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Multidrug resistance (MDR) considered as global crisis facing poultry industry. Migratory birds play very important role in the dissemination of antimicrobial resistant pathogen during their fly way specially to poultry farms. Therefore, 750 samples from migratory birds and 300 samples from broiler chicken farms and its environment were collected during the winter seasons of five years (2019 to 2023). The samples were subjected to the isolation of Salmonella enterica and Escherichia coli with the detection of antimicrobial resistance (phenotypic and genotypic) with insight to the genetic similarity between the isolates from migratory birds and broiler chickens' farms. Different members of Enterobacteriaceae were isolated; Salmonella enterica, Escherichia coli, Citrobacter, Enterobacter, Klebsiella, Proteus, Providencia, Serratia, Hafnia. 298 (28.4%) of S. enterica strains belonging to 27 serovars. S. Typhimurium, S. Kentucky, S. Enteritidis and S. Shangani were the common 4 serotypes between migratory birds and farms. Meanwhile, we found 489 (46.6%) isolates of E. coli belonging to 24 serogroups and O91, O128, O26, O125, O55, O103 and O159 were the common 7serogroups between migratory birds and farms samples. The majority of Salmonella (91.6%; 274 out of 298) and E. coli (92%; 450 out of 489) were MDR. The MDRI range of Salmonella and E. coli was 0.08- 1.The genetic similarity between the isolates of migratory birds and broiler chicken farms were detected by ERICPCR and hot map. This study suggests the continuous applications of surveillance programs for migratory birds and biosecurity measures in poultry farms. [ABSTRACT FROM AUTHOR]

The Chilean Technical Manual for Milk Dietary Service (SEDILE) was evaluated to determine its effectiveness in ensuring the microbiological safety and vitamin D adequacy of a commercially available powdered infant formula (PIF) used in SEDILE. The evaluation focused on whether adherence to the manual's guidelines positively influenced these factors. Both the PIF and the reconstituted PIF (RIF) were found to be free from Cronobacter sakazakii and Salmonella enterica contamination, with levels of total coliforms and Escherichia coli within acceptable limits. Moreover, the vitamin D content in the formula was within the expected range. These findings suggest that following the Chilean Technical Manual for SEDILE contributes to the microbiological safety and nutritional adequacy of RIF in dietary services. [ABSTRACT FROM AUTHOR]

Non-typhoidal Salmonella (NTS) is one of the top causes of diarrhea worldwide. Ceftriaxone is commonly recommended as the initial treatment option for Salmonella infections due to its antibacterial effectiveness. The objective of this study was to investigate the molecular epidemiological characteristics of NTS and to compare the phenotypic and genotypic profiles of antimicrobial resistance in multidrug-resistant Salmonella strains by sequencing 329 NTS strains collected from a county-level hospital between 2018 and 2021. Multi-locus sequence typing (MLST), antimicrobial resistance genes and plasmid types were identified by BacWGSTdb 2.0 webserver. Phylogenetic analysis of all NTS strains was carried out using Snippy and Gubbins software. The transferability of ceftriaxone resistant plasmids was confirmed through plasmid conjugation assays, and verified by S1-PFGE-Southern blot assays. The predominant serotypes among all NTS strains were Typhimurium (161/329), Enteritidis (49/329) and London (45/329). The most common sequence type observed was ST34 (86/329), followed by ST19 (72/329) and ST11 (47/329). The antimicrobial resistance of Salmonella to a wide range of antimicrobials showed an overall increase. Out of these 37 (11.24%) ceftriaxone-resistant strains, with the majority of them (33/37) being blaCTX−M. The predominant plasmid types identified were IncHI2 (14/21) and IncI1 (6/21), ranging in size from 70 kb to 360 kb. The conjugation efficiency was calculated with the high conjugation efficiency of 1.1 × 10− 5 to 9.3 × 10− 2. The strains varied widely, ranging from 3 to 45,024 single nucleotide polymorphisms (SNPs). There are close linkages observed among the predominant lineage, with an average of 78 SNPs between each pair of ST34 strains. The findings contribute to our understanding of the transmission and resistance mechanisms of multidrug-resistant Salmonella, thereby facilitating the development of effective control strategies. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Gallinarum (S. Gallinarum) is an avian-specific pathogen responsible for fowl typhoid, a severe systemic disease with high mortality in chickens. This disease poses a substantial burden to the poultry industry, particularly in developing countries like China. However, comprehensive genome datasets on S. Gallinarum are lacking. Here, we present the most extensive S. Gallinarum genome dataset, comprising 574 well-collated samples. This dataset consists of 366 genomes sequenced in our laboratory and 208 publicly available genomes, collected from various continents over the past century. Using in silico prediction, we categorized S. Gallinarum into three distinct biovars. Regarding antimicrobial resistance, 238 strains (41.5%) carried antimicrobial resistance genes (ARGs) with a total of 635 records, while 232 strains (40.4%) exhibited multi-drug resistance. Mobile genomic elements (MGEs) serve as critical drivers for ARGs. Our dataset includes 5,636 MGEs records, with most MGEs belonging to prophages and plasmids. This dataset expands our understanding of the genomic characteristics of S. Gallinarum, providing valuable resources for future genomic studies to improve disease management. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Gallinarum (S. Gallinarum) is an avian-specific pathogen responsible for fowl typhoid, a severe systemic disease with high mortality in chickens. This disease poses a substantial burden to the poultry industry, particularly in developing countries like China. However, comprehensive genome datasets on S. Gallinarum are lacking. Here, we present the most extensive S. Gallinarum genome dataset, comprising 574 well-collated samples. This dataset consists of 366 genomes sequenced in our laboratory and 208 publicly available genomes, collected from various continents over the past century. Using in silico prediction, we categorized S. Gallinarum into three distinct biovars. Regarding antimicrobial resistance, 238 strains (41.5%) carried antimicrobial resistance genes (ARGs) with a total of 635 records, while 232 strains (40.4%) exhibited multi-drug resistance. Mobile genomic elements (MGEs) serve as critical drivers for ARGs. Our dataset includes 5,636 MGEs records, with most MGEs belonging to prophages and plasmids. This dataset expands our understanding of the genomic characteristics of S. Gallinarum, providing valuable resources for future genomic studies to improve disease management. [ABSTRACT FROM AUTHOR]

This study evaluated the biological characteristics of seaweeds Turbinaria ornata, Ulva lactuca, and Gracilaria crassa. Among the seaweeds tested, ethyl acetate extract of Ulva lactuca exhibited the highest antibacterial activity against Salmonella enterica, Staphylococcus aureus, and Pseudomonas aeruginosa. The phytochemical analysis of ULME and ULEA showed the presence of most of the tested phytochemicals, whereas only amino acids, tannins, glycosides, and carbohydrates were detected by ULHE. The DPPH scavenging property of U. lactuca exerted the maximum antioxidant property of 62.54% (ULME), 75.64% (ULEA), and 39.55% (ULHE), whereas the alpha amylase inhibitory property (µg/mL) of ULME, ULEA, and ULHE was, respectively, 80.99, 51.15, and 49.23. ULME, ULEA, and ULHE exhibited the greatest alpha-glucosidase inhibition, with IC50 values (g/mL) of 116.12, 45.59, and 170.10 correspondingly. ULEA also showed potent mosquito-larvicidal effects against Aedes aegypti larvae with the maximum lethal concentration values with LC50 and LC90 values (mg/mL) being 11.55 and 65.97, respectively. FTIR analysis of ULME, ULHE, and ULEA were found to have various functional groups, including alkanes, carboxylic acids, alkenes, alkynes, aldehydes, amides and alkanes, ketones, and aromatics, while HPLC revealed a strong peak at 4.760 retention time. In conclusion, Ulva lactuca, particularly its ethyl acetate extract, demonstrates significant antibacterial, antioxidant, and enzyme-inhibitory properties, highlighting its therapeutic and biotechnological potential. Its diverse phytochemicals and effective mosquito-larvicidal activity further support its broad application prospects. [ABSTRACT FROM AUTHOR]

