Phage-induced bacterial morphological changes reveal a phage-derived antimicrobial affecting cell wall integrity.

In a looming post-antibiotic era, antibiotic alternatives have become key players in the combat against pathogens. Although recent advances in genomic research allow scientists to fully explore an organism's genome in the search for novel antibacterial molecules, laborious work is still needed in order to dissect each individual gene product for its antibacterial activity. Here, we exploited phage-induced bacterial morphological changes as anchors to explore and discover a potential phage-derived antimicrobial embedded in the phage genome. We found that, upon vibriophage KVP40 infection, Vibrio parahaemolyticus exhibited morphological changes similar to those observed when treated with mecillinam, a cell wall synthesis inhibitor, suggesting the mechanism of pre-killing that KVP40 exerts inside the bacterial cell upon sieging the host. Genome analysis revealed that, of all the annotated gene products in the KVP40 genome that are involved in cell wall degradation, lytic transglycosylase (LT) is of particular interest for subsequent functional studies. A single-cell morphological analysis revealed that heterologous expression of wild-type KVP40-LT induced similar bacterial morphological changes to those treated with the whole phage or mecillinam, prior to cell burst. On the contrary, neither the morphology nor the viability of the bacteria expressing signal-peptide truncated- or catalytic mutant E80A- KVP40-LT was affected, suggesting the necessity of these domains for the antibacterial activities. Altogether, this research paves the way for the future development of the discovery of phage-derived antimicrobials that is guided through phage-induced morphological changes.

Pathogenicity of clinical Salmonella enterica serovar Typhimurium isolates from Thailand in a mouse colitis model.

Salmonella enterica serovar Typhimurium (S. Typhimurium [STM]) is a leading cause of nontyphoidal salmonellosis (NTS) worldwide. The pathogenesis of NTS has been studied extensively using a streptomycin-pretreated mouse colitis model with the limited numbers of laboratory STM strains. However, the pathogenicity of the clinically isolated STM (STMC) strains endemic in Thailand in mice has not been explored. The aim of this study was to compare the pathogenicity of STMC strains collected from Northern Thailand with the laboratory STM (IR715) in mice. Five STMC isolates were obtained from the stool cultures of patients with acute NTS admitted to Maharaj Nakorn Chiang Mai Hospital in 2016 and 2017. Detection of virulence genes and sequence type (ST) of the strains was performed. Female C57BL/6 mice were pretreated with streptomycin sulfate 1 day prior to oral infection with STM. On Day 4 postinfection, mice were euthanized, and tissues were collected to analyze the bacterial numbers, tissue inflammation, and cecal histopathological score. We found that all five STMC strains are ST34 and conferred the same or reduced pathogenicity compared with that of IR715 in mice. A strain-specific effect of ST34 on mouse gut colonization was also observed. Thailand STM ST34 exhibited a significant attenuated systemic infection in mice possibly due to the lack of spvABC-containing virulence plasmid.

Altered gut microbiota ameliorates bone pathology in the mandible of obese-insulin-resistant rats.

