Context
First narrow-spectrum antibiotic successfully eliminates Fusobacterium nucleatum, a gum disease pathogen
About Narrow-Spectrum Antibiotics:
- Antibiotics that target a selected group of bacterial types.
- Action: Effective against either gram-positive or gram-negative bacteria, but not both.
- Applied when the causative organism is known.
- Advantages:
- Limited impact on the body’s normal microorganisms compared to broad-spectrum antibiotics.
- Reduced bacterial resistance due to specificity.
- Avoids spread of drug-resistant infections.
- Examples: Azithromycin, Clarithromycin, Erythromycin.
About Gram-Positive vs. Gram-Negative Bacteria:
- Gram-Negative Bacteria:
- Surrounded by a thin peptidoglycan cell wall and an outer membrane with lipopolysaccharide.
- Gram-Positive Bacteria:
- Lack an outer membrane but have a thicker peptidoglycan layer.
- Gram Staining:
- Gram-Positive: Retains violet dye, staining bacteria violet due to the thick peptidoglycan layer.
- Gram-Negative: Loses violet dye, staining bacteria red due to the thin peptidoglycan layer.
- Gram-Positive Infections: MRSA, strep infections, toxic shock syndrome.
- Gram-Negative Infections: Salmonella, pneumonia, UTIs, bacterial meningitis, gonorrhea.
- Diagnosis: Knowing whether the bacteria are gram-positive or gram-negative helps select the most effective antibiotics.
Fusobacterium nucleatum:
- Common opportunistic bacterium found in the oral cavity and gastrointestinal tract.
- Causes infectious diseases in the oropharynx and other oral areas.
Source:
Medical express
Previous Year Question
Consider the following statements:
1. Biofilms can form on medical implants within human tissues.
2. Biofilms can form on food and food processing surfaces.
3. Biofilms can exhibit antibiotic resistance.
Which of the statements given above are correct?
[UPSC Civil Services Exam – 2022 Prelims]
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: (b)