This study developed a postbiotic fermentation solution for fresh oyster preservation with the use of food waste soy whey. Lactiplantibacillus plantarum 299V was able to proliferate in soy whey within 24 h without any supplementation. Pacific oysters (Magallana gigas) were immersed in the postbiotic fermentation solution and stored at 4 °C for 12 days. Pathogenic bacteria Vibrio parahaemolyticus and Salmonella enterica introduced by bioaccumulation were suppressed to levels below the detection limit (<2 log CFU/g) within 4 days. The spoilage-related microbial parameters and chemical parameters were maintained at low levels across the 12 days. Sensory evaluation revealed that the product had a positive effect on most of the participants (>60%). Overall, the postbiotic fermentation solution reported in this study enhanced the shelf life and safety of oysters in a sustainable way and could also be recognized as an innovative probiotic vehicle with potential implications for human health promotion. [ABSTRACT FROM AUTHOR]

Sprouts are popular due to their high nutritional content, including vitamins, minerals, antioxidants, and enzymes. However, the conditions favorable for sprouting, such as warm and humid environments, are also ideal for the growth of bacteria, including food‐borne pathogens. Here, we analyzed the growth and developed predictive models of locally isolated and commercial strains of Salmonella enterica and Listeria monocytogenes in alfalfa sprouts under various constant temperatures, ranging from 5°C to 25°C. Our findings indicated that these pathogens could grow at 5°C in sprouts, albeit with a low growth rate. A rapid increase in concentration occurred at temperatures of 10°C and above. The fitted models demonstrated high performance, with R2 values ranging from 0.964 to 0.997 and RMSE values ranging from 0.15 to 0.51, respectively. Based on the fitted values, bias factor (Af) values varied between 1.01 and 1.06, with all accuracy factor (Bf) values at 1.00. Acceptable prediction zone (APZ) values ranged from 81.8% to 100%. Validation of the models under dynamic temperature conditions for specific strains showed acceptable performance. This study enhances our understanding of S. enterica and L. monocytogenes growth in alfalfa sprouts. The findings of this study could be used to improve the risk assessment of these pathogens in alfalfa sprouts. [ABSTRACT FROM AUTHOR]

The search for synergies between natural products and commercial antibiotics is a promising strategy against bacterial resistance. This study determined the antimicrobial capacity of Nerol (NE) and Tannic Acid (TA) against 14 pathogenic bacteria, including ESKAPE pathogens. TA exhibited the lowest Minimum Inhibitory Concentrations (MICs) at 162.5 µg/mL against Pasteurella aerogenes and 187.5 µg/mL against Acinetobacter baumannii (WHO priority 1). NE showed its lowest MIC of 500 µg/mL against both Pasteurella aerogenes and Salmonella enterica. A total of 35 combinations of NE and 13 of TA with eight commercial antibiotics were analyzed. For NE, combinations with Streptomycin and Gentamicin were effective against Salmonella enterica, Bacillus subtilis, and Streptococcus agalactiae, with antibiotic MIC reductions between 75.0 and 87.5%. TA showed six synergies with Chloramphenicol, Ampicillin, Erythromycin, and Streptomycin against Acinetobacter baumannii, Streptococcus agalactiae, and Pasteurella aerogenes, with MIC reductions between 75.0 and 93.7%. Additionally, 31 additive effects with antibiotics for NE and 8 for TA were found. Kinetic studies on these synergies showed complete inhibition of bacterial growth, suggesting that natural products enhance antibiotics by facilitating their access to targets or preventing resistance. Given their safety profiles recognized by the EPA and FDA, these natural products could be promising candidates as antibiotic enhancers. [ABSTRACT FROM AUTHOR]

Adding essential oils in an edible coating could be an alternative for the food industry to control foodborne pathogens. In 2014, EFSA published a report highlighting the risk associated with Salmonella spp. and Norovirus in fresh and frozen berries. This study aimed to evaluate the efficacy of an edible coating (RP-7) with carvacrol and citral on reducing the population of Salmonella enterica, Escherichia coli O157:H7, Listeria monocytogenes, and murine Norovirus (MNV-1) in frozen strawberries and blueberries. Before evaluating the efficacy, the best method for applying the coating on fruit was studied. The immersion method was selected, with an optimal drying time of 45 min. After this, the berries were frozen and stored for one, two, three, four, and eight weeks at −18 °C. In strawberries, all bacteria were reduced to below 0.7 log cfu/strawberry in the eighth week, and the MNV-1 infectivity showed a reduction of nearly 2 logarithmic units. In blueberries, S. enterica and E. coli O157:H7 were reduced to 0.8 log cfu/blueberries within a week, and MNV-1 achieved a reduction of 0.8 logarithmic units at the end of the assay. The application of RP-7 affected the studied microorganisms in frozen strawberries and blueberries. [ABSTRACT FROM AUTHOR]

Simple Summary: Salmonella enterica subsp. enterica infections critically affect cattle health, producing high rates of morbidity and mortality in calves and reducing the performance of adult cows. Some European countries implemented surveillance and control programs decades ago, but in Italy, there is no national control program for dairy cows. This study describes an outbreak of Salmonella Bredeney in a dairy herd and the consequent control strategies applied. Control strategies included sample collection visits to the farm in order to identify the prevalence of Salmonella spp. and assess biosecurity levels. In this outbreak, there was a higher prevalence in calves and this condition was associated with poor biosecurity practices. Subsequently, the practitioner and farmer were provided with a health management plan to reduce the prevalence and control the outbreak. During the follow-up period, monitoring and testing revealed repeated negative results, indicating adequate control over the outbreak. The procedures undertaken in this project made it possible to collect useful data for the definition of measures for the management of outbreaks of salmonellosis in dairy cows. Salmonellosis in dairy cattle represents an increasing problem for both animal and public health. Nevertheless, in Italy, there is no control plan in place on dairy farms. The aim of this study was to describe a Salmonella Bredeney outbreak that occurred on a dairy farm and the measures that were adopted to control the outbreak. Management consisted in identifying the spread of infection and assessing the environmental contamination of Salmonella spp. and the associated risk factors. After the farm visit, laboratory investigations showed that 48% of rectal swabs collected from calves and 33% of environmental samples were positive for S. Bredeney, and a poor biosecurity level was detected. The farmer and practitioner were provided with a health management plan to control the spread of Salmonella spp., followed by a monitoring period and a follow-up visit in which all samples resulted negative. The results demonstrated the efficacy of indirect prophylaxis measures in reducing the circulation of Salmonella spp., leading to the extinction of the outbreak. Collaboration with farmers, practitioners, and public health veterinarians and the introduction of measures reported in the health management plan constitute a possible model for the management of Salmonella spp. outbreaks in dairy herds, even in complex farm situations. [ABSTRACT FROM AUTHOR]

The misuse of antibiotics has led to high levels of drug-resistance in specific pathogens, promoting the search of molecules from different natural sources or the design of novel drug candidates. Medicinal and edible plants are a rich source of bioactive compounds, in particular those of polyphenol class. In the present work, we screen the antimicrobial properties of an aqueous extract prepared from the leaves of Ugni molinae (Turz) against a panel of pathogenic bacteria strains formed by Helicobacter pylori (ATCC 43504), Listeria monocytogenes (ATCC 7644), Staphylococcus aureus (ATCC 9144), Escherichia coli (ATCC 11775), and Salmonella enterica (ATCC 13076). Preliminary fast HPLC-micro fractionation allows the identification of potential urease inhibitors using high throughput urea-phenol microplate assay. Afterwards, preparative fractionation by Centrifugal Partition Chromatography (CPC) allow to select the specific bioactive fractions. A combination of antimicrobial tests, enzyme assays and molecular docking resulted in the identification by HPLC-MS/MS of two quercetin-O-(6"-O-galloyl)-hexosides as the most dominant compounds in the active CPC-fractions. These bioactive compounds were quercetin-3-O-(6"-O-galloyl)-8-galactopyranoside (hyperin 6"-gallate) and quercetin-3-O-ß-D-(6"-O-galloyl)- ß-glucopyranoside (tellimoside). The molecular docking evaluation revealed that hyperin-6"-gallate enter the binding site of urease and bind in through pi-cation, pi-pi, and H-bond interactions. In concordance with the in-silico assay, the CPC fraction containing this compound has the lowest values of IC50 for Jack bean (0.41 ± 0.08 µg/mL) and Helicobacter pylori (0.28 ± 0.08 µg/mL) ureases, respectively. Moreover, Label-Free Microscale Thermophoresis (MST) analysis suggest that this flavonoid forms a complex with urease, even inducing protein aggregation. In conclusion, Ugni molinae leaves has potent anti-urease flavonoids that can contribute to significantly reduce the acclimation of H. pylori in the acidic environmental of gastric mucosa. [ABSTRACT FROM AUTHOR]

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 β-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 β-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. [ABSTRACT FROM AUTHOR]

