In vitro and in vivo evaluation of Weissella cibaria and Lactobacillus plantarum for their protective effect against cadmium and lead toxicities.

Thirty-two lactic acid bacteria (LAB) isolates were obtained from fermenting cassava mash and wara (African soft cheese) and screened for their resistance to cadmium and lead toxicities at 550-1050 mg l-1 and probiotic potentials. Four LAB strains that tolerated the heavy metals at 1050 mg l-1 were selected for antioxidative capacities, tolerance to acid, bile salts and simulated gastric and intestinal tract and safety status. The results revealed that Weissella cibaria WD2 and Lactobacillus plantarum CaD1 exhibited comparatively higher antioxidative capacities, survived in simulated gastric and intestinal transit, tolerated acid and bile salt and possessed safety status. The two strains were employed for the in vivo studies, which was monitored in male albino Wistar rats using skim milk as a carrier for the cultures over a period of 28 days. The rats given the cultures of W. cibaria WD2 and L. plantarum CaD1 in addition with the administration of heavy metals had improved renal and hepatic impairment, while damage was observed in rats fed with cadmium and lead only. Weissella cibaria WD2 and L. plantarum CaD1 demonstrated probiotic potentials and safety status. These strains can be used to effectively amend hepatic and renal histopathological alterations in rats caused by ingestion of cadmium and lead. SIGNIFICANCE AND IMPACT OF THE STUDY: This present study highlights the presence of lactic acid bacteria (LAB) from traditional fermented foods that were cadmium and lead resistant and possessed probiotic potentials. Weissella cibaria WD2 and Lactobacillus plantarum CaD1 selected for the in vivo studies ameliorated the build-up of cadmium and lead in the organs of the animals. This indicated that good cadmium and lead binding and probiotic lactic acid bacteria can be used to prevent exposure to these heavy metals.

Probiotic potentials of yeasts isolated from some cereal-based Nigerian traditional fermented food products.

AIMS: To determine the starter culture and multifunctional potentials of yeast strains from some cereal-based Nigerian traditional fermented food products. METHODS AND RESULTS: Yeast isolates were screened for enzyme production and identified by sequencing the D1/D2 region of 26S rDNA. Pichia kluyveri LKC17, Issatchenkia orientalis OSL11, Pichia kudriavzevii OG32, Pichia kudriavzevii ROM11 and Candida tropicalis BOM21 exhibited the highest protease, lipase and phytase activity. They were selected and further evaluated for gastrointestinal survival and adherence ability. Although strain-specific, they retained viability at 37°C and showed survival at pH 2·0., I. orientalis OSL11 showed the highest survival at 2% bile salts concentration and P. kudriavzevii ROM11 showed the least survival. The yeast strains showed strong autoaggregation ability (81·24-91·85%) and hydrophobicity to n-hexadecane (33·61-42·30%). The highest co-aggregation ability was detected for P. kudriavzevii OG32 and Escherichia coli (71·57%). All the yeast strains removed cholesterol in the range of 49·03-74·05% over 48 h and scavenged for free radicals in methanol reaction system. CONCLUSIONS: In this study, we isolated new yeast strains with multifunctional potentials that can be used as functional starter cultures to produce cereal-based probiotic products. SIGNIFICANCE AND IMPACT OF THE STUDY: The development of probiotic yeast strains as starter culture to improve the quality attributes and confer functional value on cereal-based traditional fermented foods is beneficial.

Analysis of the contrast between natural occurrence of toxigenic Aspergilli of the Flavi section and aflatoxin B1 in cassava.

Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin produced by Aspergilli of the section Flavi that may contaminate food, in the field or during storage. Cassava represents an important staple food in sub-Saharan Africa. The analysis of aflatoxigenic fungi in 36 cassava samples obtained from producers in Benin indicated that 40% were contaminated by Aspergilli of the section Flavi. Upon morphological and molecular characterization of the 20 isolates, 16 belonged to Aspergillus flavus, 2 to Aspergillus parvisclerotigenus and 2 to Aspergillus novoparasiticus. This is the first time that this latter species is isolated from food. Although most of these isolates were toxigenic on synthetic media, no AFB1 contamination was observed in these cassava samples. In order to determine the action of cassava on AFB1 synthesis, a highly toxigenic strain of A. flavus, was inoculated onto fresh cassava and despite a rapid development, no AFB1 was produced. The anti-aflatoxin property was observed with cassava from different geographical origins and on other aflatoxigenic strains of the section Flavi, but it was lost after heating, sun drying and freezing. Our data suggest that fresh cassava is safe regarding AFB1 contamination, however, processing may alter its ability to block toxinogenesis leading to secondary contamination.

