% (231/231) of them exhibited resistance to at least one antibiotic, with 98.3% (227/231) demonstrating multidrug resistance (MDR). Both MIC and MBEC measurements indicated varying degrees of increased AMR after BF formation of the bacteria. The optimal conditions for BF formation were observed at 37°C after 48 h of incubation, with an initial bacterial concentration of 1.2 × 10 CFU/mL. Notably, NaCl had a significant inhibitory effect on BF formation, while glucose and Trypticase Soy Broth (TSB) positively influenced BF formation. The results of the study emphasized the need for effective preventive and control strategies to address the challenges posed by the BF formation and MDR of SP in the field.
PubMed: 37720478
DOI: 10.3389/fvets.2023.1248584 -
Microbiology Resource Announcements Sep 2023This work was performed on commercially purchased CVCC519 originally isolated from chicken intestinal content. The Sanguinarine-resistant strain XM3104 was isolated...
This work was performed on commercially purchased CVCC519 originally isolated from chicken intestinal content. The Sanguinarine-resistant strain XM3104 was isolated from Sanguinarine-induced CVCC519. To identify possible mechanisms underlying resistance, the complete genomes of CVCC519 and XM3104 were sequenced using PromethION and next-generation sequencing.
PubMed: 37594281
DOI: 10.1128/MRA.00095-23 -
Frontiers in Microbiology 2023Pullorum disease is one of the common bacterial infectious diseases caused by (), which can result in a decrease in the reproductive performance of laying hens, thus...
INTRODUCTION
Pullorum disease is one of the common bacterial infectious diseases caused by (), which can result in a decrease in the reproductive performance of laying hens, thus causing considerable economic losses. However, studies about the characteristics of intestinal microbiota with pullorum and their potential association with reproductive performance in hens are still limited. This study was to identify the gut microbiota associated with in poultry.
METHODS
A total of 30 hens with -negative (PN) and 30 hens with -positive (PP) were analyzed for hatching eggs laid in 2 weeks (HEL), fertilization eggs (FE), chick number (CN), and microbial structure.
RESULTS
There were significant differences in HEL ( < 0.01), FE ( < 0.01), and CN ( < 0.01) between PP and PN. Histomorphological observations showed abnormal morphology of the ovaries and fallopian tubes and low integrity of epithelial tissue in the ileum and cecum in PP. 16S rRNA gene sequencing revealed that beneficial cecal microbes, such as , and , were positively correlated with reproductive performance and had lower abundance in PP ( = 0.001). Furthermore, diminished phosphotransferase system (PTS) and pentose phosphate pathway, butanoate metabolism and oxidative phosphorylation were also found in PP.
DISCUSSION
Taken together, this study clarified the morphological characteristics of the reproductive tract and intestines of chickens infected with and preliminarily explored the potential association between cecal microbiota and reproductive performance in hens. Our data may provide a reference for revealing the intestinal microbial characteristics of hens in resisting pullorum and exploring novel approaches to infection control in future studies.
PubMed: 37577434
DOI: 10.3389/fmicb.2023.1216542 -
Frontiers in Veterinary Science 2023Most cases of chicken salmonellosis are caused by serovar Gallinarum biovars Gallinarum and Pullorum, which lead to a significant morbidity and fatality rate. Although...
Most cases of chicken salmonellosis are caused by serovar Gallinarum biovars Gallinarum and Pullorum, which lead to a significant morbidity and fatality rate. Although the conventional Kaufmann-White scheme is the reliable method for the serotyping of , it does not distinguish between closely related biotypes like . Pullorum and . Gallinarum. Herein, we conducted a single one-step multiplex PCR assay that can identify and distinguish between . Pullorum and . Gallinarum in an accurate manner. This PCR method was based on three genes, including for . Pullorum identification, for . Gallinarum identification, and as the genus-level reference gene for . By comparing . Pullorum to . Gallinarum and other serovars of study revealed that only the former has a deletion of 126 bp-region in the carboxyl terminus of . The gene does not exist in . Gallinarum. However, it is present in all other serotypes. The multiplex PCR approach utilizes unique sets of primers that are intended to specifically target these three different genes. The established PCR method was capable of distinguishing between the biovars Pullorum and Gallinarum from the 29 distinct serotypes as well as the 50 distinct pathogens that are not , showing excellent specificity and exclusivity. The minimal amount of bacterial cells required for PCR detection was 100 CFU, while the lowest level of genomic DNA required was 27.5 pg/μL for both . Pullorum and . Gallinarum. After being implemented on the clinical isolates collected from a poultry farm, the PCR test was capable of distinguishing the two biovars Pullorum and Gallinarum from the other strains. The findings of the PCR assay were in line with those of the traditional serotyping and biochemical identification methods. This new multiplex PCR could be used as a novel tool to reinforce the clinical diagnosis and differentiation of . Pullorum and . Gallinarum, particularly in high-throughput screening situations, providing the opportunity for early screening of infections and, as a result, more effective management of the illness among flocks.
PubMed: 37476820
DOI: 10.3389/fvets.2023.1220118