Light-Induced Clusterization of Gold Nanoparticles: A New Photo-Triggered Antibacterial against E. coli Proliferation.

Metallic nanoparticles show plasmon resonance phenomena when irradiated with electromagnetic radiation of a suitable wavelength, whose value depends on their composition, size, and shape. The damping of the surface electron oscillation causes a release of heat, which causes a large increase in local temperature. Furthermore, this increase is enhanced when nanoparticle aggregation phenomena occur. Local temperature increase is extensively exploited in photothermal therapy, where light is used to induce cellular damage. To activate the plasmon in the visible range, we synthesized 50 nm diameter spherical gold nanoparticles (AuNP) coated with polyethylene glycol and administered them to an E. coli culture. The experiments were carried out, at different gold nanoparticle concentrations, in the dark and under irradiation. In both cases, the nanoparticles penetrated the bacterial wall, but a different toxic effect was observed; while in the dark we observed an inhibition of bacterial growth of 46%, at the same concentration, under irradiation, we observed a bactericidal effect (99% growth inhibition). Photothermal measurements and SEM observations allowed us to conclude that the extraordinary effect is due to the formation, at low concentrations, of a light-induced cluster of gold nanoparticles, which does not form in the absence of bacteria, leading us to the conclusion that the bacterium wall catalyzes the formation of these clusters which are ultimately responsible for the significant increase in the measured temperature and cause of the bactericidal effect. This photothermal effect is achieved by low-power irradiation and only in the presence of the pathogen: in its absence, the lack of gold nanoparticles clustering does not lead to any phototoxic effect. Therefore, it may represent a proof of concept of an innovative nanoscale pathogen responsive system against bacterial infections.

Influence of vitamin D metabolites on vitamin D status, immunity and gut health of piglets.

Immediately post-weaning, piglets are prone to gastrointestinal infectious diseases. The active metabolite of vitamin D 1,25-dihydroxyvitamin D has direct impact on immune cell function and responses. Thus, a low vitamin D status may compromise the immune responses during infectious diseases. The aim of this study was to examine the effect of supplementation of different forms of vitamin D (25-OH-D3 and vitamin D3) to suckling piglets' vitamin D status at weaning. In addition, to determine whether the vitamin D status could affect the immune development in piglets and their robustness against E. coli challenge. Genetically E. coli F4 susceptible litters of piglets were divided into two treatment groups: group 1 (n = 16) provided milk formula supplemented with vitamin D3 (CON), and group 2 (n = 16) provided milk formula supplemented with 25-OH-D3 (TREAT). Piglets were offered the experimental milk formulas from day 3 after farrowing until weaning (at day 28 of age). A commercial weaner diet with high protein content were provided to induce weaning stress. Milk formulas, sow and weaner diets as well as plasma and milk samples obtained from sows (n = 8) were analysed for vitamin D metabolites. Vitamin D status in piglets was investigated by collection of plasma samples on day 3, 15, 28 and 35 of age. Eight piglets randomly selected from each dietary group (in total 16 pigs) were inoculated with E. coli F4 O149 on day 2 and 3 post-weaning. Blood samples collected on day 2 and 9 post-weaning (pre- and post E. coli inoculation, respectively) were analysed for haematological and immunological parameters including immunoglobulins, antibodies specific to E. coli O149 K88, cytokines and C-reactive protein. In addition, intestinal samples were obtained one week after E. coli inoculation to study the influence of infection and vitamin D status on immune responses at different sites of the intestine. This was accomplished by gene expression of various cytokines and tight junction proteins. In general, vitamin D status of the piglets were low. However, piglets provided TREAT during the suckling period had increased vitamin D status at weaning compared to piglets provided CON. Vitamin D was used during activation of the immune system as pigs inoculated with E. coli had lower plasma concentrations of 25-OH-D3 than non-inoculated pigs possibly due to mobilising of vitamin D in the liver. Hence, increased vitamin D status at weaning might improve piglets' resistance to E. coli infection.