Typhoidal Salmonella enterica serovars, such as Typhi and Paratyphi A, cause severe systemic infections, thereby posing a significant threat as human-adapted pathogens. This study focuses on cytolysin A (ClyA), a virulence factor essential for bacterial dissemination within the human body. We show that ClyA is exclusively expressed by intracellular S. Paratyphi A within the Salmonella-containing vacuole (SCV), regulated by the PhoP/Q system and SlyA. ClyA localizes in the bacterial periplasm, suggesting potential secretion. Deletion of TtsA, an essential Type 10 Secretion System component, completely abolishes intracellular ClyA detection and its presence in host cell supernatants. Host cells infected with wild-type S. Paratyphi A contain substantial ClyA, with supernatants capable of lysing neighboring cells. Notably, ClyA selectively lyses macrophages and erythrocytes while sparing epithelial cells. These findings identify ClyA as an intracellularly induced cytolysin, dependent on the SCV environment and secreted via a Type 10 Secretion System, with specific cytolytic activity. Typhoidal Salmonella enterica strains cause serious infections in humans. Here, Krone et al show that the bacterial protein cytolysin A is secreted intracellularly where it selectively kills specific cell types and helps to establish bacterial infection. [ABSTRACT FROM AUTHOR]

In situ imaging of genes of pathogenic bacteria can profile cellular heterogeneity, such as the emergence of drug resistance. Fluorescence in situ hybridization (FISH) serves as a classic approach to image mRNAs inside cells, but it remains challenging to elucidate genomic DNAs and relies on multiple fluorescently labeled probes. Herein, we present a dead Cas12a (dCas12a)-labeled polymerase chain reaction (CasPCR) assay for high-contrast imaging of cellular drug-resistant genes. We employed a syncretic dCas12a-green fluorescent protein (dCas12a–GFP) to tag the amplicons, thereby enabling high-contrast imaging and avoiding multiple fluorescently labeled probes. The CasPCR assay can quantify quinolone-resistant Salmonella enterica in mixed populations and identify them isolated from poultry farms. [ABSTRACT FROM AUTHOR]

Ozone is a molecule that has gained increasing interest in recent years by food industries for sanitization of food-grade surfaces. Compared to chemical sanitizers such as chlorine, hydrogen peroxide, or peracetic acid, ozone shows undeniable advantages, such as the absence of by-products that should affect human health or the possibility of generating it when needed. Therefore, the aim of this paper was the assessment of the resistance to ozonized water of two pathogenic bacteria (Listeria monocytogenes, Salmonella) and of three airborne food-spoiling fungi (Aspergillus brasiliensis, Hyphopichia burtonii, and Penicillium nordicum) inoculated on stainless steel tiles and treated in static conditions with 1 to 6 mg L−1 (pathogens) or 8.5 mg L−1 (filamentous fungi). Ozonized water gave different results based on the tested microorganisms: pathogenic bacteria proved markedly more sensible to ozone than filamentous fungi, even if great differences were observed at inter- and intra-specific levels for both categories of microorganisms. Nevertheless, the non-linear inactivation kinetics of the studied strains made the calculation of a punctual F-value difficult, so in industrial practice, adequate tailoring of the treatments to be applied, based on the registered extrinsic factors and the industrial bio-burden, would be appropriate. [ABSTRACT FROM AUTHOR]

As one of the biggest ports, the aquatic ecology of Shanghai Port has a significant impact on the health of surrounding residents and aquatic animals. Therefore, this study explored the composition and distribution of bacteria, pathogens, and ARGs at Shanghai Ports by high-throughput sequencing. The results showed that the bacterial community was dominated by the Proteobacteria at the phylum level. With the refinement of classification level, the main composition of bacteria in different samples shows significant differences. In contrast, there was no significant difference in the composition and distribution of pathogens among the samples. It indicates that pathogens and ARGs have steady community composition at Shanghai Port. Pseudomonas aeruginosa and Salmonella enterica could be regarded as candidate indicator pathogens. macB, tetA (58), and evgS were the main ARGs, and they showed a close relationship with Mycobacterium tuberculosis, Magnaporthe oryzae, Streptococcus pneumonia, Xanthomonas oryzae, and Vibrio cholerae in different sites and layers. This may lead to the transfer of ARGs between different pathogens, resulting in more threatening pathogens. The results showed that the pathogens and ARGs present posed a risk of transmission and were potentially harmful to residents in the environment. They can spread to any other ports in the world through the transmission of ballast water, posing a threat to humans and local ecology. In order to keep human health, it is necessary to pay more attention to the water environment of ports and increase the monitoring. Furthermore, it is essential to strengthen the supervision of external source pollution input due to the special features of the port. [ABSTRACT FROM AUTHOR]

Simple Summary: Salmonella enterica serovar Pullorum (S. Pullorum) is a formidable pathogen within the poultry industry and constitutes a substantial threat to global poultry production. Pullorum disease eradication and antibiotic treatment are two main strategies for controlling this disease. Therefore, understanding the prevalence and resistance characteristics of S. Pullorum is important for its control. The objective of this study was to determine the antigenic types and genotype characteristics of S. Pullorum isolates from China, and to clarify the relationship between antibiotic resistance and resistance genes. In this study, all the isolates tested were of standard antigenic types, with ST92 the predominant genotype, and 92.5% of the isolates displayed multidrug resistance. Our analysis of virulence genes indicated that the isolates expressed numerous factors associated with secretion systems. These data provide valuable information for the prevention and control of S. Pullorum infections in the poultry industry. 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 blaTEM1β, 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, blaTEM1β 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. [ABSTRACT FROM AUTHOR]

The pervasive environmental metal contamination has led to selection of heavymetal 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. [ABSTRACT FROM AUTHOR]

Succinic acid (SA), a dicarboxylic acid of industrial importance, can be efficiently produced by metabolically engineered Mannheimia succiniciproducens. Although the importance of magnesium (Mg2+) ion on SA production has been evident from our previous studies, the role of Mg2+ ion remains largely unexplored. In this study, we investigated the impact of Mg2+ ion on SA production and developed a hyper-SA producing strain of M. succiniciproducens by reconstructing the Mg2+ ion transport system. To achieve this, optimal alkaline neutralizer comprising Mg2+ ion was developed and the physiological effect of Mg2+ ion was analyzed. Subsequently, the Mg2+ ion transport system was reconstructed by introducing an efficient Mg2+ ion transporter from Salmonella enterica. A high-inoculum fed-batch fermentation of the final engineered strain produced 152.23 ± 0.99 g/L of SA, with a maximum productivity of 39.64 ± 0.69 g/L/h. These findings highlight the importance of Mg2+ ions and transportation system optimization in succinic acid production by M. succiniciproducens. [ABSTRACT FROM AUTHOR]

Objective: To investigate the diagnostic value of metagenomic next-generation sequencing (mNGS) in detecting pathogens from joint infection (JI) synovial fluid (SF) samples with previous antibiotic exposure. Methods: From January 2019 to January 2022, 59 cases with suspected JI were enrolled. All cases had antibiotic exposure within 2 weeks before sample collection. mNGS and conventional culture were performed on SF samples. JI was diagnosed based on history and clinical symptoms in conjunction with MSIS criteria. The diagnostic values, including sensitivity, specificity, positive/negative predictive values (PPV/NPV), and accuracy, were in comparison with mNGS and culture. Results: There were 47 of the 59 cases diagnosed with JI, while the remaining 12 were diagnosed with non-infectious diseases. The sensitivity of mNGS was 68.1%, which was significantly higher than that of culture (25.5%, p<0.01). The accuracy of mNGS was significantly higher at 71.2% compared to the culture at 39.0% (p <0.01). Eleven pathogenic strains were detected by mNGS but not by microbiological culture, which included Staphylococcus lugdunensis, Staphylococcus cohnii, Finegoldia magna, Enterococcus faecalis, Staphylococcus saprophytics, Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Acinetobacter pittii, Brucella ovis, andCoxiella burnetii. Antibiotic therapy was adjusted based on the mNGS results in 32 (68.1%) patients, including 12 (25.5%) and 20 (42.6%) patients, in whom treatment was upgraded and changed, respectively. All JI patients underwent surgery and received subsequent antibiotic therapy. They were followed up for an average of 23months (20-27 months), and the success rate of treatment was 89.4%. Out of the 33 patients who had positive results for pathogens, reoperation was performed in 1 case (3.03%), while out of the 14 cases with negative results for both mNGS and cultures, reoperation was performed in 4 cases (28.6%). Conclusions: mNGS has advantages over conventional culture in detecting pathogens in SF samples from JI patients previously treated with antibiotics, potentially improving clinical outcomes. [ABSTRACT FROM AUTHOR]