PURPOSE: The chronic consumption of a high-fat diet (HFD) induces obese-insulin resistance and impairs jawbone health via gut dysbiosis-stimulated inflammatory process. Our previous studies demonstrated that the probiotic Lactobacillus paracasei HII01, prebiotic xylooligosaccharide (XOS), and synbiotics improved several vital organ functions by reducing gut dysbiosis in HFD-induced obese rats. However, the impacts on the cellular level of jawbone microarchitecture have not been examined. Here, we hypothesized that the supplementation of L. paracasei HII01, XOS, and synbiotics ameliorated the bone microarchitectural pathology in HFD-fed rats by reducing systemic inflammation and other metabolic parameters. METHODS: The dietary regimes (normal or high-fat diet) were provided to 48 male Wistar rats throughout 24-week experiment. After week 12, rats were given either a vehicle, pro-, pre-, or synbiotic for an additional 12 weeks before being killed. Then, blood analyses and bone histomorphometry of the jawbones were performed. RESULTS: The HFD-fed rats developed obese-insulin resistance with significantly elevated systemic inflammation. Bone histomorphometry of these rats showed a decrease in trabecular thickness with increased osteoclasts and active erosion surfaces. Mineral apposition and bone-formation rates were also remarkably diminished. The treatment with pro-, pre-, and synbiotics equally improved metabolic disturbance, reduced systemic inflammation, increased trabecular thickness, decreased osteoclasts and active erosion surfaces and restored mineral apposition and bone-formation rates. CONCLUSION: The probiotic L. paracasei HII01, prebiotic XOS, and the synbiotics had similarly beneficial effects to improve jawbone microarchitecture in HFD-fed rats by possibly ameliorating osteoclast-related bone resorption and potentiating bone-formation activities.

Respiration of Microbiota-Derived 1,2-propanediol Drives Salmonella Expansion during Colitis.

Intestinal inflammation caused by Salmonella enterica serovar Typhimurium increases the availability of electron acceptors that fuel a respiratory growth of the pathogen in the intestinal lumen. Here we show that one of the carbon sources driving this respiratory expansion in the mouse model is 1,2-propanediol, a microbial fermentation product. 1,2-propanediol utilization required intestinal inflammation induced by virulence factors of the pathogen. S. Typhimurium used both aerobic and anaerobic respiration to consume 1,2-propanediol and expand in the murine large intestine. 1,2-propanediol-utilization did not confer a benefit in germ-free mice, but the pdu genes conferred a fitness advantage upon S. Typhimurium in mice mono-associated with Bacteroides fragilis or Bacteroides thetaiotaomicron. Collectively, our data suggest that intestinal inflammation enables S. Typhimurium to sidestep nutritional competition by respiring a microbiota-derived fermentation product.

Effects of probiotics, prebiotics or synbiotics on jawbone in obese-insulin resistant rats.

PURPOSE: Chronic high-fat diet (HFD) consumption results in gut dysbiosis, systemic inflammation, obese-insulin resistance, and osteoporosis of the jawbones. The probiotics, prebiotics or synbiotics alleviated gut dysbiosis and the metabolic disturbance in HFD-induced obesity. However, the effects on jawbone properties have not been investigated. This study aimed to investigate the effects of probiotic Lactobacillus paracasei HII01, prebiotic xylooligosaccharide (XOS), and synbiotics on the jawbone properties along with metabolic parameters, gut and systemic inflammation in HFD-fed rats. METHODS: Forty-eight male Wistar rats were fed with either a HFD or normal diet for 12 weeks. Rats in each group were subdivided into four subgroups to be treated with either vehicle, probiotics, prebiotics, or synbiotics for the additional 12 weeks. Blood samples, gut, bone marrows, and jawbones were collected to determine metabolic parameters, inflammation, and bone properties. RESULTS: The HFD-fed rats developed obese-insulin resistance, as indicated by increased body weight, dyslipidemia and decreased insulin sensitivity. Serum lipopolysaccharide levels and interleukin-6 mRNA expression in the ileum and bone marrows were elevated. Altered bone metabolism and the impaired jawbone properties were evident as indicated by decreased bone mineral density with increased trabecular separation. Reduced ultimate load and stiffness were observed in HFD-fed rats. Treatments with probiotics, prebiotics or synbiotics in HFD-fed rats improved metabolic parameters and reduced inflammation. However, no alterations in jawbone properties were found in all treatments. CONCLUSION: The osteoporosis of the jawbone occurred in obese-insulin resistance, and treatments with probiotics, prebiotics and synbiotics were not sufficient to improve the jawbone properties.

Decreased microglial activation through gut-brain axis by prebiotics, probiotics, or synbiotics effectively restored cognitive function in obese-insulin resistant rats.

