In this article. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body. It's tougher to treat than most strains of staphylococcus aureus -- or staph -- because it's resistant to some commonly used antibiotics.n this article. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body. It's tougher to treat than most strains of staphylococcus aureus -- or staph -- because it's resistant to some commonly used antibiotics.
Although enterococci have been known to be intrinsically resistant to cephalosporins for decades, the mechanism of cephalosporin resistance remains incompletely understood. Three determinants for cephalosporin resistance in E. faecalis have been described.
The medium-spectrum antibiotics bacitracin, the Erythromycin, penicillin, and the Cephalosporins (any of a group of broad-spectrum antibiotics obtained from fungi of the genus Cephalosporium) are effective primarily against Gram-positive bacteria, although the streptomycin group is effective against some Gram-negative and Gram-positive bacteria.