Growth Of Clostridium Perfringens Research Articles

The impact of indole and mucin on sporulation, biofilm formation, and enterotoxin production in foodborne Clostridium perfringens.

Indole and mucin are compounds found in the host environment as they are produced by the host or by the host-associated microbiota. This study investigated whether indole and mucin impact Clostridium perfringens growth and sporulation, as well as enterotoxin production and biofilm formation. There was no impact on growth of Cl. perfringens for up to 400µM indole and 240mg/l mucin, and neither indole nor mucin affected sporulation. Reverse-transcriptase qPCR showed that mucin strongly upregulated the expression of Cl. perfringens enterotoxin (up to 121-fold increase), whereas indole had a much more modest effect (2-fold). This was also reflected in increased Cl. perfringens enterotoxin levels in mucin-treated Cl. perfringens (as assessed by a reversed passive latex agglutination assay). Finally, mucin and indole significantly increased biofilm formation of Cl. perfringens, although the effect size was relatively small (less than 1.5 fold). These results indicate that Cl. perfringens can sense its presence in a host environment by responding to mucin, and thereby markedly increased enterotoxin production.

Effect of allyl isothiocyanate on the growth and virulence of Clostridium perfringens and its application on cooked pork

The objective of this study is to explore the antibacterial action modes and virulence-inhibitory effects of allyl isothiocyanate (AITC) against Clostridium perfringens (C. perfringens). The minimum inhibitory concentration (MIC) of AITC against vegetative cells of Cp 13124 was 0.1 μL/mL, and the time-kill kinetics analysis revealed that AITC could significantly suppress the growth of Cp 13124. According to the results from scanning electron microscopy (SEM), fluorescence microscopy, and UV absorbance substance detection, the cell membrane of Cp 13124 was damaged upon AITC treatment, causing a loss of integrity and the release of intracellular substances. Meanwhile, the fluorescence quenching experiment indicated the interaction of AIT-C with membrane proteins, which caused changes in the conformation of membrane proteins. Measurement of reactive oxygen species (ROS) and flow cytometry analysis demonstrated that AITC could induce apoptosis through oxidative stress. The formation of Cp 13124 biofilms was inhibited by AITC using the crystalline violet method, which was possibly related to the inhibition of sliding motility. Finally, low concentrations of AITC could be used as an antibacterial agent to inhibit the outgrowth of Cp 13124 in cooked pork, suggesting that AITC is a promising candidate for novel preservatives in the meat business.

Mathematical modeling of temperature and natural antimicrobial effects on germination and outgrowth of Clostridium perfringens in chilled chicken

Effects of ginger essential oil (GEO) and grape seed extract (GSE) treatments on germination and growth of Clostridium perfringens spores in chicken after linear cooling and isothermal storage were evaluated. GEO or GSE (1%) can properly inhibit the germination and growth of C. perfringens spores during cooling from 50 °C to 4 °C. The kinetic models of Gompertz and Rat-kowskyt were carried out to describe the spore germination and growth of C. perfringens in GEO- and GSE-treated chickens at 15 °C–45 °C. Results showed a high degree of fit. The addition of GEO and GSE increased the lag phase at all storage temperatures (λ), decreased the growth rate (Rmax), and extended the time it took to rise by 1 lg of bacteria in chicken compared with the control group. GSE demonstrated stronger inhibitory activity than GEO at the corresponding storage temperature. The models provided a cost-effective and fast technology for replacing traditional culture methods and evaluating the effect of temperature and plant extracts on the shelf life of meat.

