Antibiotics are vitally important medicines that can safely treat infections caused by bacteria (bacterial diseases). They can also prevent the spread of disease and reduce serious disease complications. However, overuse and improper use of antibiotics has allowed some bacteria to adapt so that they no longer respond to antibiotics – this is called antibiotic resistance.
Most antibiotics work in different ways to inhibit bacterial growth or kill bacteria. A large group of antibiotics, including penicillin, streptomycin and erythromycin, works by inhibiting bacterial protein synthesis. This process is similar to how human cells synthesize proteins; however, a few differences allow antibiotics to specifically target and block the function of specific bacterial proteins.
Many other antibiotics work by inhibiting bacterial cell wall synthesis, which is required for bacteria to grow and multiply. This process involves the partial assembly of cell wall components inside the bacterium, transporting these structures to the growing wall, and then cross-linking of the strands to form the completed wall. Antibiotics that work by this mechanism include the b-lactam antibiotics, vancomycin, and aminoglycosides.
Antibiotics are often taken by mouth or injected into a vein (intravenously, or IV). The dosage and duration of treatment are based on the severity of the infection, the type of bacteria involved, and the patient’s general health status. Many factors affect the pharmacodynamics and pharmacokinetics of antibiotics, including patient age, medication allergies, renal and hepatic function, and history with other antibiotics. Certain foods, such as milk, cheese and grapefruit juice, can interfere with the effectiveness of some antibiotics.