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1.
Animals (Basel) ; 14(18)2024 Sep 14.
Article in English | MEDLINE | ID: mdl-39335264

ABSTRACT

Pullorum disease, caused by Salmonella enterica serovar Pullorum (S. Pullorum) infection, is a major pathogenic threat to the poultry industry. In this study, 40 S. Pullorum isolates from seven provinces of China were comprehensively analyzed in terms of antigenic type and antimicrobial susceptibility, and their drug-resistance genes and virulence genes were identified with whole-genome sequencing (WGS). We show that all these isolates were standard antigenic types, with ST92 the predominant genotype (92.5%). Disk diffusion assays revealed high resistance rates to streptomycin (92.5%), ciprofloxacin (82.5%), and ampicillin (80%), and the resistance rates to streptomycin, gentamicin, ampicillin, and cefotaxime were higher in isolates from sick chickens than in those from healthy chickens. In addition, gyrA mutations and eight acquired resistance genes were identified, with aac(6')-Iaa the most prevalent, followed by blaTEM1ß, sul2, and the GyrA S83F mutation. The resistance phenotypes to streptomycin, ampicillin, and ciprofloxacin correlated strongly with the presence of the aac(6')-Iaa resistance gene, blaTEM1ß resistance gene, and gyrA mutations, respectively. Analysis of the virulence genes showed that the isolates expressed numerous factors associated with secretion systems, including SPI-1 and SPI-2. Overall, this study extends our understanding of the epidemiology and antibiotic resistance of S. Pullorum in China.

2.
Ann Clin Microbiol Antimicrob ; 23(1): 86, 2024 Sep 28.
Article in English | MEDLINE | ID: mdl-39342293

ABSTRACT

This study explored the molecular epidemiology and resistance mechanisms of 271 non-duplicate Salmonella enterica (S. enterica) strains, isolated mainly from adults (209/271) in a tertiary hospital in Hangzhou between 2020 and 2021. Through whole-genome sequencing and bioinformatics, the bacterial strains were classified into 46 serotypes and 54 sequence types (ST), with S. Enteritidis, S. 1,4,[5],12:i:-, and S. Typhimurium being the most prevalent serotypes and ST11, ST34, and ST19 the most common STs. The strains isolated from adults were primarily S. Enteritidis (59/209), while from children were mainly S. 1,4,[5],12:i:- (20/62). Worryingly, 12.55% strains were multi-drug resistant (MDR), with resistance rates to cefepime (FEP), ceftazidime (CAZ), ceftriaxone (CRO) and cefotaxime (CTX) of 7.38%, 9.23%, 15.87% and 16.24%, respectively, and resistance rates to levofloxacin (LEV) and ciprofloxacin (CIP) of 8.49% and 19.19%, respectively. It is worth noting that the resistance rates of CRO and CTX in children reached 30.65%. A total of 34 strains carried extended-spectrum ß-lactamase (ESBL) genes, dominated by blaCTX-M-65 (13/34) and blaCTX-M-55 (12/34); it is notable that one strain of S. Saintpaul carried both blaCTX-M-27 and blaCTX-M-55. The resistance mechanism to cephalosporins was mainly due to ESBL genes (20/43), and other genes included AmpC and ß-lactamase genes. The strains resistant to quinolones mainly carried qnrS1 (27/53), and others included qnrB6, aac(6')-Ib-cr, and mutations in gyrA and parC. One strain did not carry common quinolone resistance genes but had a parC (p.T57S) mutation to cause CIP resistance. This research provides vital insights into the molecular epidemiology and resistance mechanisms of clinical S. enterica, implicating possible infection control strategies.


