Question

A broad spectrum antibiotic is (a) penicillin (b) paracetamol (c) chloramphenicol (d) aspirin

Short answer

The broad spectrum antibiotic is chloramphenicol (c).

Step-by-step solution

Understanding Broad Spectrum Antibiotics

A broad spectrum antibiotic is a type of antibiotic effective against a wide range of both Gram-positive and Gram-negative bacteria. It is used to treat a variety of infections caused by different types of bacteria.

Identifying the Correct Option

From the options given: (a) Penicillin is primarily effective against Gram-positive bacteria and some Gram-negative bacteria, but it is not considered broad spectrum. (b) Paracetamol is not an antibiotic; it is a pain reliever and fever reducer. (c) Chloramphenicol is a broad spectrum antibiotic used to treat a wide range of bacterial infections. (d) Aspirin is not an antibiotic; it is used as an anti-inflammatory drug.

Choosing the Broad Spectrum Antibiotic

Based on the analysis, option (c) chloramphenicol fits the definition of a broad spectrum antibiotic because it is effective against a wide range of bacteria, both Gram-positive and Gram-negative.

Key concepts

Antibiotics

Antibiotics are powerful drugs that fight bacterial infections. They have been revolutionary in medicine, helping to treat infections that were once deadly. Antibiotics come in different types, each targeting specific bacteria or a spectrum of bacteria. Their main function is to stop bacteria from growing or to kill them outright.
Antibiotics are usually categorized based on whether they are effective against Gram-positive, Gram-negative bacteria, or both.

• Gram-Positive Antibiotics: Target bacteria with a thick peptidoglycan wall.
• Gram-Negative Antibiotics: Penetrate the outer membrane of bacteria with thinner peptidoglycan walls.
• Broad Spectrum Antibiotics: Effective against a wide range of bacteria, including both Gram-positive and Gram-negative.

It's crucial to use antibiotics wisely to avoid antibiotic resistance, which occurs when bacteria evolve and become immune to these drugs. Always complete prescribed antibiotic courses and never use antibiotics for viral infections.

Gram-positive bacteria

Gram-positive bacteria are a group of bacteria that have a thick cell wall made mostly of a substance called peptidoglycan. This thick wall is what gives them their name. When tested in the lab using a method called Gram staining, they retain a violet color.
Some common infections caused by Gram-positive bacteria include:

• Streptococcal Infections: Such as strep throat.
• Staphylococcal Infections: Often related to skin infections or more serious conditions like pneumonia.

Gram-positive bacteria can be targeted by specific antibiotics, but some broad spectrum antibiotics also work against them. These bacteria play a significant role both in disease and in beneficial processes such as cheese making and probiotics.

Gram-negative bacteria

Gram-negative bacteria have a more complex cell wall structure compared to Gram-positive bacteria. Their cell wall includes a thin layer of peptidoglycan and an outer membrane, which makes it difficult for certain antibiotics to penetrate.
During Gram staining, Gram-negative bacteria do not retain the violet dye but instead take up a pink or red color.

• Escherichia coli (E. coli): Some strains can cause food poisoning.
• Salmonella: Known for causing foodborne illnesses.

Gram-negative bacteria are often more resistant to antibiotics due to their unique cell wall structure, necessitating the use of broad spectrum antibiotics or specific antibiotics designed to breach their defenses. These bacteria are important for the nitrogen cycle and in gut health but can also cause serious infections.

Chloramphenicol

Chloramphenicol is a classic example of a broad spectrum antibiotic, meaning it is effective against a wide range of bacteria, including both Gram-positive and Gram-negative types. It works by inhibiting protein synthesis in bacteria, thereby stopping their growth.
Despite its effectiveness, chloramphenicol is used with caution due to potential severe side effects, including bone marrow suppression. As a result, it is not commonly used except in cases where no safer alternatives are available, or in resource-limited settings.
Its use requires careful monitoring and is generally reserved for serious infections, such as typhoid fever or bacterial meningitis, where the benefits outweigh the risks.

• Use with caution: Only when alternative treatments are unavailable.
• Strict monitoring: Regular blood tests to check for side effects.

Understanding when and how to use antibiotics like chloramphenicol is essential to effectively treat infections while preventing the risks of adverse effects and antibiotic resistance.