Groundwater promotes emergence of asporogenic mutants of emetic Bacillus cereus.

Bacillus cereus is a ubiquitous endospore-forming bacterium, which mainly affects humans as a food-borne pathogen. Bacillus cereus can contaminate groundwater used to irrigate food crops. Here, we examined the ability of the emetic strain B. cereus F4810/72 to survive abiotic conditions encountered in groundwater. Our results showed that vegetative B. cereus cells rapidly evolved in a mixed population composed of endospores and asporogenic variants bearing spo0A mutations. One asporogenic variant, VAR-F48, was isolated and characterized. VAR-F48 can survive in sterilized groundwater over a long period in a vegetative form and has a competitive advantage compared to its parental strain. Proteomics analysis allowed us to quantify changes to cellular and exoproteins after 24 and 72 h incubation in groundwater, for VAR-F48 compared to its parental strain. The results revealed a significant re-routing of the metabolism in the absence of Spo0A. We concluded that VAR-F48 maximizes its energy use to deal with oligotrophy, and the emergence of spo0A-mutated variants may contribute to the persistence of emetic B. cereus in natural oligotrophic environments.

Ferrous sulfate oral solution in young children with iron deficiency anemia: An open-label trial of efficacy, safety, and acceptability.

BACKGROUND: This study evaluated the efficacy, safety, and acceptability of a new ferrous sulfate oral solution (Tardyferon® 20 mg/mL) in young children with mild or moderate iron deficiency anemia (IDA). METHODS: This was a multicenter, national, single-arm, open-label study. Children aged 6-53 months presenting with mild or moderate IDA (i.e., blood hemoglobin (Hb) ranging from 7.0 to 10.9 g/dL and serum ferritin <12 ng/mL) were eligible for inclusion. The ferrous sulfate heptahydrate solution (2 mg/kg/day) was administered orally for 3 months. If normalization of either Hb or ferritin was not achieved at month 3 the treatment was continued for another 3 months. RESULTS: Of the 100 children screened, 21 aged 6-17 months were included and received the study treatment, and 19 were analyzed for hematologic outcomes at month 3. Only one patient continued treatment for the additional 3 months. At month 3, mean ± SD Hb and ferritin levels were 12.0 ± 0.7 g/dL and 31.5 ± 19.4 ng/mL, respectively. Hemoglobin and ferritin levels were normalized in 95% (18/19) and 84% (16/19) of the patients, respectively. Treatment compliance and levels of satisfaction of both the parents and the investigators were high. Overall, 33.3% of patients (7/21) experienced at least one adverse event. Only one patient (4.8%) experienced a drug-related adverse event (upper abdominal pain). CONCLUSIONS: A 2 mg/kg daily dose of the new oral ferrous sulfate heptahydrate solution provides substantial therapeutic benefit with high levels of tolerability in young children who have mild or moderate IDA.

Impact of temperature and oxygen on the fate of Bacillus weihenstephanensis in a food-based medium.

The capacity of the Bacillus weihenstephanensis KBAB4 strain, a psychrotolerant species of the B. cereus sensu lato group, to multiply in carrot broth at 8 °C and 30 °C, in presence or absence of oxygen was determined. In aerobic carrot broth tyndallized in presence of oxygen, at both temperatures, the population of vegetative cells of B. weihenstephanensis inoculated at a level of 103 or 106 CFU/ml dropped immediately. After 16 h at 30 °C, B. weihenstephanensis reached around 103 CFU/ml, indicating that some vegetative cells had survived and multiplied, with lipid inclusions accumulated in cells, indicating possible stressing conditions. At 8 °C, no multiplication of B. weihenstephanensis was observed during 3 days to at least 12 days, depending of carrot broth batches. In anaerobic carrot broth tyndallized without oxygen, the vegetative cells of B. weihenstephanensis were not killed upon inoculation and multiplied in the broth at both 30 °C and 8 °C. Comparison with results from previous studies shows that B. weihenstephanensis behaves differently in carrot broth and in laboratory media at 8 °C with regards to presence or absence of oxygen.