Subject(s)
Anti-Bacterial Agents , Drug Resistance, Multiple, Bacterial , Microbial Sensitivity Tests , Salmonella Infections , Whole Genome Sequencing , Humans , China/epidemiology , Salmonella Infections/microbiology , Salmonella Infections/epidemiology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial/genetics , Prevalence , Adult , Child , Salmonella enterica/drug effects , Salmonella enterica/genetics , Salmonella enterica/isolation & purification , Salmonella enterica/classification , Serogroup , Genome, Bacterial , Salmonella/drug effects , Salmonella/genetics , Salmonella/isolation & purification , Salmonella/classification , Molecular Epidemiology , beta-Lactamases/genetics
3.
Poult Sci ; 103(12): 104329, 2024 Sep 12.
Article in English | MEDLINE | ID: mdl-39342690

ABSTRACT

Large-scale poultry slaughter is a highly automated process, which makes cross-contamination possible during the process due to failures in the cleaning and maintenance of automatic equipment, line speed, among other control parameters. To this end, using organic acids to decontaminate poultry meat is a unique strategy for reducing foodborne illnesses. Given the above, this work investigated the application of peracetic acid (PAA) in chicken breast and thigh cuts, to (a) evaluate the effectiveness of PAA as an antimicrobial against Enterobacteriaceae and aerobic mesophilic count (b) evaluate the impact of PAA on the color, texture and cooking loss of skinless chicken breast and chicken thighs with skin. Through the Central Composite Rotational Design (CCRD) with 11 trials and 3 replicates of the central point, the best conditions variable's concentration and time of application of PAA in the cuts were determined. In cuts treated with 1500 PAA solution, a reduction of 2.90 for Enterobacteriaceae in chicken breast was possible with conditions in the central point region and a reduction of 3.65 for Enterobacteriaceae in chicken thigh, when concentrations above 1800 ppm were applied. Peracetic acid (PAA) did not influence the physicochemical characteristics of chicken meat, since it did not change the appearance of fresh meat evaluated by objective analyses (color, texture, and cooking loss), which could impact consumer preference and acceptability.

4.
Microb Pathog ; 196: 106979, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39326804

ABSTRACT

Biofilm-mediated Salmonella enterica serovar Typhi (Salmonella Ser. Typhi) infections are a growing global health issue due to the formation of antibiotic resistance. The study aimed to discover some of the druggable target proteins of Salmonella Ser. Typhi biofilm and antibiofilm enzyme to prevent Salmonella Ser. Typhi biofilm-mediated infection. Enzymatic therapy has demonstrated effective therapeutic results against bacterial infections due to its specificity and high binding capacity to the target. Therefore, this study focused on the computational interaction between the cellulase enzyme and Salmonella Ser. Typhi biofilm targets proteins with help of the various computational experiments such as ADMET (absorption, distribution, metabolism, excretion, and toxicity), protein-protein interactions, MMGBSA, etc. Further, in vitro validations of the typhoidal biofilm and cellulose presence in Salmonella Ser. Typhi biofilm was conducted using Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy, and Raman analysis. Additionally, a minimum biofilm inhibitory concentration assay for cellulase was conducted and find out the optimized cellulase concentration which showed its inhibitory effect on the Salmonella Ser. Typhi. The cellulase antibiofilm effect was analyzed with the help of SEM analysis. Further, the cellulose content in Salmonella Ser. Typhi was quantified before and after treatment of cellulase enzyme. As a result, 58.82 % cellulose content was decreased due to cellulase treatment in Salmonella Ser. Typhi. From the seven selected typhoidal biofilm regulatory proteins of Salmonella Ser. Typhi, we identified only five potential druggable targets: BcsA, CsgE, OmpR, CsgF, and CsgD. The BcsA protein is responsible for cellulose production in Salmonella Ser. Typhi biofilm. Consequently, cellulose worked as a fascinating drug target in Salmonella Ser. Typhi biofilm. Therefore, we used cellulase as a potential antibiofilm enzyme for target-based disruption of biofilm. The cellulase showed a high binding affinity with all five identified target proteins [BcsA(-205.62 kcal/mol) > CsgE(-108.20 kcal/mol) > OmpR(-107.58 kcal/mol) > CsgF(-73.74 kcal/mol) > CsgD(-66.61 kcal/mol)] in the protein-protein interaction analysis. Our computational analysis suggests that the cellulase enzyme may be used as a potential antibiofilm enzyme against Salmonella Ser. Typhi biofilm.

