Archives de l'Institut Pasteur de Tunis最新文献

Snake venoms are rich sources of serine proteinase inhibitors that are members of the KunitzBPTI (bovine pancreatic trypsin inhibitor) family. Generally, these inhibitors are formed by 60 amino acids approximately. Their folding is characterised by a canonical loop that binds in a complementary manner to the active site of serine protease. Some variants from snake venoms show only weak inhibitory activity against proteases while others are neurotoxic. Moreover, proteases inhibitors are involved in various physiological prdcesses, such as blood coagulation, fibrinolysis, and inflammation. Also, these molecules showed an anti-tumoralpotent and anti-metastatic effect. Interestingly, KunitzBPTI peptides can have exquisite binding specificities and possess high potency for their targets making them excellent therapeutic candidates.

During the postoperative peritonitis (PPO) the main stay of treatment is the choice of probabilistic antibiotictherapy, it is also the main prognostic factor The aim of our study was to identify anappropriate antibiotic protocol to the current ecology of our unit. It was a retrospective study including 102 patients over a period of 09 years from 1 January 2003 to 3O November 2011. All of them are supported for the treatments off postoperative peritonitis in surgical intensive care unit of a service of general surgery a university hospital Charles Nicolle of Tunis. All bacteriological data (germs and sensitivity), and the terms of therapeutic modality for the empirical antibiotic therapy were listed. The incidence of PPO was Q90%.The average age of our patients was 57 +/- 18 years. The sex ratio was 1.08. One hundred and seven (107) microorganisms were isolated from 72 samples (44 microbial mono, 28 multi microbial). The frequency of gram-positive cocci (GPC) was 16.82%, the Gram-negative bacilli (BGN) was 82.2%. The Enterobacteriaceae have proved particularity resistant. Thus, the ampicillin resistance was 87.14%, that the C3G was 33.80%, the Piperacillin to Tazobactam combination, was 36.5% and that the association Ticarcillin-clavulanic acid was 43.6%. For non-fermenting BGN, Pseudomonas aeruginosa was sensitive to ticarcillin in 80% of cases, to ceftazidime in 66.6% of cases, PiperacillinTazobactam--in 71.43% of cases, imipenem in 85 72% of cases, colimycin in 100% of cases and Amiklin in 71.43% of cases. For CGP, enterococci were resistant to ampicillin in 50% of cases and vancomycin in 0% of cases. The majority of patients received triple antibiotic therapy (59.8%) or combination therapy (34.3%). The main associations were: cefotaxime + Gentamycin + Metronidazole (35.2%), Amikacin Imipenem + + Metronidazole (12.7%), Imipenem + amikacin (9.8%), Piperacillin / Tazobactam + amikacin (9.8%) + amikacin and ertapenem (5.88%). Probabilitic antibiotic therapy was addapted in 69.4% of cases. The average duration of the prescribed antibiotic was 11 days +/- 6 days. The mortality rate was 39.2%, was 32.23 days. The isolated microorganisms are those of the intestinal flora which is generally changed and thus the bacteria are selected then are multidrug resistant. Prescribing antibiotics should consider probabilistic. Thus, Imipenem-Amiklin combination seems appropriate to our ecology. This empiric antibiotic therapy is secondarily adapted to the results of susceptibility testing to limit the selection of multi-resistant organisms.