BACKGROUND: Chronic high-fat diet (HFD) consumption caused not only obese-insulin resistance, but also cognitive decline and microglial hyperactivity. Modified gut microbiota by prebiotics and probiotics improved obese-insulin resistance. However, the effects of prebiotics, probiotics, and synbiotics on cognition and microglial activity in an obese-insulin resistant condition have not yet been investigated. We aimed to evaluate the effect of prebiotic (Xyloolidosaccharide), probiotic (Lactobacillus paracasei HII01), or synbiotics in male obese-insulin resistant rats induced by a HFD. METHODS: Male Wistar rats were fed with either a normal diet or a HFD for 12 weeks. At week 13, the rats in each dietary group were randomly divided into four subgroups including vehicle group, prebiotics group, probiotics group, and synbiotics group. Rats received their assigned intervention for an additional 12 weeks. At the end of experimental protocol, the cognitive functioning of each rat was investigated; blood and brain samples were collected to determine metabolic parameters and investigate brain pathology. RESULTS: We found that chronic HFD consumption leads to gut and systemic inflammation and impaired peripheral insulin sensitivity, which were improved by all treatments. Prebiotics, probiotics, or synbiotics also improved hippocampal plasticity and attenuated brain mitochondrial dysfunction in HFD-fed rats. Interestingly, hippocampal oxidative stress and apoptosis were significantly decreased in HFD-fed rats with all therapies, which also decreased microglial activation, leading to restored cognitive function. CONCLUSIONS: These findings suggest that consumption of prebiotics, probiotics, and synbiotics restored cognition in obese-insulin resistant subjects through gut-brain axis, leading to improved hippocampal plasticity, brain mitochondrial function, and decreased microglial activation.

Probiotic Lactobacillus paracasei HII01 protects rats against obese-insulin resistance-induced kidney injury and impaired renal organic anion transporter 3 function.

The relationship between gut dysbiosis and obesity is currently acknowledged to be a health topic which causes low-grade systemic inflammation and insulin resistance and may damage the kidney. Organic anion transporter 3 (Oat3) has been shown as a transporter responsible for renal handling of gut microbiota products which are involved in the progression of metabolic disorder. The present study investigated the effect of probiotic supplementation on kidney function, renal Oat3 function, inflammation, endoplasmic reticulum (ER) stress, and apoptosis in obese, insulin-resistant rats. After 12 weeks of being provided with either a normal or a high-fat diet (HF), rats were divided into normal diet (ND); ND treated with probiotics (NDL); HF; and HF treated with probiotic (HFL). Lactobacillus paracasei HII01 1 × 108 colony forming unit (CFU)/ml was administered to the rats daily by oral gavage for 12 weeks. Obese rats showed significant increases in serum lipopolysaccharide (LPS), plasma lipid profiles, and insulin resistance. Renal Oat 3 function was decreased along with kidney dysfunction in HF-fed rats. Obese rats also demonstrated the increases in inflammation, ER stress, apoptosis, and gluconeogenesis in the kidneys. These alterations were improved by Lactobacillus paracasei HII01 treatment. In conclusion, probiotic supplementation alleviated kidney inflammation, ER stress, and apoptosis, leading to improved kidney function and renal Oat3 function in obese rats. These benefits involve the attenuation of hyperlipidemia, systemic inflammation, and insulin resistance. The present study also suggested the idea of remote sensing and signaling system between gut and kidney by which probiotic might facilitate renal handling of gut microbiota products through the improvement of Oat3 function.

Chronic treatment with prebiotics, probiotics and synbiotics attenuated cardiac dysfunction by improving cardiac mitochondrial dysfunction in male obese insulin-resistant rats.