Predator selection on phenotypic variability of cryptic and aposematic moths.

Natural selection generally favours phenotypic variability in camouflaged organisms, whereas aposematic organisms are expected to evolve a more uniform warning coloration. However, no comprehensive analysis of the phenotypic consequences of predator selection in aposematic and cryptic species exists. Using state-of-the-art image analysis, we examine 2800 wing images of 82 moth species accessed via three online museum databases. We test whether anti-predator strategy (i.e., camouflage or aposematism) explains intraspecific variation in wing colour and pattern across northern hemisphere moths. In addition, we test two mutually non-exclusive, ecological hypotheses to explain variation in colour pattern: diel-activity or dietary-niche. In this work, taking into account phylogenetic relationships, moth phenotypic variability is best explained by anti-predator strategy with camouflaged moths being more variable in wing patterning than aposematic species.

A review on aflatoxin contamination and its implications in the developing world: a sub-Saharan African perspective.

Mycotoxins contamination in some agricultural food commodities seriously impact human and animal health and reduce the commercial value of crops. Mycotoxins are toxic secondary metabolites produced by fungi that contaminate agricultural commodities pre- or postharvest. Africa is one of the continents where environmental, agricultural and storage conditions of food commodities are conducive of Aspergillus fungi infection and aflatoxin biosynthesis. This paper reviews the commodity-wise aetiology and contamination process of aflatoxins and evaluates the potential risk of exposure from common African foods. Possible ways of reducing risk for fungal infection and aflatoxin development that are relevant to the African context. The presented database would be useful as benchmark information for development and prioritization of future research. There is need for more investigations on food quality and safety by making available advanced advanced equipments and analytical methods as well as surveillance and awareness creation in the region.

Technological properties and probiotic potential of Enterococcus faecium strains isolated from cow milk.

AIM: To identify enterococci from the fermentation of milk for the production of nono, an African fermented dairy product, to determine the technological properties for suitability as starter cultures and safety as probiotics. METHODS AND RESULTS: Enterococcus faecium CM4 and Enterococcus faecium 2CM1 were isolated from raw cow's milk. The strains were phenotypically and genotypically identified. Technological properties, safety investigations, in vitro adherence properties and antimicrobial characteristics were carried out. Strong acidification and tolerance to bile salts were recorded. The strains were bile salts hydrolytic positive and no haemolysis. There was no resistance to clinically relevant antibiotics. The strains exhibited adherence to human collagen type IV, human fibrinogen and fibronectin. The bacteriocins were active against Bacillus cereus DSM 2301, Bacillus subtilis ATCC 6633, Micrococcus luteus and Listeria monocytogenes. Bacteriocins were stable at pH 4-9 and on treatment with lipase, catalase, α-amylase and pepsin, while their activity was lost on treatment with other proteases. The bacteriocins produced were heat stable at 100°C for 10 min. The bacteriocin produced by the strains was identified as enterocin A. CONCLUSIONS: The E. faecium strains in this study exhibited probiotic activity, and the safety investigations indicate their suitability as good candidates for a starter culture fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of bacteriocin-producing E. faecium strains as starter cultures in fermented foods is beneficial but, however, their safety investigations as probiotics must be greatly emphasized.

Storage insects on yam chips and their traditional management in Northern Benin.

Twenty-five villages of Northern Benin were surveyed to identify the constraints of yam chips production, assess the diversity of storage insects on yam chips, and document farmers' perception of their impacts on the stocks and their traditional management practices. Damages due to storage insects (63.9% of responses) and insufficiency of insect-resistant varieties (16.7% of responses) were the major constraints of yam chips production. Twelve insect pest species were identified among which Dinoderus porcellus Lesne (Coleoptera, Bostrichidae) was by far the most important and the most distributed (97.44% of the samples). Three predators (Teretrius nigrescens Lewis, Xylocoris flavipes Reuter, and Alloeocranum biannulipes Montrouzier & Signoret) and one parasitoid (Dinarmus basalis Rondani) all Coleoptera, Bostrichidae were also identified. The most important traditional practices used to control or prevent insect attack in yam chips were documented and the producers' preference criteria for yam cultivars used to produce chips were identified and prioritized. To further promote the production of yam chips, diversification of insect-resistant yam varieties, conception, and use of health-protective natural insecticides and popularization of modern storage structures were proposed.

