Detection of genes encoding for virulence and adherence factors in Escherichia coli isolated in slaughtered Sarda breed sheep.

In order to investigate the pathogenic profile of Escherichia coli hosted in "Sarda" sheep, autochthonous race present in Sardinia, thirty-seven E. coli strains collected from different sources (fleeces, carcass swabs and gut mucosa) of pre-chill slaughtered sheep (ewes and lambs) were serotyped using pheno- and genotypic methods. Furthermore, the presence of genes encoding for virulence factors and mediating for localized mucosal adherence factors was investigated, and pulsed-field gel electrophoresis (PFGE) characterization was performed. Twenty-one (56.8%) of the isolates belonged to O91 serogroup and sixteen (43.2%) belonged to nine different serotypes (O5:H11, O8:H14, O26:H2, O38:H26, O116:H9, O116:H11, O132:H34, O149:H?, O161:H-). Of these non-O91 strains, five (13.5%) were able to produce verocytotoxin (VT) and were ascribed to VTEC pathogroup, eleven (29.7%) were attributed to the Enteropathogenic E. coli (EPEC) pathogroup; the other strains (n.21) cannot be ascribed to a pathogenic group. However, various associated virulence genes were observed in all isolated strains. Macrorestriction analysis highlighted a large heterogeneity of the E. coli strains. The results confirm the role of sheep as reservoir of pathogenic E. coli serotypes potentially able to colonize and to damage the intestinal mucosa.

Cystic echinococcosis in the sheep: causes of its persistence in Sardinia.

The authors analyse the current epidemiological situation of sheep Cystic Echinococcosis (CE) in Sardinia, where the prevalence of ovine CE is still very high (70%) and this parasitosis is also frequently found in the human population. For this reason Sardinia represents a peculiar model for CE study, because there are particular conditions that allow Echinococcus granulosus to complete its life cycle. Some social and economical factors support the persistence of sheep CE: over 3 million Sarda breed heads are extensively bred; the presence, at farm level, of a strong relationship between dog, sheep and human; the low commercial value of meat coming from adult sheep, which results in a large number of sheep being slaughtered at home or on the farm rather than in authorized slaughterhouses. Moreover Sardinia is the only Italian region where partially successful echinococcosis control plans have been applied. The authors suggest some indirect and direct initiatives, including the use of a new vaccine against the development of this metacestode in sheep, to reduce the prevalence of CE.

Evolution and identification of lactic acid bacteria isolated during the ripening of Sardinian sausages.

Lactic acid bacteria (LAB) were isolated during the production and the ripening of Sardinian sausage, a typical Italian dry fermented sausage. Samples were taken at different stages, and 112 strains were isolated. The isolates were characterized using the micromethod proposed by Font de Valdez et al. [Font de Valdez, G., Savoy de Giori, G., Oliver, G., & De Ruiz Holgado, A. P. (1993). Development and optimization of an expensive microsystem for the biochemical characterization of lactobacilli. Microbiologie Aliments Nutrition, 11, 215-219]. Schillinger and Lücke's [Schillinger, U., & Lücke, F. K. (1987). Identification of lactobacilli from meat and meat products. Food Microbiology. (4), 199-208] scheme and the biochemical patterns given by Bergey's Manual of Systematic Bacteriology [Bergey's Manual of Systematic Bacteriology (1986). Baltimore: William and Wilkins] were used for preliminary identification. A PCR-based method was then used to confirm the results. LAB were the dominant flora during ripening. They consisted mainly of homofermentative mesophilic rods. Lactobacillus sakei (43,3%), Lactobacillus plantarum (16,6%) and Lactobacillus curvatus (13,3%) were the main isolates. The results of the biochemical identification methods agreed well with those of PCR-based identification (91% agreement).

[Determination of antibiotic chemicals using microbiological tests: evaluation of the limits of sensitivity]. / Rilevazione di chemioantibiotici con tests microbiologici: valutazione dei limiti di sensibilità.

Sensitivity of Bacillus subtilis BGA and Bacillus stearothermophilus var. calidolactis disc assays to 53 chemio-antibiotics was tested. Test-microorganisms were sown in two different mediums: PM Indicator Agar, Difco U.S.A., and Standard II Nutrient Agar, Merck Germany, modified according to Nouws. The mediums were used with or without addition of Trimethoprim (at a concentration of 0.12 or 0.024 mcg/ml of medium for B. subtilis and for B. stearothermophilus respectively). B. stearothermophilus did not grow in Standard II. However, the B. subtilis assay gave the best results with Standard II, apart for aminoglycosides. The B. stearothermophilus disc assay was the most sensitive to penicillins (Minimum Inhibiting Concentration in mcg/ml, MIC, between 0.001 and 0.004), cephalosporins (MIC between 0.003 and 0.09, apart from Ceftazidime, 0.3) and aminoglycosides (MIC between 0.03 and 0.6). The B.subtilis disc assay showed better sensitivity to quinolines (MIC between 0.05 and 4) and to some tetracyclines (oxytetracycline and chlortetracycline, MIC 0.03). Trimethoprim, where added, determined a higher sensitivity to sulfonamides (MIC between 0.025 and 0.25).

[Experimental listeriosis in chickens: microbiological and anatomo-histopathological studies and health and hygiene considerations]. / Listeriosi sperimentale dei polli: indagini microbiologiche ed anatomo-istopatologiche e considerazioni igienico-sanitaire.

The authors report the results of an experimental infection of 20 chickens with L.m. in order to verify if they became affected by Listeriosis and to individuate the degree of contamination of the meat and parenchymas and eggs. Despite the high infecting dose (160 x 10(7) micro-organism in group 1, 51 x 10(8) + cortisone in group 2, 130 x 10(8) in group 3), no signs of the disease were found in any of the animals; besides, L.m. was isolated in the faeces of only 3 subjects for 1 day post-infection and in the organs of 4 subjects for a maximum of 15 days post-infection. From a histopathological point of view only simple lymphocytic-macrophagic and eosinophilic proliferations localized in the liver and, to a lesser extent, in other parenchymas were observed. The authors advance the hypothesis that the frequent isolations of L.m. in chicken meat and eggs can be attributed to exogenous contamination in stages of slaughtering and marketing of the product.