5.
J Med Microbiol ; 73(9)2024 Sep.
Article in English | MEDLINE | ID: mdl-39320348

ABSTRACT

Introduction. Salmonella enterica is a significant enteric pathogen affecting human and livestock health. Pork production is a common source of Salmonella contamination, with emerging multidrug resistance (MDR) posing a global health threat.Gap statement. Salmonella contamination and antimicrobial resistance (AMR) profiles in the pig production chain are underreported.Aim. To investigate the prevalence of S. enterica in the pig production chain and characterise their AMR profiles.Methodology. We collected 485 samples from pig farms, a standard pig abattoir and retail markets in Patthalung and Songkhla provinces in southern Thailand. Antimicrobial susceptibility testing was performed on these samples, and AMR profiles were determined.Results. S. enterica was detected in 68.67% of farm samples, 45.95% of abattoir samples and 50.67% of retail market samples. Analysis of 264 isolates, representing 18 serotypes, identified S. enterica serotype Rissen as the most prevalent. The predominant resistance phenotypes included ampicillin (AMP, 91.29%), tetracycline (TET, 88.26%) and streptomycin (STR, 84.47%). Over 80% of isolates showed resistance to three or more antimicrobial classes, indicating MDR. The AMP-STR-TET resistance pattern was found in nearly 70% of all MDR isolates across the production chain.Conclusions. The high prevalence of MDR is consistent with extensive antimicrobial use in the livestock sector. The presence of extensively resistant S. enterica highlights the urgent need for antimicrobial stewardship. Strengthening preventive strategies and control measures is crucial to mitigate the risk of MDR Salmonella spreading from farm to fork.


Subject(s)
Abattoirs , Anti-Bacterial Agents , Drug Resistance, Multiple, Bacterial , Microbial Sensitivity Tests , Salmonella Infections, Animal , Salmonella enterica , Animals , Salmonella enterica/drug effects , Salmonella enterica/isolation & purification , Swine , Thailand/epidemiology , Anti-Bacterial Agents/pharmacology , Salmonella Infections, Animal/microbiology , Salmonella Infections, Animal/epidemiology , Prevalence , Swine Diseases/microbiology , Swine Diseases/epidemiology , Farms , Food Microbiology
6.
J Agric Food Chem ; 2024 Sep 19.
Article in English | MEDLINE | ID: mdl-39298407

ABSTRACT

The prevalence of foodborne pathogenic bacteria, especially drug-resistant strains, such as Salmonella enterica, poses serious threats to public health, highlighting the requirement for the development of rapid and precise detection methods. Herein, a CRISPR/Cas12a-triggered visible-light-driven photoelectrochemical (PEC) assay (CasPEC) was developed using a SiO2-quenched BiVO4/MoS2 p/n-type heterojunction as the photoactive material. The CRISPR/Cas12a recognition endowed the CasPEC assay with high specificity capable of resolving single-nucleotide polymorphisms (SNPs) and identifying SNP-involved drug-resistant bacteria. SiO2 was linked to the surface of the BiVO4/MoS2 heterojunction by single-stranded DNA (ssDNA), which would be cleaved by target-activated CRISPR/Cas12a. This cleavage of ssDNA resulted in the detachment of SiO2, thereby achieving a "signal-on" PEC output. Leveraging the multiple-turnover CRISPR cleavage and the outstanding photoactive performance of PEC signaling, the CasPEC assay for S. enterica showed a detection limit of 103 colony-forming units (CFU)/mL and the ability to detect as few as 0.01% drug-resistant strains. The CasPEC assay can accurately sense the S. enterica contamination in complex food matrices, including beef and milk. These findings demonstrated the great potential of the CasPEC assay for detecting pathogenic bacterial contamination in food, particularly concerning food safety related to SNP-involved drug-resistant bacteria.