Sustainability analysis of bioethanol production from grain and tuber starchy feedstocks.

A comparative sustainability study of bioethanol production from selected starchy feedstocks that are abundantly available was carried out in this work. This is to ensure the safe, reliable, and efficient production and consumption of fuel-grade bioethanol. The analysis utilised the established economic minimum bioethanol plant capacity of 158,000 m3/annum. The processing flowsheet model utilised was the same for each feedstock. The sustainability study's economic, environmental, and energy perspectives were investigated. The economic and environmental indices were assessed using Superpro Designer and openLCA sustainability software, respectively. Exergy and lost work were subsequently estimated manually with Microsoft Excel. The economic analyses showed that the plants using cassava and sweet potato initially had the highest return on investment (ROI) of 64.41 and 41.96% respectively at a minimum of 80% plants' capacity utilisation. The break-even point occurs at a bioethanol price of $3.27 per gallon, beyond which positive net present values were obtained for the four processes. The least profitable plant was based on sorghum recording an ROI value of 34.11%. The environmental assessment on the four selected feedstocks showed that the processes based on cassava, corn, sweet potato, and sorghum recorded encouraging global warming potential (GWP) of 0.2452, 0.2067, 2.5261, and 0.2099 kg CO2 equivalent respectively. Cassava and corn emerged as the two most economically viable feedstocks when economic parameters were adjusted to include pollutants emission/discharge costs but with a slight decrease in profitability indices. The lost work analyses showed that distillation columns were the least energy-efficient units in the four bioethanol production routes assessed, recording loss work of about 61, 68, 34, and 49 MW for cassava, sweet potato, corn, and sorghum processing plants respectively. However, the net energy balance (NEB) and energy renewability results of the four production routes showed that the processes utilising the four selected starchy biomass feedstocks are more sustainable compared to fossil fuels.

[Major salmonellosis in Benin]. / Salmonelloses majeures au Bénin.

Although salmonellosis is a common endemo-epidemic disease in Benin, there is a paucity of data about it. The purpose of this cross-sectional study was to determine the incidence of major salmonellosis requiring hospitalizaton and to describe its epidemiological, clinical, and serologic features as well as treatment and outcome. Consecutive cases observed at the Medical Department of Parakou University Hospital in Benin between January 1, 2005 and December 31 2007 were included. Salmonellosis was defined on the basis of clinical and serological criteria. Among the 2,520 patients hospitalized during the study period, salmonellosis was diagnosed in 135 (5.4% [95% CI 4.5%-6.3%]). Highest incidences were observed in January, July, October and November. The main symptoms were headache, fever, fatigue and abdominal pain. The Salmonella typhi serotype was identified in 94.8% of patients. Two patients presented co-infection, i.e., Salmonella typhi with paratyphi A in one case and Salmonella typhi with paratyphi B in the other. Fluoroquinolones were used for treatment in 79.3% of patients. Outcome was favorable in 62.2%. The main complications were,typhoid digestive perforation in 11.1%, and gastrointestinal bleeding in 8.1%. The mortality rate was 4.4% (n=6). These data are consistent with previous reports in the literature and confirm the frequency and severity of salmonellosis in Benin.

Behavioural thresholds of blue tit colour vision and the effect of background chromatic complexity.