Transcriptome Analysis Reveals the Multiple Functions of pBD2 in IPEC-J2 Cells against E. coli.

Defensins play an important role in fighting bacteria, and are a good candidate for bactericidal agents. However, the function and mechanism of defensins in regulating host responses against bacteria is unclear. In this study, transcriptome analysis was used to study the comprehensive functions of pBD2 in IPEC-J2 cells against E. coli. In total, 230 differentially expressed genes (DEGs) were identified in IPEC-J2 cells between the control and E. coli groups, and were found by KEGG analysis to be involved in many signaling pathways related to immunity. Furthermore, 812 DEGs were observed between E. coli and E. coli +pBD2 groups, involved in the ribosome, oxidative phosphorylation, and certain disease pathways. Among these, 94 overlapping DEGs were in the two DEG groups, and 85 DEGs were reverse expression, which is involved in microRNA in cancer, while PTEN and CDC6 were key genes according to PPI net analysis. The results of qRT-PCR verified those of RNA-seq. The results indicated that pBD2 plays an important role against E. coli by acting on the genes related to immune response, cell cycle, ribosomes, oxidative phosphorylation, etc. The results provide new insights into the potential function and mechanism of pBD2 against E. coli. Meanwhile, this study provides a certain theoretical basis for research and the development of novel peptide drugs.

Recombinant porcine beta defensin 2 alleviates inflammatory responses induced by Escherichia coli in IPEC-J2 cells.

pBD2 is one of the porcine beta defensins with broad antimicrobial activity, and plays an important role in immune regulation. However, the activities and mechanisms of pBD2 regulating host resistance to Escherichia coli infection are unclear. In this study, the immunomodulatory activity and mechanisms of recombinant pBD2 against Escherichia coli infection were explored in IPEC-J2 cells. Recombinant pBD2 had no obvious effect on the growth of cells below 80 µg/mL, however, it reduced the number of E. coli adhering to cells. Furthermore, pBD2 restored the abnormal expression of ZO-1 and occludin in cells challenged with E. coli. pBD2 treatment also reduced cell apoptosis and decreased the expression of the apoptosis-related genes Cox-2 and Caspase-3, and decreased the expression of the pro-inflammatory IL-6, IL-8, IL-1α and TNF-α, and Cxcl2 and Ccl20. pBD2 also reduced the expression of TAK1, and inhibited the phosphorylation of NF-κB p65 following E. coli infection. In addition, pBD2 was localized in the cytoplasm. Collectively, pBD2 appeared to penetrate cells and alleviate inflammatory responses via the TAK1-NF-κB signaling pathway. Our results revealed the immunomodulatory activity of recombinant pBD2 against E. coli and provided insights into the molecular mechanisms that protected cells from E. coli infection.

A Double-Blind, Randomized Intervention Study on the Effect of a Whey Protein Concentrate on E. coli-Induced Diarrhea in a Human Infection Model.

Infectious diseases are a major cause of morbidity and mortality worldwide. Nutritional interventions may enhance resistance to infectious diseases or help to reduce clinical symptoms. Here, we investigated whether a whey protein concentrate (WPC) could decrease diarrheagenic Escherichia coli-induced changes in reported stool frequency and gastrointestinal complaints in a double-blind, parallel 4-week intervention study. Subjects were randomly assigned to a whey hydrolysate placebo group, a low-dose WPC group or a high-dose WPC group. After 2 weeks of consumption, subjects (n = 121) were orally infected with a high dose of live but attenuated diarrheagenic E. coli (strain E1392/75-2A; 1E10 colony-forming units). Subjects recorded information on stool consistency and the frequency and severity of symptoms in an online diary. The primary outcome parameters were a change in stool frequency (stools per day) and a change in Gastrointestinal Symptom Rating Scale (GSRS) diarrhea score between the first and second days after infection. Neither dose of the whey protein concentrate in the dietary treatment affected the E. coli-induced increase in stool frequency or GSRS diarrhea score compared to placebo treatment. The composition of the microbiota shifted between the start of the study and after two weeks of consumption of the products, but no differences between the intervention groups were observed, possibly due to dietary guidelines that subjects had to adhere to during the study. In conclusion, consumption of the whey protein concentrate by healthy adults did not reduce diarrhea scores in an E. coli infection model compared to a whey hydrolysate placebo control.