Epigenetic mechanisms can generate bacterial lineages capable of spontaneously switching between distinct phenotypes. Currently, mathematical models and simulations propose epigenetic switches as a mechanism of adaptation to deal with fluctuating environments. However, bacterial evolution experiments for testing these predictions are lacking. Here, we exploit an epigenetic switch in Salmonella enterica, the opvAB operon, to show clear evidence that OpvAB bistability persists in changing environments but not in stable conditions. Epigenetic control of transcription in the opvAB operon produces OpvABOFF (phage-sensitive) and OpvABON (phage-resistant) cells in a reversible manner and may be interpreted as an example of bet-hedging to preadapt Salmonella populations to the encounter with phages. Our experimental observations and computational simulations illustrate the adaptive value of epigenetic variation as an evolutionary strategy for mutation avoidance in fluctuating environments. In addition, our study provides experimental support to game theory models predicting that phenotypic heterogeneity is advantageous in changing and unpredictable environments. [ABSTRACT FROM AUTHOR]

The most serious problem in public health is salmonellosis, a common disease in horse. The aim of this study was to investigate the shedding of Salmonella serotypes in healthy Caspian pony. We examined 143 pony's fecal samples collected from the north of Iran belonging to different ages and sexes. Samples were cultured, then identification of isolates were performed by common bacteriological methods and polymerase chain reaction (PCR). The PCR was also used to explore the presence of fimA and salmonella secreted effector L (SseL) genes as virulence factors in the isolates and all were assigned to antibiotic susceptibility test via disc diffusion method. Results showed two fecal samples (1.39%) contaminated with Salmonella and further examination demonstrated the isolates belonging to S. enterica serotype typhimurium. Both serotypes were isolated from female and <6 years of age group of ponies and we detected fimA and SseL genes in the isolates. Observing multiple drug resistance and virulence genes in isolates is of utmost importance from both clinical and public health perspectives. It is highly likely that we face instances of salmonellosis in animals or humans that lead to severe infections and fail to respond to treatment in future. This study revealed that the occurrence of Salmonella was low in ponies, however, regarding the presence of virulence factors with multidrug resistant trend in this zoonotic bacterium, establishment of good hygienic measurement to prevent the transmission of bacteria between animal and human is necessary. [ABSTRACT FROM AUTHOR]

The present study investigated the microbiological safety of the increasingly popular plant‐based milk alternatives. No (10/27) or only very low microbial counts (17/27) were detected in the tested products. These were mainly identified as spore formers via MALDI‐ToF‐MS. Three products contained Bacillus cereus group isolates, which were able to form considerable amounts of enterotoxins and exhibited cytotoxicity towards CaCo‐2 cells. Preliminary tests showed good growth of B. cereus, Listeria monocytogenes, and Salmonella enterica in all tested products (maximum bacterial counts: 5 × 1012 cfu/mL). These experiments also revealed strain‐, time‐, and temperature‐, but especially product‐specific enterotoxin production of B. cereus. In propagation and persistence tests according to DIN EN ISO 20976‐1:2019‐09, rapid bacterial proliferation was also detected in all products. B. cereus generally showed lower bacterial counts (106–107 cfu/mL) compared to L. monocytogenes and S. enterica (108–109 cfu/mL), but was detectable in a larger number of products over the test period of 6 weeks. pH values decreased (20/27) over time and visual and/or olfactory alterations (24/27) were observed. The present study provides information on the occurrence, growth and persistence of pathogenic bacteria in plant‐based drinking milk alternatives. It also points out that the accompanying changes in pH, odor, and appearance are not necessarily recognizable to the consumer. Practical Application: The present study contributes to the understanding of the microbial risk related to plant‐based drinking milk alternatives. It is crucial that the manufacturer ensures that particularly spore formers have been effectively eliminated from the products. Among them, especially toxin‐producing bacteria can pose a risk to the consumer, as these products promote proliferation and persistence of the bacteria. [ABSTRACT FROM AUTHOR]

Aims The increasing prevalence of AmpC β-lactamase (AmpC)- and extended-spectrum β-lactamase (ESBL)- producing food pathogens is a serious public health concern. AmpC- and ESBL-producing Salmonella species pose a high risk of food contamination. This study aimed to investigate changes in the prevalence of Salmonella among food handlers in Japan from 2006 to 2021 using 100 randomly selected isolates from 2006, 2012, 2018, and 2021 with different serotypes and antimicrobial resistance patterns. Methods and results The average Salmonella isolation rate was 0.070% (19 602/27 848 713). Serotyping revealed that the most common serotypes were Enteritidis in 2006, Infantis in 2012, Agoueve/Cubana in 2018, and Schwarzengrund in 2021. Antimicrobial susceptibility testing showed that Salmonella isolates exhibited the highest resistance to streptomycin (<40%), followed by tetracycline (<20%–40%). Moreover, 6% of the Salmonella isolates produced cephalosporinases with the bla CMY-2, bla CTX-M-14, and bla TEM genes. The annual incidence of cephalosporin resistance has increased. Plasmid conjugation assays revealed that cephalosporin-resistant Salmonella spp. transmitted their resistance to Escherichia coli. Additionally, plasmid genome analysis showed that the insertion sequence IS 26 was encoded in the upstream and downstream regions of bla CTX-M-14 and qnrS1 in the IncHI1 plasmid, which could be transmitted to other bacteria. Conclusions The tested Salmonella isolates showed high resistance to specific antibiotics, with differences in resistance depending on the serotype. Further increase and spread of transmissible cephalosporin-resistant strains should be noted. [ABSTRACT FROM AUTHOR]

Aims Characterize global genomic features of 86 genomes of Salmonella Gallinarum (SG) and Pullorum (SP), which are important pathogens causing systemic infections in poultry. Methods and results All genomes harbored efflux pump encoding gene mdsA and gold tolerance genes golS and golT. Aminoglycoside (aac(6′)-Ib, aadA5, aph(6)-Id, aph(3′')-Ib, ant(2′')-Ia), beta-lactam (bla TEM-1, bla TEM-135), efflux pump (mdsB), fosfomycin (fosA3), sulfonamide (sul1, sul2), tetracycline [ tet(A) ], trimethoprim (dfrA17), acid (asr), and disinfectant (qacEdelta1) resistance genes, gyrA, gyrB , and parC quinolone resistance point mutations, and mercury tolerance genes (mer) were found in different frequencies. Additionally, 310 virulence genes, pathogenicity islands (including SPI-1, 2, 3, 4, 5, 6, 9, 10, 12, 13, and 14), plasmids [IncFII(S), ColpVC, IncX1, IncN, IncX2, and IncC], and prophages (Fels-2, ST104, 500465-1, pro483, Gifsy-2, 103 203_sal5, Fels-1, RE-2010, vB_SenS-Ent2, and L-413C) were detected. MLST showed biovar-specific sequence types, and core genome MLST showed country-specific and global-related clusters. Conclusion SG and SP global strains carry many virulence factors and important antimicrobial resistance genes. The diverse plasmids and prophages suggest genetic variability. MLST and cgMLST differentiated biovars and showed profiles occurring locally or worldwide. [ABSTRACT FROM AUTHOR]

Salmonella Pullorum (S. Pullorum) and Salmonella Gallinarum (S. Gallinarum) are two biovars of Salmonella enterica serovar Gallinarum, responsible for pullorum disease and fowl typhoid, which are the most prevalent and pathogenic forms of salmonellosis in poultry in developing countries. Traditional differentiation methods for S. Pullorum and S. Gallinarum are based on distinct clinical manifestations and biochemical traits, given their indistinguishable nature via serological assays alone. Molecular differentiation methods such as allele-specific PCR and dual PCR combined with gel electrophoresis or enzyme digestion have also been used to discriminate S. Pullorum and S. Gallinarum, but the detection efficiency is not high. This investigation introduces a Fluorescence Resonance Energy Transfer (FRET) PCR assay targeting the pegB gene, exclusively found in specific Salmonella serovars such as S. Pullorum and S. Gallinarum, and exhibiting conserved single-nucleotide polymorphisms across these two biovars. High-resolution melting curve analysis demonstrates distinct dissolution profiles, facilitating the precise discrimination of S. Pullorum and S. Gallinarum. This FRET-PCR assay exhibits a detection limit of 10 copies per reaction and has been rigorously validated utilizing 17 reference strains and 39 clinical isolates. The innovation presented herein provides a valuable tool for the rapid differentiation of S. Pullorum and S. Gallinarum, thereby enhancing diagnostic efficiency and molecular surveillance of poultry Salmonella. The developed pegB-targeting FRET-PCR assay presents a promising alternative to current cumbersome and time-consuming diagnostic modalities, offering significant potential for expedited identification and control of Salmonella in poultry and mitigating economic losses associated with Salmonella contamination in poultry production. [ABSTRACT FROM AUTHOR]