Vision is a vital attribute to foraging, navigation, mate selection and social signalling in animals, which often have a very different colour perception in comparison to humans. For understanding how animal colour perception works, vision models provide the smallest colour difference that animals of a given species are assumed to detect. To determine the just-noticeable-difference, or JND, vision models use Weber fractions that set discrimination thresholds of a stimulus compared to its background. However, although vision models are widely used, they rely on assumptions of Weber fractions since the exact fractions are unknown for most species. Here, we test; i) which Weber fractions in long-, middle- and shortwave (i.e. L, M, S) colour channels best describe the blue tit (Cyanistes caeruleus) colour discrimination, ii) how changes in hue of saturated colours and iii) chromatic background noise impair search behaviour in blue tits. We show that the behaviourally verified Weber fractions on achromatic backgrounds were L: 0.05, M: 0.03 and S: 0.03, indicating a high colour sensitivity. In contrast, on saturated chromatic backgrounds, the correct Weber fractions were considerably higher for L: 0.20, M: 0.17 and S: 0.15, indicating a less detailed colour perception. Chromatic complexity of backgrounds affected the longwave channel, while middle- and shortwave channels were mostly unaffected. We caution that using a vision model whereby colour discrimination is determined in achromatic viewing conditions, as they often are, can lead to misleading interpretations of biological interactions in natural - colourful - environments.

Virulence factors produced by strains of Staphylococcus aureus isolated from urinary tract infections.

Staphylococcus aureus infections are widely prevalent in West Africa and are often associated with urinary tract infections (UTIs). Virulence factors from S. aureus have rarely been described for such infections. The purpose of the current study was to determine the prevalence of toxins and adhesion factors obtained from S. aureus isolated from presumed primary UTIs at the Cotonou University Hospital (CUH) in Benin as compared with the Strasbourg University Hospital (SUH) in France. Both ambulatory and hospitalised patients were included in the study. Sixty-five independent strains of S. aureus from CUH and 35 strains from SUH were obtained over a four-month period. Virulence factors were characterised by immunodetection or multiplex polymerase chain reaction, and meticillin susceptibility was recorded. Approximately 50% of all isolates produced at least one enterotoxin. No isolate from SUH produced Panton-Valentine leucocidin (PVL), whereas 21.5% of the S. aureus isolates from CUH produced PVL (P<0.01). Six of 14 (43%) PVL-positive isolates were meticillin-resistant. At SUH, the incidence of MRSA (57%) was significantly higher (P<0.01) than at CUH (14%). Genes encoding clumping factor B, and elastin and laminin binding proteins were detected in almost all isolates (80%), irrespective of the geographical origin. The results for elastin binding protein differed significantly from published data regarding isolates from other clinical origins. Staphylococcal toxins and adhesion factors may be important in the physiopathology of UTI.

[Production lead time of coagulase in 180 Staphylococcus aureus strains collected at Abidjan]. / Delai de production de la coagulase chez 180 souches de Staphylococcus aureus isolees a Abidjan.

INTRODUCTION: The pathogenic capacity of S. aureus is related.to the production of many virulence factors of which the coagulase. Several genotypes of coagulase were described and are associated to various populations of S. aureus. According the susceptibility to methicillin, methicillin-resistant strains of S. aureus, are described. The aim of this subject was to study the coagulase expression of Staphylococcus aureus according to the site of infection, patient origin and the resistance against methicillin. MATERIAL AND METHODS: The study is related about 180 strains of S. aureus collected in the three University Teaching Hospital of Abidjan. S. aureus are identified with laboratory classical methods. Coagulase delay was determined by the test of the coagulase on citrated rabbit plasma at 2, 4 and 18 hours. The resistance against methicillin was researched by disc diffusion agar technique. RESULTS: In 60% of cases, the bacterial strains gave a coagulum at the end of four hours, fast coagulase, against 40% of strains whose coagulating activity appeared at 18 h, slow coagulase. Fast coagulase strains are isolated from the majority of infections (55% to 71%), in hospital patients (66%) and in paediatrics (58%). Fast coagulase strains are methicillin-resistant in 65% of cases against 48.5% of methicillin-susceptible and low coagulase strains (p < 0.0001). CONCLUSION: According to the production lead time of the coagulase, fast coagulase and slow coagulase variants of S. aureus coexisted. The expression of the coagulase is not related to the site of infection and the origin of the patients. On the other hand, the type of coagulase is associated to resistance of methicillin. However, the time of formation of the coagulum typed by the test of the coagulase, didn't constitute a sufficient discriminating factor in the medical following and the treatment of infections caused by S. aureus.

Extracellular polysaccharide from Weissella confusa OF126: Production, optimization, and characterization.

