Upper respiratory tract infections 20% of them are caused by bacteria and 70-80% by viruses. Bacteria are mainly found in the oral cavity in the form of colonizing bacteria such as Streptococcus hemolyticus. The next most common are Haemophilus influenzae, as well as Streptococcus pneumoniae and Staphylococcus staphylococcus, all of which are Gram-positive bacteria. Of course there are some Gram (-) bacteria, but they are less common. In fact, most upper respiratory tract infections are caused by viral infections, and only a small percentage are caused by bacteria. Most of these bacterial infections are also secondary to viral infections, so antibiotics can be applied to bacterial infections. If it is a viral infection, antibiotics are usually not needed, and it is self-healing and can be cured in about a week.