PURPOSE: In metabolic syndrome, the composition of gut microbiota has been disrupted, and is associated with left ventricular (LV) dysfunction. Several types of prebiotics, probiotics, and synbiotics have been shown to exert cardioprotection by restoring gut microbiota from dysbiosis and reducing systemic inflammation. However, the effects of prebiotics such as xylooligosaccharides (XOS); probiotics such as Lactobacillus paracasei STII01 HP4, and synbiotics on metabolic and LV function in obese insulin-resistant rats have not been investigated. In this study, we hypothesized that prebiotics and probiotics improve metabolic parameters, heart rate variability (HRV), blood pressure (BP), and LV function by attenuating cardiac mitochondrial dysfunction, systemic inflammation, and oxidative stress, and that synbiotics provide greater efficacy than a single regimen in obese insulin resistance. METHODS: Rats were fed with either normal diet or high-fat diet (HFD) for 12 weeks and then rats in each dietary group were randomly subdivided into four subgroups to receive either a vehicle, prebiotics, probiotics, or synbiotics for another 12 weeks. Metabolic parameters, BP, HRV, LV function, cardiac mitochondrial function, systemic inflammation, and oxidative stress were determined. RESULTS: HFD-fed rats had obese insulin resistance with markedly increased systemic inflammatory marker [Serum LPS; ND; 0.6 ± 0.1 EU/ml vs. HFD; 5.7 ± 1.2 EU/ml (p < 0.05)], depressed HRV, and increased BP and LV dysfunction [%ejection fraction; ND; 93 ± 2% vs. HFD; 83 ± 2% (p < 0.05)]. Prebiotics, probiotics, and synbiotics attenuated insulin resistance by improving insulin sensitivity and lipid profiles. All interventions also improved HRV, BP, LV function [%ejection fraction; HFV; 81 ± 2% vs. HFPE; 93 ± 3%, HFPO; 92 ± 1%, HFC; 92 ± 2% (p < 0.05)] by attenuating mitochondrial dysfunction, oxidative stress, and systemic inflammation in obese insulin-resistant rats. CONCLUSION: Prebiotics, probiotics, and synbiotics shared similar efficacy in reducing insulin resistance and LV dysfunction in obese insulin-resistant rats.

Diet, gut microbiota and cognition.

The consumption of a diet high in fat and sugar can lead to the development of obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease and cognitive decline. In the human gut, the trillions of harmless microorganisms harboured in the host's gastrointestinal tract are called the 'gut microbiota'. Consumption of a diet high in fat and sugar changes the healthy microbiota composition which leads to an imbalanced microbial population in the gut, a phenomenon known as "gut dysbiosis". It has been shown that certain types of gut microbiota are linked to the pathogenesis of obesity. In addition, long-term consumption of a high fat diet is associated with cognitive decline. It has recently been proposed that the gut microbiota is part of a mechanistic link between the consumption of a high fat diet and the impaired cognition of an individual, termed "microbiota-gut-brain axis". In this complex relationship between the gut, the brain and the gut microbiota, there are several types of gut microbiota and host mechanisms involved. Most of these mechanisms are still poorly understood. Therefore, this review comprehensively summarizes the current evidence from mainly in vivo (rodent and human) studies of the relationship between diet, gut microbiota and cognition. The possible mechanisms that the diet and the gut microbiota have on cognition are also presented and discussed.

Gut inflammation provides a respiratory electron acceptor for Salmonella.

Salmonella enterica serotype Typhimurium (S. Typhimurium) causes acute gut inflammation by using its virulence factors to invade the intestinal epithelium and survive in mucosal macrophages. The inflammatory response enhances the transmission success of S. Typhimurium by promoting its outgrowth in the gut lumen through unknown mechanisms. Here we show that reactive oxygen species generated during inflammation react with endogenous, luminal sulphur compounds (thiosulphate) to form a new respiratory electron acceptor, tetrathionate. The genes conferring the ability to use tetrathionate as an electron acceptor produce a growth advantage for S. Typhimurium over the competing microbiota in the lumen of the inflamed gut. We conclude that S. Typhimurium virulence factors induce host-driven production of a new electron acceptor that allows the pathogen to use respiration to compete with fermenting gut microbes. Thus the ability to trigger intestinal inflammation is crucial for the biology of this diarrhoeal pathogen.