Pullorum disease, an intestinal disease in chickens caused by Salmonella enterica serovar pullorum (S. Pullorum), is a significant threat to the poultry industry and results in substantial economic losses. The bacteria's transmission, both vertical and horizontal, makes it difficult to completely eliminate it. Control strategies for pullorum disease primarily involve stringent eradication programs that cull infected birds and employ antibiotics for treatment. However, eradication programs are costly, and antibiotic use is restricted. Therefore, developing alternative control strategies is essential. Increasingly, studies are focusing on modulating the gut microbiota to control intestinal diseases. Modulating the chicken gut microbiota may offer a novel strategy for preventing and controlling pullorum disease in poultry. However, the impact of S. Pullorum on the chicken gut microbiota has not been well established, prompting our exploration of the relationship between S. Pullorum and the chicken gut microbiota in this study. In this study, we initially analyzed the dynamic distribution of the gut microbiota in chickens infected with S. Pullorum. Alpha diversity analysis revealed a decrease in observed OTUs and the Shannon diversity index in the infected group, suggesting a reduction in the richness of the chicken gut microbiota due to S. Pullorum infection. Principal coordinate analysis (PCoA) showed distinct clusters between the gut microbiota of infected and uninfected groups, indicating S. Pullorum infection changed the chicken gut microbiota structure. Specifically, S. Pullorum infection enriched the relative abundance of the genera Escherichia-Shigella (65% in infected vs. 40.6% in uninfected groups) and Enterococcus (10.8% vs. 3.7%) while reducing the abundance of Lactobacillus (9.9% vs. 32%) in the chicken microbiota. Additionally, based on the observed changes in the chicken gut microbiota, we isolated microorganisms, including Bifidobacterium pseudolongum, Streptococcus equi and Lacticaseibacillus paracasei (L. paracasei), which were decreased by S. Pullorum infection. Notably, the L. paracasei Lp02 strain was found to effectively inhibit S. Pullorum proliferation in vitro and alleviate its infection in vivo. We found that S. Pullorum infection reduced the richness of the chicken gut microbiota and enriched the relative abundance of the genera Escherichia-Shigella and Enterococcus while decreasing the abundance of the anaerobic genus Lactobacillus. Furthermore, microbiota analysis enabled the isolation of several antimicrobial microorganisms from healthy chicken feces, with a L. paracasei strain notably inhibiting S. Pullorum proliferation in vitro and alleviating its infection in vivo. Overall, this research enhances our understanding of the interaction between gut microbiota and pathogen infection, as well as offers new perspectives and strategies for modulating the chicken gut microbiota to control pullorum disease. [ABSTRACT FROM AUTHOR]

Salmonella infections are a serious global health concern, particularly in developing countries, and are further exacerbated by the emergence of antibiotic resistance. San‐Huang‐Xie‐Xin‐Tang (SHXXT), a traditional herbal medicine with potent anti‐inflammatory properties, has recently gained attention as an alternative treatment. Our study emphasizes on the importance of precise timing in accordance with traditional Chinese medicine principles. A mouse infection model was established while different administration times of SHXXT were recorded for the body weight, clinical scores, bacterial counts in blood, and organs. Additionally, cytokine levels, fatty acids, and amino acids in the serum were also monitored. We found that administering SHXXT 1 day after Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infection (T1 group) leads to positive outcomes. This includes restoration of body weight, improved clinical scores, and reduced bacterial counts in blood and vital organs. Interferon‐gamma levels remained consistently high across all treatment groups 6 days post‐infection. However, the T1 group showed exclusive suppression of serum levels of tumor necrosis factor‐alpha (TNF‐α) and interleukin‐1 beta (IL‐1β). The timing of administration significantly influenced serum fatty acid concentrations, countering Salmonella‐induced disruptions, aligning with TNF‐α and IL‐1β levels. SHXXT had also restored amino acid profiles disrupted by the infection, with notable effects when administered at the correct timing. Our research highlights SHXXT's potential in treating S. Typhimurium infection, emphasizing the importance of precise timing in line with traditional Chinese medicine principles for effective treatment at different disease stages. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovars are zoonotic bacterial that cause foodborne enteritis. Due to bacteria's antibiotic resistance, using bacteriophages for biocontrol and treatment is a new therapeutic approach. In this study, we isolated, characterized, and analyzed the genome of vB_SenS_TUMS_E19 (E19), a broad host range Salmonella bacteriophage, and evaluated the influence of E19 on liquid eggs infected with Salmonella enterica serovar Enteritidis. Transmission electron microscopy showed that the isolated bacteriophage had a siphovirus morphotype. E19 showed rapid adsorption (92% in 5 min), a short latent period (18 min), a large burst size (156 PFU per cell), and a broad host range against different Salmonella enterica serovars. Whole-genome sequencing analysis indicated that the isolated phage had a 42 813 bp long genome with 49.8% G + C content. Neither tRNA genes nor those associated with antibiotic resistance, virulence factors, or lysogenic formation were detected in the genome. The efficacy of E19 was evaluated in liquid eggs inoculated with S. Enteritidis at 4 and 25 °C, and results showed that it could effectively eradicate S. Enteritidis in just 30 min and prevented its growth up to 72 h. Our findings indicate that E19 can be an alternative to a preservative to control Salmonella in food samples and help prevent and treat salmonellosis. [ABSTRACT FROM AUTHOR]

The effects of juice pH, type of acidulant, and post-treatment refrigeration on the high-pressure processing (HPP) inactivation of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in acid beverages were evaluated. Inoculated apple, orange, and grape juices (at their original pH and adjusted to pH 4.00, 4.50, and 5.00) were treated at 550 MPa for 1 min at 5 °C. In addition, inoculated model solutions acidified to a pH of 5.00 with acetic, citric, malic, and tartaric acids were treated at 400 MPa for 1 min at 5 °C. The effect of refrigerated storage for 24 h after treatment on pathogen inactivation in both experiments was also assessed. A greater than 5-log reduction of the three pathogens inoculated was achieved in all juices immediately after HPP at the juices' original pH, and of L. monocytogenes under all experimental conditions. Refrigerated storage for 24 h after HPP treatment improved the inactivation of E. coli O157:H7, to >5-log reduction, at pH 4.00 in apple juice and of Salmonella in the three juices at pH 4.00. The type of acidulant did not significantly (p > 0.01) affect E. coli or Salmonella inactivation in acidified model solutions but a greater than 5-log reduction after HPP was only achieved for L. monocytogenes when acetic acid was used. The effectiveness of HPP for pathogen inactivation depended largely on product pH and the target pathogen of concern. [ABSTRACT FROM AUTHOR]

Salmonella enterica is a major food-borne pathogen causing food poisoning. The use of bacteriophages as alternative biocontrol agents has gained renewed interest due to the rising issue of antibiotic-resistant bacteria. We isolated and characterized three phages targeting Salmonella: SPN3US, SPN3UB, and SPN10H. Morphological and genomic analyses revealed that they belong to the class Caudoviricetes. SPN3UB, SPN3US, and SPN10H specifically target bacterial surface molecules as receptors, including O-antigens of lipopolysaccharides, flagella, and BtuB, respectively. The phages exhibited a broad host range against Salmonella strains, highlighting their potential for use in a phage cocktail. Bacterial challenge assays demonstrated significant lytic activity of the phage cocktail consisting of the three phages against S. typhimurium UK1, effectively delaying the emergence of phage-resistant bacteria. The phage cocktail effectively reduced Salmonella contamination in foods, including milk and pork and chicken meats, during cold storage. These results indicate that a phage cocktail targeting different host receptors could serve as a promising antimicrobial strategy to control Salmonella. [ABSTRACT FROM AUTHOR]

