Toxigenic potential and antimicrobial susceptibility of Bacillus cereus group bacteria isolated from Tunisian foodstuffs

International audienceBackground: Despite the importance of the B. cereus group as major foodborne pathogens that may cause diarrheal and/or emetic syndrome(s), no study in Tunisia has been conducted in order to characterize the pathogenic potential of the B. cereus group. The aim of this study was to assess the sanitary potential risks of 174 B. cereus group strains isolated from different foodstuffs by detecting and profiling virulence genes (hblA, hblB, hblC, hblD, nheA, nheB, nheC, cytK, bceT and ces), testing the isolates cytotoxic activity on Caco-2 cells and antimicrobial susceptibility towards 11 antibiotics. Results: The entertoxin genes detected among B. cereus isolates were, in decreasing order, nheA (98.9%), nheC (97.7%) and nheB (86.8%) versus hblC (54.6%), hblD (54.6%), hblA (29.9%) and hblB (14.9%), respectively encoding for Non-hemolytic enterotoxin (NHE) and Hemolysin BL (HBL). The isolates are multi-toxigenic, harbouring at least one gene of each NHE and HBL complexes associated or not to bceT, cytK-2 and ces genes. Based on the incidence of virulence genes, the strains were separated into 12 toxigenic groups. Isolates positive for cytK (37,9%) harbored the cytK-2 variant. The detection rates of bceT and ces genes were 50.6 and 4%, respectively. When bacteria were incubated in BHI-YE at 30°C for 18 h and for 5 d, 70.7 and 35% of the strains were shown to be cytotoxic to Caco-2 cells, respectively. The cytotoxicity of B. cereus strains depended on the food source of isolation. The presence of virulence factors is not always consistent with cytotoxicity. However, different combinations of enterotoxin genetic determinants are significantly associated to the cytotoxic potential of the bacteria. All strains were fully sensitive to rifampicin, chloramphenicol, ciprofloxacin, and gentamycin. The majority of the isolates were susceptible to streptomycin, kanamycin, erythromycin, vancomycin and tetracycline but showed resistance to ampicillin and novobiocin. Conclusion: Our results contribute data that are primary to facilitate risk assessments in order to prevent food poisoning due to B. cereus group

Identification of the bacteria and their metabolic activities associated with the microbial spoilage of custard cream desserts

The famous French dessert “ile flottante” consists of a sweet egg white foam floating on a vanilla custard cream,which contains highly nutritive raw materials, including milk, sugar and egg. Spoilage issues are therefore a keyconcern for the manufacturers. This study explored the bacterial diversity of 64 spoiled custard cream dessertsmanufactured by 2 French companies. B. cereus group bacteria, coagulase negative Staphylococcus, Enterococcus and Leuconostoc spp. were isolated from spoiled products. Thirty-one bacterial isolates representative of the main spoilage species were tested for their spoilage abilities. Significant growth and pH decrease were observed regardless of species. While off-odours were detected with B. cereus group and staphylococci, yoghurt odours were detected with Enterococcus spp. and Leuconostoc spp. B. cereus group bacteria produced various esters and several compounds derived from amino acid and sugar metabolism. Most Staphylococci produced phenolic compounds. Enterococcus spp. and Leuconostoc spp. isolates produced high levels of compounds derived from sugar metabolism. Each type of spoilage bacteria was associated with a specific volatile profile and lactic acid was identified as a potential marker of spoilage of custard cream-based desserts. These findings provide valuable information for manufacturers to improve food spoilage detection and prevention of chilled desserts made with milk and egg

Osteoprotegerin in relation to insulin resistance and blood lipids in sub-Saharan African women with and without abdominal obesity

