Staphylococcus aureus are facultative anaerobic Gram-positive cocci, that is a major cause of hospital acquired (nosocomial) infection of surgical wounds and infections associated with indwelling medical devices. S. aureus causes food poisoning by releasing enterotoxins into food, and toxic shock syndrome by release of superantigens into the blood stream. Over the last decade, VRSA (Vancomycin Resistant S. aureus) strains have become endemic in hospitals worldwide. The VRSA phenotype of S. aureus Mu50 is the result of changes to the cell wall structure. In comparison with MRSA strains, Mu50 and Mu50-like strains have a thickened cell wall, release more cell wall material into the culture medium and have increased rates of autolysis (Ref.1). The fine structure of the[..]

Staphylococcus aureus are Gram-positive nonmotile coccus that grows in aerobic and anaerobic conditions, in which it forms grape-like clusters. S. aureus is one of the major causes of community-acquired and hospital-acquired infections. It produces numerous toxins including superantigens that cause unique disease entities such as toxic-shock syndrome and staphylococcal scarlet fever. S. aureus MW2 is a typical community-acquired strain of MRSA (Methicillin-Resistant S. aureus) isolated in 1998 in North Dakota (Ref.1).The staphylococcal cell wall is 50 percent peptidoglycan by weight consisting of alternating polysaccharide subunits of N-Acetylglucosamine and N-Acetylmuramic acid with 1, 4-Beta linkages. The peptidoglycan chains are cross-linked by tetrapeptide chains[..]

Staphylococcus aureus is a gram-positive bacterium grouped with Bacillus sp on the basis of ribosomal RNA sequences. This immobile coccus grows in aerobic and anaerobic conditions, in which it forms grape-like clusters. Its main habitats are the nasal membranes and skin of warm-blooded animals, in which it causes a range of infections from mild, such as skin infections and food poisoning, to life-threatening, such as pneumonia, sepsis, osteomyelitis, and infectious endocarditis. The organism produces many toxins and is highly efficient at overcoming antibiotic effectiveness (Ref.1). Over the past decades, the incidence of S. Aureus infections has increased dramatically owing to the emergence of antibiotic-resistant strains, such as MRSA (Methicillin-Resistant S.[..]

Staphylococcus epidermidis is a Gram-positive non motile bacterium that grows in aerobic and anaerobic conditions, in which it forms grape-like clusters. It produces numerous toxins including superantigens that cause unique disease entities and has emerged as a causative agent of infections often associated with implanted medical devices. The S. aureus and S. epidermidis genomes are syntenic throughout their lengths and share a core set of 1,681 ORF (Open Reading Frames) (Ref.1 & 2).The cell wall of S. epidermidis is 50 percent peptidoglycan by weight consisting of alternating polysaccharide subunits of N-Acetylglucosamine and N-Acetylmuramic acid with 1, 4-Beta linkages. The peptidoglycan chains are cross-linked by tetrapeptide chains bound to N-Acetylmuramic acid[..]

Staphylococci are known as clustering Gram-positive cocci, nonmotile, non-spore forming facultatively anaerobic that classified in two main groups, coagulase-positive and coagulase-negative. Staphylococcus epidermidis with the highest percentage has the prominent role among coagulase-negative Staphylococci that is the most important reason of clinical infections. Staphylococcus, is one of the five significant microorganisms that are located on human skin and mucosal surfaces with the ability of causing nosocomial infections due to the wide usage of medical implants and devices, hence until 1980 S. epidermidis was considered as an opportunistic microorganism, while in accordance to various infections increasement such as cardiovascular, CNS shunts,[..]

The Group-A Streptococcus (Streptococcus pyogenes) remains an important human pathogen, associated with a range of superficial skin and throat infections as well as a variety of more serious invasive infections and autoimmune sequelae such as acute rheumatic fever and post-streptococcal glomerulonephritis (Ref.1). S. pyogenes strains are grouped into two classes on the basis of post infectious sequelae associated with each strain, Class-I is responsible for rheumatic fever and Class-II is responsible for acute glomerulonephritis. S. pyogenes strain SF370 (Serotype M1) was originally isolated from a patient with a wound infection. The Serotype M1 is among the most prevalent in terms of involvement in severe invasive infections (Ref.2 & 3).As is the case in other[..]

