anti-Salmonella Activity Research Articles

Enhancing Deer Sous Vide Meat Shelf Life and Safety with Eugenia caryophyllus Essential Oil against Salmonella enterica.

Modern lifestyles have increased the focus on food stability and human health due to evolving industrial goals and scientific advancements. Pathogenic microorganisms significantly challenge food quality, with Salmonella enterica and other planktonic cells capable of forming biofilms that make them more resistant to broad-spectrum antibiotics. This research examined the chemical composition and antibacterial and antibiofilm properties of the essential oil from Eugenia caryophyllus (ECEO) derived from dried fruits. GC-MS analyses identified eugenol as the dominant component at 82.7%. Additionally, the study aimed to extend the shelf life of sous vide deer meat by applying a plant essential oil and inoculating it with S. enterica for seven days at 4 °C. The essential oil demonstrated strong antibacterial activity against S. enterica. The ECEO showed significant antibiofilm activity, as indicated by the MBIC crystal violet test results. Data from MALDI-TOF MS analysis revealed that the ECEO altered the protein profiles of bacteria on glass and stainless-steel surfaces. Furthermore, the ECEO was found to have a beneficial antibacterial effect on S. enterica. In vacuum-packed sous vide red deer meat samples, the anti-Salmonella activity of the ECEO was slightly higher than that of the control samples. These findings underscore the potential of the ECEO's antibacterial and antibiofilm properties in food preservation and extending the shelf life of meat.

Antisalmonella Activity and Modes of Action of Extracts, Fractions and Cerevisterol from Impatiens burtonii against Multi-Drug Resistant Salmonella

Antisalmonella Activity and Modes of Action of Extracts, Fractions and Cerevisterol from Impatiens burtonii against Multi-Drug Resistant Salmonella

Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice

Abstract. Ngemenya MN, Itoe LO, Awah LA, Asongana R, Ndip RA. 2024. Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice. Asian J Nat Prod Biochem 22: 43-50. The emergence of multidrug resistance has significantly compromised the treatment of Salmonella infections. The anti-Salmonella activity, toxicity, and biochemical effects of Moringa oleifera Lam. leaf crude extracts were studied by disc diffusion and microdilution against Multidrug-Resistant (MDR) strains. Cytotoxicity was investigated on monkey kidney epithelial cells (LLCMK2) and acute toxicity in BALB/c mice. Both hexane (MOHEX) and methanol (MOMET) extracts produced small zones of inhibition of 8mm at 1 mg and 2 mg per disc, indicating weak activity, but the minimum inhibitory concentration showed high (0.0625 mg/mL) to low activity (10 mg/mL) activity. No minimum bactericidal concentration was recorded at the concentrations tested. The 50% cytotoxic concentration (CC50) for methanol and hexane extracts were 2524 µg/mL and 5004 µg/mL, respectively, indicating a low risk of toxicity. No mortality or adverse effects were recorded in the acute toxicity test. Both extracts had no significant effects (p < 0.05) on renal function and one liver enzyme (alanine aminotransferase), but MOMET significantly increased aspartate aminotransferase (p = 0.04), suggesting possible liver toxicity. The study shows that M. oleifera leaves possess bacteriostatic activity against multidrug-resistant Salmonella and are non-toxic; hence, it is a potential alternative treatment against multidrug-resistant Salmonella. Further studies of fractions and pure natural products of the extracts should be pursued.

Characterization of the Effects of a Novel Probiotic on Salmonella Colonization of a Piglet-Derived Intestinal Microbiota Using Improved Bioreactor.

The carriage of Salmonella in pigs is a major concern for the agri-food industry and for global healthcare systems. Humans could develop salmonellosis when consuming contaminated pig products. On the other hand, some Salmonella serotypes could cause disease in swine, leading to economic losses on farms. The purpose of the present study was to characterize the anti-Salmonella activity of a novel Bacillus-based probiotic using a bioreactor containing a piglet-derived intestinal microbiota. Two methods of probiotic administration were tested: a single daily and a continuous dose. Salmonella enumeration was performed using selective agar at T24h, T48h, T72h, T96h and T120h. The DNA was extracted from bioreactor samples to perform microbiome profiling by targeted 16S rRNA gene sequencing on Illumina Miseq. The quantification of short-chain fatty acids (SCFAs) was also assessed at T120h. The probiotic decreased Salmonella counts at T96 for the daily dose and at T120 for the continuous one. Both probiotic doses affected the alpha and beta diversity of the piglet-derived microbiota (p < 0.05). A decrease in acetate concentration and an increase in propionate proportion were observed in the continuous condition. In conclusion, the tested Bacillus-based product showed a potential to modulate microbiota and reduce Salmonella colonization in a piglet-derived intestinal microbiota and could therefore be used in vivo.