Iron Pharmacokinetics in Women with Iron Deficiency Anaemia Following A Single Oral Dose of a Novel Formulation of Tardyferon (Prolonged Release Ferrous Sulphate).

Numerous iron-containing preparations are available on the market; these vary in dosage, salt, chemical state of iron (ferric or ferrous) and in the iron delivery process (immediate or prolonged-release). Tardyferon® is a prolonged-release tablet containing 80 mg ferrous sulphate. The formulation has recently been modified; changes to the excipients which constitute the inert formulation matrix have allowed a decrease in tablet size for easier swallowing. The aim of this multicenter open-label study was to characterize the serum pharmacokinetics of iron in non-pregnant women aged 23-45 years with iron deficiency anaemia (IDA) following single oral administration of 160 mg Tardyferon® under fasting conditions. Blood samples were collected from the 29 participants before dosing and until 24 h post-dosing. Serum iron concentrations were determined using a routine colorimetric analytical method; pharmacokinetic parameters were derived using a non-compartmental approach. In these patients, median time to maximum serum concentrations (Tmax) was 4 h. Serum profiles were consistent with prolonged release; iron levels were elevated up to 12 h after dosing, with mean C12h still more than 7 times higher than baseline (CT0), and mean C2h and C8h representing 69.7% and 81.9% of the Cmax, respectively. In vitro dissolution testing performed on the clinical batch also demonstrated prolonged release of iron from this formulation. A single oral dose of 160 mg Tardyferon® administered under fasting conditions to this target population resulted in a long-lasting release of iron in the gastrointestinal tract, leading to optimal iron absorption. Moreover, Tardyferon® was well tolerated.

Cereulide production by Bacillus weihenstephanensis strains during growth at different pH values and temperatures.

Besides Bacillus cereus, some strains of the psychrotolerant, potentially foodborne pathogen Bacillus weihenstephanensis can produce the emetic toxine (cereulide). This toxin is a heat- and acid-stable cyclic dodecadepsipeptide that causes food intoxication with vomiting. However, some severe clinical cases with lethal outcomes have been described. If cereulide can be produced during refrigerated storage, it will not be inactivated by reheating food, representing an important risk of food intoxication for consumers. In this paper, we determined the capacity of the B. weihenstephanensis strains BtB2-4 and MC67 to grow and produce cereulide on agar media at temperatures from 8 °C to 25 °C and at a pH from 5.4 to 7.0. At 8 °C, strain BtB2-4 produced quantifiable amounts of cereulide, whereas the limit of detection was reached for strain MC67. For BtB2-4, cereulide production increased 5-fold between 8 °C and 10-15 °C and by more than 100-fold between 15 °C and 25 °C. At temperatures of 10 °C and higher, cereulide concentrations were within the range of those reported by previous works in foods implicated in emetic poisoning. At 25 °C, decreasing the pH to 5.4 reduced cereulide production by strain BtB2-4 by at least 20-fold.

Heat-resistance of psychrotolerant Bacillus cereus vegetative cells.

Spores of psychrotolerant strains of the foodborne pathogen Bacillus cereus can multiply during storage of cooked or pasteurized, refrigerated foods and can represent a risk if these cells are not eliminated during reheating of food product before consumption. We determined the heat-resistance of psychrotolerant B. cereus vegetative cells at different heating temperatures in laboratory medium and compared it with that of thermotolerant B. cereus vegetative cells. The z values, based on times for a 3 log10 reduction, of the vegetative cells of the three psychrotolerant phylogenetic groups of B. cereus varied between 3.02 °C and 4.84 °C. The temperature at which a 3 log10 reduction was achieved in 10 min varied between 47.6 °C and 49.2 °C for psychrotolerant vegetative cells and it was around 54.8 °C for thermotolerant vegetative cells. Moreover, 0.4 min at 60 °C would be sufficient for a 6 log10 CFU/ml reduction of the most heat resistant psychrotolerant B. cereus vegetative cells. These data clearly showed that psychrotolerant B. cereus vegetative cells can be rapidly eliminated by a mild heat treatment such as food reheating.