Streptococcus pneumoniae (also known as Pneumococcus or Diplococcus pneumoniae) is a Gram-positive coccus and is among the most significant causes of bacterial disease in humans. It is responsible for a high proportion of cases of pneumonia, acute otitis media, acute sinusitis, bacteremia and meningitis. There are 90 known serotypes of S. pneumoniae, each of which produces a structurally different capsular polysaccharide; during infection. These serotypes function by inhibiting host complement-mediated phagocytosis. The parental S. pneumoniae strain for R6 is R36A, which is a nonencapsulated strain is derived from the capsular Type 2 clinical isolate strain D39. The pneumococcal plasma membrane is surrounded by a layer of peptidoglycan, a three-dimensional,[..]

Streptococcus pneumoniae (also known as Pneumococcus or Diplococcus pneumoniae) is a Gram-positive coccus and is among the most significant causes of bacterial disease in humans. It is responsible for a high proportion of cases of pneumonia, acute otitis media, acute sinusitis, bacteremia and meningitis. There are 90 known serotypes of S. pneumoniae, each of which produces a structurally different capsular polysaccharide; during infection. These serotypes function by inhibiting host complement-mediated phagocytosis. The pneumococcal plasma membrane is surrounded by a layer of peptidoglycan, a three-dimensional, cross-linked mesh that protects the bacterial cell from changes in osmotic pressure and plays key roles in shape determination and daughter cell formation. The[..]

Streptococcus agalactiae, or Group-B Streptococcus is a Gram-positive nonmotile bacterium and is the leading cause of bacterial sepsis, pneumoniae and meningitidis in neonates in U.S. and Europe. It usually behaves as a commensal organism that colonizes the gastrointestinal or genital tract of 25-40% of healthy women, but it can cause life-threatening invasive infection in susceptible hosts: newborn infants, pregnant women, and adults with underlying chronic illnesses. First recognized as a pathogen in bovine mastitis, S. agalactiae (Group-B Streptococci [GBS]) is distinguished from other pathogenic streptococci by the cell wall-associated group B carbohydrate. S. agalactiae strain NEM316 is responsible for a fatal septicemia and belongs to the Capsular Serotype-II. It[..]

Streptococcus thermophilus is one of the most economically important lactic acid bacteria used in the manufacture of yogurt and cheeses. This bacterium belongs to the group of GRAS (Generally Recognized As Safe) bacteria which is an exception in the Streptococcus genus. S. thermophilus is used, along with Lactobacillus sp., as a starter culture for the manufacture of several important fermented dairy foods, including yogurt and Mozzarella cheese. Its use has increased significantly during the past two decades, as a result of the tremendous increase in consumption of these products (Ref. 1 & 2).The cell wall of these Gram-positive bacteria constitutes a multifaceted fabric that is essential for survival, shape, and integrity. D-Alanine occurs to the extent of 1 to 2[..]

Legionella pneumophila is the causative agent of Legionnaires' disease, which replicates as an intracellular parasite of amoebae and persists in the environment as a free-living microbe (Ref.1). D-Alanine is a necessary precursor in the biosynthesis of cell wall in this bacterium. L-Alanine is also a product of several other metabolic pathways like Cyanoamino Acid Metabolism, Selenoamino Acid Metabolism, Alanine and Aspartate, and D-Arginine and D-Ornithine Metabolism(Ref.2). The naturally occurring L-Alanine isomer is racemized to its D-form through the action of a class of enzymes called alr (alanine racemase). This enzyme is ubiquitous among prokaryotes and with very few exceptions are absent in eukaryotes.alr belongs to the class of Isomerase enzymes,[..]

Lactiplantibacillus plantarum (previously Lactobacillus plantarum) is a member of the facultative heterofermentative group of Gram-positive Lactobacilli that are frequently isolated from plant material and various fermented foods. Lactobacilli produce lactic acid and are used for many different things, including yogurt production and the maintenance of healthy intestinal microflora. Lactobacilli are commonly associated with the gastrointestinal tract of humans. L. plantarum is the dominating bacterial species in most naturally fermented foods. It is an excellent alternative to antibiotics, and makes use of its potential to block receptor sites for Gram-negative bacteria. L. plantarum is capable of metabolizing semi resistant fibers, such as, onions, garlic, artichoke,[..]