The most often used medications for treating Mycobacterium avium complex (MAC) infection include macrolides (e.g., clarithromycin, azithromycin), ethambutol, and rifamycin (e.g., rifabutin, rifampin). The first-line medications include clarithromycin or azithromycin in combination with ethambutol and rifabutin. There is some evidence that levofloxacin may be an effective alternative treatment option. Treatment of M. tuberculosis infections requires the use of multiple drugs because no single drug can kill all mycobacteria. The most common first-line medication combinations for treating tuberculosis include isoniazid, rifampin, pyrazinamide, and ethambutol. Other medications used alone or together include amikacin, capreomycin, kanamycin, and para-aminosalicylic acid (PAS). At present time, there is no vaccine available to prevent MAC or TB infections. However, there are studies ongoing to develop vaccines against these bacteria. Antibiotics are also used to control bacterial infections caused by other organisms such as Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Some antibiotics are broad-spectrum while others are more specific. This means that they will kill only certain types of bacteria without affecting others.