Combined effect of anaerobiosis, low pH and cold temperatures on the growth capacities of psychrotrophic Bacillus cereus.

Psychrotrophic strains of the foodborne pathogen Bacillus cereus can multiply during the refrigerated storage of food products. The aim of this study was to determine the impact of anaerobiosis on the growth of two psychrotrophic B. cereus strains exposed to acidic pH at a cold temperature in a laboratory medium. At 10 °C, growth occurred at pH values equal to or higher than 5.7 during anaerobiosis, whereas aerobic growth was observed from pH 5.4. Growth rates during aerobiosis were similar at pH 5.4 and pH 7. No growth was observed for the two tested strains at 8 °C without oxygen regardless of the pH; however, both strains grew at this temperature from pH 5.4 in the presence of oxygen. These pH growth limits in aerobiosis are consistent with those reported for different strains and different foods or media, but no other studies have described anaerobic growth at acidic pH values. The maximal B. cereus concentration was approximately 6.0 log10 CFU/ml for cultures in the absence of oxygen and approximately 8.0 log10 CFU/ml for cultures in the presence of oxygen. In conclusion, we found that the combination of anaerobiosis, pH < 5.7 at 10 °C, or anaerobiosis and temperatures ≤8 °C prevent psychrotrophic B. cereus growth.

Assessment of iron deficiency and anemia in pregnant women: an observational French study.

AIM: We explored the prevalence and management of iron deficiency and anemia among pregnant women in France. PATIENTS & METHODS: In this prospective, observational, multicenter registry study, randomly selected investigators (gynecologists/obstetricians/midwives registered in the CEGEDIM(®) database) assessed pregnant women presenting for a consultation. Participants completed a questionnaire at study inclusion. RESULTS: A total of 1506 patients were enrolled by 95 investigators. Overall, investigators estimated a moderate or significant risk of iron deficiency in almost 60% of women. The overall prevalence of anemia (15.8%) increased with longer pregnancy duration. Medication (mainly iron-based) was prescribed to 57.3% of patients. CONCLUSION: In French clinical practice, the estimated risk of iron deficiency and prevalence of anemia during pregnancy align with expectations and are managed according to national/international recommendations.

The Water Cycle, a Potential Source of the Bacterial Pathogen Bacillus cereus.

The behaviour of the sporulating soil-dwelling Bacillus cereus sensu lato (B. cereus sl) which includes foodborne pathogenic strains has been extensively studied in relation to its various animal hosts. The aim of this environmental study was to investigate the water compartments (rain and soil water, as well as groundwater) closely linked to the primary B. cereus sl reservoir, for which available data are limited. B. cereus sl was present, primarily as spores, in all of the tested compartments of an agricultural site, including water from rain to groundwater through soil. During rain events, leachates collected after transfer through the soil eventually reached the groundwater and were loaded with B. cereus sl. In groundwater samples, newly introduced spores of a B. cereus model strain were able to germinate, and vegetative cells arising from this event were detected for up to 50 days. This first B. cereus sl investigation in the various types of interrelated environments suggests that the consideration of the aquatic compartment linked to soil and to climatic events should provide a better understanding of B. cereus sl ecology and thus be relevant for a more accurate risk assessment of food poisoning caused by B. cereus sl pathogenic strains.

Unsaturated fatty acids from food and in the growth medium improve growth of Bacillus cereus under cold and anaerobic conditions.