Abstract 13988: A Devastating Case of Clostridial Infective Endocarditis

Introduction: Cardiac necrotizing soft tissue infections (NSTI) have been scarcely reported in the literature. We present a rare case of a disseminated NSTI with myocardial involvement secondary to embolic phenomena from emphysematous infective endocarditis (IE). Case presentation: 73-year-old female on dialysis with atrial fibrillation and diabetes mellitus was transferred for multifocal strokes evidenced on magnetic resonance imaging. Presented with leukocytosis, lactic acidosis, acute liver failure, and right upper extremity (RUE) NSTI. She was started on antibiotics and vasopressors and taken emergently to the operating room for RUE amputation. Following surgery, an electrocardiogram revealed anterior STEMI. Bedside transthoracic echocardiogram noted a severely reduced ejection fraction and a mitral valve vegetation. Computed tomography of head and chest revealed pneumomyocardium, portal venous gas, and pneumocephalus. Blood cultures revealed growth of Clostridium perfringens. With severe multi-organ failure and a poor prognosis, comfort care was elected, and the patient expired. Figures: A: RUQ subcutaneous gas. B: Chest wall gas. C: pneumocephalus. D: pneumomyocardium. E: MV vegetation. Discussion: Septic embolization is a devastating sequela of IE. Vegetations > 1cm have increased embolic potential and all-cause mortality. The most common site of embolization is the central nervous system; however, coronary embolization can also occur. Clostridial endocarditis is rare, despite being documented as the first cause of anaerobic IE. Mortality rate of clostridial NSTI and shock exceeds 50%. Source control and rapid identification of infection are paramount for treatment success. A multidisciplinary approach should be employed when treating Clostridial infections, specifically endocarditis. Our case highlights the need for prompt recognition of IE and the interplay of multimodal imaging in the diagnosis of disseminated infection.

Production of nitrite-free frankfurter-type sausages by combining ε-polylysine with beetroot extracts: An assessment of microbial, physicochemical , and sensory properties

The current study investigated the utilization of ε-polylysine (ε-PL) and beetroot extract (BE) as suitable nitrite substitutes in frankfurter-type sausages packaged in vacuum polyethylene bags. The sample's technological, safety, antimicrobial, and organoleptic attributes were analyzed during 30 days of storage at 4 °C. Compared with controls, the sausages containing ϵ-PL with BE had no significant differences in the water activity and proximate composition. The results showed that the T5 and T4 samples had the highest residual nitrite and total phenolic contents at day 45. Incorporating ε-PL and BE into frankfurter-type sausages prevented the increase of pH and maintained samples' pink color and texture consistency during storage. T3 and T4 samples could effectively delay the growth of total viable count, coliform, Clostridium perfringens, mold, and yeasts within acceptable limitations during refrigerated storage.

A case of severe intravascular haemolysis.

An 80-year-old man, who had a history of hypertension, diabetes, ischaemic heart disease and Klebsiella liver abscess with drainage performed 15 years ago, was admitted for right-sided abdominal pain and symptomatic anaemia. Initial blood tests showed anaemia (88 g/L), leukocytosis (32.4 × 10 9 /L), mildly deranged renal function tests and elevated total bilirubin to 178 µmol/L. Peripheral blood smear (Figure 1) showed marked spherocytosis and moderate polychromasia, as well as neutrophilia with toxic neutrophils and occasional myelocytes. Subsequent blood tests performed, including clotting profile, liver and renal function tests, were reported to be unfit for analysis by automated analyzers due to gross haemolysis. The centrifuged plasma from the patient (left tube (Figure 2)) showed gross haemolysis and was reddish-brown in colour, compared to the tube of centrifuged plasma obtained from a normal control on its right. An urgent computed tomography scan of the abdomen showed a liver abscess with multiple gas locules (Figure 3) with perforation into the intraperitoneal cavity. His condition deteriorated rapidly due to septic shock with severe metabolic acidosis and succumbed within 8 hours of admission despite empirical antibiotics and active resuscitation. Postmortem examination was performed. Blood culture grew Escherichia coli (E. coli), while the pus from the liver abscess yielded heavy growth of Clostridium perfringens (C. perfringens), moderate growth of E. coli and scanty growth of Klebsiella. This was a case of severe intravascular haemolysis secondary to liver abscess due to E. coli and gas-forming C. perfringens. Risk factors for C. perfringens septicaemia include diabetes, a recent history of gastrointestinal surgery and gastrointestinal malignancy [1]. It is important to have a high index of suspicion for C. perfringens septicaemia when coming across cases where blood samples are grossly haemolyzed with features of intravascular haemolysis including spherocytosis and polychromasia observed in the peripheral blood smear, as there can be rapid progression and high fatality (mortality up to ∼70%–100% [2]). Blood culture should be taken as soon as possible and sent for Gram stain, empirical antibiotics quickly administered, timely surgical intervention and aggressive supportive therapy should be provided for the best chance of cure. None. The authors declare that they have no conflict of interest. No funding has been received for this work. No reproduction of material from other sources has been utilized in the preparation of this manuscript. We comply to practice guidelines on research integrity and publishing ethics. No patient identifiable images or data have been included in the manuscript. Data sharing is not applicable to this article as no new data were created or analyzed in this manuscript.

