Broad-spectrum antibiotic and narrow-spectrum antibiotic

On the basis of target specificity, antibiotics are classified into two types:

Broad-spectrum antibiotic: Those antibiotics that attack a wide range of pathogens are called broad-spectrum antibiotic.

Advantages:

They are beneficial when an infection is caused by multiple groups of bacteria or when infection is suspected but the causative organism is unknown.

Limitations:

As they attack many different kinds of pathogens, they kill normal bacteria also. They also aid in the development of antimicrobial resistance. Due to the continuous exposure to the same antibiotic, microbes may develop changes in their structure or function and becomes resistant to the antibiotic.

Examples:

Ciprofloxacin, Ampicillin, Rifampin, Tetracyclines, Chloramphenicol, Amoxicillin, Ticarcillin etc.

Narrow-spectrum antibiotic: They are effective against a specific organism. They are helpful when a known organism causes infection.

Advantages:

As they are effective against a particular organism, they will not kill the normal microorganisms of host body. So, it has less ability to cause superinfection. Also, they will develop less antimicrobial resistance.

Limitations:

They can be used only if causative agent is known.

Examples:

Bacitracin, Dapsone, Gentamicin, Methicillin, Clindamycin, Vancomycin, Azithromycin etc.