In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containing fraction of spinach, but not the hydrophilic fraction, restored growth of B. cereus under cold and anaerobiosis when added to the chemically defined medium. This fraction was rich in unsaturated, low melting point fatty acids. Addition of phosphatidylcholine containing unsaturated, low melting point, fatty acids similarly improved B. cereus anaerobic growth at cold temperature. Addition of hydrogenated phosphatidylcholine containing saturated, high melting point, fatty acids did not modify growth. Fatty acids from phospholipids, from spinach and from hydrogenated phosphatidylcholine, although normally very rare in B. cereus, were inserted in the bacterium membrane. Addition of phospholipids rich in unsaturated fatty acids to cold and anaerobic cultures, increased fluidity of B. cereus membrane lipids, to the same level as those from B. cereus normally cold adapted, i.e. grown aerobically at 15 °C. B. cereus is therefore able to use external fatty acids from foods or from the growth medium to adapt its membrane to cold temperature under anaerobiosis, and to recover the maximal population density achieved at optimal temperature.

Low temperatures and fermentative metabolism limit peptidoglycan digestion of Bacillus cereus. Impact on colony forming unit counts.

The impact of fermentative metabolism at low temperature on cell division of Bacillus cereus was studied. Fermentation at 37 °C had no influence on the division of bacteria. Aerobic cultures at 15 °C produced larger cells than at 37 °C, but cell division was normal. In fermentative cultures at 15 °C, no increase in CFU ml(-1) was observed. However, A(600) increased, due to formation of long filaments. Transmission electronic microscopy and light microscopy with fluorescent staining showed several nucleic acid entities separated by a hydrophobic membrane, indicating that each filament contained several individual cells attached by peptidoglycan. When left in air at room temperature, one filament gave several daughter cells, this means that one CFU formed by one filament may represent a greater contamination potential than one CFU formed by a single cell. Division was observed in cultures at 15 °C with anaerobic respiration in the presence of nitrates. Possible filamentous growth must thus be taken into account to avoid underestimating B. cereus growth in vacuum or modified atmosphere packaged foods stored at low temperature.

LDL-cholesterol target values and actual values in patients with type 2 diabetes (T2D) uncontrolled on oral antidiabetic monotherapy: the lipid results of the French ESCALADE survey.

AIM: While new European guidelines have recommended much lower LDL-c target values than current 2005 French HAS guidelines, it appears that even those ones are not widely implemented. This lipid-side of the ESCALADE study was designed to determine the LDL-c target values of GPs, diabetologists (DIABs) and cardiologists (CARDIOs) and the consistency of actual values in patients with type 2 diabetes (T2D) uncontrolled on antidiabetic monotherapy. METHODS: ESCALADE was a national multicentre, observational, descriptive, transversal survey. One thousand and three hundred GPs and 350 specialists (DIABs and CARDIOs) agreed to include respectively three and four patients each. For each patient, the physician had to set the LDL-c target value that was compared to the calculated HAS target value. The actual LDL-c value was recorded and compared to those target values. RESULTS: A total of 412 GPs, 137 DIABs and 27 CARDIOs included respectively 699, 364 and 66 patients. Among them 19.6% had cardiovascular disease (CVD) and 56.9% were on lipid-lowering therapy (LLT). The physician's target value was in concordance with HAS value in 37.3% (GPs), 35.4% (DIABs) and 57.4% (CARDIOs) of the cases. Physicians overestimated the risk in respectively 42.7%, 54.1% and 21.3%. However, very high risk was underestimated in respectively 38.1%, 22.0% and 25.6% of the patients and the actual LDL-c value was in the target range (<100mg/dL) for only 28% of the very high-risk patients. CONCLUSION: Physicians tend to overestimate the CVD risk in patients with T2D and set lower LDL-c target values than HAS calculated values. Nevertheless, patients with a very high risk are largely under-treated.

Influence of anaerobiosis and low temperature on Bacillus cereus growth, metabolism, and membrane properties.

