Finally, when all of these other measures have failed and a bacterial infection is present, an antibiotic will be prescribed. The most common symptoms of acute sinusitis of a bacterial nature are pain, pressure, and thick and colored nasal drainage. However, not all colored drainage means that there is a bacterial infection present. According to the Center for Disease Control , only two percent of colds will progress to result in bacterial sinusitis. Thus, most upper respiratory infections should NOT be treated with antibiotics. Antibiotics should be reserved for upper respiratory infections which last longer than ten days, or which worsen after four or five days of treatment. The use of antibiotics for nonbacterial upper respiratory infections has resulted in a severe problem with the emergence of bacteria which are resistant to multiple forms of antibiotics, and some bacteria are currently only treatable with intravenous antibiotics.