The production, optimization, and characterization of exopolysaccharide (EPS) from Weissella confusa OF126 and the in-vitro probiotic potentials of this strain was investigated. The EPS produced on sucrose modified-MRS broth was characterized. The purified EPS had an average molecular weight of 1.1 × 106 Da. HPLC analysis revealed the presence of glucose monomers, indicating its homopolysaccharide nature. The structural characteristics of the EPS were investigated by FTIR, and NMR spectroscopy. FTIR spectroscopy revealed the presence of hydroxyl, carboxyl, N-acetyl and amine groups. NMR analysis confirmed that the EPS contained α-(1 → 6) linkage and α-(1 → 3) branched linkage. The EPS showed strong in-vitro antioxidant activity. Four significant factors were optimized using Central Composite Design (CCD) and Response Surface Methodology (RSM). The predicted optimum conditions for EPS production were cultivation time (48.50 h), sucrose concentration (24.00 g/L), pH (7.00) and yeast extract (2.50%).The EPS produced was predicted to be 3.10 g/L, while the experimental yield was 3.00 g/L. This strain was found to possess desirable probiotic attributes by its ability to survive at pH 2.0 and in the presence of bile salts (0.50% (w/v)) for 4 h. The results obtained from this study demonstrate W. confusa OF126 as a promising probiotic and the EPS produced can find useful applications in industries.

Donor risk factors for renal graft thrombosis.

Graft thrombosis is one of the most devastating complications of transplantation. In obtaining consent prior to transplant, it is useful to share potential risk factors with the recipient. In order to do this, we explored the impact of different risk factors that could contribute to this complication. Using multivariate analysis we found that neither multiple vessels nor vascular injury had a bearing on the risk of graft thrombosis but atheroma did (P < .02).

[Incidence of infections dues to Escherichia coli strains producing extended spectrum betalactamase, in the Zou/Collines Hospital Centre (CHDZ/C) in Benin]. / Incidence d'infections liées à Escherichia coli producteur de bêta lactamase à spectre élargi au Centre hospitalier départemental du Zou et Collines au Bénin.

OBJECTIVES: Over a 6-month period, extended-spectrum betalactamase (ESBL)-producing isolates of Escherichia coli (EC) were collected from in-patients and their environment at the Zou-Collines Hospital Centre (CHDZ/C) in Benin. The aim of this study was to determine the incidence of ESBL and to describe their phenotypic susceptibility to antibiotics in a secondary hospital (500 beds) in Benin. METHODS: From 15 May to 15 November 2005, clinical informations and samples were collected from patients suspected to have nosocomial infections. The isolates were identified, tested for antimicrobial susceptibility and analysed for the presence of ESBL genes blaTEM and blaSHV by PCR. RESULTS: One hundred ninety-seven enterobacteria were isolated from the clinical samples of 342 patients, these isolates included 143 EC and 32/143 (22%) of these isolates produced ESBL. Forty-six EC were isolated from the environment and 7 (15%) of them produced ESBL. Except for Imipenem for which the difference was not significant, the isolates producing ESBL were more resistant to the other antibiotics (especially to third generation cephalosporins: Ceftriaxone, Cefotaxime, Ceftazidime (P<0.00001)) than non-ESBL producing isolates. Both ESBL genes blaSHV and blaTEM were identified in the EC ESBL strains from patient and from the environment. CONCLUSION: This study shows the presence of ESBL genes among EC in various wards of the CHDZ/C hospital proving that there is a need to implement a strict hospital infection control program and a regular surveillance of resistance to antimicrobial agents.

Predisposing factors for biliary complications following liver transplantation.

INTRODUCTION: Biliary complications remain a major cause of morbidity and mortality in patients following liver transplantation. We sought to identify possible risk factors predisposing to biliary complications after OLT using duct-to-duct biliary reconstruction. MATERIALS AND METHODS: We retrospectively reviewed 5 years of prospectively collected donor and recipient data between April 1999 and April 2004. We evaluated the presence of biliary complications, donor and recipient age, cold ischemia time, hepatic artery thrombosis, non-heart-beating donor (NHBD), and graft steatosis (>30%). The results were compared with a control group of OLT patients without biliary complications. RESULTS: Among 173 OLT recipients, biliary complications occurred in 28 patients (16.2%), of whom 12 were leaks, 15 strictures, and 1 a nonanastomotic intrahepatic stricture. The mortality following biliary complications was 11%, compared to 6% in the control group. CONCLUSION: Biliary complications remain a persistent problem in OLT. Analysis of risk factors identified hepatic artery thrombosis and steatosis as predisposing factors. With greater experience, NHBD livers may also prove to be at greater risk of biliary complications.

