The penicillin metabolite-carrier protein complexes are large enough to stimulate the immune system and cause an immediate allergic reaction. This allergic reaction can manifest itself in many different ways - two of the most common manifestations are a rash or difficulty breathing. Cephalosporins Cephalosporins are another widely used class of antibiotics. They are similar to penicillins in structure, but in general, can treat a broader range of infections. For example, these antibiotics are used to treat strep throat, cellulitis, E. coli infections, pneumonia, upper respiratory infections, sinus infections, and gonorrhea .
Cephalosporins act by disrupting the bacterial cell wall.
Cephalosporin-Resistant Bacteria Microorganisms that are resistant to cephalosporins have emerged. However, cephalosporin-resistant bacteria are not as prevalent as those resistant to penicillin. Some people are allergic to cephalosporins. Sulfa Drugs Sulfa drugs are the oldest antibiotics available and are also among the best. Sulfa was first used in 1930's.