Β-lactam antibiotic reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent (a small fraction of which are truly IgE-mediated allergic reactions, see amoxicillin rash). Anaphylaxis will occur in approximately 0.01% of patients. There is perhaps a 5%-10% cross-sensitivity between penicillin-derivatives, cephalosporins, and carbapenems; but this figure has been challenged by various investigators. Nevertheless, the risk of cross-reactivity is sufficient to warrant the contraindication of all β-lactam antibiotics in patients with a history of severe allergic reactions (urticaria, anaphylaxis, interstitial nephritis) to any β-lactam antibiotic. A Jarisch–Herxheimer reaction may occur after initial treatment of a spirochetal
Antibiotic gastric juices and hydrogen peroxide). It also excluded synthetic antibacterial compounds such as the sulfonamides. In current usage, the term "antibiotic" is applied to any medication that kills bacteria or inhibits their growth, regardless of whether that medication is produced by a microorganism or not. The term "antibiotic" derives from "anti" + βιωτικός ("biōtikos"), "fit for life, lively", which comes from βίωσις ("biōsis"), "way of life", and that from βίος ("bios"), "life". The term "antibacterial" derives from Greek ἀντί ("anti"), "against" + βακτήριον ("baktērion"), diminutive of βακτηρία ("baktēria"), "staff, cane", because the first bacteria to be discovered were rod-shaped. The