7.
Vet J ; 308: 106240, 2024 Sep 12.
Article in English | MEDLINE | ID: mdl-39276848

ABSTRACT

Salmonellosis, a zoonotic gastrointestinal disease, presents a significant global health burden with a high incidence rate. Transmission primarily occurs through the consumption of contaminated poultry products, although water and contact with asymptomatic animals are also vectors. The disease's pervasiveness has prompted international health organizations to advocate for robust prevention and control strategies. This study focuses on the in-silico design of a multi-epitope vaccine targeting Salmonella enterica serovar Typhimurium's fimH protein, a fimbriae component crucial for bacterial adhesion and pathogenicity. The vaccine construct was developed by identifying and synthesizing non-allergenic, antigenic, and non-toxic epitopes for both Cytotoxic T Lymphocytes and Helper T Lymphocytes. Adjuvants were incorporated to enhance immunogenicity, and the vaccine's structure was modeled using advanced bioinformatics tools. The proposed vaccine demonstrated promising antigenicity and immunogenicity profiles, with a favorable physical-chemical property analysis. The vaccine's structures, designed by computational analysis, suggests high likelihood to native protein configurations. Antigenicity and allergenicity assessments validate the vaccine's immunogenic potential and hypoallergenic nature. Physicochemical evaluations indicate favorable stability and solubility profiles, essential for vaccine efficacy. This comprehensive approach to vaccine design expressed in Chlorella vulgaris holds promises for effective salmonellosis control. The multi-epitope vaccine, designed through meticulous in-silico methods, emerges as a promising candidate for controlling salmonellosis. Its strategic construction based on the fimH protein epitopes offers a targeted approach to elicit a robust immune response, potentially curbing the spread of this disease in poultry.

8.
J Biol Chem ; : 107758, 2024 Sep 09.
Article in English | MEDLINE | ID: mdl-39260696

ABSTRACT

S. Typhi, the cause of typhoid fever, is a bacterial pathogen of substantial global importance. Typhoid toxin is a secreted AB-type toxin that is a key S. Typhi virulence factor encoded within a 5-gene genetic islet. Four genes in this islet have well-defined roles in typhoid toxin biology, however the function of the fifth gene is unknown. Here, we investigate the function of this gene, which we name ttaP. We show that ttaP is co-transcribed with the typhoid toxin subunit cdtB, and we perform genomic analyses that indicate that TtaP is very highly conserved in typhoid toxin islets found in diverse salmonellae. We show that TtaP is a distant homolog of group XIV secreted phospholipase A2 (PLA2) enzymes, and experimentally demonstrate that TtaP is a bona fide PLA2. Sequence and structural analyses indicate that TtaP differs substantially from characterized PLA2s, and thus represents a novel class of PLA2. Secretion assays revealed that TtaP is neither co-secreted with typhoid toxin, nor is it required for toxin secretion. Although TtaP is a phospholipase that remains associated with the S. Typhi cell, assays that probed for altered cell envelope integrity failed to identify any differences between wild-type S. Typhi and a ttaP deletion strain. Collectively, this study identifies a biochemical activity for the lone uncharacterized typhoid toxin islet gene and lays the groundwork for exploring how this gene factors into S. Typhi pathogenesis. This study further identifies a novel class of PLA2, enzymes that have a wide range of industrial applications.

9.
Front Microbiol ; 15: 1454763, 2024.
Article in English | MEDLINE | ID: mdl-39290517

ABSTRACT

The pervasive environmental metal contamination has led to selection of heavy-metal resistance genes in bacteria. The pco and sil clusters are located on a mobile genetic element and linked to heavy-metal resistance. These clusters have been found in Salmonella enterica serovars isolated from human clinical cases and foods of animal origin. This may be due to the use of heavy metals, such as copper, in animal feed for their antimicrobial and growth promotion properties. The sil cluster can be found alone or in combination with pco cluster, either in the chromosome or on a plasmid. Previous reports have indicated that sil, but not pco, cluster contributes to copper resistance in S. enterica Typhimurium. However, the role of the pco cluster on the physiology of non-typhoidal S. enterica remains poorly understood. To understand the function of the pco gene cluster, a deletion mutant of pcoABCD genes was constructed using allelic exchange mutagenesis. Deletion of pcoABCD genes inhibited growth of S. enterica in high-copper medium, but only under anaerobic environment. Complementation of the mutant reversed the growth phenotype. The survival of S. enterica in RAW264.7 macrophages was not affected by the loss of pcoABCD genes. This study indicates that the acquired pco cluster is crucial for copper detoxification in S. enterica, but it is not essential for intracellular replication within macrophages.