Intestinal inflammation allows Salmonella to use ethanolamine to compete with the microbiota.

Conventional wisdom holds that microbes support their growth in vertebrate hosts by exploiting a large variety of nutrients. We show here that use of a specific nutrient (ethanolamine) confers a marked growth advantage on Salmonella enterica serovar Typhimurium (S. Typhimurium) in the lumen of the inflamed intestine. In the anaerobic environment of the gut, ethanolamine supports little or no growth by fermentation. However, S. Typhimurium is able to use this carbon source by inducing the gut to produce a respiratory electron acceptor (tetrathionate), which supports anaerobic growth on ethanolamine. The gut normally converts ambient hydrogen sulfide to thiosulfate, which it then oxidizes further to tetrathionate during inflammation. Evidence is provided that S. Typhimurium's growth advantage in an inflamed gut is because of its ability to respire ethanolamine, which is released from host tissue, but is not utilizable by competing bacteria. By inducing intestinal inflammation, S. Typhimurium sidesteps nutritional competition and gains the ability to use an abundant simple substrate, ethanolamine, which is provided by the host.

Usual intake of one-carbon metabolism nutrients in a young adult population aged 19-30 years: a cross-sectional study.

One-carbon nutrients play an important role in epigenetic mechanisms and cellular methylation reactions. Inadequate intake of these nutrients is linked to metabolic perturbations, yet the current intake levels of these nutrients have rarely been studied in Asia. This cross-sectional study surveyed the usual dietary intake of one-carbon nutrients (folate, choline and vitamins B2, B6 and B12) among Thai university students aged 19-30 years (n 246). Socioeconomic background, health information, anthropometric data and 24-h dietary recall data were collected. The long-term usual intake was estimated using the multiple-source method. The average usual intake levels for men and women were (mean ± sd) 1⋅85 ± 0⋅95 and 2⋅42 ± 8⋅7 mg/d of vitamin B2, 1⋅96 ± 1⋅0 and 2⋅49 ± 8⋅7 mg/d of vitamin B6, 6⋅20 ± 9⋅5 and 6⋅28 ± 12 µg/d of vitamin B12, 195 ± 154 and 155 ± 101 µg dietary folate equivalent/d of folate, 418 ± 191 and 337 ± 164 mg/d of choline, respectively. Effect modification by sex was observed for vitamin B2 (P-interaction = 0⋅002) and choline (P-interaction = 0⋅02), where every 1 mg increase in vitamin B2 and 100 mg increase in choline intake were associated with a 2⋅07 (P = 0⋅01) and 0⋅81 kg/m2 (P = 0⋅04) lower BMI, respectively, in men. The study results suggest that Thai young adults meet the recommended levels for vitamins B2, B6 and B12. The majority of participants had inadequate folate intake and did not achieve recommended intake levels for choline. The study was approved by the Ethics Committee at the Faculty of Medicine, Chiang Mai University. This trial was registered at www.thaiclinicaltrials.gov (TCTR20210420007).

The Extract of Perilla frutescens Seed Residue Attenuated the Progression of Aberrant Crypt Foci in Rat Colon by Reducing Inflammatory Processes and Altered Gut Microbiota.