Synthesis of Piperidine Conjugated Quinoxalines as Potential Antibiofilm Agents

Background: The most common cause of food-borne illness is bacterial or viral contamination. Although there are several therapeutics available to combat these microbes, they lost their efficacy in long-term medication. Because, over a period of time, microbes developed resistance against drugs and this antimicrobial resistance is a serious threat to global public health as a consequence of the widely disseminated and careless use of antimicrobials. Therefore, there is a need to develop some new chemical moieties with a safety factor and better efficacy. A series of substituted N-(1-benzylpiperidin-4- yl)quinoxalin-2-amines (5a-j) (5ab, 5ac) were synthesized and screened for their in vitro antibacterial activity against Salmonella paratyphi, a well-known food-borne pathogen. Methods: Experimental methods, agar diffusion and broth microdilution assays were carried out to evaluate the antibacterial activity of the lead compounds. Further, antibiofilm methods, crystal violet, and MTT assays were subjected to investigate their biofilm inhibition capacity against S. paratyphi. Results: Among the tested compounds, 5b, 5e, 5h, and 5j bearing 4-chloro, 3,4-dimethoxy, 4-methyl and thienyl groups on the phenyl ring of quinoxalines emerged as potential candidates having significant antisalmonella activity. In these four potential candidates, compounds 5b and 5h were effective against Salmonella whereas compounds 5e and 5j effectively inhibited the biofilm formation of Salmonella. Conclusion: N-(1-benzylpiperidin-4-yl)quinoxalin-2-amines (5a-j) (5ab, 5ac) were synthesized and evaluated for antisalmonella activity against S. paratyphi. Among the series of compounds, four compounds significantly showed good activity and emerged as antibacterial agents for further studies in the future.

Inhibition of Salmonella growth in exudates drained from poultry meat by bacteriophage cocktail-containing absorbent food pad

Absorbent food pads are commonly used to absorb exudate drained from food to maintain initial food quality throughout shelf life. However, the absorbed exudate often serves as a nutrient for contaminating pathogens in the pads, requiring appropriate antimicrobial strategies. Here, we developed bacteriophage cocktail-containing absorbent food pads, called phage pads, by impregnating commercial absorbent food pads with a phage cocktail consisting of two Salmonella phages, ФYMFM0293 and ФYMFM0433, followed by air drying for 14 h. The prepared phage pad demonstrated reliable phage titers and water absorbing capacity, and its anti-Salmonella activity was maintained for 84 days under simulated storage conditions. Consistent with the efficient inhibition of in vitro Salmonella growth by the phage cocktail, Salmonella spiked directly on the phage pad at ∼7-log CFU/pad was significantly suppressed for 48 h at 4 °C. When Salmonella-contaminated chicken meat was loaded, Salmonella loads below the detection limit were achieved within the phage pad, in contrast to the control pad, throughout 7 days of refrigerated storage. Considering its stable long-term activity and efficient reduction of specific foodborne pathogens in food exudates, the phage cocktail-containing absorbent food pads could be an effective antibacterial strategy to ensure microbial safety during food distribution to consumers.

Citrus limon Essential Oil: Chemical Composition and Selected Biological Properties Focusing on the Antimicrobial (In Vitro, In Situ), Antibiofilm, Insecticidal Activity and Preservative Effect against Salmonella enterica Inoculated in Carrot.

