The body sites of 163 heifers, bedding and feedstuff samples, flies, and hands and nares of the research personnel were sampled in order to determine the sources of Staphylococcus aureus in a dairy herd other than the lactating mammary gland. Lesions on the udder of lactating animals and the air in the milking parlor were also sampled. Staphylococci isolated from bedding samples were identified as to species. Staphylococcus aureus was isolated from all sources examined except flies. An enrichment procedure was necessary for isolating S. aureus from two bedding samples although other Staphylococcus species were present in high numbers. The designation "environmental staphylococci" is proposed for Staphylococcus species that were apparently free-living in the environment.
The efficacy of Baird-Parker agar, Baird-Parker agar with bacitracin (0.8 μg/ml), Baird-Parker agar supplemented with acriflavin (7 μg/ml), polymyxin (20 units/ml) and sulphonamides (55 μg/ml), KRANEP agar, mannitol salt agar, and Staphylococcus medium 110 agar for the isolation and enumeration of Staphylococcus species was investigated. Bovine blood agar was used as the control medium. Thirty-seven staphylococci strains representing 23 species and 19 non-Staphylococcus species were tested. None of the six selective media supported the growth of all 37 Staphylococcus strains. The number of Staphylococcus species that grew on a specific medium ranged from only the S. aureus strains on Baird-Parker agar supplemented with acriflavin, polymyxin, and sulphonamides, to all but S. warneri BG 647 on Staphylococcus medium 110 agar. Strains of Bacillus, Corynebacterium, and Micrococcus grew on all six selective media.
Members of the bacterial population of two types of Portuguese dry smoked sausages (chouriços) were identified and characterized. A total of 77 isolates were recovered from chouriços type Alentejano and Ribatejano, after 120 days at 20 ± 5 ºC in modified atmosphere package (55 % N 2 /45 % CO 2 ) using non-selective and selective media. Based on phenotypic (cell morphology and fermentation profile) and genotypic (16SrDNA sequencing) characters, the isolates were grouped into the following genera: Bacillus, Enterococcus, Clostridium, Staphylococcus, Pediococcus, Lactobacillus and Paenibacillus. The species identified were: Enterococcus faecium (24.7 %), Bacillus subtilis (23.4 %), Staphylococcus epidermidis (14.3 %), B. cereus (7.8 %), Pediococcus acidilactici (6.5 %) Bacillus pumilus (6.5 %), Clostridium bifermentans (3.9 %), B. licheniformis, and Enterococcus faecalis (2.6 %). Major differences observed between the two varieties of chouriço were the absence of Pediococcus species and the presence of high numbers of isolates identified as Staphylococcus epidermidis in chouriço type Alentejano and, the high incidence of Bacillus species in sausage type Ribatejano. Differences found between products may be due to spices formulation in each type of product, the type of natural casings used and, the hygienic quality of the raw meat.
ResumenSe identificaron y caracterizaron los miembros de la población bacteriana de dos tipos de chorizos portugueses. Un total de 77 aislados fueron recuperados de los chouriços tipo Alentejano y Ribatejano, después de 120 días de almacenamiento con empaque en atmósfera modificada (55 % N 2 / 45 % CO 2 ) a 20 ± 5 °C usando medios de cultivo selectivos y no selectivos. Con base en caracteres del fenotipo (morfología celular y perfil de fermentación) y del genotipo (secuencia del 16SrDNA) los aislados fueron agrupado en los siguientes géneros:
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