Adriana Sanna

Antiherpevirus activity of Artemisia arborescens essential oil and inhibition of lateral diffusion in Vero cells

BackgroundNew prophylactic and therapeutic tools are needed for the treatment of herpes simplex virus infections. Several essential oils have shown to possess antiviral activity in vitro against a wide spectrum of viruses.AimThe present study was assess to investigate the activities of the essential oil obtained from leaves of Artemisia arborescens against HSV-1 and HSV-2MethodsThe cytotoxicity in Vero cells was evaluated by the MTT reduction method. The IC50 values were determined by plaque reduction assay. In order to characterize the mechanism of action, yield reduction assay, inhibition of plaque development assay, attachment assay, penetration assay and post-attachment virus neutralization assay were also performed.ResultsThe IC50 values, determined by plaque reduction assay, were 2.4 and 4.1 μg/ml for HSV-1 and HSV-2, respectively, while the cytotoxicity assay against Vero cells, as determined by the MTT reduction method, showed a CC50 value of 132 μg/ml, indicating a CC50/IC50 ratio of 55 for HSV-1 and 32.2 for HSV-2. The antiviral activity of A. arborescens essential oil is principally due to direct virucidal effects. A poor activity determined by yield reduction assay was observed against HSV-1 at higher concentrations when added to cultures of infected cells. No inhibition was observed by attachment assay, penetration assay and post-attachment virus neutralization assay. Furthermore, inhibition of plaque development assay showed that A. arborescens essential oil inhibits the lateral diffusion of both HSV-1 and HSV-2.ConclusionThis study demonstrates the antiviral activity of the essential oil in toto obtained from A. arborescens against HSV-1 and HSV-2. The mode of action of the essential oil as antiherpesvirus agent seems to be particularly interesting in consideration of its ability to inactivate the virus and to inhibit the cell-to-cell virus diffusion.

Comparison of the susceptibility testing of clinical isolates of Mycobacterium tuberculosis by the XTT colorimetric method and the NCCLS standards method

The susceptibility or resistance of clinical isolates of Mycobacterium tuberculosis were determined by a method incorporating the 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and compared with results obtained by the National Committee for Clinical Laboratory Standards approved standard method (M24-T2). One hundred percent of all isolates demonstrated agreement between the susceptibility and resistance to isoniazid, rifampicin, and ethambutol obtained by the two methods, suggesting that the XTT-based method could provide a useful means for the rapid determination of antimycobacterial susceptibility of clinical isolates of M. tuberculosis.

Novel N-aryl- and N-heteryl phenazine-1-carboxamides as potential agents for the treatment of infections sustained by drug-resistant and multidrug-resistant Mycobacterium tuberculosis.

We investigated the in vitro activity of a new class of N-aryl and N-heteryl phenazine-1-carboxamide derivatives against Mycobacterium tuberculosis H37Rv and against drug-resistant ATCC M. tuberculosis strains. The activity against M. tuberculosis in J774 macrophage cells was also investigated. In most cases, minimum inhibitory concentrations (MICs) ranging between 0.19 mg/L and 0.79 mg/L were found, and comparable MIC values were obtained against 26 susceptible and 5 drug-resistant clinical isolates. Several derivatives were shown to be effective in inhibiting the growth both of susceptible and resistant strains at comparable concentrations. Results obtained indicate that these compounds could represent a promising class of agents useful for the treatment of M. tuberculosis infections caused by drug-resistant strains.

Hygiene and health risks associated with the consumption of edible lamellibranch molluscs

Edible lamellibranch molluscs are frequently the cause of very serious outbreaks of food poisoning. Microbiological suitability for human consumption, according to EC Reg. n. 1441/2007, is only based on two faecal bacteriological contamination parameters (Escherichia coli and Salmonella) and does not consider other microorganisms which are naturally present within the marine environment and are potentially pathogenic such as those belonging to the genus Vibrio. In this study, a total of 540 samples of edible lamellibranch molluscs (mussels, clams and oysters) bred in Sardinia were analyzed for E. coli and Salmonella, according to EC Reg n. 1441/2005, and for the presence of Vibrios of major public health interest. Environmental parameters (seawater temperature and salinity) were also recorded. The 40% (n=216) of samples were positive for Vibrio while the levels of E. coli were above the legal European limit only in 6.4% of samples. A correlation between the presence of micro-organisms of faecal origin and potentially harmful Vibrios to human health was not observed. Vibrio alginolyticus was the most common in 68% of isolated species, followed by Vibrio parahaemolyticus in 22.6%, Vibrio cholerae in 6% and Vibrio vulnificus in 1.1%. Virulence gene (trh sequence) was present in 1.6% of the V. parahaemolyticus-positive samples. The V. cholerae, V. vulnificus and V. alginolyticus strains detected were non toxigenic. The absence of genes encoding major virulence factors in the studied strains does not exclude the possibility of exposure to pathogenic strains. This study indicates the potential health risk associated with the presence of pathogenic Vibrios in edible lamellibranch molluscs bred in Sardinia, where shellfish production is very important to the local economy.

