Difference Between Antibiotics and Antibacterial

Antibiotics, antibacterial agents, antifungal agents, and antiviral agents are various chemicals used in fighting infections caused by bacteria, fungi, and viruses. Some originate from nature and are used as natural extracts. Some are redeveloped or modified or completely synthesized by synthetic chemists. When our natural immunity fails to fight an infection, these drugs help recover the normal body functioning.


The term “antibiotics” is made up of “anti” which means “against” and “bio” which means “life” in Greek. According to the definition by Selman Waksman et al in 1942, antibiotic is a “substance produced by a microorganism that is antagonistic to another microorganism’s growth in high dilution”. Antibiotics are used against bacteria and fungi, to fight infections. These have the ability to destroy or slow down bacteria/fungal growth inside our bodies. Antibiotics are naturally synthesized in fungi, to compete with neighboring bacterial growth. The first ever antibiotic discovered was penicillin by Alexander Fleming. It was a secretion from the fungus Penicillium.

When the body’s natural immunity fails to fight bacterial or fungal attacks the body weakens and fall ill. Antibiotics which stop bacteria growth are known as bacteriostatic agents. Antibiotics, which kill bacteria inside the body, are known as bacteriocidal agents. Antibiotics cannot destroy viruses. Therefore, when an infection occurs it is important to find out the cause; if it is caused by viruses, giving antibiotics may be useless.

As mentioned in the introduction antibiotics were initially extracted from natural sources. Then semi-synthetic antibiotics became the trend. Beta- lactam antibiotics are one such group. Antibiotics such as sulfonamides, quinolones, and oxazolidinones are completely synthesized antibiotics. Dosages and durations of antibiotic intake should be properly monitored. Withdrawal from using the antibiotic when the symptoms start to fade should not be encouraged. This may cause antibiotic resistance, which makes it difficult to cure a second time infection of the same type of bacteria.


Among the groups of antibiotics available, antibacterial substances are the most prominent group. Most antibacterial agents are produced by fungi. Not all bacteria are harmful and pathogenic. There are various bacteria strains residing inside and outside the body. Many pathogenic bacteria cause various diseases to humans and other animals. Bacteria are responsible for illnesses such as syphilis, tuberculosis, meningitis, cholera etc.

Various antibacterial compounds are isolated from fungi. Among them penicillin drugs such as amoxicillin and coxacillin are used frequently. Streptomycin is extracted from a fungus and used against streptococcus infections causing strep throat. Cephalosporins, carbapenems, aminoglycosides are other antibacterial compounds which are frequently prescribed. Similar to antibiotics antibacterial agents are also divided to natural, synthetic and semi-synthetic substances. Among the synthetic antibacterial agents, compounds like sulfonamides are popular. These are usually small molecules with low molecular weights. Some antibacterial compounds have a broad spectrum which could be used for many infections. Some antibacterial compounds are specific for particular bacterial strains.

What is the difference between Antibiotic and Antibacterial?

• Antibiotics are used against both bacteria and fungi, but antibacterial compounds are used against bacteria only.

• Antibiotics is a larger class of drugs of which antibacterial substances is a major subclass.