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.
Causes of Acute Sinus Infection. Acute sinusitis usually follows a viral infection in the upper respiratory tract, but allergy-causing substances (allergens) or pollutants may also trigger acute sinusitis. A Viral infection damages the cells of the sinus lining, leading to inflammation.