The Broad Host Range Phage vB_CpeS_BG3P Is Able to Inhibit Clostridium perfringens Growth.

Clostridium perfringens is an important pathogen for both humans and animals, causing human foodborne disease and necrotic enteritis in poultry. In the present study, a C. perfringens-specific phage, vB_CpeS_BG3P (designated as BG3P hereafter), was isolated from chicken farm sewage. Both electron microscopy and phylogenetic analysis suggested that phage BG3P is a novel phage belonging to Siphoviridae family. Phage BG3P exhibited a broad host range against different C. perfringens isolates (90.63% of strains were infected). Sequencing of the complete genome revealed a linear double-stranded DNA (43,528 bp) with 28.65% GC content. After sequence analysis, 73 open reading frames (orfs) were predicted, of which only 13 were annotated with known functions. No tRNA and virulence encoding genes were detected. It should be noted that the protein of orf 15 has 97.92% homology to C. perfringens-specific chloramphenicol resistance protein, which has not been reported for any C. perfringens phage. Phylogenetic analysis of the ssDNA binding protein demonstrated that this phage is closely related to C. perfringens phages phiSM101 and phi3626. In considering future use as an antimicrobial agent, some biological characteristics were observed, such as a good pH (3–11) stability and moderate temperature tolerance (<60 °C). Moreover, bacteriophage BG3P showed a good antimicrobial effect against C. perfringens liquid cultures. Thus, phage treatment with MOI ≥ 100 completely inhibited bacterial growth compared to untreated cultures. Although phage BG3P shows good lytic efficiency and broad host range in vitro, future development and application may need to consider removal of the chloramphenicol-like resistance gene or exploring its lysin for future antibacterial applications.

Hydrogen-rich water partially alleviate inflammation, oxidative stress and intestinal flora dysbiosis in DSS-induced chronic ulcerative colitis mice

PurposeOxidative damage and intestinal flora dysbiosis play important roles in the progression of chronic ulcerative colitis (UC). This study explored the effect and mechanism of molecular hydrogen in chronic UC. Materials and methodsMale C57BL/6 mice (19.6 ​± ​0.4 ​g, 7 weeks) were randomly divided into 3 groups: normal control (NC) group, UC (Dextran Sulfate Sodium, DSS) group, and hydrogen-rich water (HRW, 0.8 ​ppm)-treated UC (DSS ​+ ​HRW) group. Mice in the DSS treatment group were treated with DSS for the following 3 cycles to establish chronic UC model: the first 2 cycles consisted of 2.5% DSS for 5 days, followed by drinking water for 16 days, and a third cycle consisted of 2% DSS for 4 days, followed by drinking water for 10 days. The mice in the DSS ​+ ​HRW group were administered HRW daily throughout the experiment. ResultsThe mice in the DSS groups developed typical clinical signs of colitis. HRW treatment partially ameliorated colitis symptoms, improved histopathological changes, significantly increased glutathione (GSH) concentration and decreased TNF-α level. Notably, HRW treatment significantly inhibited the growth of Enterococcus faecalis, Clostridium perfringens and Bacteroides fragilis (P ​< ​0.05 vs. DSS group), with the relative abundance that was close to the levels in the NC group. Microarray analysis revealed that 252 genes were significantly modified after HRW treatment compared with those in the DSS treatment alone group, and 17 genes were related to inflammation, including 9 interferon-stimulated genes (ISGs). ConclusionsHydrogen-rich water partially alleviates inflammation, oxidative stress and intestinal flora dysbiosis in DSS-induced chronic UC mice.

Natural Extracts as Inhibitors of Microorganisms and Lipid Oxidation in Emulsion Sausage during Storage.