Escherichia coli O103 outbreak associated with minced celery among hospitalized individuals in Victoria, British Columbia, 2021.

Background: In April 2021, a Shiga toxin-producing Escherichia coli (E. coli) (STEC) O103 outbreak was identified among patients at two hospitals in Victoria, British Columbia (BC). The objective of this study is to describe this outbreak investigation and identify issues of food safety for high-risk products prepared for vulnerable populations. Methods: Confirmed cases of E. coli O103 were reported to the Island Health communicable disease unit. The provincial public health laboratory conducted whole genome sequencing on confirmed case isolates, as per routine practice for STEC in BC. Exposure information was obtained through case interviews and review of hospital menus. Federal and local public health authorities conducted an inspection of the processing plant for the suspect source. Results: Six confirmed cases of E. coli O103 were identified, all related by whole genome sequencing. The majority of cases were female (67%) and the median age was 61 years (range 24-87 years). All confirmed cases were inpatients or outpatients at two hospitals and were exposed to raw minced celery within prepared sandwiches provided by hospital food services. A local processor supplied the minced celery exclusively to the two hospitals. Testing of product at the processor was infrequent, and chlorine rinse occurred before mincing. The spread of residual E. coli contamination through the mincing process, in addition to temperature abuse at the hospitals, are thought to have contributed to this outbreak. Conclusion: Raw vegetables, such as celery, are a potential source of STEC and present a risk to vulnerable populations. Recommendations from this outbreak include more frequent testing at the processor, a review of the chlorination and mincing process and a review of hospital food services practices to mitigate temperature abuse.

Passive immunotherapy using chicken egg yolk antibody (IgY) against diarrheagenic E. coli: A systematic review and meta-analysis.

BACKGROUND: Animal diarrhea due to diarrheagenic Escherichia coli (E. coli) has been a major concern in the field of livestock farming leading to a severe loss of domesticated animals. This systematic review aims to analyze medical shreds of evidence available in the literature and to discover the effect of IgY in treatment and protection against E. coli diarrhea. METHODS AND RESULTS: Research reports that aimed to evaluate the effect of IgY against E. coli diarrhea were searched and collected from several databases (Science Direct, Springer link, Wiley, T&F). The collected studies were screened based on the inclusion criteria. 19 studies were identified and included in the meta-analysis. The pooled relative risk ratios were calculated for the studies and found to be statistically significant to support the therapeutic effect of IgY against E. coli diarrhea but the 95% confidence interval of a majority of studies includes a relative risk of 1. This variability between the effect of IgY in the overall estimate and individual studies accounts due to the presence of methodological heterogeneity. In addition, subgroup analysis revealed the grounds for heterogeneity. CONCLUSIONS: This systematic review and meta-analysis provide concrete evidence for the favorable effect of IgY as a prophylactic and therapeutic modality against E. coli diarrhea. Yet, more research pieces of evidence with standardized animal studies aimed to utilize IgY against E. coli are vital. Further studies and trials on human subjects could open new perspectives in the application IgY as a therapeutic agent.

Epidemiology of Invasive Escherichia coli Infection and Antibiotic Resistance Status Among Patients Treated in US Hospitals: 2009-2016.

