Tigecycline molecule. Computer model of a molecule of the MRSA antibiotic drug tigecycline (brand name Tygacil, chemical formula C29.H39.N5.O8). Atoms (balls) are colour-coded: carbon (yellow), hydrogen (grey), nitrogen (blue) and oxygen (red). The drug has been developed to treat drug-resistant bacterial infections including, but not restricted to methicillin- resistant Staphylococcus aureus (MRSA) bacterial infections. These infections kill many people because the bacteria have developed a resistance to normal antibiotic drugs. Tigecycline was developed by the Wyeth pharmaceutical company, and medical trials started in 2004.