Food additives are required to maintain the freshness and quality of foods, particularly meats. However, chemical additives may not be preferred by consumers, and natural materials with antimicrobial and antioxidant effects may be used as replacements for common chemical additives. Accordingly, in this study, we compared the antimicrobial and antioxidant activities of natural compounds extracted with ethanol and hot water, and emulsion sausage prepared with natural ethanol extracts was analyzed for pH, color, thiobarbituric acid reactive substances (TBARS), and Clostridium perfringens growth during storage. The antimicrobial activities of 49 natural extract candidates against Listeria monocytogenes, C. perfringens, Salmonella spp., and Escherichia coli were analyzed, and six natural materials with excellent antibacterial activities, i.e., Elaeagnus umbellata Thunb. f. nakaiana (Araki) H. Ohba, Punica granatum L., Ecklonia cava, Nelumbo nucifera Gaertner, and Schisandra chinensis (Turcz.) Baill., and Rubus coreanus Miq. were evaluated to determine their total polyphenol contents and DPPH radical scavenging activities. The total polyphenol contents of ethanol extracts were higher than those of hot water extracts, whereas DPPH radical scavenging activity was found to be higher in hot water extracts. The TBARS values of emulsion sausages were significantly increased as storage time increased, and the TBARS values of emulsion sausages prepared with natural extracts were lower than those of control sausages. Natural extract-treated emulsion sausages showed a 99% reduction in bacterial contents compared with untreated sausages on day 2, with greater than 99.9% reduction after day 3. Thus, these results demonstrated that natural extracts could have applications as natural preservatives in meat products.

Predictive model for growth of Clostridium perfringens during cooling of cooked pork supplemented with sodium chloride and sodium pyrophosphate

A dynamic model was developed to predict growth of Clostridium perfringens in cooked ground pork supplemented with salt (0–3% wt/wt) and sodium pyrophosphate (0–0.3% wt/wt) under varying temperatures. C. perfringens (NCTC 8238, NCTC 8239, and NCTC 10240) spores were heat shocked, cooled, and inoculated into ground pork. Isothermal bacterial growth was quantified with variable salt and phosphate concentrations at temperatures ranging from 15 to 51 °C. The primary Baranyi model was fitted to all C. perfringens growth profiles and gave a satisfactory fit (R2 ≥ 0.85). A quadratic polynomial secondary model was developed (P < 0.0001) to predict the maximum specific growth rate as a function of temperature, salt, and phosphate concentrations (R2 = 0.93). A dynamic model was developed and validated using growth data retrieved from 7 published studies. Thirty three out of 44 predictions were within the acceptable prediction zone (−0.5 ≤ prediction error ≤ 1.0). The developed predictive model can be used to minimize the risk of C. perfringens in pork products supplemented with additives during cooling.

Effect of combination of Oxyrase and sodium thioglycolate on growth of Clostridium perfringens from spores under aerobic incubation

Clostridium perfringens is a strictly anaerobic pathogen that requires absence of oxygen for its growth in laboratory experiments, which is usually attained by using an anaerobic chamber or anaerobic jars. However, it has been demonstrated that C. perfringens may survive for short periods of times due to its adaptive response to O2. Therefore, the objective of this study was to explore the application of Oxyrase (OX) and sodium thioglycolate (ST) as oxygen scavengers, used alone or in combination, for observation of the growth of C. perfringens under aerobic incubation.The growth of C. perfringens from spores in Schaedler Anaerobe Agar containing different levels and combinations of OX and ST was observed at temperatures between 20 and 50 °C. The kinetic parameters, including lag time, specific growth rate, and maximum cell concentrations in the stationary phase, were determined.The results indicated that ST at concentrations of 0.025 and 0.05% (w/w), although allowing eventual growth of C. perfringens, prolonged its lag times, while OX at 1.5% only allowed growth at a lower growth rate in comparison to anaerobic incubation. OX at 3% enhanced the growth of C. perfringens at temperatures between 30 and 50 °C, while higher levels of OX were needed in the medium to support the growth of C. perfringens during storage at 25 °C (>6% OX) and 20 °C (>9% OX), due to the effect of temperature on enzyme activity. No significant difference was found in the kinetic parameters of C. perfringens incubated aerobically with OX and the control (without OX or ST) in an anaerobic chamber. Therefore, OX at appropriate concentrations may allow the observation of the growth of C. perfringens under aerobic incubation conditions without the need of an anaerobic device.