10.
Front Bioinform ; 4: 1415078, 2024.
Article in English | MEDLINE | ID: mdl-39184336

ABSTRACT

Monitoring data submitted to the National Center for Biotechnology Information's Pathogen Detection whole-genome sequence database, which includes the foodborne bacterial pathogens Listeria monocytogenes, Salmonella enterica, and Escherichia coli, has proven effective for detecting emerging outbreaks. As part of the submission process, new sequence data are typed using a whole-genome multi-locus sequence typing scheme and clustered with sequences already in the database. Publicly available text files contain the results of these analyses. However, contextualizing and interpreting this information is complex. We present the Rapid Intuitive Pathogen Surveillance (RIPS) tool, which shows the results of the NCBI Rapid Reports, along with appropriate metadata, in a graphical, interactive dashboard. RIPS makes the information in the Rapid Reports useful for real-time surveillance of genome sequence databases.

11.
Article in English | MEDLINE | ID: mdl-39212846

ABSTRACT

Foodborne diseases triggered by various infectious micro-organisms are contributing significantly to the global disease burden as well as to increasing mortality rates. Salmonella enterica belongs to the most prevalent form of bacteria accountable for significant burden of foodborne illness across the globe. The conventional therapeutic approach to cater to Salmonella enterica-based infections relies on antibiotic therapy, but the rapid emergence of the antibiotic resistance strains of Salmonella sp. necessitates the development of alternative treatment and prevention strategies. In light of this growing concern, the scientific community is rigorously exploring novel phytochemicals harnessed from medicinally important plants as a promising approach to curb Salmonella enterica infections. A variety of phytochemicals belonging to alkaloids, phenols, flavonoid, and terpene classes are reported to exhibit their inhibitory activity against bacterial cell communication, membrane proteins, efflux pumps, and biofilm formation among drug resistant Salmonella strains. The present review article delves to discuss the emergence of antibiotic resistance among Salmonella enterica strains, various plant sources, identification of phytochemicals, and the current state of research on the use of phytochemicals as antimicrobial agents against Salmonella enterica, shedding light on the promising potential of phytochemicals in the fight against this pathogen.

12.
Bull Exp Biol Med ; 177(2): 281-286, 2024 Jun.
Article in English | MEDLINE | ID: mdl-39096449

ABSTRACT

Different methods for fixing biofilms of Staphylococcus aureus and Salmonella enterica for light and electron microscopy were compared. Paraformaldehyde fixation did not preserve biofilm integrity during dehydration; Ito-Karnovsky fixation revealed cell morphology, but did not preserve the matrix. Ruthenium red combined with aldehydes allowed the matrix to be preserved and visualized. An analysis of the ultrastructure of S. aureus and S. enterica cells in biofilms and suspensions at various fixations is presented. The ultrastructure of the biofilm matrix has been described.


Subject(s)
Biofilms , Salmonella enterica , Staphylococcus aureus , Biofilms/growth & development , Staphylococcus aureus/physiology , Salmonella enterica/physiology , Salmonella enterica/ultrastructure , Salmonella enterica/growth & development , Formaldehyde , Fixatives/pharmacology , Fixatives/chemistry , Microscopy, Electron , Polymers
13.
Microbiol Resour Announc ; 13(9): e0000924, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39162441

ABSTRACT

We present a complete genome of Salmonella enterica subsp. enterica serovar Hessarek isolated from a human stool from an outbreak linked to egg consumption in South Australia. Orientation of the rrn operon and characteristics of the Salmonella virulence plasmid indicates that this serovar is virulent toward humans and birds.

14.
Microbiol Resour Announc ; 13(9): e0028924, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39162450

ABSTRACT

Antimicrobial exposure can potentially lead to increased antimicrobial resistance plasmid transfer. Sequencing data were collected from the RNA of pairs of Salmonella enterica and Escherichia coli exposed or not exposed to tetracycline over time to determine differences in transcription-associated tetracycline exposure during in vitro conjugation experiments.