The postoperative peritonitis (POP) remains formidable conditions due to a high mortality rate of between 20 and 80%. The purpose of this study is to identify risk factors for mortality. This study is a retrospective, descriptive analysis carried out over a period of 09 years (1/1/2003 - 30/11/2011) and interesting 102 patients supported for POP following general surgery. Achieved in department of General Surgery B Charles Nicolle hospital Tunis. The parameters measured included epidemiological data, data related to the Initial Surgical Intervention and reoperation for POP, terms of management and evolution. Bacteriological data were also seized. The incidence of POP was 0.90%. The average age of our patients was 58 +/- 19 years with a sex ratio of 1.08. Forty-seven percent of our patients belonged to the ASAII class. The initial operation was performed urgently in 49 patients (48%) with a majority belonging to the class II Altemeier (49.01%). Colorectal pathology (373%) and hepatobiliay (176%) were the most frequent reasons for the initial intervention. The frequency of clinical signs were fever (75.5%), hypothermia (6.9%), abdominal pain (725%), abdominal distension (46.1%), productive gastric aspiration (30.4%), abdominal defense (25.5%), externalizing the digestive fluid (25.5%), vomiting (19.6%), diarrhea (12.7%), tachycardia (569%), oliguria (42.2%), respiratory failure (40.2%), hypotension (35.3%), neuropsychiatric disorders ( 23.5%) and jaundice (69%). The treatment period was 2.95 +/- 3.16 days. The surgical recovery time was 78 days +/- 5.66. At the time of reoperation, the APACHE II score was 8.43 +/- 6.26 and 25.1 +/- MPI score 8.53. The POP was generalized in 52.9% of cases with purulent peritoneal fluid in 51% of cases. The most common cause was the dropping of the anastomosis (59.8%). Empirical antibiotic therapy was appropriate in 69.44 % of cases. The mortality rate was 39.2%. Multivariate analysis using multiple logistic regression identified the following factors as independent mortality factors: Age > or = 60 years (RR = 6.089), multiple organ failure (RR = 18.019), non-appropriate empiric antibiotic therapy (RR = 6.541), stercoral aspect of peritoneal fluid (RR 6.412). Despite a low frequency, the POP are burdened with a high mortality rate. The improved prognosis requires early diagnosis in order to allow a appropriate load medicosurgical support before the installation of multiorgan failure syndrome. Among the independent factors associated with mortality that we have identifed, the not adapted empiric antibiotic therapy is the main factor on which we can act.

Accurate assessment of diagnostic tests may be biased if an imperfect reference test is used for comparison; such a situation exists for the diagnosis of canine leishmaniasis. We compared classical diagnostic tests for Leishmania infantum with Latent Class Analysis (LCA), to assess whether we could make a more accurate calculation of diagnostic accuracy. Microscopy (Lymph node aspirate), serological test (IFAT), and molecular tests (LAMP and PCR) data were recorded for 75 dogs captured in Tunisian endemic area and suspected of leishmaniasis. Sensitivity and specificity estimates with the 2 x 2 contingency tables (Microscopy as gold standard) were broadly corroborated by LCA. However, the LCA provided a way to control the study limitations (small sample size) as well as for confounding factors. It also produces consistent estimates of the test characteristics. LCA estimation of the sensitivity and specifcity of the LAMP cpb assay (se: 68.7% [95% CI 573-80%] and sp: 86.2 [95% CI 749-975%]) is higher as compared to classical calculations (se: 54.2% [95% CI 38.2-69.5%] and sp: 80% [95% CI 65.2-89.5%). Considering the lack of an adequate reference standard, LCA proved to be a useful tool to independently evaluate diagnostic methods.

L-amino acid oxidases (LAAOs) are flavoenzymes widely found in several organisms, including venoms snakes, where they contribute to the toxicity of ophidian envenomation. Their toxicity is primarily due to enzymatic activity, but other mechanisms have been proposed recently which require further investigation. LAAOs exert biological and pharmacological effects, including actions on platelet aggregation and the induction of apoptosis, hemorrhage and cytotoxicity. These proteins present a high biotechnological potentialfor the development of antimicrobial, antitumor and antiprotozoan agents. This review summarizes the biochemical properties, structural characteristics and various biological functions of snake venoms' LAAO. Furthermore, the putative mechanisms of action, were well detailed.

Eco-climatic conditions are often associated with the occurrence of West Nile Disease (WND) cases. Among the complex set of biotic and abiotic factors influencing the emergence and spread of this vector-borne disease, two main variables have been considered to have a great influence on the probability of West Nile Virus (WNV) introduction and circulation in Tunisia: the presence of susceptible bird populations and the existence of geographical areas where the environmental and climatic conditions are more favourable to mosquito multiplications. The aim of this study was to identify and classify the climatic and environmental variables possibly associated with the occurrence of WNVhuman cases in Tunisia. The following environmental and climatic variables have been considered: wetlands and humid areas, Normalised Difference Vegetation Index (NDVI), temperatures and elevation. A preliminary analysis for the characterization of main variables associated with areas with a history of WNV human cases in Tunisia between 1997 and 2011 has been made. This preliminary analysis clearly indicates the closeness to marshes ecosystem, where migratory bird populations are located, as an important risk factor for WNV infection. On the contrary the temperature absolute seems to be not a significant factor in Tunisian epidemiological situation. In relation to NDVI values, more complex considerations should be made.

