Elucidation of enterotoxigenic Bacillus cereus outbreaks in Austria by complementary epidemiological and microbiological investigations, 2013.

Identifying Bacillus cereus as the causative agent of a foodborne outbreak still poses a challenge. We report on the epidemiological and microbiological investigation of three outbreaks of food poisoning (A, B, and C) in Austria in 2013. A total of 44% among 32 hotel guests (A), 22% among 63 employees (B) and 29% among 362 residents of a rehab clinic (C) fell sick immediately after meal consumption. B. cereus isolated from left overs or retained samples from related foods were characterized by toxin gene profiling, and molecular typing using panC sequencing and M13-PCR typing (in outbreak A and C). We identified two B. cereus strains in outbreak A, and six B. cereus strains, each in outbreak B and C; we also found Staphylococcus aureus and staphylococcal enterotoxins in outbreak A. The panC sequence based phylogenetic affiliation of the B. cereus strains, together with findings of the retrospective cohort analyses, helped determining their etiological role. Consumption of a mashed potatoes dish in outbreak A (RR: ∞), a pancake strips soup in outbreak B (RR 13.0; 95% CI 1.8-93.0) and for outbreak C of a fruit salad (RR 1.50; 95% CI 1.09-2.00), deer ragout (RR: 1.99; 95% CI 1.23-3.22) and a cranberry/pear (RR 2.46; 95% CI 1.50-4.03)were associated with increased risk of falling sick. An enterotoxigenic strain affiliated to the phylogenetic group with the highest risk of food poisoning was isolated from the crème spinach and the strawberry buttermilk, and also from the stool samples of the one B. cereus positive outbreak case-patient, who ate both. Our investigation of three food poisoning outbreaks illustrates the added value of a combined approach by using epidemiological, microbiological and genotyping methods in identifying the likely outbreak sources and the etiological B. cereus strains.

MAL overexpression leads to disturbed expression of genes that influence cytoskeletal organization and differentiation of Schwann cells.

In the developing peripheral nervous system, a coordinated reciprocal signaling between Schwann cells and axons is crucial for accurate myelination. The myelin and lymphocyte protein MAL is a component of lipid rafts that is important for targeting proteins and lipids to distinct domains. MAL overexpression impedes peripheral myelinogenesis, which is evident by a delayed onset of myelination and reduced expression of the myelin protein zero (Mpz/P0) and the low-affinity neurotrophin receptor p75(NTR). This study shows that MAL overexpression leads to a significant reduction of Mpz and p75(NTR) expression in primary mouse Schwann cell cultures, which was already evident before differentiation, implicating an effect of MAL in early Schwann cell development. Their transcription was robustly reduced, despite normal expression of essential transcription factors and receptors. Further, the cAMP response element-binding protein (CREB) and phosphoinositide 3-kinase signaling pathways important for Schwann cell differentiation were correctly induced, highlighting that other so far unknown rate limiting factors do exist. We identified novel genes expressed by Schwann cells in a MAL-dependent manner in vivo and in vitro. A number of those, including S100a4, RhoU and Krt23, are implicated in cytoskeletal organization and plasma membrane dynamics. We showed that S100a4 is predominantly expressed by nonmyelinating Schwann cells, whereas RhoU was localized within myelin membranes, and Krt23 was detected in nonmyelinating as well as in myelinating Schwann cells. Their differential expression during early peripheral nerve development further underlines their possible role in influencing Schwann cell differentiation and myelination.

Effect of reducing the n-6/n-3 fatty acid ratio on the maternal and fetal leptin axis in relation to infant body composition.