Among sixty-eight pseudomonads, isolate QCS59 from the rhizosphere of H. schimperi was selected based on its siderophore level. Production was optimal in Kings B supplemented with 2% peptone and 0.5% fructose at pH 6.5 and 25 °C for 72 h. Additionally, the threshold potential of iron was found at a concentration of 10 µM. After purification, the acidified siderophore presented a maximum absorption peak of 360 nm, while the neutral form presented a maximum of 414 nm, confirming its pyoverdine (PVD) nature. Furthermore, a major peak appeared at a retention time (RT) of 27.5 min during RP-HPLC, confirming its homogeneity. Interestingly, it demonstrated effective antibacterial activity, especially against Escherichia coli ATCC 8739, with a minimum inhibitory concentration (MIC) of 6.3 µg/mL and a minimum bactericidal concentration (MBC) of 12.5 µg/mL. At ½ the MIC value, it inhibited 82.1% of well-established biofilms of Salmonella enterica. There was an increase in malondialdehyde (MDA) and antioxidative enzymes, especially catalase (CAT) in the treated bacteria because of the peroxidation of membrane lipids and oxidative stress, respectively. SEM proved cellular lysis and surface malformation in most of the treated bacteria. This study concludes that QCS59 siderophore is a promising antibacterial candidate for treating wastewater bacteria and skin pathogens. [ABSTRACT FROM AUTHOR]

The development of a rapid, sensitive, specific method for detecting foodborne pathogens is paramount for supplying safe food to enhance public health safety. Despite the significant improvement in pathogen detection methods, key issues are still associated with rapid methods, such as distinguishing living cells from dead, the pathogenic potential or health risk of the analyte at the time of consumption, the detection limit, and the sample-to-result. Mammalian cell-based assays analyze pathogens' interaction with host cells and are responsive only to live pathogens or active toxins. In this study, a human embryonic kidney (HEK293) cell line expressing Toll-Like Receptor 5 (TLR-5) and chromogenic reporter system (HEK dual hTLR5) was used for the detection of viable Salmonella in a 96-well tissue culture plate. This cell line responds to low concentrations of TLR5 agonist flagellin. Stimulation of TLR5 ligand activates nuclear factor-kB (NF-κB)—linked alkaline phosphatase (AP-1) signaling cascade inducing the production of secreted embryonic alkaline phosphatase (SEAP). With the addition of a ρ-nitrophenyl phosphate as a substrate, a colored end product representing a positive signal is quantified. The assay's specificity was validated with the top 20 Salmonella enterica serovars and 19 non-Salmonella spp. The performance of the assay was also validated with spiked food samples. The total detection time (sample-to-result), including shortened pre-enrichment (4 h) and selective enrichment (4 h) steps with artificially inoculated outbreak-implicated food samples (chicken, peanut kernel, peanut butter, black pepper, mayonnaise, and peach), was 15 h when inoculated at 1–100 CFU/25 g sample. These results show the potential of HEK-DualTM hTLR5 cell-based functional biosensors for the rapid screening of Salmonella. [ABSTRACT FROM AUTHOR]

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This study examined the prevalence and antibiotic resistance pattern of bla CTX-M extended-spectrum β-lactamase positive Salmonella species isolated from a hospital in Weifang. Salmonella strains were isolated from hospitalized patients from January 2018 to April 2023. Whole-genome sequencing was performed by Illumina platform. CTX-M-producing Salmonella were identified by Comprehensive Antibiotic Research Database (CARD). Strain susceptibility to six antimicrobial agents was assessed by BD Phoenix™ M50 System. MLST analysis confirmed sequence types and additionally, serotypes were determined by SeqSero2. Genetic environments of bla CTX-M genes were analyzed by Isfinder and BLASTn. Single nucleotide polymorphisms were used to construct a phylogenetic tree to analyze homology. A total of 34 CTX-M-producing Salmonella were detected. The most prevalent serotype was Salmonella enterica subsp. enterica 1,4,[5],12:i:- (14/34, 41.18%), belonging to ST34, followed by Salmonella Enteritidis (10/34, 29.41%), belonging to ST11. The highest resistance rate was detected to ampicillin (97.06%), followed by ceftriaxone (94.12%) and ceftazidime (58.83%). In CTX-M-producing Salmonella five types of bla CTX-M genes were identified, the most prevalent was bla CTX-M-55 (47.06%, 16/34), followed by bla CTX-M-14, bla CTX-M-65, bla CTX-M-125, and bla CTX-M-27 at 26.47% (9/34), 11.77% (4/34), 8.82% (3/34), and 5.88% (2/34), respectively. Apart from bla CTX-M, 40 antibiotic resistance genes were also detected, conveying resistance to multiple drugs and the most frequent genes were namely, mcr-1.1, aph(6)-Id, aph(3″)-Ib, oqxAB, qnrB6, qnrS1. According to genetic environment analysis, the insertion sequence IS Ecp1 was prevalent upstream of the bla CTX-M gene. Our study demonstrates that multiple resistance genes are carried by clinical isolates of Salmonella spp. however, the dominant ESBL genotype is CTX-M-55, that is associated with IS Ecp1. [ABSTRACT FROM AUTHOR]

The speciation of Salmonella occurred by acquisition of genomic islands from other bacterial species and continued to diverge into subspecies and serovars with diferent range of host. S. enterica serovar Typhimurium (STM) is a generalist pathogen infecting hosts that include birds, mice, and humans, whilst S. enterica serovar Typhi (STY) is a restricted-host pathogen, infecting only humans. Despite their ranges of hosts, STM and STY possess 97-98% identity. Gain of genes by horizontal transference and loss of genes by mutations, are believed essential for differentiation of Salmonella. Salmonella pathogenicity island 3 (SPI-3) is an example combining these two processes. SPI-3 encodes misL and marT, among other genes. In STM, misL is required for gut colonization. Furthermore, protein MarT, positively regulates expression of misL by binding to misL-promoter. On the other hand, in SPI-3 of STY, marT and misL are pseudogenes. Interestingly, the gene t3766 (gene involved in resistance to H2O2) is present only in STY and is negatively regulated when marTSTM is heterologously expressed in STY. Based on the view that MarT might regulate genes implicated in virulence, this work searched for new genes regulated by MarT. In silico searches for possible MarT target genes were performed, and 4 genes were selected for further analysis as they contained at least 2 copies of the consensus MarT-binding sequence in their promoters. Mutating marT in STM or heterologously expressing marTSTM in STY confirmed that MarT negatively regulates ORF STY1408 or STM14_2003, its homologue in STM. STY1408 encodes for a putative protein with homology to methyl accepting chemotaxis proteins, which participate in chemotaxis and motility. Therefore, STY1408 was named mrmI (MarT-regulated motility gene I). Motility assays confirmed that the product of mrmI modulates motility. In addition, in vitro infection of cells with STM and STY mutants in mrmI reduces association with cells at 1, 3 and 24 h post-infection. Oral infection of mice showed that a mrmI null mutant was defective in producing systemic disease. Therefore, we conclude that MarT regulated mrmI, is involved in virulence of Salmonella. While pseudogenization of marT might modulate the fitness of narrow host range STY. [ABSTRACT FROM AUTHOR]

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 multidrugresistant 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. [ABSTRACT FROM AUTHOR]

Contamination of poultry products by Salmonella enterica serovar Typhimurium (STm) is a major cause of foodborne infections and outbreaks. This study aimed to assess the diversity and antimicrobial resistance (AMR) carriage of STm in three chicken processing plants using genomic sequencing. It also aimed to investigate whether any particular strain types were associated with cases of human illness. Multilevel genome typing (MGT) was used to analyze 379 STm isolates from processed chicken carcasses. The diversity of chicken STm sequence types (STs) increased from MGT1 (2 STs) to MGT9 (257 STs). STs at MGT5 to MGT9 levels that were unique to one processing plant and shared among the processing plants were identified, likely reflecting the diversity of STm at their farm source. Fifteen medium resolution MGT5 STs matched those from human infections in Australia and globally. However, no STs matched between the chicken and human isolates at high resolution levels (MGT8 or MGT9), indicating the two STm populations were phylogenetically related but were unlikely to be directly epidemiologically linked. AMR genes were rare, with only a blaTEM-1 gene carried by a 95 kb IncI1 Alpha plasmid being identified in 20 isolates. In conclusion, subpopulations that were widespread in processing plants and had caused human infections were described using MGT5 STs. In this STM population, AMR was rare with only sporadic resistance to a single drug class observed. The genomic analysis of STm from chicken processing plants in this study provided insights into STm that contaminate meat chickens early in the food production chain. [ABSTRACT FROM AUTHOR]

