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.
Second generation cephalosporins include cefaclor, cefoxitin, cefprozil, cefonicid, and cefuroxime; these have broader antibacterial activity, and additional sensitive organisms including Citrobacter, Enterobacter, Haemophilus influenzae, Neisseria and Serratia species.econd generation cephalosporins include cefaclor, cefoxitin, cefprozil, cefonicid, and cefuroxime; these have broader antibacterial activity, and additional sensitive organisms including Citrobacter, Enterobacter, Haemophilus influenzae, Neisseria and Serratia species.