OBJECTIVE: To investigate the effect of reducing the n-6/n-3 fatty acid ratio in maternal nutrition on the maternal and cord blood leptin axis and their association with infant body composition up to 2 years. DESIGN AND METHODS: 208 healthy pregnant women were randomized to either a dietary intervention to reduce the n-6/n-3 fatty acid ratio from 15th week of gestation until 4 months postpartum or a control group. Leptin, soluble leptin receptor and free leptin index were determined in maternal and cord plasma and related to infant body composition assessed by skinfold thicknesses up to 2 years. RESULTS: The intervention had no effect on either the maternal or fetal leptin axis. Maternal leptin in late pregnancy was inversely related to infant weight and lean body mass (LBM) up to 2 years, after multiple adjustments. Cord leptin was positively related to weight, body fat, and LBM at birth, and inversely associated with weight, BMI, fat mass, and LBM at 2 years and weight gain up to 2 years. The contribution of cord leptin to infant outcomes was overall stronger compared with maternal leptin. CONCLUSIONS: Both, maternal and fetal leptin were associated with subsequent infant anthropometry with a greater impact of fetal leptin.

Breast milk fatty acid profile in relation to infant growth and body composition: results from the INFAT study.

BACKGROUND: There is some evidence that the n-6/n-3 long-chain polyunsaturated fatty acids (LCPUFAs) ratio in early nutrition, and thus in breast milk, could influence infant body composition. METHODS: In an open-label randomized controlled trial (RCT), 208 healthy pregnant women were allocated to a dietary intervention (supplementation with 1,200 mg n-3 LCPUFAs per day and instructions to reduce arachidonic acid (AA) intake) from the 15th wk of gestation until 4 mo of lactation or to follow their habitual diet. Breast milk LCPUFAs at 6 wk and 4 mo postpartum were related to infant body composition assessed by skinfold thickness (SFT) measurements and ultrasonography during the first year of life. RESULTS: Dietary intervention significantly reduced breast milk n-6/n-3 LCPUFAs ratio. In the whole sample, early breast milk docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n-3 LCPUFAs at 6 wk postpartum were positively related to the sum of four SFT measurements at age 1. Breast milk AA and n-6 LCPUFAs at 6 wk postpartum were negatively associated with weight, BMI, and lean body mass (LBM) up to 4 mo postpartum. CONCLUSION: Breast milk n-3 LCPUFAs appear to stimulate fat mass growth over the first year of life, whereas AA seems to be involved in the regulation of overall growth, especially in the early postpartum period.

Effect of reducing the n-6:n-3 long-chain PUFA ratio during pregnancy and lactation on infant adipose tissue growth within the first year of life: an open-label randomized controlled trial.

BACKGROUND: The composition of long-chain PUFAs (LCPUFAs) in the maternal diet may affect obesity risk in the mother's offspring. OBJECTIVE: We hypothesized that a reduction in the n-6 (omega-6):n-3 (omega-3) LCPUFA ratio in the diet of pregnant women and breastfeeding mothers may prevent expansive adipose tissue growth in their infants during the first year of life. DESIGN: In a randomized controlled trial, 208 healthy pregnant women were randomly assigned to an intervention (1200 mg n-3 LCPUFAs as a supplement per day and a concomitant reduction in arachidonic acid intake) or a control diet from the 15th wk of pregnancy to 4 mo of lactation. The primary outcome was infant fat mass estimated by skinfold thickness (SFT) measurements at 4 body sites at 3-5 d, 6 wk, and 4 and 12 mo postpartum. Secondary endpoints included sonographic assessment of abdominal subcutaneous and preperitoneal fat, fat distribution, and child growth. RESULTS: Infants did not differ in the sum of their 4 SFTs at ≤1 y of life [intervention: 24.1 ± 4.4 mm (n = 85); control: 24.1 ± 4.1 mm (n = 80); mean difference: -0.0 mm (95% CI: -1.3, 1.3 mm)] or in growth. Likewise, longitudinal ultrasonography showed no significant differences in abdominal fat mass or fat distribution. CONCLUSIONS: We showed no evidence that supplementation with n-3 fatty acids and instructions to reduce arachidonic acid intake during pregnancy and lactation relevantly affects fat mass in offspring during the first year of life. Prospective long-term studies are needed to explore the efficacy of this dietary approach for primary prevention. This trial was registered at clinicaltrials.gov as NCT00362089.