Rapid and accurate identification of Salmonella enterica serotypes Typhi and Paratyphi (A, B and C), the causal agents of enteric fever, is critical for timely treatment, case management and evaluation of health policies in low and middle-income countries where the disease still remains a serious public health problem. The present study describes the development of a multiplex assay (EFMAtyping) for simultaneous identification of pathogens causing typhoid and paratyphoid fever in a single reaction by the MeltArray approach, which could be finished within 2.5 h. Seven specific genes were chosen for differentiation of typhoidal and nontyphoidal Salmonella. All gene targets were able to be detected by the EFMAtyping assay, with expected Tm values and without cross-reactivity to other relevant Salmonella serovars. The limit of detection (LOD) for all gene targets was 50 copies per reaction. The LOD reached 102–103 CFU/ml for each pathogen in simulated clinical samples. The largest standard deviation value for mean Tm was below 0.5 °C. This newly developed EFMAtyping assay was further evaluated by testing 551 clinical Salmonella isolates, corroborated in parallel by the traditional Salmonella identification workflow, and serotype prediction was enabled by whole-genome sequencing. Compared to the traditional method, our results exhibited 100% of specificity and greater than 96% of sensitivity with a kappa correlation ranging from 0.96 to 1.00. Thus, the EFMAtyping assay provides a rapid, high throughput, and promising tool for public health laboratories to monitor typhoid and paratyphoid fever. [ABSTRACT FROM AUTHOR]

In mammals, enteric salmonellas can use tetrathionate (ttr), formed as a by-product from the inflammatory process in the intestine, as electron acceptor in anaerobic respiration, and it can fuel its energy metabolism by degrading the microbial fermentation product 1,2-propanediol. However, recent studies have shown that this mechanism is not important for Salmonella infection in the intestine of poultry, while it prolongs the persistence of Salmonella at systemic sites in this species. In the current study, we show that ΔttrApduA strains of Salmonella enterica have lower net survival within chicken-derived HD-11 macrophages, as CFU was only 2.3% (S. Enteritidis ΔttrApduA), 2.3% (S. Heidelberg ΔttrApduA), and 3.0% (S. Typhimurium ΔttrApduA) compared to wild-type strains after 24 h inside HD-11 macrophage cells. The difference was not related to increased lysis of macrophages, and deletion of ttrA and pduA did not impair the ability of the strains to grow anaerobically. Further studies are indicated to determine the reason why Salmonella ΔttrApduA strains survive less well inside macrophage cell lines. [ABSTRACT FROM AUTHOR]

Simple Summary: One of the main concerns associated with phage applications is the potential emergence of bacterial variants exhibiting reduced susceptibility to bacteriophages, which may jeopardize the success of such applications, as occurs with antibiotics. In this work, we studied the emergence of reduced-phage-susceptibility variants in broiler trials challenged with Salmonella enterica serovar Infantis and treated with the PhagoVet product. We characterized the bacteriophages composing the PhagoVet product at both a microscopic and genomic level, which displayed a broad host range of infection against 271 strains representing 18 Salmonella serovars. Our results indicate that the emergence of reduced-phage-susceptibility variants is unlikely to compromise the efficacy of oral PhagoVet against S. Infantis. Salmonella enterica serovar Infantis (S. Infantis) poses a growing issue in the poultry sector, with phage-based products emerging as a safe and effective control measure. This study investigated the emergence of reduced-phage-susceptibility variants (RPSV) of S. Infantis in PhagoVet-treated broilers, given that RPSV could undermine phage treatment efficacy. The bacteriophages in the PhagoVet product were characterized using transmission electron microscopy (TEM), genome sequencing, and infection profiling. Furthermore, two broiler trials were conducted: a challenge group (T1) and a challenge-and-treated group (T2). The S. Infantis infective dose was set at 104 and 106 colony-forming units (CFUs) per animal, with PhagoVet administration at 106 and 108 plaque-forming units (PFUs) per animal, in Trials 1 and 2, respectively. The results revealed that the four PhagoVet bacteriophages belonged to different genera. PhagoVet evidenced broad-spectrum efficacy against 271 strains representing 18 Salmonella serovars. In Trial 1, PhagoVet reduced bacterial counts in feces to nearly undetectable levels by day 42, with no RPSV detected. However, in Trial 2, three and five RPSVs were detected in feces and ceca, respectively. Consequently, PhagoVet demonstrated efficacy against S. Infantis in broilers, and the potential impact of RPSV is deemed unlikely to compromise its efficacy. [ABSTRACT FROM AUTHOR]

Kombucha, a beverage traditionally obtained through the fermentation of tea, is believed to have beneficial health properties. Therefore, characterizing the microorganisms responsible for this fermentation is essential to demonstrate its potential health benefits and to identify candidates for new probiotics. In this study, four probiotic yeast strains isolated from kombucha tea were identified, by the PCR-RFLP analysis of the ribosomal ITS region and the sequence of the D1/D2 domain of the 26S rDNA, as Brettanomyces bruxellensis (UVI55 and UVI56) and B. anomalus (UVI57 and UVI58). Properties relevant to probiotics were also studied in these strains. All of them showed excellent survival in simulated gastric (99%-100%) and duodenal (95%-100%) juices. The ability to self-aggregate (38%-100%), adhesion to xylene (15%-50%) and, above all, adhesion to Caco-2 cells (4%-21%), revealed its potential capacity to adhere to the intestinal epithelium. In addition, the tested strains showed excellent antioxidant capacity (82%-94%), antimicrobial activity against different pathogens (Escherichia coli, Staphylococcus aureus, Salmonella enterica, Listeria monocytogenes, and Bacillus cereus), as well as remarkable cytotoxic activity against colon, melanoma and ovarian tumor cell lines. Finally, using Caenorhabditis elegans as a model, strain UVI56 exhibited ability to both extend the lifespan of the nematode and protect it against infection by S. enterica. These results support the probiotic and functional properties of the analyzed strains. In conclusion, the study revealed that kombucha tea could be a source of potential probiotics that contribute to its health-promoting properties and that the characterized Brettanomyces strains could be exploited directly as probiotics or for the development of new functional foods. [ABSTRACT FROM AUTHOR]

Whole genome sequencing is replacing traditional laboratory surveillance methods as the primary tool to track and characterize clusters and outbreaks of the foodborne and zoonotic pathogen Salmonella enterica (S. enterica). In this study, 438 S. enterica isolates representing 35 serovars and 13 broad vehicle categories from one hundred epidemiologically confirmed outbreaks were evaluated for genetic variation to develop epidemiologically relevant interpretation guidelines for Salmonella disease cluster detection. The Illumina sequences were analyzed by core genome multi-locus sequence typing (cgMLST) and screened for antimicrobial resistance (AR) determinants and plasmids. Ninety-three of the one hundred outbreaks exhibited a close allele range (less than 10 allele differences with a subset closer than 5). The remaining seven outbreaks showed increased variation, of which three were considered polyclonal. A total of 16 and 28 outbreaks, respectively, showed variations in the AR and plasmid profiles. The serovars Newport and I 4,[5],12:i:-, as well as the zoonotic and poultry product vehicles, were overrepresented among the outbreaks, showing increased variation. A close allele range in cgMLST profiles can be considered a reliable proxy for epidemiological relatedness for the vast majority of S. enterica outbreak investigations. Variations associated with mobile elements happen relatively frequently during outbreaks and could be reflective of changing selective pressures. [ABSTRACT FROM AUTHOR]

Since the use of antibiotics as growth promoters in animal feed has been restricted or banned in several countries, finding suitable alternatives is crucial for maintaining animal health. In this study, a novel formate acidifier named sodium diformate (NaDF) was synthesized, and the effects on growth performance and the prevention effects against Salmonella enterica serovar Pullorum infections in chickens were assessed. In broilers, NaDF supplementation improved growth performance, as evidenced by increased body weights and reduced feed conversion ratios. At 38 days of age, NaDF supplementation increased the levels of growth-hormone and ghrelin in the serum, lowered pH values in the gut, improved duodenal morphology, as shown by increased villus length/crypt depth ratios. NaDF also modulated the abundance of beneficial and harmful bacteria without changing the general microbiota diversity and short-chain fatty acids levels, which would be beneficial for maintaining gut homeostasis during its use. NaDF exhibited a broad spectrum of antibacterial activity in vitro. Supplementation with NaDF effectively decreased S. Pullorum colonization in the cecum, liver and spleen in chickens, and mitigated pathological changes in the tissues. Therefore, as a novel acidifier, NaDF can improve chicken growth performance by increasing growth-related hormones levels while maintaining the diversity of gut microbiota, and also resist intestinal bacterial infection. These results provided evidences for the application of NaDF as an effective and safe animal feed in poultry farming. [ABSTRACT FROM AUTHOR]