The inhibitory effects of spice essential oils and rapidly prediction on the growth of Clostridium perfringens in cooked chicken breast

In this study, the effects of spices essential oils on the growth of C. perfringens were investigated. The in vitro inhibitory activities and minimum inhibitory concentrations (MIC) of different essential oils on C. perfringens were determined using the Oxford cup and two-fold dilution method. And two models (the parameter-adjusted Gompertz kinetic model, and least square support vector machine (LS-SVM) model) were used to rapidly predict the relative growth/survival of C. perfringens in cooked chicken breast under different essential oil concentrations. The results indicated that cinnamon essential oil exhibited a notable inhibitory effect on C. perfringens in vitro. Moreover, cinnamon essential oil had the lowest inhibitory concentration, and the growth of C. perfringens ceased completely at 19.12 mg/mL and 22.72 mg/mL, respectively. By comparing, the LS-SVM model is the optimum model. The prediction accuracy of the LS-SVM model was greater than 0.99, and the degree of fitting is higher than adjusted Gompertz kinetic model. The results present illustrate that the model using LS-SVM has high prediction accuracy and can be employed to predict the number of C. perfringens under different essential oils. This work could contribute to control and rapid assessment of food safety hazards of C. perfringens during meat processing.

Growth of Clostridium perfringens in cooked chicken during cooling: One-step dynamic inverse analysis, sensitivity analysis, and Markov Chain Monte Carlo simulation

The objective of this study was to determine the kinetic parameters and apply Markov Chain Monte Carlo (MCMC) simulation to predict the growth of Clostridium perfringens from spores in cooked ground chicken meat during dynamic cooling. Inoculated samples were exposed to various cooling conditions to observe dynamic growth. A combination of 4 cooling profiles was used in one-step inverse analysis with the Baranyi model as the primary model and the cardinal parameters model as the secondary model. Six kinetic parameters of the Baranyi model and the cardinal parameters model, including Q0, Ymax, μopt, Tmin, Topt, and Tmax, were estimated.The estimated Tmin, Topt, and Tmax were 14.8, 42.9, and 50.5 °C, respectively, with a μopt of 5.25 h−1 and maximum cell density of 8.4 log CFU/g. Correlation analysis showed that both Q0 and Ymax are weakly correlated to other parameters, while the remaining parameters are mostly mildly to strongly correlated with each other. Although it may be difficult to estimate highly correlated parameters using a single temperature profile, one-step analysis with multiple different temperature profiles helped estimate them successfully.The estimated parameters were used as the prior information to construct the posterior distribution for Bayesian analysis. MCMC simulation was used to predict the bacterial growth using different dynamic temperature profiles for validation of the accuracy of the predictive models. The MCMC simulation results showed that the Bayesian analysis produced more accurate predictions of bacterial growth during cooling than the deterministic method. With Bayesian analysis, the root-mean-square-error (RMSE) of prediction was only 0.1 log CFU/g with all residual errors within ±0.25 log CFU/g. Therefore, Bayesian analysis is recommended for predicting the growth of C. perfringens in cooked meat during cooling.

Lactose and Bovine Milk Oligosaccharides Synergistically Stimulate B. longum subsp. longum Growth in a Simplified Model of the Infant Gut Microbiome.

Increasing awareness of the importance of a healthy Bifidobacterium-rich microbiome has led to a need for more knowledge on how different prebiotic carbohydrates specifically impact the infant microbiome, especially as a community instead of single bacterial targets. In this study, we combined proton nuclear magnetic resonance (1H NMR) metabolomics and molecular biology methods for quantification of bacteria to compare the prebiotic effect of bovine milk oligosaccharides (BMO) and synthetic galacto oligosaccharides (GOS) using mono- and cocultures of eight major bacteria related to a healthy infant microbiome. The results revealed that BMO treatments supported growth of Bifidobacterium longum subsp. longum and Parabacteroides distasonis, while at the same time growth of Clostridium perfringens and Escherichia coli was inhibited. In addition, there was a synergistic effect of combining lactose and BMO in regards to reducing C. perfringens, maintaining stable numbers of P. distasonis and simultaneously increasing numbers of the beneficial B. longum subsp. longum. These results indicate that the oligosaccharide composition plays a vital role in shaping the developing microbiota.

