Staphylococcus aureus is a gram positive bacteria that causes variety of infections including skin infections, pneumonia, sepsis and endocarditis. While 25 to 30 percent of healthy adults have staphylococci bacteria localized on the skin and mucous membranes, this gram positive, aerobic bacteria becomes pathogenic when there is damage or injury to the skin, giving the bacteria systemic access to the organs and tissues. The individuals most at risk for developing a staph infection include injection drug users, individuals with skin injuries as well as individuals with a weakened immune system. Antibiotics such as flucloxacillin, vancomycin and linezolid are effective at treating staph infections.
Flucloxacillin
Flucloxacillin is an antibiotic used for the treatment of Staphylococcus aureus infections. According to the Merck Manual, flucloxacillin is a penicillinase, resistant beta lactam antibiotic, meaning it is resistant to the secretion of penicillinase by Staphylococcus. Penicillinase is an enzyme secreted by different strains of Staphylococcus that destroys the antibacterial properties of antibiotics. Flucloxacillin's mode of action involves disrupting the bacterial cell wall. Flucloxacillin binds to penicillin-binding proteins within the cell wall, thus preventing the cross linkage of peptidoglycan, an essential component of a functional bacterial cell wall. The prevention of the cross linkage of bacterial peptidoglycan forces the bacteria to release autolytic enzymes, which lyse the cell membrane and consequently, results in bacterial cell death.
Vancomyin
Methicillin resistant Staphylococcus aureus (MSRA) are strains of Staphylococcus aureus infections acquired within the hospital and are considered extremely dangerous due their extreme resistance to a wide range of beta-lactam antibiotics such as flucloxacillin and methicillin. Methicillin resistant Staphylococcus aureus is considered a fatal infection because the individuals most at risk already have a weakened immune system due to undergoing surgical procedures, or because they are kidney dialysis patients. Vancomyin is a glycopeptide antibiotic used for the treatment of methicillin resistant Staphylococcus aureus infections. The mechanism by which vancomyin exerts its bactericidal actions involves the prevention of the transpeptidation reactions required to build the peptidoglycan cross chains, notes Microbelibrary.org. By binding to a chain of five amino acids in the cell wall, vancomyin effectively prevents the addition of further amino acids and sugar monomers, thus causing the bacteria to release autolysins to destroy the nonfunctional cell wall.
Linezolid
Linezolid is an antibiotic used for the treatment of Staphylococcus aureus strains that are resistant to beta lactam antibiotics such as flucloxacillin, as well as vancomyin. These strains of Staphylococcus aureus are resistant to the class of antibiotics that lyse bacterial cell walls, thus linezolid inhibits the growth of bacteria by a different mechanism. Linezolid inhibits the synthesis and translation of proteins required by Staphylococcus aureus to multiply and divide. By interfering with the assembly of the initiation complex required for protein translation, linezolid contains the spread of infection and ultimately the immune cells destroy the remaining bacterial colonies.
