What are Narrow-Spectrum Antibiotics?

About Narrow-Spectrum Antibiotics:

• Antibiotics are classified as “narrow-spectrum” or “broad-spectrum” depending on the range of bacterial types they affect. 
• Narrow-spectrum antibiotics are active against a selected group of bacterial types.
• They can act on either gram +ve or gram –ve but not both.
• They are used for the specific infection when the causative organism is known. 
• They will not kill as many of the normal microorganisms in the body as the broad-spectrum antibiotics. 
• Because they target very specific bacteria, they don't cause an increase in bacterial resistance and avoid the spread of drug-resistant infections.
• Examples include Azithromycin, Clarithromycin, Erythromycin, etc.

Gram-Positive vs. Gram-Negative Bacteria:

• Gram-negative bacteria are surrounded by a thin peptidoglycan cell wall, which itself is surrounded by an outer membrane containing lipopolysaccharide.
• Gram-positive bacteria lack an outer membrane but are surrounded by layers of peptidogly can many times thicker than is found in the Gram-negatives. 
• Gram staining is a technique that uses violet dye to distinguish between gram-positive and gram-negative bacteria.
• If the bacteria are gram-positive, the thick peptidoglycan layer in their cell walls will retain the dye, and they will stain violet.
• If the bacteria are gram-negative, the dye will leak out of the thin peptidoglycan layer, and the bacteria will stain red.
• Gram-positive infections include MRSA (methicillin-resistant Staphylococcus aureus) infections, strep infections, and toxic shock syndrome.
• Gram-negative infections include salmonella infections, pneumonia, urinary tract infections, bacterial meningitis, and gonorrhea.
• Knowing whether bacteria is gram-positive or gram-negative can help your health care provider identify the type of infection you have and which antibiotics will be most effective in treating it.

What is Fusobacterium nucleatum?

• It is a common oral opportunistic bacterium which exists in the oral cavity and gastrointestinal tract of humans.
• It causes different infectious diseases in the oropharynx and other parts of the oral cavity.

Q1: What are antibiotics?

Antibiotics are medicines that fight bacterial infections in people and animals. They work by killing the bacteria or by making it hard for the bacteria to grow and multiply.

Source: First narrow-spectrum antibiotic successfully eliminates Fusobacterium nucleatum, a gum disease pathogen