BackgroundOsteoprotegerin (OPG), a soluble member of the tumor necrosis factor receptor superfamily that inhibits bone resorption, has been suggested as a potential marker of cardiovascular risk. This study aimed to assess the relationship between insulin resistance, lipid profile and OPG levels in obese and non-obese sub-Saharan African women.MethodsSixty obese (44) and non-obese (16) volunteer women aged 18 to 40years were recruited in this cross-sectional study. Their clinical (age, height, weight, waist circumference, systolic and diastolic blood pressures) and biochemical parameters (fasting blood glucose, total cholesterol, high density lipoprotein-cholesterol (HDL-C)) were measured using standard methods. Insulin levels were measured using an electrochemiluminescence immunoassay, while OPG levels were measured using the ELISA technique. Low density lipoprotein-cholesterol (LDL-C), body mass index (BMI) and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) were calculated using standard methods. Abdominal obesity was defined as a waist circumference ≥ 80cm.ResultsOPG levels were higher in obese than in normal subjects, though the difference was not significant (p = 0.9). BMI, waist circumference, percent body fat and systolic blood pressure were significantly higher in obese than in non-obese subjects (p < 0.05). In these subjects, only age significantly correlated with OPG levels (r = 0.831, p = 0.003), while none of the anthropometric nor metabolic parameter did, even after adjustment for age. In obese subjects, OPG levels fairly correlated with HDL-C (r = 0.298, p = 0.058), and significantly correlated with HOMA-IR (r = −0.438, p = 0.018). After adjustment for age, OPG levels remained negatively correlated to HOMA-IR (r = −0.516, p = 0.020) and LDL-C (r = −0.535, p = 0.015) and positively correlated to HDL-C (r = 0.615, p = 0.004). In multiple linear regression analysis, age was a main determinant of OPG levels in non-obese (β = 0.647, p = 0.006) and obese (β = 0.356, p = 0.044) women. HDL-C was also associated to OPG levels in obese women (β = 0.535, p = 0.009).ConclusionThe positive correlation of OPG with HDL-C and HOMA-IR, and its negative correlation with LDL-C suggest that it may be a marker of insulin sensitivity/resistance and atherogenic risk in obese African women

Association of serum leptin and adiponectin with anthropomorphic indices of obesity, blood lipids and insulin resistance in a Sub-Saharan African population

Abstract Background There is little data on the metabolic effects of adipokines in sub-Saharan African populations. This study aimed to explore the potential relationship of leptin and adiponectin, with obesity, plasma lipids and insulin resistance in a Cameroonian population. Methods We enrolled 167 men and 309 women aged ≥18 years from the general population in Cameroon. Data were collected on waist circumference (WC), body mass index (BMI), waist-to-hip ratio (WHR), body fat (BF%), fasting blood glucose, plasma lipids, adiponectin, leptin, insulin and homeostasis model for assessment of insulin resistance (HOMA-IR). Pearson’s correlation and multiple stepwise linear regression analyses were used to determine correlates of leptin and adiponectin serum levels. Results The prevalence of obesity was higher in women compared to men (p < 0.0001), and Central obesity which is more prevalent particularly in women (WC = 42.4 %, WHR = 42.3 %), is almost for 90 % comparable to %BF (42.7 %). Adiponectin negatively with BMI (r = −0.294, p < 0.0001), WC (r = −0.294, p < 0.0001), %BF (r = −0.122, p = 0.028), WHR (r = −0.143, p = 0.009), triglycerides (r = −0.141, p = 0.011), HOMA-IR (r = −0.145, p = 0.027) and insulin (r = −0.130, p = 0.048). Leptin positively correlated with BMI (r = 0.628), WC (r = 0.530), BF% (r = 0.720), (all p < 0.0001); with DBP (r = 0.112, p = 0.043), total cholesterol (r = 0.324, p < 0.0001), LDL-cholesterol (r = 0.298, p < 0.0001), insulin (r = 0.320, p < 0.001 and HOMA-IR (r = 0.272, p < 0.0001). In multiple stepwise regression analysis, adiponectin was negatively associated with WC (β = −0.38, p = 0.001) and BF% (β = 0.33, p < 0.0001), while leptin was positively associated with BF% (β = 0.60, p < 0.0001), total cholesterol (β = 0.11, p = 0.02) and HOMA-IR (β = 0.11, p = 0.02). When controlled for gender, HOMA-IR was found significantly associated to adiponectin (β = 0.13, p = 0.046), but not BF%, while the association previously found between leptin and HOMA-IR disappeared; BMI and WC were significantly associated with leptin (β = 0.18, p = 0.04 & β = 0.19, p = 0.02 respectively). Conclusion This study, which includes a population who was not receiving potentially confounding medications, confirms the associations previously observed of adiponectin with reduced adiposity especially central adiposity and improved insulin sensitivity. Confirmatory associations were also observed between leptin and obesity, blood lipids and insulin resistance for the first time in an African population. Gender was significant covariate interacting with insulin sensitivity/insulin resistance and obesity indexes associations in this population

Validation of the Body Scan®, a new device to detect small fiber neuropathy by assessment of the sudomotor function: agreement with the Sudoscan®