Perilla frutescens (PF) seed residue is a waste from perilla oil production that still contains nutrients and phytochemicals. This study aimed to investigate the chemoprotective action of PF seed residue crude ethanolic extract (PCE) on the inflammatory-induced promotion stage of rat colon carcinogenesis and cell culture models. PCE 0.1 and 1 g/kg body weight were administered by oral gavage to rats after receiving dimethylhydrazine (DMH) with one week of dextran sulfate sodium (DSS) supplementation. PCE at high dose exhibited a reduction in aberrant crypt foci (ACF) number (66.46%) and decreased pro-inflammatory cytokines compared to the DMH + DSS group (p < 0.01). Additionally, PCE could either modulate the inflammation induced in murine macrophage cells by bacterial toxins or suppress the proliferation of cancer cell lines, which was induced by the inflammatory process. These results demonstrate that the active components in PF seed residue showed a preventive effect on the aberrant colonic epithelial cell progression by modulating inflammatory microenvironments from the infiltrated macrophage or inflammatory response of aberrant cells. Moreover, consumption of PCE could alter rat microbiota, which might be related to health benefits. However, the mechanisms of PCE on the microbiota, which are related to inflammation and inflammatory-induced colon cancer progression, need to be further investigated.

A novel coli myophage and antibiotics synergistically inhibit the growth of the uropathogenic E. coli strain CFT073 in stoichiometric niches.

Urinary tract infections are widespread bacterial infections affecting millions of people annually, with Escherichia coli being the most prevalent. Although phage therapy has recently gained interest as a promising alternative therapy for antibiotic-resistant bacteria, several studies have raised concerns regarding the evolution of phage resistance, making the therapy ineffective. In this study, we discover a novel coli myophage designated as Killian that targets E. coli strains, including the uropathogenic E. coli (UPEC) strain CFT073. It requires at least 20 minutes for 90% of its particles to adsorb to the host cells, undergoes subcellular activities for replication for 30 minutes, and eventually lyses the cells with a burst size of about 139 particles per cell. Additionally, Killian can withstand a wide variety of temperatures (4-50°C) and pHs (4-10). Genome analysis reveals that Killian's genome consists of 169,905 base pairs with 35.5% GC content, encoding 276 open reading frames; of these, 209 are functionally annotated with no undesirable genes detected, highlighting its potential as an antibiotic alternative against UPEC. However, after an 8-hour phage treatment at high multiplicities of infection, bacterial density continuously increases, indicating an onset of bacterial growth revival. Thus, the combination study between the phage and three different antibiotics, including amikacin, ciprofloxacin, and piperacillin, was performed and showed that certain pairs of phage and antibiotics exhibited synergistic interactions in suppressing the bacterial growth revival. These findings suggest that Killian-antibiotic combinations are effective in inhibiting the growth of UPEC. IMPORTANCE Phage therapy has recently been in the spotlight as a viable alternative therapy for bacterial infections. However, several studies have raised concerns about the emergence of phage resistance that occurs during treatment, making the therapy not much effective. Here, we present the discovery of a novel E. coli myophage that, by itself, can effectively kill the uropathogenic E. coli, but the emergence of bacterial growth revival was detected during the treatment. Phage and antibiotics are then combined to improve the efficiency of the phage in suppressing the bacterial re-growth. This research would pave the way for the future development of phage-antibiotic cocktails for the sustainable use of phages for therapeutic purposes.

Gut Microbiota-Mediated Pharmacokinetic Drug-Drug Interactions between Mycophenolic Acid and Trimethoprim-Sulfamethoxazole in Humans.

