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.
There are two types of sinusitis: 1  Acute sinusitis is when symptoms are present for 4 weeks or less. It is caused by bacteria growing in the sinuses.  Chronic sinusitis is when swelling and inflammation of the sinuses are present for longer than 3 months.