The impact of simultaneous anaerobiosis and low temperature on growth parameters, metabolism, and membrane properties of Bacillus cereus ATCC 14579 was studied. No growth was observed under anaerobiosis at 12°C. In bioreactors, growth rates and biomass production were drastically reduced by simultaneous anaerobiosis and low temperature (15°C). The two conditions had a synergistic effect on biomass reduction. In anaerobic cultures, fermentative metabolism was modified by low temperature, with a marked reduction in ethanol production leading to a lower ability to produce NAD(+). Anaerobiosis reduced unsaturated fatty acids at both low optimal temperatures. In addition, simultaneous anaerobiosis and low temperatures markedly reduced levels of branched-chain fatty acids compared to all other conditions (accounting for 33% of total fatty acids against more 71% for low-temperature aerobiosis, optimal-temperature aerobiosis, and optimal-temperature anaerobiosis). This corresponded to high-melting-temperature lipids and to low-fluidity membranes, as indicated by differential scanning calorimetry, 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy, and infrared spectroscopy. This is in contrast to requirements for cold adaptation. A link between modification in the synthesis of metabolites of fermentative metabolism and the reduction of branched-chain fatty acids at low temperature under anaerobiosis, through a modification of the oxidizing capacity, is assumed. This link may partly explain the impact of low temperature and anaerobiosis on membrane properties and growth performance.

Lactate dehydrogenase A promotes communication between carbohydrate catabolism and virulence in Bacillus cereus.

The diarrheal potential of a Bacillus cereus strain is essentially dictated by the amount of secreted nonhemolytic enterotoxin (Nhe). Expression of genes encoding Nhe is regulated by several factors, including the metabolic state of the cells. To identify metabolic sensors that could promote communication between central metabolism and nhe expression, we compared four strains of the B. cereus group in terms of metabolic and nhe expression capacities. We performed growth performance measurements, metabolite analysis, and mRNA measurements of strains F4430/73, F4810/72, F837/76, and PA cultured under anoxic and fully oxic conditions. The results showed that expression levels of nhe and ldhA, which encodes lactate dehydrogenase A (LdhA), were correlated in both aerobically and anaerobically grown cells. We examined the role of LdhA in the F4430/73 strain by constructing an ldhA mutant. The ldhA mutation was more deleterious to anaerobically grown cells than to aerobically grown cells, causing growth limitation and strong deregulation of key fermentative genes. More importantly, the ldhA mutation downregulated enterotoxin gene expression under both anaerobiosis and aerobiosis, with a more pronounced effect under anaerobiosis. Therefore, LdhA was found to exert a major control on both fermentative growth and enterotoxin expression, and it is concluded that there is a direct link between fermentative metabolism and virulence in B. cereus. The data presented also provide evidence that LdhA-dependent regulation of enterotoxin gene expression is oxygen independent. This study is the first report to describe a role of a fermentative enzyme in virulence in B. cereus.

Fnr mediates carbohydrate-dependent regulation of catabolic and enterotoxin genes in Bacillus cereus F4430/73.

We had previously demonstrated that Fnr is required for fermentative growth and oxic production of hemolysin BL (Hbl) and non-hemolytic enterotoxin (Nhe) in the food-borne pathogen Bacillus cereus F4430/73. In the present work, the regulatory impact of Fnr on microaerobic growth and enterotoxin production in response to carbohydrates was examined using glucose, fructose, sucrose or a glucose-fructose mixture as carbon and energy sources. Growth parameters, byproduct spectra and transcription levels of catabolic and enterotoxin genes were analyzed in a strain lacking Fnr in comparison to the parental F4430/73 strain. The results showed that B. cereus prefers glucose to other carbohydrates for microaerobic growth, and that lacking of Fnr less strongly affected the respiro-fermentative catabolism of glucose than fructose and, to a lesser extent than sucrose. In addition, lacking of Fnr strongly decreased expression of hbl and nhe genes, leading to the absence of Hbl and low production of Nhe independently of the carbohydrate used as carbon source. We conclude that Fnr is an important element for carbon source regulation in B. cereus F4430/73 and that the regulation of enterotoxin gene expression in response to carbohydrates may represent one aspect of overall catabolite control mediated by Fnr.

The production of Bacillus cereus enterotoxins is influenced by carbohydrate and growth rate.

