![]() ![]() ![]() aureus i) to affect leukocytes, sebaceous glands and subcutaneous tissues ii) to increase propagation of infection and iii) to inactivate the effect of β-lactam antibiotics. The role of enzymes like coagulase, catalase, hyaluronidase, lipase, heat-resistant nuclease, staphylokinase and β-galactosidase is to disrupt cell structure, degrade cell lipids and hyaluronic acid, and to convert fibrinogen to fibrin. aureus penetrates the subcutaneous tissues and reaches the blood stream, it can infect almost any organ, most notably bone tissue and cardiac valves. aureus secretes various toxins and enzymes which are responsible for the lesions during the development of the infection. aureus is responsible for resistance to opsonophagocytosis, the formation biofilm and adhesion to the host cell matrix. Due to the production of surface-associated factors like microbial surface components recognizing adhesive matrix molecules (MSCRAMM), protein A, polysaccharide A, peptidoglycan and a clumping factor, S. aureus produces a wide range of virulence factors which can be divided into different groups. Production of enterotoxins and other virulent factors aureus includes production of coagulase, alkaline phosphatase, proteases, lipases, and esterases and some strains also produce lecithinase. Besides that, the typical enzymatic activity of S. They also coagulate animal plasma with the assistance of a coagulase and the clumping factor. Most strains hydrolyse native animal proteins (casein, gelatine, fibrin), lipids, phospholipoproteins and Tween. Under aerobic conditions, acids are produced from glucose, lactose, maltose and mannitol, under anaerobic conditions acids are produced from many other sugars and alcoholic sugars. aureus belongs among chemo-organotrophs with a respiratory and fermentative metabolism. Arginine seems to be essential for enterotoxin B production. Deprivation of any amino acid is much less responsive in SEA production than for SEB or SEC production. Glutamic acid, leucine and tyrosine are not required for growth, but they are essential for enterotoxin production. įor growth it requires B vitamins (thiamine and nicotic acid), inorganic salts and amino acids as a nitrogen source, especially arginine, cystein, proline and valine. In dependence on growth conditions, the colony pigmentation varies from grey, grey-white with yellowish to orange shades with typical β-haemolysis on the blood agar. It creates smooth, convex, lustrous, circular colonies reaching a size of 0.5-1.5 µm in diameter and growing in an irregular three-dimensional bunch of grapes-like clusters of cells. aureus is a Gram-positive, facultative anaerobic, catalase-positive, oxidase-negative, non-motile microorganism that does not form spores. The name of the organism is derived from Greek words staphyle (a bunch of grapes) and coccus (grain or berry). It was firstly described by Sir Alexander Ogston in 1882 and 2 years later Rosenbach isolated it in a pure culture and introduced the name Staphylococcus aureus. aureus) belongs to the genus Staphylococcus and to the family Staphylococcaceae. Staphylococcus aureus – general description aureus growth during the fermentation of young raw milk cheese means prevention against staphylococcal enterotoxin production.Ģ. The growth of Staphylococcus aureus and potential production of heat-stable enterotoxins with respect to the food matrices and conditions of food preparation represent a potential, even actual threat of a public health menace residing in food poisoning outbreaks. aureus is competitive in milk and dairy environments it is quite sensitive to higher lactic acid concentration. ![]() The initial period to reach pH 5.3 lasted on average up to 30 h in upland artisanal ewes’ cheese production stations. aureus is able to multiply rapidly, especially during the initial phase of preparation when natural lactic acid bacteria are in lag phase and a sufficient amount of lactic acid has not been produced. This chapter deals with the behaviour of coagulase-positive staphylococci as their populations belong to the ubiquitous microflora of ewes’ milk. Then it is usually sent to a cheese factory for production of the soft Slovakian „Bryndza” cheese. The cheese is curdled with rennet, fermented by native lactic acid bacteria and briefly ripened for 7 to 10 d. This fact concerns also the short ripened ewes’ lump cheese traditionally produced immediately after milking in Slovakian upland cottages. The safety and quality of fermented raw foods are generally determined by the presence of pathogenic and spoilage microorganisms, their interaction with lactic acid bacteria, intrinsic, extrinsic and technological factors. ![]()
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