Sulfonamide antibiotics that can cause a reaction. Antibiotics containing chemicals called sulfonamides can trigger a reaction if you have a sulfa allergy. These antibiotics include combination drugs: 1  Sulfamethoxazole-trimethoprim (Septra, Bactrim).
4. Staphylococcus aureus. Staphylococcus aureus is a common type of skin bacterium that may be found in areas such as the skin, nasal cavities, and respiratory tract. While some staph strains are harmless, others such as methicillin-resistant Staphylococcus aureus (MRSA) , can cause serious health issues.. Staphylococcus aureus. Staphylococcus aureus is a common type of skin bacterium that may be found in areas such as the skin, nasal cavities, and respiratory tract. While some staph strains are harmless, others such as methicillin-resistant Staphylococcus aureus (MRSA) , can cause serious health issues.
Estimates place the number of individual bacteria on the surface of one square inch (6.5 square cm) of human skin at 50 million, though this figure varies greatly over the average 20 square feet (1.9 m 2) of human skin. Oily surfaces, such as the face, may contain over 500 million bacteria per square inch (6.5 cmÂ²). Despite these vast quantities, all of the bacteria found on the skin's surface would fit into a volume the size of a pea. In general, the microorganisms keep one another in check and are part of a healthy skin.