Enterotoxin production is a key factor in Bacillus cereus food poisoning. Herein, the effect of the growth rate (mu) on B. cereus toxin production when grown on sucrose was studied and the Hemolytic BL enterotoxin (HBL) and nonhemolytic enterotoxin (Nhe) production by B. cereus was compared according to carbohydrate at mu = 0.2 h(-1). The anaerobic growth was carried out on continuous cultures in synthetic medium supplemented with glucose, fructose, sucrose, or an equimolar mixture of glucose and fructose. Concerning the HBL and Nhe enterotoxin production: (1) the highest enterotoxin production has occurred at mu = 0.2 h(-1) when growing on sucrose; (2) HBL production was repressed when glucose was consumed and the presence of fructose (alone or in mixture) cancelled glucose catabolite repression; (3) the consumption of sucrose increased Nhe production, which was not affected by the catabolite repression. Furthermore, analysis of the fermentative metabolism showed that whatever the mu or the carbon source, B. cereus used the mixed acid fermentation to ferment the different carbohydrates. The enterotoxin productions by this strain at mu = 0.2 h(-1) are highly influenced by the carbohydrates that do not involve any fermentative metabolism changes.

Acid tolerance response is low-pH and late-stationary growth phase inducible in Bacillus cereus TZ415.

The acid tolerance of foodborne pathogen Bacillus cereus TZ415 was examined. B. cereus was more tolerant to an acid challenge at pH 4.0 when cells were grown at low pH in regulated batch cultures of rich J Broth (JB) medium. The pH-inducible acid tolerance response (ATR) was maximal at pH 5.0, a sublethal growth condition inducing a remarkable cell elongation. During growth at regulated pH 7.0 and 6.0, B. cereus TZ415 became more acid sensitive from lag to stationary growth phase and the acid tolerance of cells reached its maximum level in late-stationary growth phase. The ATR induced at pH 5.5 and 5.0 was not affected by growth phase. Cellular protein profiles were analysed as a function of growth phase and medium pH. The Hemolysin BL (HBL) enterotoxin was only detected when cells were grown at pH 7.0.

[Factors associated with the opinion of hypercholesterolemic patients on the duration of their treatment. Results of the FRACTION study]. / Facteurs associés à l'opinion des patients hypercholestérolémiques sur la durée de leur traitement. Résultats de l'enquête FRACTION.

INTRODUCTION: The treatment of hypercholesterolemia is regularly limited by non compliance over the long-term. Studies conducted on the subject underline the interest of considering compliance as a behaviour composed of multiple determinants that require better knowledge. The patients' opinion concerning the severity and evolution of their health problem, as well as the use and duration of their treatment, are, in this context, essential. OBJECTIVES: Based on the hypothesis that hypercholesterolemic patients who believe that their problem only requires short-term treatment are "candidates" for poor compliance, we attempted to identify the factors that determine their opinion on the duration of treatment. METHODS: 1595 files of hypercholesterolemic patients, who had participated in a survey describing how they represented cholesterol and its impact on their health (the FRACTION study), were analyzed. Two groups of opposing opinion on the duration of treatment for hypercholesterolemia (limited or prolonged) were formed. Their socio-demographic and clinical characteristics and the way they represented their health were compared. The factors predicting their opinion on the duration of treatment were identified. RESULTS: The opinion that only short-term treatment was required was associated with younger age, lower education, the fact of not (or not yet) being treated pharmacologically, personal experience of the disease (presence of hypertension, cardiovascular family history or perception of diminished health), little correct knowledge on cholesterol and hypercholesterolemia and greater erroneous beliefs or prejudice with regard to treatment. After adjustment to the socio-demographic and clinical factors, many representations of health continue to predict the opinion in favor of short-term treatment. CONCLUSION: This study demonstrates, for the first time, the importance of knowledge on health, beliefs and personal judgement that are among the determinating factors of patients' opinion on the duration of their treatment. It shows the justification of their individual approach to compliance, behaviour highly influenced by the representation each patient has of his health. It emphasizes the interest of personalizing educative messages addressed to hypercholesterolemic patients, by taking into better account the potential factors of resistance to compliance.