Growth of Clostridium perfringens in roasted chicken and braised beef during cooling – One-step dynamic analysis and modeling

Roasted chicken (RC) and braised beef (BB) are two important commercial products widely consumed in China. Prepared with a mixture of different spices and other ingredients, these products may be contaminated with Clostridium perfringens spores. The spores may germinate, outgrow, and multiply to a dangerous level during cooling after cooking if the cooling process is not sufficiently fast, causing outbreaks of food poisoning due to production of C. perfringens enterotoxin.This study was conducted to investigate the growth of C. perfringens from spores in these products under various cooling conditions and to develop predictive models. Inoculated samples were exposed to different cooling profiles to observe the bacterial growth. Analyzed with the one-step dynamic kinetic analysis method, various kinetic parameters were determined. The estimated Tmin, Topt, and Tmax were 8.8, 46.4, and 51.5 °C in RC, and 10.3, 43.5, and 53.4 °C in BB, all agreeing well with the cardinal temperatures of this microorganism in meats. The optimum specific growth rate (μopt) was 6.06 ln CFU/g per h in RC, and 5.64 ln CFU/g per h in BB.The validation of the growth models showed that the RMSE of prediction was relatively low (0.2–0.3 log CFU/g). The majority (94%) of the residual errors of prediction was within ±0.5 log CFU/g, and 76% within ±0.3 log CFU/g of the experimental observations. While accurate, the predictions are mostly fail-safe. The estimated kinetic parameters and predictive models developed in this study can be used to predict the growth of C. perfringens in RC and BB during cooling after cooking to prevent the outbreaks caused by the growth of this pathogen.

Green Alternatives to Synthetic Antioxidants, Antimicrobials, Nitrates, and Nitrites in Clean Label Spanish Chorizo.

Natural extracts obtained from fruit and vegetable processing are important sources of phenolic compounds and nitrates, with excellent antioxidant and antimicrobial properties. The aim of this study was to characterize and determine the antioxidant and antimicrobial capacity of several natural extracts (citric (Ct), acerola (Ac), rosemary (R), paprika, garlic, oregano, beet (B), lettuce (L), arugula (A), spinach (S), chard (Ch), celery (Ce), and watercress (W)), both in vitro and applied to a cured meat product (chorizo). For that, the volatile compounds by GC-MS and microbial growth were determined. The total phenolic and nitrate contents were measured and related with their antioxidant capacity (measured by DPPH, ABTS, FRAP, and ORAC methods) and antimicrobial capacity against Clostridium perfringens growth in vitro. In order to study the antioxidant and antimicrobial activities of the extracts in food, their properties were also measured in Spanish chorizo enriched with these natural extracts. R and Ct showed the highest antioxidant capacity, however, natural nitrate sources (B, L, A, S, Ch, Ce, and W) also presented excellent antimicrobial activity against C. perfringens. The incorporation of these extracts as preservatives in Spanish chorizo also presented excellent antioxidant and antimicrobial capacities and could be an excellent strategy in order to produce clean label dry-cured meat products.

Comparison of Thioglycollate Broth with Liver Extract (BQ Vaccine Medium) with Traditionally Used Culture Media for Mass Scale Production of Clostridium perfringens Type D

Thioglycollate broth with Liver Extract (BQ vaccine medium) was used to produce mass scale yield of Clostridium perfringens Type D. Upon growth of Clostridium perfringens in different culture media the OD value of bacterial growth in BQ vaccine medium, Reinforced Culture Medium (RCM), Cooked Meat Medium (CMM) and Nutrient Broth (NB) was 2.260, 2.184, 2.096 and 1.984 respectively. Mice Lethality result of growth in BQ vaccine medium was equal to that of RCM while growth in CMM and NB had very less lethality. ELISA percentage positivity for Epsilon toxins in the supernatant of growth in BQ medium at 450 nm wavelength at dilution of 320 and 640 was higher than that of all the culture media under comparison. It was concluded that BQ was an excellent culture medium for the development of Enterotoxaemia vaccine producing maximum concentration of epsilon toxin than any culture media used before.