BACKGROUND: Published data is limited on the prevalence and risk of recurrence of extraintestinal invasive Escherichia coli infections (IEIs) in the United States. METHODS: The analysis included all inpatient and hospital-based outpatient visits occurring between 2009 and 2016 at hospitals with continuous microbiology data submission to the Premier Healthcare Database for 90 days before and 12 months after the admission or visit. IEI was defined as having positive E. coli culture from a normally sterile site (eg, blood, cerebrospinal fluid). The prevalence of IEI, 12-month risk of recurrent IEI, and antibiotic resistance were assessed. RESULTS: Overall, 144 944 725 hospital visits among 37 207 510 patients were analyzed, and 71 909 IEI events occurred in 67 583 patients, corresponding to an IEI prevalence of 0.50 events per 1000 visits and 1.82 events per 1000 patients. Recurrence was common: 26.9 per 1000 patients had a recurrent IEI in the 12 months after their infection. Most infections were community acquired (66.4%), and urosepsis was most common clinical syndrome (66.0%). The 30-day risk of IEI among patients undergoing transrectal ultrasound-guided prostate biopsy was high: 5.03 events per 1000 patients. Among all IEI cases with antibiotic susceptibility testing, 9.18% were resistant to extended-spectrum cephalosporins, 28.22% to fluoroquinolones, and 0.14% to carbapenems. Resistance to extended-spectrum cephalosporins increased from 5.46% to 12.97% during the 8-year study period. CONCLUSIONS: This real-world study indicates a substantial burden of IEI and recurrent IEI exists in the United States, as well as increasing resistance to extended-spectrum cephalosporins. Future research should explore risk factors of recurrent IEI aiming to effectively prevent such infections.

Dietary Soluble and Insoluble Fiber With or Without Enzymes Altered the Intestinal Microbiota in Weaned Pigs Challenged With Enterotoxigenic E. coli F18.

Post-weaning diarrhea caused by enterotoxigenic E. coli (ETEC) causes significant economic losses for pig producers. This study was to test the hypotheses that an ETEC challenge disrupts intestinal microbial homeostasis and the inclusion of dietary soluble (10% sugar beet pulp) or insoluble fiber (15% corn distillers dried grains with solubles) with or without exogenous carbohydrases will protect or restore the gut microbial homeostasis in weaned pigs. Sixty crossbred piglets (6.9 ± 0.1 kg) were blocked by body weight and randomly assigned to one of six treatments (n = 10), including a non-challenged control (NC), ETEC F18-challenged positive control (PC), ETEC-challenged soluble fiber without (SF-) or with carbohydrases (SF+), and ETEC-challenged insoluble fiber without (IF-) or with carbohydrases (IF+). Pigs were housed individually and orally received either ETEC inoculum or PBS-sham inoculum on day 7 post-weaning. Intestinal contents were collected on day 14 or 15. The V4 region of the bacterial 16S rRNA was amplified and sequenced. High-quality reads (total 6,671,739) were selected and clustered into 3,330 OTUs. No differences were observed in α-diversity among treatments. The ileal microbiota in NC and PC had modest separation in the weighted PCoA plot; the microbial structures were slightly altered by SF+ and IF- compared with PC. The PC increased ileal Escherichia-Shigella (P < 0.01) and numerically decreased Lactobacillus compared to NC. Predicted functional pathways enriched in the ileal microbiota of PC pigs indicated enhanced activity of Gram-negative bacteria, in agreement with increased Escherichia-Shigella. The SF+ tended to decrease (P < 0.10) ileal Escherichia-Shigella compared to PC. Greater abundance of ileal Streptococcus, Turicibacter, and Roseburia and colonic Prevotella were observed in SF- and SF+ than PC (P < 0.05). Pigs fed IF + had greater Lactobacillus and Roseburia than PC pigs (P < 0.05). The ETEC challenge reduced total volatile fatty acid (VFA) compared with NC (P < 0.05). The SF+ tended to increase (P < 0.10) and SF- significantly increased (P < 0.05) colonic total VFA compared with PC. Collectively, ETEC challenge disrupted gut microbial homeostasis and impaired microbial fermentation capacity. Soluble fiber improved VFA production. Dietary fiber and carbohydrases altered microbiota composition to maintain or restore microbial homeostasis.

