What are the types of antibiotics?

There are hundreds of different types of antibiotics, which are usually grouped together based on how they work. The group of antibiotics in each class typically have similar chemical and pharmacologic properties. Each class of antibiotic is only effective against certain types of bacteria.

Common classes of antibiotics include: 

• Penicillins – The Penicillins class includes antibiotics such as penicillin, amoxicillin, flucloxacillin, and co-amoxiclav. These are effective for treating a wide range of infections including chest, skin, and urinary tract infections. 
• Tetracyclines - Doxycycline, tetracycline, and lymecycline are some of the antibiotics in the Tetracyclines class. These are all broad-spectrum against many different types of bacteria. They are used to treat conditions such as skin infections including acne and rosacea, periodontitis (gum disease), eye infections, intestinal and urinary tract infections, and sexually transmitted diseases.
• Lincomycins - Lincomycins are used in the treatment of serious infections such as intra-abdominal infections, bone and joint infections, pelvic inflammatory disease, and lower respiratory tract infections. Some forms are also used as a topical treatment for acne and some types of bacterial vaginal infections. Clindamycin and lincomycin are the two types of antibiotics in this class. 
• Macrolides - Macrolides such as erythromycin, azithromycin, and clarithromycin are effective for treating chest and lung infections and are widely used to treat community-acquired pertussis and pneumonia. They can also be used to treat penicillin-resistant strains of bacteria or as an alternative for people who are allergic to penicillin. 
• Aminoglycosides – The Aminoglycosides class of antibiotics includes gentamicin and tobramycin, which are used to treat very serious infections such as septicaemia. They are mostly administered by injection and only in a hospital because of the potential to cause serious side effects such as kidney damage. 
• Cephalosporins - Cephalosporins, which include cephalexin, cefaclor, and cefadroxil are used to treat a variety of common infections such as ear, lung, and skin infections as well as a few serious infections such as meningitis and septicaemia. 
• Carbapenems - Carbapenems such as meropenem, doripenem, and imipenem, are wide-spectrum antibiotics that are generally used to treat serious life-threatening infections such as pneumonia, stomach or kidney infections and multidrug-resistant hospital-acquired infections. Also known as beta-lactam antibiotics, they are often used as a last line of defense to prevent resistance. 
• Fluoroquinolones – Antibiotics in the Fluoroquinolones class, such as levofloxacin and ciprofloxacin, are broad-spectrum synthetic antibiotics. They are only used in extreme cases when other antibiotics prove ineffective because of the high risk of serious side effects.