Mycophenolic acid (MPA) and trimethoprim-sulfamethoxazole (TMP-SMX) are commonly prescribed together in certain groups of patients, including solid organ transplant recipients. However, little is known about the pharmacokinetic drug-drug interactions (DDIs) between these two medications. Therefore, the present study aimed to determine the effects of TMP-SMX on MPA pharmacokinetics in humans and to find out the relationship between MPA pharmacokinetics and gut microbiota alteration. This study enrolled 16 healthy volunteers to take a single oral dose of 1000 mg mycophenolate mofetil (MMF), a prodrug of MPA, administered without and with concurrent use of TMP-SMX (320/1600 mg/day) for five days. The pharmacokinetic parameters of MPA and its glucuronide (MPAG) were measured using high-performance liquid chromatography. The composition of gut microbiota in stool samples was profiled using a 16S rRNA metagenomic sequencing technique during pre- and post-TMP-SMX treatment. Relative abundance, bacterial co-occurrence networks, and correlations between bacterial abundance and pharmacokinetic parameters were investigated. The results showed a significant decrease in systemic MPA exposure when TMP-SMX was coadministered with MMF. Analysis of the gut microbiome revealed altered relative abundance of two enriched genera, namely the genus Bacteroides and Faecalibacterium, following TMP-SMX treatment. The relative abundance of the genera Bacteroides, [Eubacterium] coprostanoligenes group, [Eubacterium] eligens group, and Ruminococcus appeared to be significantly correlated with systemic MPA exposure. Coadministration of TMP-SMX with MMF resulted in a reduction in systemic MPA exposure. The pharmacokinetic DDIs between these two drugs were attributed to the effect of TMP-SMX, a broad-spectrum antibiotic, on gut microbiota-mediated MPA metabolism.

Corrigendum: Pathogen genomics and phage-based solutions for accurately identifying and controlling Salmonella pathogens.

[This corrects the article DOI: 10.3389/fmicb.2023.1166615.].

Pathogen genomics and phage-based solutions for accurately identifying and controlling Salmonella pathogens.

Salmonella is a food-borne pathogen often linked to poultry sources, causing gastrointestinal infections in humans, with the numbers of multidrug resistant (MDR) isolates increasing globally. To gain insight into the genomic diversity of common serovars and their potential contribution to disease, we characterized antimicrobial resistance genes, and virulence factors encoded in 88 UK and 55 Thai isolates from poultry; the presence of virulence genes was detected through an extensive virulence determinants database compiled in this study. Long-read sequencing of three MDR isolates, each from a different serovar, was used to explore the links between virulence and resistance. To augment current control methods, we determined the sensitivity of isolates to 22 previously characterized Salmonella bacteriophages. Of the 17 serovars included, Salmonella Typhimurium and its monophasic variants were the most common, followed by S. Enteritidis, S. Mbandaka, and S. Virchow. Phylogenetic analysis of Typhumurium and monophasic variants showed poultry isolates were generally distinct from pigs. Resistance to sulfamethoxazole and ciprofloxacin was highest in isolates from the UK and Thailand, respectively, with 14-15% of all isolates being MDR. We noted that >90% of MDR isolates were likely to carry virulence genes as diverse as the srjF, lpfD, fhuA, and stc operons. Long-read sequencing revealed the presence of global epidemic MDR clones in our dataset, indicating they are possibly widespread in poultry. The clones included MDR ST198 S. Kentucky, harboring a Salmonella Genomic Island-1 (SGI)-K, European ST34 S. 1,4,[5],12:i:-, harboring SGI-4 and mercury-resistance genes, and a S. 1,4,12:i:- isolate from the Spanish clone harboring an MDR-plasmid. Testing of all isolates against a panel of bacteriophages showed variable sensitivity to phages, with STW-77 found to be the most effective. STW-77 lysed 37.76% of the isolates, including serovars important for human clinical infections: S. Enteritidis (80.95%), S. Typhimurium (66.67%), S. 1,4,[5],12:i:- (83.3%), and S. 1,4,12: i:- (71.43%). Therefore, our study revealed that combining genomics and phage sensitivity assays is promising for accurately identifying and providing biocontrols for Salmonella to prevent its dissemination in poultry flocks and through the food chain to cause infections in humans.

Activity of a Bacteriophage Cocktail to Control Salmonella Growth Ex Vivo in Avian, Porcine, and Human Epithelial Cell Cultures.

