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.
Normal Flora. Millions and millions of healthy bacteria, called normal flora, colonize the outside of your skin. These bacteria live on your skin and use dead skin cells for their energy. Though normal flora bacteria are not usually harmful, they can cause infections if they enter your body through a wound.Most of these organisms are considered healthy bacteria because they prevent very harmful bacteria, called pathogens, from growing on your skin.hough normal flora bacteria are not usually harmful, they can cause infections if they enter your body through a wound. Most of these organisms are considered healthy bacteria because they prevent very harmful bacteria, called pathogens, from growing on your skin.