Phloretin Protects Macrophages from E. coli-Induced Inflammation through the TLR4 Signaling Pathway.

Macrophages are the cells of the first-line defense system, which protect the body from foreign invaders such as bacteria. However, Gram-negative bacteria have always been the major challenge for macrophages due to the presence of lipopolysaccharides on their outer cell membrane. In the present study, we evaluated the effect of phloretin, a flavonoid commonly found in apple, on the protection of macrophages from Escherichia coli infection. RAW 264.7 cells infected with standard E. coli, or virulent E. coli K1 strain were treated with phloretin in a dose-dependent manner to examine its efficacy in protection of macrophages. Our results revealed that phloretin treatment reduced the production of nitric oxide (NO) and generation of reactive oxygen species along with reducing the secretion of proinflammatory cytokines induced by the E. coli and E. coli K1 strains in a concentration-dependent manner. Additionally, treatment of phloretin downregulated the expression of E. coli-induced major inflammatory markers i.e. cyclooxygenase-2 (COX-2) and hemeoxygenase-1 (HO-1), in a concentration dependent manner. Moreover, the TLR4-mediated NF-κB pathway was activated in E. coli-infected macrophages but was potentially downregulated by phloretin at the transcriptional and translational levels. Collectively, our data suggest that phloretin treatment protects macrophages from infection of virulent E. coli K1 strain by downregulating the TLR4-mediated signaling pathway and inhibiting NO and cytokine production, eventually protecting macrophages from E. coli-induced inflammation.

Dysregulation of Lipid Metabolism in Mkp-1 Deficient Mice during Gram-Negative Sepsis.

Mitogen-activated protein kinase phosphatase (Mkp)-1 exerts its anti-inflammatory activities during Gram-negative sepsis by deactivating p38 and c-Jun N-terminal kinase (JNK). We have previously shown that Mkp-1+/+ mice, but not Mkp-1-/- mice, exhibit hypertriglyceridemia during severe sepsis. However, the regulation of hepatic lipid stores and the underlying mechanism of lipid dysregulation during sepsis remains an enigma. To understand the molecular mechanism underlying the sepsis-associated metabolic changes and the role of Mkp-1 in the process, we infected Mkp-1+/+ and Mkp-1-/- mice with Escherichia coli i.v., and assessed the effects of Mkp-1 deficiency on tissue lipid contents. We also examined the global gene expression profile in the livers via RNA-seq. We found that in the absence of E. coli infection, Mkp-1 deficiency decreased liver triglyceride levels. Upon E. coli infection, Mkp-1+/+ mice, but not Mkp-1-/- mice, developed hepatocyte ballooning and increased lipid deposition in the livers. E. coli infection caused profound changes in the gene expression profile of a large number of proteins that regulate lipid metabolism in wildtype mice, while these changes were substantially disrupted in Mkp-1-/- mice. Interestingly, in Mkp-1+/+ mice E. coli infection resulted in downregulation of genes that facilitate fatty acid synthesis but upregulation of Cd36 and Dgat2, whose protein products mediate fatty acid uptake and triglyceride synthesis, respectively. Taken together, our studies indicate that sepsis leads to a substantial change in triglyceride metabolic gene expression programs and Mkp-1 plays an important role in this process.

Radiosynthesis and Biodistribution of 99mTc-Metronidazole as an Escherichia coli Infection Imaging Radiopharmaceutical.