We examined the activity of phages to control the growth of chicken and swine Salmonella strains in avian (CHIC-8E11), porcine (IPEC-1), and human (HT-29) cell cultures. We optimized a six-phage cocktail by selecting the five most effective myoviruses and a siphovirus that have optimal lysis on prevalent serovars. We observed ∼20% of 7 log10 PFU/well phage and 3-6 log10 CFU bacterial adhesions, and 3-5 log10 CFU bacterial invasion per 2 cm2 of the cultured cells at 2 h post-treatment. The invasive bacteria when plated had a variable reduced susceptibility to the phages. After phage application at an MOI of 10, the prophylaxis regimen had better efficacy at controlling bacterial growth with an up to 6 log10 CFU/well reduction as compared with the 1-2 log10 CFU/well bacterial reduction observed in the remedial and coinfection regimens. Our data support the development of these phages to control salmonellosis in chickens, pigs, and humans.

Clinical Characteristics, Antimicrobial Resistance, Virulence Genes and Multi-Locus Sequence Typing of Non-Typhoidal Salmonella Serovar Typhimurium and Enteritidis Strains Isolated from Patients in Chiang Mai, Thailand.

Non-typhoidal salmonellosis (NTS) caused by ingesting Salmonella enterica contaminated food or drink remains a major bacterial foodborne disease. Clinical outcomes of NTS range from self-limited gastroenteritis to life-threatening invasive NTS (iNTS). In this study, we isolated Salmonella spp. from the stool and blood of patients hospitalized at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, between 2016-2021 (a total of 395 cases). Then, serovar Typhimurium and Enteritidis were identified and further characterized by multiplex PCR, and multi-locus sequence typing. Our data show that multidrug resistance (MDR) sequence type 34 (ST34) and ST11 are the predominant sequence types for serovars Typhimurium and Enteritidis, respectively. Most S. Typhimurium ST34 lacks spvB, and most S. Enteritidis ST11 harbor sseI, sodCI, rpoS and spvB genes. NTS can be found in a wide range of ages, and anemia could be a significant factor for S. Typhimurium infection (86.3%). Both S. Typhimurium (6.7%) and S. Enteritidis (25.0%) can cause iNTS in immunocompromised patients. S. Typhimurium conferred MDR phenotype higher than S. Enteritidis with multiple antibiotic resistance indexes of 0.22 and 0.04, respectively. Here, we characterized the important S. Typhimurium, S. Enteritidis, and human clinical factors of NTS within the region.

Enriched Riceberry Bran Oil Exerts Chemopreventive Properties through Anti-Inflammation and Alteration of Gut Microbiota in Carcinogen-Induced Liver and Colon Carcinogenesis in Rats.

Riceberry has recently been acknowledged for its beneficial pharmacological effects. Riceberry bran oil (RBBO) exhibited anti-proliferation activity in various cancer cell lines. However, animal studies of RBBO on anti-carcinogenicity and its molecular inhibitory mechanism have been limited. This study purposed to investigate the chemopreventive effects of RBBO on the carcinogen-induced liver and colorectal carcinogenesis in rats. Rats were injected with diethylnitrosamine (DEN) and 1,2-dimethylhydrazine (DMH) and further orally administered with RBBO equivalent to 100 mg/kg body weight of γ-oryzanol 5 days/week for 10 weeks. RBBO administration suppressed preneoplastic lesions including hepatic glutathione S-transferase placental form positive foci and colorectal aberrant crypt foci. Accordingly, RBBO induced hepatocellular and colorectal cell apoptosis and reduced pro-inflammatory cytokine expression. Interestingly, RBBO effectively promoted the alteration of gut microbiota in DEN- and DMH-induced rats, as has been shown in the elevated Firmicutes/Bacteroidetes ratio. This outcome was consistent with an increase in butyrate in the feces of carcinogen-induced rats. The increase in butyrate reflects the chemopreventive properties of RBBO through the mechanisms of its anti-inflammatory properties and cell apoptosis induction in preneoplastic cells. This would indicate that RBBO containing γ-oryzanol, phytosterols, and tocols holds significant potential in the prevention of cancer.