chemical formula a combination of symbols used to express the chemical components of a substance. empirical formula a chemical formula that expresses the proportions of the elements present in a substance.
The bacteria streptococcus pneumoniae is the most common cause of acute bacterial sinusitis. This type of bacteria can be resistant to the most common types of antibiotics at standard dosages, although there are other antibiotics that can be used to treat the condition.
Bacterial sinusitis most often occurs as a complication of a viral common cold. Bacteria that are normally present in the nose and throat take advantage of the viral infection to invade the inflamed sinus passages.