15.
China CDC Wkly ; 6(33): 825-833, 2024 Aug 16.
Article in English | MEDLINE | ID: mdl-39211441

ABSTRACT

Introduction: Highly fluoroquinolone-resistant Salmonella enterica serovar Kentucky (S. Kentucky) of sequence type (ST) 198 has emerged as a global multidrug-resistant (MDR) clone, posing a threat to public health. Methods: Whole genome sequencing and antibiotic susceptibility testing was used to characterize the population structure and evolutionary history of 54 S. Kentucky isolates recovered from food and human clinical cases in Beijing from 2016 to 2023. Results: All 54 S. Kentucky ST198 isolates exhibited resistance to quinolones, carrying point mutations in the quinolone resistance-determining regions (gyrA_S83F and parC_S80I). Resistance to other antibiotics (folate pathway inhibitors, cephems, aminoglycosides, phenicols, rifamycin, fosfomycin, macrolides, and tetracyclines), mediated by the sul1, sul2, dfrA14, bla CTX-M, bla TEM-1B, aac(3)-Id, aadA2, aadA7, aph(3')-I, aph(3'')-Ib, rmtB, floR, arr-2, fosA, mph(A), and tet(A) genes, was also observed in different combinations. The Beijing S. Kentucky ST198 evolutionary tree was divided into clades 198.2-1 and 198.2-2, which were further differentiated into three subclades: 198.2-2A, 198.2-2B, and 198.2-2C. Compared with the extended-spectrum ß-lactamase-encoding gene bla CTX-M-14b in 198.2-1, the co-existence of bla CTX-M-55 and bla TEM-1B, as well as chromosomally located qnrS1, was detected in most 198.2-2 isolates, which showed more complex MDR phenotypes. S. Kentucky ST198 outbreak isolates derived from two predominant clonal sources: 198.2-1 with cgST236434 and 198.2-2A with cgST296405. Conclusions: The S. Kentucky population in Beijing is genetically diverse, consisting of multiple co-circulating lineages that have persisted since 2016. Strengthening surveillance of food and humans will aid in implementing measures to prevent and control the spread of AMR.

16.
Cureus ; 16(7): e65090, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39171062

ABSTRACT

Salmonella-induced peritonitis, secondary to spontaneous gastrointestinal perforation, is a rare but potentially life-threatening condition. We present a case of a 62-year-old female with a history of systemic hypertension, who presented with diffuse abdominal pain and altered bowel habits. Initial evaluation suggested acute gastroenteritis, but worsening symptoms led to emergent exploratory laparotomy, revealing a gastric/duodenal perforation. Peritoneal fluid analysis and culture confirmed Salmonella Paratyphi A infection. The patient underwent an emergency laparotomy with omental patch repair and received intravenous ceftriaxone, leading to a full recovery. This case underscores the importance of considering Salmonella infection in the differential diagnosis of peritonitis, prompt surgical intervention, and appropriate antimicrobial therapy for optimal management and outcomes. Further research on epidemiological trends, host-pathogen interactions, and antibiotic resistance should be explored. Clinical studies should refine diagnostic criteria and treatment protocols, while animal models can aid in understanding pathophysiology and vaccine development for Salmonella peritonitis. Public health interventions and environmental studies will enhance prevention and control strategies.