Optimization of solid-state fermentation conditions of Bacillus licheniformis and its effects on Clostridium perfringens-induced necrotic enteritis in broilers

ABSTRACT In the present study, we examined the growth parameters of Bacillus licheniformis in solid-state fermentation (SSF) and evaluated the effects of Bacillus licheniformis-fermented products on Clostridium perfringens-challenged broilers. During four and six days of SSF, the highest viable biomass was observed at 5% glucose, 10% soybean meal, 3% yeast, and 50% initial moisture content. The Bacillus licheniformis SSF products were heat- and acid-resistant. Furthermore, the fermented products were able to inhibit the growth of Clostridium perfringens and Staphylococcus aureus [...]

Growth of Clostridium perfringens in sous vide cooked ground beef with added grape seed extract

The growth of Clostridium perfringens from spore inocula was studied in sous vide cooked ground beef with added 0 to 3% grape seed extract (GSE). C. perfringens did not grow at 4 °C with or without GSE present. Lag time (LT) was 95 h in control samples at 15 °C, whereas 1–3% GSE addition significantly (p < .05) extended LT to 244 h or longer. Generation time (GT) in 3% GSE added beef was similar to that of control (19 h, 3% GSE versus 18 h, control) at 15 °C. At 20 °C, GT was 1.5 h in samples without GSE; however, 1–3% GSE addition extended GT about 2–3 folds (p < .05). Lag time at 20 °C was 23 h in control samples, while LT was 40–59 h in samples containing GSE. Interestingly, GSE did not affect LT at 25 °C; however, significantly (p < .05) longer GT was observed in 3% GSE added samples than the other sample groups. Additionally, GSE from 1 to 3% in beef extended the period needed to reach 6 log cfu/g at 15 or 20 °C, while 3% GSE was required at 25 °C. The findings suggest that GSE exhibits concentration and temperature dependent inhibitory effect on growth of C. perfringens in sous vide cooked ground beef. Grape seed extract can be used to extend the shelf-life and ensure the microbiological safety of sous vide cooked meat products.

Ethanolamine utilization supports Clostridium perfringens growth in infected tissues

Clostridium perfringens possesses the ethanolamine (EA) utilization (eut) system encoded within the eut operon, which utilizes the EA as a carbon, nitrogen and energy source. To determine the role of the eut system in C. perfringens growth, an in-frame deletion of the eutABC genes was made in strain HN13 to generate the eutABC-deleted mutant strain HY1701. Comparison of HN13 and HY1701 growth in media supplemented with 1.0% glucose and/or 1.0% EA showed that glucose enhanced the growth of both strains, whereas EA enhanced HN13 growth, but not that of HY1701, indicating that the eut system is necessary for C. perfringens to utilize EA. The two-component regulatory system EutVW is needed to induce eut gene expression in response to EA whereas the global virulence regulator VirRS differentially controlled eut gene expression depending on glucose and EA availability. To assess the role of the eut system in vivo, an equal number of HN13 and HY1701 cells were injected into the right thigh muscles of mice. Mice infected with HY1701 showed fewer symptoms than those injected with HN13. The mortality rate of mice infected with HY1701 tended to be lower than for mice infected with HN13. In addition, in infected tissues from mice injected with a mixture of HN13 and HY1701, HN13 outnumbered HY1701. PCR screening demonstrated that C. perfringens isolated from gas gangrene and sporadic diarrhea cases carried both eut genes and the perfringolysin O gene (pfoA) as well as the phospholipase C gene (plc). However, pfoA was not detected in isolates from food poisoning patients and healthy volunteers. Culture supernatants prepared from HN13 grown in media containing 7.5% sheep red blood cells induced significantly higher eutB expression levels compared to those from plc- and/or pfoA-deletion mutants. Together, these results indicate that the eut system plays a nutritional role for C. perfringens during histolytic infection.