Renal graft function after prolonged agonal time in non-heart-beating donors.

To deal with the increasing gap between organ demand and supply for kidney transplantation, many centers have started to use non-heart-beating (NHB) donors. When we initiated our program to utilize kidneys from such donors in 1998, we had no protocol for the maximal agonal period. This however was audited in retrospect. Our current wait time is now a maximum of 5 hours. Concern has been expressed in the past about possible deterioration in the quality of the organs with a protracted agonal time. We aimed in this study to examine the effect of prolonging agonal period on the quality of kidneys retrieved from Maastricht category III donors: A total of 40 kidneys were transplanted from 29 category III donors between 1998 and 2004. Eleven kidneys had donor agonal times of >5 hours; the remainder, agonal times <5 hours. Both groups were matched for donor and recipient factors. The mean glomerular filtration rates at 12 months for <5 hours versus >5 hours agonal time were 43.8 +/- 4.4 versus 49.8 +/- 5.8, respectively (P = .24) and at 24 months, 46.83 +/- 8.99 versus 37.67 +/- 3.85, respectively (P = .24). In conclusion, intermediate graft function is comparable to ones with shorter agonal time, although we await long-term results.

Diabetic donors as a source of non-heart-beating renal transplants.

Due to the organ shortage, many renal transplantation centers attempt to increase the donor pool by using non-heart-beating donors (NHBDs). These kidneys are generally regarded as "marginal" grafts. Many centers do not consider transplantation from an NHBD with a history of diabetes as it is a more suboptimal donor. We began our NHBD program in 1998 and have performed 5 renal transplants from diabetic NHBDs. Viability testing identified kidneys suitable for single or dual transplantation. Although kidneys from brain stem dead donors with diabetes have been used successfully, our data suggested that kidneys from diabetic NHBDs can also be used although we still need long-term results.

Agonal period in potential non-heart-beating donors.

The shortage of donor kidneys for renal transplantation is becoming more severe as the gap between the number of patients waiting for renal transplantation and the number of cadaveric organs available continues to widen. Therefore, many centres have started using non-heart-beating (NHB) donors. There was no clear plan for maximal duration of agonal period in Maastricht category NHB donors after withdrawal of treatment in Newcastle. This withdrawal has been audited in retrospect. Our current wait time is now a maximum of 5 hours; however, previously there have been some considerably longer periods. Concern has always been expressed about poor quality with protracted periods. Nonuse in this review of 58 kidneys can be expressed against time: 0 to 2 hours 13%, 2 to 5 hours 33%, and >5 hours 45%. Therefore, though the nonuse rate was significantly different between 0 to 2 hours and >5 hours (P < .05, chi-square), there were 16 transplants performed with kidneys >2 hours and 12 transplanted >5 hours. In conclusion, although good usable kidneys can still be used with protracted withdrawal, there are considerable logistical difficulties with our 5-hour cut-off, which means that one third of potential kidneys will not be utilized.

Dual renal transplantation for kidneys from marginal non-heart-beating donors.

Kidneys transplanted from non-heart-beating donors (NHBD) are generally regarded as marginal or extended criteria grafts due to the associated period of warm ischemia. The most prolonged periods occurring in the category II (uncontrolled) donor. This potential for injury can adversely affect the glomular filtration rate (GFR), which in severe cases results in primary nonfunction. Viability testing can identify a group of kidneys that, although unsuitable for solitary transplantation, may be considered for dual transplant. This retrospective study examined a series of 11 dual renal transplants, comparing 3- and 12-month GFR outcome data with 81 single NHBD transplants. The mean GFR at 3 months in the dual group was 47.6 and at 12 months was 48.6. In the single group the GFR at 3 months was 40.6 and at 12 months was 41.9. Thus using viability testing to identify NHBD kidneys suitable for dual transplant appears reliable and predictable.