Detection of Virulence Genes and Growth Potential in Listeria monocytogenes Strains Isolated from Ricotta Salata Cheese

Ricotta Salata is a traditional ripened and salted whey cheese made in Sardinia (Italy) from sheeps milk. This product is catalogued as ready-to-eat food (RTE) since it is not submitted to any further treatment before consumption. Thus, foodborne pathogens, such as Listeria monocytogenes, can represent a health risk for consumers. In September 2012, the FDA ordered the recall of several batches of Ricotta Salata imported from Italy linked to 22 cases of Listeriosis in the United States. This study was aimed at evaluating the presence and virulence properties of L. monocytogenes in 87 samples of Ricotta Salata produced in Sardinia. The ability of this product to support its growth under foreseen packing and storing conditions was also evaluated in 252 samples. Of the 87 samples 17.2% were positive for the presence of L. monocytogenes with an average concentration of 2.2 log10 cfu/g. All virulence-associated genes (prfA, rrn, hlyA, actA, inlA, inlB, iap, plcA, and plcB) were detected in only one isolated strain. The Ricotta Salata samples were artificially inoculated and growth potential (δ) was assessed over a period of 3 mo. The value of the growth potential was always >0.5 log10 cfu/g under foreseen packing and storing conditions. This study indicates that Ricotta Salata supports the L. monocytogenes growth to levels that may present a serious risk to public health, even while stored at refrigeration temperatures.

Exploring the thiazole scaffold for the identification of new agents for the treatment of fluconazole resistant Candida

Abstract Cyclohexyliden- and 2-methylcyclohexyliden-hydrazo-4-arylthiazoles were synthesized and tested as antifungal agents. All compounds exhibited minimal inhibitory concentration (MIC) values comparable with those of fluconazole (FLC). Moreover, some compounds showed fungicidal activity at low concentration. Worth noting five out of nine compounds were active towards Candida albicans 25 FLC resistant isolated from clinical specimens. The cellular toxicity was evaluated and none of the compounds is toxic at the MIC. On the basis of our data we can conclude that these derivatives are promising agents for the treatment of resistant C. albicans.

Design, synthesis, SAR and biological investigation of 3-(carboxymethyl)rhodanine and aminothiazole inhibitors of Mycobacterium tuberculosis Zmp1

Sixteen 3-(carboxymethyl)rhodanines, and twelve aminothiazoles as rhodanine-mimetics were designed, synthesized and tested as inhibitors of the Zmp1 enzyme from Mycobacterium tuberculosis (Mtb). Almost all rhodanines (5a-d, 5f-n, and 7a-b) exhibited Zmp1 inhibition with IC50 values in the range 1.3-43.9 µM, whereas only aminothiazoles 12b and 12d proved active with IC50 values of 41.3 and 35.7 µM, respectively. Structure-activity relationships (SAR) were coupled with molecular modeling studies to highlight structural determinants for Zmp1 inhibition. Moreover, rhodanines 5a and 5c induced 23.4 and 53.8% of Mtb growth inhibition in THP-1 infected cells, respectively, at the non-toxic concentration of 10 µg/ml. This work represents a step forward in targeting Zmp1 by small molecules.

Presence of Trihalomethanes in ready-to-eat vegetables disinfected with chlorine

ABSTRACT Trihalomethanes (THMs) – CHCl3, CHCl2Br, CHClBr2 and CHBr3 – are drinking water disinfection by-products (DBPs). These compounds can also be absorbed by different types of foods, including ready-to-eat (RTE) fresh vegetables. The potential absorption of THMs during washing of RTE vegetables could pose a potential risk to consumers’ health. The concentration of THMs in the water used in the manufacturing process of these products shall not exceed the limit of 100 or 80 µgL−1 according to European Union (EU) and United States legislation, respectively. By contrast, there is little information about the presence of such compounds in the final product. This study evaluated the concentration of THMs in different types of RTE vegetables (carrots, iceberg lettuce, lettuce, mixed salad, parsley, parsley and garlic, rocket salad, valerian) after washing with chlorinated water. In the 115 samples analysed, the average value of total THMs was equal to 76.7 ng g−1. Chloroform was the THM present in the largest percentage in all the RTE vegetables. These results show that the process of washing RTE vegetables should be optimised in order to reduce the risk for consumers associated with the presence of DBPs.