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.
These bacteria are resistant to the groups of antibiotics that are commonly used to treat these types of infections (penicillins, cephalosporins) and to antibiotics normally reserved for more severe infections (eg, fluoroquinolones, gentamicin). coli cholecystitis/cholangitis requires antibiotics such as third-generation cephalosporins that cover E coli and Klebsiella organisms.