New goals for industry and science have led to increased awareness of food safety and healthier living in the modern era. Here, one of the challenges in food quality assurance is the presence of pathogenic microorganisms. As planktonic cells can form biofilms and go into a sessile state, microorganisms are now more resistant to broad-spectrum antibiotics. Due to their proven antibacterial properties, essential oils represent a potential option to prevent food spoilage in the search for effective natural preservatives. In this study, the chemical profile of Citrus limon essential oil (CLEO) was evaluated. GC-MS analysis revealed that limonene (60.7%), β-pinene (12.6%), and γ-terpinene (10.3%) are common constituents of CLEO, which prompted further research on antibacterial and antibiofilm properties. Minimum inhibitory concentration (MIC) values showed that CLEO generally exhibits acceptable antibacterial properties. In addition, in situ antimicrobial research revealed that vapour-phase CLEO can arrest the growth of Candida and Y. enterocolitica species on specific food models, indicating the potential of CLEO as a preservative. The antibiofilm properties of CLEO were evaluated by MIC assays, crystal violet assays, and MALDI-TOF MS analysis against S. enterica biofilm. The results of the MIC and crystal violet assays showed that CLEO has strong antibiofilm activity. In addition, the data obtained by MALDI-TOF MS investigation showed that CLEO altered the protein profiles of the bacteria studied on glass and stainless-steel surfaces. Our study also found a positive antimicrobial effect of CLEO against S. enterica. The anti-Salmonella activity of CLEO in vacuum-packed sous vide carrot samples was slightly stronger than in controls. These results highlight the advantages of the antibacterial and antibiofilm properties of CLEO, suggesting potential applications in food preservation.

Cananga oil inhibits Salmonella infection by mediating the homeostasis of purine metabolism and the TCA cycle

Ethnopharmacology relevanceCananga oil (CO) is derived from the flowers of the traditional medicinal plant, the ylang-ylang tree. As a traditional antidepressant, CO is commonly utilized in the treatment of various mental disorders including depression, anxiety, and autism. It is also recognized as an efficient antibacterial insecticide, and has been traditionally utilized to combat malaria and acute inflammatory responses resulting from bacterial infections both in vitro and in vivo. Aim of the studyThe objective of this study is to comprehensively investigate the anti-Salmonella activity and mechanism of CO both in vitro and in vivo, with the expectation of providing feasible strategies for exploring new antimicrobial strategies and developing novel drugs. MethodsThe in vitro antibacterial activity of CO was comprehensively analyzed by measuring MIC, MBC, growth curve, time-killing curve, surface motility, biofilm, and Live/dead bacterial staining. The analysis of the chemistry and active ingredients of CO was conducted using GC-MS. To examine the influence of CO on the membrane homeostasis of Salmonella, we conducted utilizing diverse techniques, including ANS, PI, NPN, ONPG, BCECF-AM, DiSC3(5), and scanning electron microscopy (SEM) analysis. In addition, the antibacterial mechanism of CO was analyzed and validated through metabolomics analysis. Finally, a mouse infection model of Salmonella typhimurium was established to evaluate the toxic side effects and therapeutic effects of CO. ResultsThe antibacterial effect of CO is the result of the combined action of the main chemical components within its six (palmitic acid, α-linolenic acid, stearic acid, benzyl benzoate, benzyl acetate, and myristic acid). Furthermore, CO disrupts the balance of purine metabolism and the tricarboxylic acid cycle (TCA cycle) in Salmonella, interfering with redox processes. This leads to energy metabolic disorders and oxidative stress damage within the bacteria, resulting in bacterial shock, enhanced membrane damage, and ultimately bacterial death. It is worth emphasizing that CO exerts an effective protective influence on Salmonella infection in vivo within a non-toxic concentration range. ConclusionThe outcomes indicate that CO displays remarkable anti-Salmonella activity both in vitro and in vivo. It triggers bacterial death by disrupting the balance of purine metabolism and the TCA cycle, interfering with the redox process, making it a promising anti-Salmonella medication.

Investigation of the anti-salmonellal and antiplasmodial properties of leaf extracts of Rourea coccinea Beninese medicinal plant

Rourea coccinea, also called Byrsocarpus coccineus is a medicinal plant widely used in primary health care in West Africa and in this case in Benin. In the present study, the hydroethanolic extract of these leaves was investigated for its anti-salmonella and antiplasmodial properties. The evaluation of anti-salmonella activity was carried out by the micro dilution method associated with resazurine while that of antiplasmodial activity by method described by Syber Green. Minimum inhibitory concentrations (MICs) of the hydroethanolic extract against Salmonella strains were higher than 2000 μg/mL. This extract was active against multidrug-resistant Plasmodium falciparum strains (PfDd2) with an inhibitory concentration (IC50) of 32.26 μg/mL. These works on Rourea coccinea justify that the plant has a clearly remarkable antiplasmodial activity rather than anti-salmonella one and its use in traditional medicine to treat malaria in Benin.