BackgroundSudomotor dysfunction is one of the earliest manifestations of small fiber neuropathy (SFN), reflecting the alteration of sympathetic C fiber innervation of the sweat glands. Among other techniques, such innervation can be assessed by measuring electrochemical skin conductance (ESC) in microsiemens (μS). In this study, ESC was measured at the feet to detect distal SFN. For this objective, the performance of a new device, the Body Scan® (Withings, France), intended for home use, was compared with that of a reference device, the Sudoscan® (Impeto Medical, France), which requires a hospital setting.MethodsIn patients with diabetes with or without neuropathy or non-diabetic patients with lower-limb neuropathy, the diagnostic performance of the Body Scan® measurement was assessed by calculating its sensitivity (Se) and specificity (Sp) to detect at least moderate SFN (Se70 and Sp70), defined by a value of feet ESC ≤ 70 μS and &gt; 50 μS on the Sudoscan® measure, or severe SFN (Se50 and Sp50), defined by a value of feet ESC ≤ 50 μS on the Sudoscan® measure. The agreement between the two devices was assessed with the analysis of Bland–Altman plots, mean absolute error (MAE), and root mean squared error (RMSE) calculations. The repeatability of the measurements was also compared between the two devices.ResultsA total of 147 patients (52% men, mean age 59 years old, 76% diabetic) were included in the analysis. The sensitivity and specificity to detect at least moderate or severe SFN were: Se70 = 0.91 ([0.83, 0.96]), Sp70 = 0.97 ([0.88, 0.99]), Se50 = 0.91 ([0.80, 0.98]), and Sp50 = 0.99 ([0.94, 1]), respectively. The bias and 95% limits of agreement were 1.5 [−5.4, 8.4]. The MAE was 2.9 and the RMSE 3.8. The intra-sample variability was 2.0 for the Body Scan® and 2.3 for the Sudoscan®.ConclusionThe ESC measurements provided by the Body Scan® were in almost perfect agreement with those provided by the reference device, the Sudoscan®, which validates the accuracy of the Body Scan® for the detection of SFN. By enabling simple, rapid, and autonomous use by the patient at home, this new technique will facilitate screening and monitoring of SFN in daily practice.Clinical trial registrationClinicalTrials.gov, identifier NCT05178459

Impact de la différence d'âge entre donneur et receveur sur la fonctionnalité du greffon en transplantation pulmonaire : étude sur une cohorte nationale multicentrique COLT (Cohort of Lung Transplantation)