Bacterial infection poses life-threatening challenge to humanity and stimulates to the researchers for developing better diagnostic and therapeutic agents complying with existing theranostic techniques. Nuclear medicine technique helps to visualize hard-to-diagnose deep-seated bacterial infections using radionuclide-labeled tracer agents. Metronidazole is an antiprotozoal antibiotic that serves as a preeminent anaerobic chemotherapeutic agent. The aim of this study was to develop technetium-99m-labeled metronidazole radiotracer for the detection of deep-seated bacterial infections. Radiosynthesis of 99mTc-metronidazole was carried by reacting reduced technetium-99m and metronidazole at neutral pH for 30 min. The stannous chloride dihydrate was used as the reducing agent. At optimum radiolabeling conditions, ~ 94% radiochemical was obtained. Quality control analysis was carried out with a chromatographic paper and instant thin-layer chromatographic analysis. The biodistribution study of radiochemical was performed using Escherichia coli bacterial infection-induced rat model. The scintigraphic study was performed using E. coli bacterial infection-induced rabbit model. The results showed promising accumulation at the site of infection and its rapid clearance from the body. The tracer showed target-to-non-target ratio 5.57 ± 0.04 at 1 h post-injection. The results showed that 99mTc-MNZ has promising potential to accumulate at E. coli bacterial infection that can be used for E. coli infection imaging.

Young Pigs Consuming Lysozyme Transgenic Goat Milk Are Protected from Clinical Symptoms of Enterotoxigenic Escherichia coli Infection.

Background: Diarrheal diseases in infancy and childhood are responsible for substantial morbidity and mortality in developing nations. Lysozyme, an antimicrobial component of human milk, is thought to play a role in establishing a healthy intestinal microbiota and immune system. Consumption of breast milk has been shown to prevent intestinal infections and is a recommended treatment for infants with diarrhea.Objective: This study aimed to examine the ability of lysozyme-rich goat milk to prevent intestinal infection.Methods: Six-week-old Hampshire-Yorkshire pigs were assigned to treatment groups balanced for weight, sex, and litter and were fed milk from nontransgenic control goats (GM group) or human lysozyme transgenic goats (hLZM group) for 2 wk before they were challenged with porcine-specific enterotoxigenic Escherichia coli (ETEC). Fecal consistency, complete blood counts, intestinal histology, and microbial populations were evaluated.Results: Pigs in the hLZM group had less severe diarrhea than did GM pigs at 24 and 48 h after ETEC infection (P = 0.01 and 0.05, respectively), indicating a less severe clinical disease state. Relative to baseline, postmilk hLZM pigs had 19.9% and 137% enrichment in fecal Bacteroidetes (P = 0.028) and Paraprevotellaceae (P = 0.003), respectively, and a 93.8% reduction in Enterobacteriaceae (P = 0.007), whereas GM pigs had a 60.9% decrease in Lactobacillales (P = 0.003) and an 83.3% enrichment in Burkholderiales (P = 0.010). After ETEC infection, hLZM pigs tended to have lower amounts (68.7% less) of fecal Enterobacteriaceae than did GM pigs (P = 0.058). There were 83.1% fewer bacteria translocated into the mesenteric lymph nodes of hLZM pigs than into those of GM pigs (P = 0.039), and hLZM pigs had 34% lower mucin 1 and 61% higher tumor necrosis factor-α expression in the ileum than did GM pigs (P = 0.046 and 0.034, respectively).Conclusion: Results of this study indicate that human lysozyme milk consumption before and during ETEC infection has a positive effect on clinical disease, intestinal mucosa, and gut microbiota in young pigs.

Ex vivo and in vivo evaluation of microemulsion based transdermal delivery of E. coli specific T4 bacteriophage: A rationale approach to treat bacterial infection.

This study is focused on the development and evaluation of transdermal delivery of E. coli-specific T4 bacteriophages both ex-vivo and in-vivo using microemulsion as delivery carrier in eradicating the infection caused by E. coli. Microemulsions were prepared by mixing selected oil, surfactants and aqueous phase containing bacteriophages. The formulations were subjected to physicochemical characterization, ex-vivo and in-vivo permeation, stability studies, histological and immunofluorescence examination. The colloidal system exhibits a uniform size distribution, of finite size (150-320nm). Transmission electron microscopy revealed the encapsulation of bacteriophage in the aqueous globule. Ex-vivo permeation across skin was successfully achieved as 6×106PFU/mL and 6.7×106PFU/mL of T4 permeated from ME 6% and 10%, respectively. ME 6% was found to be thermodynamically stable and in-vivo permeation resulted in 5.49×105PFU/mL of bacteriophages in the blood of the E. coli challenged rats, while 2.48×105PFU/mL was detected in germ free rats, at the end of the study. Infected rats that were treated with bacteriophage were survived while significant mortality was observed in others. Histological and IL-6 immunofluorescence examination of the tissues revealed the efficacy/safety of the therapy. The microemulsion-based transdermal delivery of bacteriophage could be a promising approach to treat the infections caused by antibiotic-resistant bacteria.