Anti-Salmonella Activity of Thymus serpyllum Essential Oil in Sous Vide Cook-Chill Rabbit Meat.

Food is generally prepared and vacuum-sealed in a water bath, then heated to a precise temperature and circulated in a sous vide machine. Due to its affordability and ease of use, this cooking method is becoming increasingly popular in homes and food service businesses. However, suggestions from manufacturers and chefs for long-term, low-temperature sous vide cooking raise questions about food safety in the media. In this study, heat treatment with different times and wild thyme essential oil (EO) in sous vide-processed rabbit longissimus dorsi muscle were found to inactivate Salmonella enterica. The rabbit meat samples were vacuum-packed in control groups, in the second group the rabbit meat samples were injected with S. enterica, and in the third group were meat samples infected with S. enterica with Thymus serpylum EO additive. The vacuum-packed samples were cooked sous vide for the prescribed time at 55, 60, and 65 °C. At 5, 15, 30, and 60 min, the quantities of S. enterica, total bacterial counts, and coliform bacteria were measured in groups of sous vide rabbit meat. Microbiological analyses of rabbit meat samples on days 1 and 7 were evaluated. In this study, total viable counts, coliforms bacteria, and number of Salmonella spp. were identified. After incubation, isolates from different groups of microorganisms were identified by the mass spectrometry technique. For each day measured, the test group exposed to a temperature of 55 °C for 5 min had a greater number of total microbiota. The most isolated microorganisms by MALDI-TOF MS Biotyper from the control and treated groups were Lactococcus garvieae and in the treated groups also S. enterica. Based on our analysis of sous vide rabbit meat samples, we discovered that adding 1% of thyme essential oil to the mixture reduced the amount of Salmonella cells and increased the overall and coliform bacterial counts. The microbiological quality of sous vide rabbit meat that was kept for seven days was positively impacted by the addition of thyme essential oil.

Phytochemical screening, evaluation of anti-salmonella activity and acute toxicity of Azadirachta indica (A. Juss) oil seeds

Phytochemical screening, evaluation of anti-salmonella activity and acute toxicity of Azadirachta indica (A. Juss) oil seeds

Anti-Salmonella Activity of a Novel Peptide, KGGDLGLFEPTL, Derived from Egg Yolk Hydrolysate.

The present study aimed to characterize the mode of action of a novel antimicrobial peptide isolated from egg yolk hydrolysate. The EYHp6, KGGDLGLFEPTL, exhibited inhibition against Salmonella enterica serovar Typhimurium TISTR 292 and S. enterica serovar Enteritidis DMST 15679 with a MIC value of 2 mM. In contrast, S. enterica serovar Newport ATCC 6962 and other strains of Typhimurium and Enteritidis were inhibited at 4 mM. EYHp6 increased the cell membrane permeability of S. Typhimurium TISTR 292, leading to DNA leakage. Membrane integrity determined by propidium iodide and SYTO9 staining visualized by confocal microscopy demonstrated that EYHp6 at 1 × MIC induced disruption of cell membranes. Electron microscopy revealed that treatment of S. Typhimurium with EYHp6 led to damage to the cell membrane, causing the leakage of intracellular contents. Synchrotron-based Fourier-transform infrared spectroscopy indicated that EYHp6 killed S. Typhimurium by targeting fatty acids and nucleic acids in the cell membrane. The peptide did not show hemolytic activity up to 4 mM. These findings suggest that EYHp6 could be a promising antibacterial agent for controlling the growth of S. enterica.