Salmonellosis associated with reptiles is a well‐researched topic, particularly in China and the United States, but it occurs less frequently in Europe. The growth of the human population and changes in the environment could potentially increase the interaction between humans and free‐living reptiles, which are an unidentified source of Salmonella species. In this study, we sought to explore this issue by comparing the microbiota of free‐living European grass snakes, scientifically known as Natrix natrix, with that of captive banded water snakes, or Nerodia fasciata. We were able to isolate 27 strains of Salmonella species from cloacal swabs of 59 N. natrix and 3 strains from 10 N. fasciata. Our findings revealed that free‐living snakes can carry strains of Salmonella species that are resistant to normal human serum (NHS). In contrast, all the Salmonella species strains isolated from N. fasciata were sensitive to the action of the NHS, further supporting our findings. We identified two serovars from N. natrix: Salmonella enterica subspecies diarizonae and S. enterica subspecies houtenae. Additionally, we identified three different virulotypes (VT) with invA, sipB, prgH, orgA, tolC, iroN, sitC, sifA, sopB, spiA, cdtB and msgA genes, and β‐galactosidase synthesised by 23 serovars. The identification of Salmonella species in terms of their VT is a relatively unknown aspect of their pathology. This can be specific to the serovar and pathovar and could be a result of adaptation to a new host or environment. [ABSTRACT FROM AUTHOR]

Antibiotic misuse has led to the development and spread of multidrug-resistant (MDR) microorganisms. This study evaluated the antibacterial activity of n-hexane, ethyl acetate, and aqueous extracts of the marine sponge Amphimidon chloros. The antibacterial activity of n-hexane, ethyl acetate, and aqueous extracts was evaluated using broth microdilution and disc diffusion. The chemical composition of the extracts was analysed using Liquid Chromatography-Mass spectrometry (LC-MS). The antibacterial potency of the extracts was in the following order: aqueous > n-hexane > ethyl acetate extracts. The most significant inhibitory activity of the aqueous extract was against Shigella flexneri, with an inhibition zone of 20.6 mm. Klebsiella pneumonia, Pseudomonas aeruginosa, and Listeria monocytogenes were utterly resistant to ampicillin and chloramphenicol; however, the aqueous extract efficiently inhibited these bacteria. The extract MIC ranged from 0.0195-2.5 mg/mL. With maximal inhibition against Staphylococcus aureus (0.0195 mg/mL), Bacillus cereus (0.0390 mg/mL), Shigella flexneri (0.0390 mg/mL), and Salmonella enterica (0.0781 mg/mL). While L. monocytogenes (0.3125 mg/mL) and S. aureus (0.625 mg/mL) were the only Gram-positive bacteria inhibited, the ethyl acetate extract was equally effective (MIC of 0.3125 mg/mL) against Gram-negative bacteria, including K. pneumonia, S. typhi, S. enterica, Enterobacter aerogenes, and E. coli. The n-hexane extract inhibited S. aureus, S. flexneri, and S. enterica with a MIC value of 0.1562/mL. The most prevalent phytochemicals in the aqueous and n-hexane extracts from the LC-MS study were nakinadine and kermaphidine. The study revealed that the aqueous extract of A. chloros possesses both Gram-positive and Gram-negative antibacterial activity. [ABSTRACT FROM AUTHOR]

Salmonella enterica subsp. enterica serotype Enteritidis (S. Enteritidis) is one of the major causes of foodborne infections and is responsible for many national and multi-country foodborne outbreaks worldwide. In Greece, human salmonellosis is a mandatory notifiable disease, with laboratory surveillance being on a voluntary basis. This study aims to provide the first insights into the genetic characteristics and antimicrobial resistance profiles of 47 S. Enteritidis human isolates using whole-genome sequencing (WGS) technology. The S. Enteritidis population was mainly resistant to fluoroquinolones due to gyrA point mutations, whereas one isolate presented a multi-resistant plasmid-mediated phenotype. ST11 was the most frequent sequence type, and phylogenetic analysis through the cgMLST and SNP methods revealed considerable genetic diversity. Regarding virulence factors, 8 out of the 24 known SPIs and C63PI were detected. Due to the observed variability between countries, it is of utmost importance to record the circulating S. Enteritidis strains' structure and genomic epidemiology at the national level. WGS is a valuable tool that is revolutionizing our approach to Salmonella by providing a deeper understanding of these pathogens and their impact on human health. [ABSTRACT FROM AUTHOR]

Bacteriocins produced by a number of lactic acid bacteria (LAB) comprise a variety of antimicrobial proteins that may be used as antibiotic alternative in food preservation. The present study aimed to isolate and characterize LAB-derived bacteriocin-like substances (BLS) from local fermented foods. A total of twenty-one bacterial strains were isolated and subjected to an antibacterial assay. Five isolates designated as AB1, AB2, AK1, AK2, AnK1 showed inhibitory activity against selected indicator organisms and were subjected to further characterization. Upon BLAST analysis of the 16S rRNA gene sequences, the isolates showed close relationship to Lactobacillus plantarum with similarity ranging from 91 to 97%. Moreover, the antibacterial metabolite production of the isolates was observed to peak on the 5th to 7th day of incubation. Since AnK1 showed the highest zone of inhibition among 5 isolates, it was selected for characterization of the BLS isolated by ammonium sulfate precipitation and anion exchange chromatography. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the AnK1-BLS had a single band and a molecular weight around 15 kDa, and a total protein concentration of 7.06 µg/mL. Interestingly, AnK1-BLS had a broad antimicrobial spectrum on both gram-negative and gram-positive food-borne pathogens, including Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, and Bacillus subtilis. Moreover, the purified AnK1-BLS exhibited good thermal stability when heated at 80‒121°C. Likewise, its inhibitory activity was not affected by pH in the range of 3.0 to 6.5, with maximum activity recorded at pH 3.0. The results suggest that AnK1-BLS may have application prospects in the food industry. Further studies on the complete protein characterization of AnK1-BLS is recommended to fully harness its capabilities. [ABSTRACT FROM AUTHOR]

Aims: Our aim is to characterize through whole‐genome sequencing (WGS) the antimicrobial resistance (AMR) and heavy metal tolerance (HMT) genes content, plasmid presence, virulence potential and genomic diversity of the rare non‐typhoid Salmonella enterica serovar Orion (S. Orion) from 19 countries of the African, American, Eastern Mediterranean, European, Southeastern Asia and Western Pacific regions. Methods and Results: Totally 324 S. Orion genomes were screened for AMR, HMT and virulence genes, plasmids and Salmonella Pathogenicity Islands (SPIs). Genomic diversity was investigated using Multi‐Locus Sequence Typing (MLST) and core‐genome MLST (cgMLST). Efflux pump encoding genes mdsA and mdsB were present in all genomes analysed, while quinolone chromosomal point mutations and aminoglycoside, beta‐lactam, colistin, lincosamide, macrolide, phenicol, sulphonamide, trimethoprim, tetracycline and disinfectant resistance genes were found in 0.3%–5.9%. A total of 17 genomes (5.2%) from Canada, the United Kingdom, the USA and Tanzania showed a potential multi‐drug resistance profile. Gold tolerance genes golS and golT were detected in all genomes analysed, while arsenic, copper, mercury, silver and tellurium tolerance genes were found in 0.3%–35.5%. Col(MGD2) was the most frequently detected plasmid, in 15.4% of the genomes. Virulence genes related to adherence, macrophage induction, magnesium uptake, regulation, serum resistance, stress adaptation, type III secretion systems and six SPIs (1, 2, 3, 4, 5, 9, 12, 13, 14 and C63PI) were detected. ST639 was assigned to 89.2% of the S. Orion genomes, while cgMLST showed core‐genome STs and clusters of strains specific by countries. Conclusion: The high virulence factor frequencies, the genomic similarity among some non‐clinical and clinical strains circulating worldwide and the presence of a strain carrying a resistance gene against a last resource antimicrobial like colistin, highlight the potential risk of S. Orion strains for public health and food safety and reinforce the importance to not underestimate the potential hazard of rare non‐typhoid Salmonella serovars. [ABSTRACT FROM AUTHOR]