Efficacy of Bacillus subtilis and bacitracin methylene disalicylate on growth performance, digestibility, blood metabolites, immunity, and intestinal microbiota after intramuscular inoculation with Escherichia coli in broilers.

This experiment was conducted to evaluate the effect of Bacillus subtilis (BS) on broiler performance and health after intramuscular inoculation with E. coli and compare its effect with a growth promoter antibiotic. In a completely randomized design manner, 360 male Ross 308 chicks were divided into 6 treatments and 5 replicates of 12 chicks in each replicate. Experimental treatments included control diet, control + E. coli (0.5 mL of culture containing 108 CFU of E. coli/ml), control + 0.1% BS, control + 0.05% bacitracin methylene disalicylate (BMD), control + E. coli and BS, and control + E. coli and BMD in a factorial arrangement (3 × 2). Addition of BMD or BS to the control diet significantly (P < 0.01) increased body weight and decreased FCR, but E. coli challenge adversely reduced (P < 0.01) body weight and increased FCR, so that the addition of BMD or BS did not compensate growth reduction. E. coli challenged chicks had the lowest vaccine titers for ND, IB, AI, and IBD and the highest were observed in chicks fed BS. The E. coli challenge significantly (P < 0.01) increased albumin, globulin, cholesterol, triglyceride, LDL, ALT, and ALP indices. Addition of BMD and BS decreased albumin and globulin in challenged chick's plasma but had no effect on plasma lipid profile concentration. The E. coli challenge decreased villus height and increased crypt depth and goblet cell numbers significantly (P < 0.01). In birds subjected to BMD or BS, crypt depth decreased and villus height increased (P < 0.01), compared with the control diet. Challenge of E. coli significantly (P < 0.01) increased the bacterial population of E. coli, coliforms, and Salmonella in cecal parts of broilers' intestines. In challenged birds receiving BMD or BS, E. coli, coliform, and Salmonella populations of ceca showed a significant (P < 0.01) reduction. Both BMD and BS increased the digestibility of nutrients significantly (P < 0.01), but a reduction was observed in E. coli challenged groups. Results of the study suggest that spore-forming probiotics are partially effective in unsuitable rearing situations such as colibacillosis in which the load of harmful bacteria is high.

Technetium-99m-Labeled Sulfadiazine: a Targeting Radiopharmaceutical for Scintigraphic Imaging of Infectious Foci Due To Escherichia coli in Mouse and Rabbit Models.

Bacterial infection is one of the vital reasons of morbidity and mortality, especially in developing countries. It appears silently without bothering the geological borders and imposes a grave threat to humanity. Nuclear medicine technique has an important role in helping early diagnosis of deep-seated infections. The aim of this study was to develop a new radiopharmaceutical 99mTc-labeling sulfadiazine as an infection imaging agent. Radiolabeling of sulfadiazine with technetium-99m (99mTc) was carried out using stannous tartrate as a reducing agent in the presence of gentistic acid at pH = 5. The quality control tests revealed ~98% labeling efficiency. Paper chromatographic (PC) and instant thin-layer chromatographic (ITLC) techniques were used to analyze radiochemical yield. Biodistribution and infection specificity of the radiotracer were performed with Escherichia coli (E. coli) infection-induced rats. Scintigraphy and glomerular filtration rate (GFR) study was performed in E. coli-infected rabbits. Scintigraphy indicated E. coli infection targeting potential of 99mTc-SDZ, while biodistribution study showed minimal uptake of 99mTc-SDZ in non-targeted tissues. The uptake in the kidneys was found 2.56 ± 0.06, 2.09 ± 0.10, and 1.68 ± 0.09% at 30 min, 1 h, and 4 h, respectively. The infected muscle (target) to non-infected muscle (non-target) ratio (T/NT) was found 4.49 ± 0.04, 6.78 ± 0.07, and 5.59 ± 0.08 at 30 min, 1 h, and 4 h, respectively.