Potentials of beetroot (Beta vulgaris L.) peel extract for quality enhancement of refrigerated beef meat

Given the significant quantity of betalain pigments, beetroot represents a potential source of natural colorants that can be employed in the food industry. The present investigation explored the impact of ethanolic beetroot peel (EBP) extract in beef meat preservation. EBP displayed a 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect with an IC50 value of 0.96 mg/mL. The anti-S. aureus, anti-L. monocytogenes, anti-E. coli, and anti-Salmonella enterica activity was assessed, and the minimum inhibitory concentration was ≤1.5 mg/mL. EBP extracts at three concentrations of 0.075%, 0.15%, and 0.3%, and butylated hydroxytoluene (BHT) concentration of 0.01%, employed at its recommended limit, were incorporated in refrigerated raw minced beef meat. The impact of these treatments on chemical stability, instrumental color, microbiological and sensory attributes of meat was monitored for 14 days at 4°C. At different levels, EBP extract led to a decrease in lipid/protein oxidation parameters and delayed microbial load throughout storage, with improved instrumental color and sensory traits. Interestingly, EBP extract at 0.3% has the strongest preservative effect until the end of storage. Using principal component analysis, effective discrimination was elucidated by linking sensory traits with chemical oxidation behavior, microbial alterations, and instrumental color. This investigation proved that EBP could be an encouraging natural additive in the meat industry.

Ligilactobacillus salivarius 7247 Strain: Probiotic Properties and Anti-Salmonella Effect with Prebiotics.

The Ligilactobacillus salivarius 7247 (LS7247) strain, originally isolated from a healthy woman's intestines and reproductive system, has been studied for its probiotic potential, particularly against Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) as well as its potential use in synbiotics. LS7247 showed high tolerance to gastric and intestinal stress and effectively adhered to human and animal enterocyte monolayers, essential for realizing its probiotic properties. LS7247 showed high anti-Salmonella activity. Additionally, the cell-free culture supernatant (CFS) of LS7247 exhibited anti-Salmonella activity, with a partial reduction upon neutralization with NaOH (p < 0.05), suggesting the presence of anti-Salmonella factors such as lactic acid (LA) and bacteriocins. LS7247 produced a high concentration of LA, reaching 124.0 ± 2.5 mM after 48 h of cultivation. Unique gene clusters in the genome of LS7247 contribute to the production of Enterolysin A and metalloendopeptidase. Notably, LS7247 carries a plasmid with a gene cluster identical to human intestinal strain L. salivarius UCC118, responsible for class IIb bacteriocin synthesis, and a gene cluster identical to porcine strain L. salivarius P1ACE3, responsible for nisin S synthesis. Co-cultivation of LS7247 with SE and ST pathogens reduced their viability by 1.0-1.5 log, attributed to cell wall damage and ATP leakage caused by the CFS. For the first time, the CFS of LS7247 has been shown to inhibit adhesion of SE and ST to human and animal enterocytes (p < 0.01). The combination of Actigen prebiotic and the CFS of LS7247 demonstrated a significant combined effect in inhibiting the adhesion of SE and ST to human and animal enterocytes (p < 0.001). These findings highlight the potential of using the LS7247 as a preventive strategy and employing probiotics and synbiotics to combat the prevalence of salmonellosis in animals and humans caused by multidrug resistant (MDR) strains of SE and ST pathogens.

New active packaging based on encapsulated carvacrol, with emphasis on its odour masking strategies

New active polyethylene packaging with both antioxidant and antimicrobial properties was designed and produced using three different concentrations of encapsulated carvacrol. Films containing 10%, 20% and 30% of active capsules showed strong antioxidant activity as hydroxyl (OH·) radical scavengers, while only films containing 30% capsules showed anti-Salmonella enterica activity. Storage of active packaging rolls in sealed aluminium bags maintained both the antioxidant and antimicrobial properties of the films for up to 9 months. Two strategies were used to control or eliminate the strong odour of the developed packaging materials: odour masking spray and multilayer packaging. Migration tests were carried out to assess the safety of packaging. The most successful strategy was the development of two active multilayer packaging materials (polyethylene terephthalate (PET)/adhesive/active low density polyethylene (LDPE) with 10% capsules and aluminium/adhesive/active LDPE with 10% capsules) which reduced the oxidation of packaged crisps stored at 60 °C for 30 days by up to 45%, measured as malonaldehyde using the TBARS assay. In addition, the packaging materials did not affect the organoleptic properties of the stored crisps as determined by sensory analysis. These results show that this novel bifunctional (antioxidant and antimicrobial) active packaging can protect fatty foods from oxidation processes while preserving their organoleptic properties.

Curative anti-typhoid effect of Detarium microcarpum Guill. & Perr. (Leguminosae) hydroethanolic extract root bark based-on in vivo and molecular docking analyses.