17.
Front Microbiol ; 15: 1387830, 2024.
Article in English | MEDLINE | ID: mdl-39211316

ABSTRACT

Salmonella enterica is a foodborne pathogen associated with both typhoid and non-typhoid illness in humans and animals. This problem is further exacerbated by the emergence of antibiotic-resistant strains of Salmonella enterica. Therefore, to meet public health and safety, there is a need for an alternative strategy to tackle antibiotic-resistant bacteria. Bacteriophages or (bacterial viruses), due to their specificity, self-dosing, and antibiofilm activity, serve as a better approach to fighting against drug-resistant bacteria. In the current study, a broad-host range lytic phage phiSalP219 was isolated against multidrug-resistant Salmonella enterica serotypes Paratyphi from a pond water sample. Salmonella phage phiSalP219 was able to lyse 28/30 tested strains of Salmonella enterica. Salmonella phage phiSalP219 exhibits activity in acidic environments (pH3) and high temperatures (70°C). Electron microscopy and genome analysis revealed that phage phiSalP219 is a member of class Caudoviricetes. The genome of Salmonella phage phiSalP219 is 146Kb in size with 44.5% GC content. A total of 250 Coding Sequence (CDS) and 25 tRNAs were predicted in its genome. Predicted open reading frames (ORFs) were divided into five groups based on their annotation results: (1) nucleotide metabolism, (2) DNA replication and transcription, (3) structural proteins, (4) lysis protein, and (5) other proteins. The absence of lysogeny-related genes in their genome indicates that Salmonella phage phiSalP219 is lytic in nature. Phage phiSalP219 was also found to be microbiologically safe (due to the absence of toxin or virulence-related genes) in the control of Salmonella enterica serovar Typhimurium infections in the ready-to-eat meat and also able to eradicate biofilm formed by the same bacterium on the borosilicate glass surface.

18.
mBio ; 15(9): e0164224, 2024 Sep 11.
Article in English | MEDLINE | ID: mdl-39152718

ABSTRACT

Bacteria acquire P primarily as inorganic orthophosphate (Pi, PO43-). Once internalized, Pi is rapidly assimilated into biomass during the synthesis of ATP. Because Pi is essential, but excessive ATP is toxic, the acquisition of environmental Pi is tightly regulated. In the bacterium Salmonella enterica (Salmonella), growth in Pi-limiting environments activates the membrane sensor histidine kinase PhoR, leading to the phosphorylation of its cognate transcriptional regulator PhoB and subsequent transcription of genes involved in adaptations to low Pi. Pi limitation promotes PhoR kinase activity by altering the conformation of a membrane signaling complex comprised of PhoR, the multicomponent Pi transporter system PstSACB and the regulatory protein PhoU. However, the identity of the Pi-starvation signal and how it controls PhoR activity remain unknown. Here, we identify conditions where the PhoB and PhoR signal transduction proteins can be maintained in an inactive state when Salmonella is grown in media lacking Pi. Our results demonstrate that PhoB/PhoR is activated by an intracellular P-insufficiency signal.IMPORTANCEIn enteric bacteria, the transcriptional response to phosphorus (P) starvation is controlled by a specialized signal transduction system comprised of a membrane-bound, multicomponent signal sensor, and a cytoplasmic transcriptional factor. Whereas this system has been primarily studied in the context of phosphate (Pi) starvation, it is currently unknown how this stress initiates signal transduction. In the current study, we establish that this signaling system is regulated by a cytoplasmic signal arising from insufficient P. We demonstrate that rather than responding to extracellular conditions, cells couple the activation of their P starvation response to the availability of cytoplasmic P. This regulatory logic may enable cells to prevent toxicity resulting from excessive Pi acquisition and hinder the onset of a P starvation response when their metabolic demands are being met through the consumption of P sources other than Pi.


Subject(s)
Bacterial Proteins , Gene Expression Regulation, Bacterial , Phosphorus , Salmonella enterica , Signal Transduction , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Phosphorus/metabolism , Salmonella enterica/genetics , Salmonella enterica/metabolism , Phosphorylation , Phosphates/metabolism
19.
Microbiol Resour Announc ; 13(9): e0000624, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39162457

ABSTRACT

In this study, we performed whole-genome sequencing of three ciprofloxacin-resistant Salmonella Reading strains isolated from poultry meat. Genomes of S. Reading strains contained an average of 4.81 Mbp size with 52.1% GC. The isolates exhibited blaOXA-10, aac [6']-Iaa, aadA1, cmlA1, qnrS1, and tetA resistance genes and IncX1 and IncX2 plasmids.

20.
Microbiol Resour Announc ; 13(9): e0058624, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39162465

ABSTRACT

Oxford Nanopore long reads of simulated bacterial communities from fresh spinach and surface water were generated (R9.4.1+SQK-LSK109 and R10.4+SQK-LSK112; 0.5, one, and two million reads). Salmonella enterica serotype Heidelberg, Montevideo, or Typhimurium was included alone or in combination in the spinach community, while the water community harbored Pseudomonas aeruginosa.

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