Acetylsalicylic acid supplementation improves protein utilization efficiency while vitamin E supplementation reduces markers of the inflammatory response in weaned pigs challenged with enterotoxigenic E. coli.

BACKGROUND: This experiment was conducted to test the hypothesis that vitamin E (Vit E) and acetylsalicylic acid (ASA), a cyclooxygenase-2 (COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E2 (PGE2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli. METHODS: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs (Landrace × Large White) weighing 6.6 ± 0.04 kg (mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation (50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate). RESULTS: Acetylsalicylic acid supplementation improved average daily gain (P < 0.05) and tended to improve feed:gain ratio (P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved (P < 0.001) amino acid utilization efficiency (as assessed by plasma urea level) and tended to decrease (P < 0.10) PGE2 production in the liver without affecting small intestinal histology and tight junction protein mRNA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration (P < 0.001) and plasma haptoglobin content (P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs. CONCLUSIONS: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE2 and inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli.

High cell selectivity and low-level antibacterial resistance of designed amphiphilic peptide G(IIKK)(3)I-NH(2).

On the basis of cell cultures involving bacterial strains (Escherichia coli 5α and Bacillus subtilis 168) and a mammalian cell line (NIH 3T3), the potent antibacterial activity and distinct selectivity from designed amphiphilic peptides G(IIKK)nI-NH2 (n = 2-4) have been demonstrated. This work extends these studies to multidrug resistant pathogens (ESBL-producing E. coli) and primary human cells (HDFa), followed by the in vivo mouse model investigation of ESBL-producing bacterial infection. G(IIKK)3I-NH2 exhibits high antibacterial activity against the pathogenic strain both in vitro and in vivo while displaying low toxicity toward the primary cells and the mice. Peptide molecules can kill bacteria by selectively interacting with bacterial membranes, causing structural disruptions. Furthermore, multidrug resistant ESBL-producing bacteria do not develop resistance after multiple treatments with G(IIKK)3I-NH2. The high cellular selectivity, low toxicity toward mammalian hosts and noninducing bacterial resistance indicate great potential for developing the peptides as anti-infection agents.

The immunopotentiating effects of shark-derived protein hydrolysate.

OBJECTIVE: Peptides derived from natural sources can act as immunomodulating agents and prevent infections. The aim of this study was to investigate the immunopotentiating and protective effects of a shark-derived protein hydrolysate (SPH) against an enterotoxigenic Escherichia coli H10407 infection in a murine model. METHODS: Mice were fed an aqueous solution of SPH for 7 days before being inoculated with an experimental enterotoxigenic Escherichia coli H10407 infection. After euthanasia, small intestines were removed for histological study and the number of IgA and IgG producing cells was determined by direct immunofluorescence. Cytokines were measured in the serum and the intestinal fluid. RESULTS: The oral administration of SPH enhanced the gut barrier function via up-regulation of immunoglobulin A-producing cells and intestinal cytokines production, including interleukin-6 and tumor necrosis factor-α. The increase of transforming growth factor-ß and interleukin-10 contribute to the down-regulation of uncontrolled-inflammatory reaction induced by E. coli infection. From these results, the anti-inflammatory properties of SPH may be caused by regulation and priming mechanisms of the immune system. CONCLUSION: Enzymatic protein degradation confers immunomodulating and protective potentials to shark proteins and the resulted peptides could be used as an alternative therapy to reduce the risk of bacterial infections and inflammatory-related diseases.