Detarium microcarpum is used to treat typhoid fever, a major public health problem, by indigenous population in Africa. Though its preventive activities have been documented, the curative effect is still to be confirmed. This study aimed at evaluating the curative effects of the hydroethanolic extract of Detarium microcarpum root bark on Salmonella typhimurium-induced typhoid in rat and exploring the in-silico inhibition of some bacterial key enzymes. In vitro antioxydant, in vivo antisalmonella of the extract and in silico molecular docking assay on the isolated compounds were carried out to explore the anti-salmonella effects of Detarium microcarpum. The in vitro antioxidant properties of the extract were evaluated using DPPH, ABTS and FRAP tests. The anti-salmonella activity of the extract was assessed through feacal sample from Salmonella typhimurium-infected rat cultured in Salmonella-Shigella agar (SS agar) medium. The affinity of isolated compounds (Rhinocerotinoic acid and Microcarposide) from the extract were performed on four key enzymes (Adenylosuccinate lyase, Acetyl coenzyme A synthetase, Thymidine phosphorylase and LuxS-Quorum sensor) using molecular docking simulation to elucidate the molecular level inhibition mechanism. Crude extract of D. microcarpum root bark showed variable activities on DPPH (RSa50: 6.09±1.04μg/mL), ABTS (RSa50: 24.46±0.27), and FRAP (RSa50: 23.30±0.23). The extract at all the doses exhibited significant healing effect of infected rats, with the complete clearance. The extract restored hematological, biochemical and histological parameters closed to the normal control. The molecular docking results indicates that rhinocerotinoic acid and microcarposide present more affinity to the LuxS-Quorum sensor and Acetyl coenzyme A synthetase protein as compared to the others. These results demonstrate potent anti-typhoid activities of the hydroethanolic of Detarium microcarpum root bark extract through antioxidant properties and high inhibitory affinity of its compounds on some bacterial key enzymes that justify its use as traditional medicine to typhoid fever.

Effective reduction of Salmonella Enteritidis in broiler chickens using the UPWr_S134 phage cocktail.

Salmonella is a poultry-associated pathogen that is considered one of the most important zoonotic bacterial agents of contaminated food of animal origin including poultry products. Many efforts are taken to eliminate it from the food chain, and phages are one of the most promising tools to control Salmonella in poultry production. We investigated the usefulness of the UPWr_S134 phage cocktail in reducing Salmonella in broiler chickens. For this purpose, we analyzed the survivability of phages in the harsh environment encountered in the chicken gastrointestinal tract, which has low pH, high temperatures, and digestive activity. Phages in the cocktail UPWr_S134 showed the ability to remain active after storage at temperatures ranging from 4 to 42°C, reflecting temperatures of storage conditions, broiler handling, and the chicken body, and exhibited robust pH stability. We found that although simulated gastric fluids (SGF) caused phage inactivation, the addition of feed to gastric juice allows maintenance of UPWr_S134 phage cocktail activity. Further, we analyzed UPWr_S134 phage cocktail anti-Salmonella activity in live animals such as mice and broilers. In an acute infection model in mice, the application of doses of 107 and 1014 PFU/ml UPWr_S134 phage cocktail resulted in delaying symptoms of intrinsic infection in all analyzed treatment schedules. In Salmonella-infected chickens orally treated with the UPWr_S134 phage cocktail the number of pathogens in internal organs in comparison to untreated birds was significantly lower. Therefore we concluded that the UPWr_S134 phage cocktail could be an effective tool against this pathogen in the poultry industry.

Phytochemical Screening and Evaluation of the Anti-Salmonella Activity of Leaf Extracts of Telfairia occidentalis Hook. F. (Cucurbitaceae) on Salmonella typhii Cell Culture