Thèse présentée sous la forme d'une " thèse article "Background: Since increase in the age of donors over 65 years, lung transplantation (LTx) teams were faced with the acceptance of donor-derived grafts with a significant age difference from recipient. Our objective was to evaluate the impact of donor-recipient age difference (DA) on the allograft outcome.Methods: Recipients prospectively included between 2009 and 2013 in the French cohort of lung transplantation (COLT) and adjudicated into “stable” or “CLAD” (chronic lung allograft dysfunction) at 3 years by a panel of experts. Patients were divided into three groups according to DA (DA +10 years). Logistic regression was performed to estimate factors associated with DA. Survival analysis assessed the influence of DA on CLAD specifically.Results: 331 patients were included, 248 stables and 83 CLAD (61 BOS, 16 RAS and 6 mixed). In multivariate analysis DA was not associated with primary graft dysfunction, acute cellular rejection or side effects of immunosuppressive drugs. Survival analysis did not demonstrated DA as a risk factor for CLAD (DA as continue variable: HR 1.01, 95%CI [0.99; 1.04], p=0.25).Conclusion: Our study did not demonstrate early or long-term negative impact of DA on allograft outcome. Age mismatching is not associated with graft failure and appears not be a limiting marginal criterion to lung selection.Contexte : la transplantation pulmonaire (TP) est une thérapeutique reconnue pour des patients sélectionnés ayant une insuffisance respiratoire au stade terminal. Compte tenu des difficultés d’accessibilité à la TP pour des candidats toujours plus nombreux, et de plus en plus âgés, et eu égard à l’inadéquation entre le nombre de donneurs et de receveurs sur liste d’attente, des mesures correctives ont été prises. Ainsi, les critères d’acceptabilité des greffons ont été progressivement élargis, parmi lesquels l’âge limite des donneurs a été repoussé au-delà de 65 ans. Les équipes de TP ont été ainsi confrontées à l’acceptation des greffons issus de donneurs (D) ayant une différence d’âge importante avec le receveur (R), avec un impact mal connu sur la fonctionnalité du greffon à moyen et long terme. Le suivi de la cohorte nationale COLT (COhort in Lung Transplantation) offrait l’opportunité de répondre à cette question fondamentale.Patients et méthodes : Il s’agit d’une étude prospective sur cohorte rétrospective portant sur des receveurs ayant eu une TP dans 9 centres français de TP habilités entre 2009 et 2013, inclus dans la cohorte longitudinale COLT. Étaient exclus les TP faites en Super-Urgence (SU), les R décédés dans les 3 ans post TP sans dysfonction chronique du greffon (CLAD) et les ré-transplantations. Les patients étaient répartis en trois groupes selon la différence d’âge D-R (DA) définie par l’âge du D moins celui du R. 3 groupes ont été constitués : groupe (DA +10) dans lequel le D était plus âgé que le R de plus de 10 ans ; groupe (DA -10 ; +10) soit un D dont l’âge correspondait à celui de R à +/- 10 ans. Le critère de jugement principal était la survenue de CLAD dans les 3 ans post-TP en fonction de la DA. Les objectifs secondaires étaient de préciser si la DA impactait la survenue de complications post opératoires précoces (dysfonction primaire du greffon, durée de ventilation mécanique post-opératoire, recours à une trachéotomie de sevrage ventilatoire, recours à une épuration extra-rénale,) et tardives à 1 an (infections bactériennes et mycotiques, rejet aigu cellulaire et humoral) et 3 ans (HTA, diabète, insuffisance rénale, cancer).Résultats : 331 patients ont été inclus, 117 dans le groupe (DA +10). L’âge médian des R était de 47 ans iqr [30 ; 58] et celui des D était de 45 ans iqr[31 ; 56]. Une CLAD à 3 ans a été observée chez 30% des patients du groupe (DA +10). Il n’a pas été trouvé d’impact significatif de la DA entre D et R sur la survenue de CLAD à 3 ans (p=0.28), ni sur le délai de d’apparition des critères de CLAD (p=0.33). La DA n’a pas été retrouvée comme un facteur de risque accru de complications précoces ou tardives.Conclusion : notre étude, sur une large cohorte de patients transplantés pulmonaires, réalisée en France sur 3 ans n’a pas montré d’impact négatif à court et long termes de la DA sur la fonctionnalité du greffon après une TP. Ces résultats confortent le fait que la seule DA n’est pas un facteur péjoratif du résultat ultérieur de la TP

Microbial Quality of Industrial Liquid Egg White: Assumptions on Spoiling Issues in Egg-Based Chilled Desserts

As a 1st step, this study aimed at investigating the microbial quality of liquid egg white in a French eggprocessing company. Thirty raw and 33 pasteurized liquid egg white samples were analyzed. Pasteurization was globally found efficient on mesophilic contaminants (1.7 ± 1.6 and 0.8 ± 0.9 log CFU/mL in raw and pasteurized samples, respectively), including for the control of Salmonella. However,Gram-positive enterococci were still detected in the pasteurized samples. As a 2nd step, a representative bacterial collection was built for exploring the spoilage issue in egg-based chilled desserts. Custard cream was chosen as growth medium since this food is widely used for the production of French chilled desserts. All of the 166 isolates of the bacterial collection were shown to be able to grow and to induce spoilage of the custard cream at refrigeration temperature (10 °C). Several spoilage types were highlighted in the custard cream, on the basis of changes regarding pH, consistency, production of holes or gas. As a 3rd step, bacterial enzymatic activities were explored on custard cream-based agar media. The bacterial collection was reduced to 43 isolates, based on further selection regarding the genera and the spoilage types previously highlighted. Albeit to different degrees, all these isolates were able to produce proteases. A large part of these isolates also expressed lipolytic and amylolytic activities. This studyemphasizes the need to control egg white contamination and especially with Gram-positive heat-resistant Enterococi, in order to guarantee the shelf life of egg-based chilled desserts

cfxA expression in oral clinical Capnocytophaga isolates

International audienceCapnocytophaga spp. are commensal bacteria involved in oral and systemic diseases, with a variable susceptibility to beta-lactams. The cfxA gene expression level was assessed using quantitative RT-PCR, and reasons of the observed misexpression were discussed, as insertion of foreign genetic material, contributing to dissemination and evolution of antibiotic resistance gene

Les mondes britanniques, une communauté de destins ? Introduction

International audienc