Toxins from animal venoms are small peptide molecules able to interact with a wide range of specific cellular targets in order to modulate their activity, which enables them to act in many physiological and pathological processes. Recently, structuralandpharmacologicalstudieshaveshown the involvement of these biological agents in the pathogenesis of many diseases like diabetes, cancer paralysis, autoimmune diseases or neurological disorders. Nevertheless, the only punfication from scorpion venoms of theses peptides still doesn't offer sufficient quantities to allow conducting the pharmacological and structure-function studies. The solid phases peptide synthesis (SPPS) is a methodology that allows us to produce non-limited quantities of structural analogsfrom these peptides-toxins in. In this paper; we will try to highlight the importance of this methodology, and peptide engineering in general, in obtaining peptides of interest. We are also going to elucidate the problems encountered during the chemical synthesis of some betides and explain how to overcome them.

Ruta chalepensis L. (Rutaceae), is an ancient aromatic medicinal plant still used in the traditional medicine of many countries as a laxative, antiinflammatory, analgesic, antispasmodic, abortifacient, antiepileptic, emmenagogue and for dermatopathy treatment. Regarding increasing prevalence of mycotoxins and inefficiency of methods used to decrease them, it is possible to use plants metabolites to decrease mycotoxins. This study was carried out to evaluate chemical composition, antifungal and anticandidal activities of R. chalepensis extracts. The chemical composition of its essential oil was analyzed by gas chromatography coupled with mass spectrometry (GCMS). The major components of R. chalepensis essential oil were menthol (49.92%), linalool (31.1%) and 2-hexanal (5.2%). The antifungal and anticandidal effects of the essential oil and methanolic extract of R. chalepensis leaves were studied by disc diffusion assay and broth dilution method. The obtained results showed that R. chalepensis extracts had a significant fungicidal effect against Aspergillus niger, Aspergillus flavus and Candida albicans. The inhibition zones diameters and the minimum inhibitory concentration values for tested microorganisms were in the range of 11-17 mm and 3.25-6.25% (v/v), respectively. The methanolic extract showed much better antimicrobial activity than the essential oil against three tested micro-organisms

In this work, survival tests are conducted in oligotrophic seawater using pathogenic bacterial strains: Escherichia coli entéroagrégative, Salmonella Typhimurium and Vibrio parahaemolyticus. After 26 days of incubation in seawater, the three bacterial strains are exposed to sunlight for nine hours. Bacterial cells of the three strains, recovered at the end of the experiment by centrifugation were tested for their sensitivity to antibiotics and their enzymatic and metabolic profile (API 20E and 20NE). The results showed a decline in the culturability of ascending chronological order: first enteroaggregative Escherichia coli (T90 = 7 days), followed by Salmonella Typhimurium (T90 = 12 days) and finally Vibrio parahaemolyticus (T90 = 43 days). Vibrio parahaemolyticus strain showed better survival under seawater conditions before and after exposure to sunlight compared to other strains tested. On the other hand, the most reduced survival time is observed for Escherichia coli, which then becomes inadequate to predict halophilic pathogenic bacteria. Also, we noted that the solar radiation in this study would be the most important factor affecting the survival of three bacterial strains incubated in oligotrophic seawater. Changes of the enzymatic and metabolic profile are more pronounced in Escherichia coli and Salmonella, which reflect a form of resistance and a response to the passage in a hostile environment. However, the rate of antibiotic susceptibility is more apparent in Vibrio (100%) compared to the wild type Escherichia coli (60%) although the latter has completely lost its power to cultivate. This result underlines the relationship between the antibiotics resistance power of VNC cells and the history of the bacterial strain.

The Vascular Endothelial Growth Factor "VEGF" plays a pivotal role in the stimulation of angiogenesis. The VEGF isoforms (A-D) and PlGF act in a coordinate fashion to develop the vascular network. Numerous proteins closely related in structure and function to VEGF-A have been reported and were grouped in the VEGF family. Some predators make use of VEGF-like molecules with devastating results for their prey. VEGF-E, investigated in 1994, is encoded by the parapoxvirus (Orf virus). VEGF-F is a common term designating molecules which were isolated from snake venom (also known as svVEGF). These proteins are disulphide-linked homodimers of 110 amino acids each and have a molecular weight of approximately 25 kDa. Their primary structures show approximately 50% identity to VEGF-A. However, unlike VEGF-A, they do not contain any N-linked glycosylation sites. They interact with heparin but have a different binding domain from that of VEGF-A. Among species, these svVEGFs vary extensively in amino acid sequences and in receptor-binding specificities towards endogenous VEGF receptors. Understanding the properties that determine the specificity of these interactions could improve our knowledge of the VEGF-receptor interactions. This knowledge is essential to the development of new drugs in angiogenesis. This knowledge is essential to the development of new drugs in angiogenesis.