Typhoid fever, a bacterial infection caused by Salmonella typhi whose treatment is by use of antibiotics. And the use of these antibiotics associated with drug resistance, high cost of medication and less accessibility to rural populations remains an issue of concern. The aim of this research was to indentify bioactive metabolites of the leaf of T. occidentalis and determine the anti-salmonella typhi activity. The antibacterial activity of the leaf extracts (aqueous maceration, decoction, infusion and ethanol maceration) of Telfairia occidentalis (Fluted pumpkin or gourd) on Salmonella typhi, was determined using the agar well diffusion technique to investigate its potential use as anti-bacterial agent. The phyto-chemical constituents, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the leaf was analyzed. The phytochemical analysis of the extracts showed the presence of saponins, flavonoids, tannins, phenolics and coumarin with the absence of phlobatanins and oxalates. The decoction of the leaves demonstrated the highest activity against S. typhi (15+/-2.7mm) at 1000mg/ml. MIC for aqueous maceration, infusion, and decoction was recorded at 62.5mg/ml and that of the ethanol maceration was at 15.625mg/ml. Due to the extraordinarily high concentration of extract needed to produce anti-salmonella activity, the study's findings imply that the leaf extract has negligible activity against Salmonella.

Defined Pig Microbiota with a Potential Protective Effect against Infection with Salmonella Typhimurium.

A balanced microbiota is a main prerequisite for the host's health. The aim of the present work was to develop defined pig microbiota (DPM) with the potential ability to protect piglets against infection with Salmonella Typhimurium, which causes enterocolitis. A total of 284 bacterial strains were isolated from the colon and fecal samples of wild and domestic pigs or piglets using selective and nonselective cultivation media. Isolates belonging to 47 species from 11 different genera were identified by MALDI-TOF mass spectrometry (MALDI-TOF MS). The bacterial strains for the DPM were selected for anti-Salmonella activity, ability to aggregate, adherence to epithelial cells, and to be bile and acid tolerant. The selected combination of 9 strains was identified by sequencing of the 16S rRNA gene as Bacillus sp., Bifidobacterium animalis subsp. lactis, B. porcinum, Clostridium sporogenes, Lactobacillus amylovorus, L. paracasei subsp. tolerans, Limosilactobacillus reuteri subsp. suis, and Limosilactobacillus reuteri (two strains) did not show mutual inhibition, and the mixture was stable under freezing for at least 6 months. Moreover, strains were classified as safe without pathogenic phenotype and resistance to antibiotics. Future experiments with Salmonella-infected piglets are needed to test the protective effect of the developed DPM.

In Vitro Characterization of Probiotic Potential of Limosilactobacillus fermentum against Salmonella Gallinarum Causing Fowl Typhoid.

Fowl typhoid, a septicaemic disease of poultry, is caused by Salmonella Gallinarum and leads to severe economic losses. The aim of the present study was to isolate, select and characterize indigenous probiotic lactobacilli with anti-Salmonella Gallinarum activity. A total 55 lactobacilli were isolated from the caeca and ileum parts of healthy chickens and identified to species level by 16S rDNA sequencing. All the isolates were initially screened for antimicrobial activity and selected isolates were further subjected to in vitro evaluation of probiotic properties. Lactobacilli isolates (n = 21) showed varying levels of activity (08-18 mm) against Salmonella Gallinarum. These selected isolates also showed tolerance to acidic conditions (pH 3 and 4). Out of these 21 isolates, 13 showed growth (>0.5 OD at 600 nm) 0.3% bile salts. Moreover, these isolates also had the ability of auto-aggregation (20.05 ± 0.62%-50.70 ± 1.40%), and co-aggregation with Salmonella Gallinarum (5.22 ± 0.21%-42.07 ± 0.70%). Results revealed that lactobacilli had a higher level of resistance to vancomycin (100%), streptomycin (100%), ciprofloxacin (95%), gentamicin (90%), doxycycline (90%), oxytetracycline (85%), and bacitracin (80%), and a lower level of resistance to penicillin (33%), erythromycin (28%), chloramphenicol (23%), fusidic acid (23%) and amoxicillin (4%). The Limosilactobacillus fermentum PC-10 and PC-76 were sensitive to most of the antibiotics. The overall results revealed that two Limosilactobacillus fermentum strains (PC-10 and PC-76) fulfill the in vitro selection criteria of probiotics, i.e, tolerance to low pH, resistance to bile salts, auto-aggregation, co-aggregation with Salmonella Gallinarum, and absence of acquired antibiotic resistance. The Limosilactobacillus fermentum PC-10 and PC-76 also inhibited the (>5 log10) growth of Salmonella Gallinarum in co-culture assay. It is concluded that Limosilactobacillus fermentum PC-10 and PC-76 may be further investigated and developed as anti-Salmonella Gallinarum probiotics for poultry.