Which organism's pathogenicity is greater because of the high lipid content of their cell wall?

Which organism's pathogenicity is greater because of the high lipid content of their cell wall?

• A. Mycobacterium
• B. Streptococcus
• C. Escherichia
• D. Staphylococcus

Answer: (A)

The key idea is that a lipid-rich, waxy cell wall creates a tough barrier that helps the organism survive harsh environments, resist many disinfectants and some antibiotics, and persist inside host cells. Mycobacterium species have cell walls loaded with mycolic acids (long-chain fatty acids), giving a very high lipid content. This waxy barrier slows or prevents entry of chemicals, drying, and immune attack, and it enables the bacteria to survive within macrophages and cause chronic infections. That combination—strong protection, environmental resilience, and intracellular persistence—boosts pathogenic potential compared with organisms that lack such a lipid-rich wall. The others listed rely more on their peptidoglycan structure or classical virulence factors rather than a lipid-heavy cell wall, so their pathogenicity isn’t driven by this waxy barrier in the same way.

The key idea is that a lipid-rich, waxy cell wall creates a tough barrier that helps the organism survive harsh environments, resist many disinfectants and some antibiotics, and persist inside host cells. Mycobacterium species have cell walls loaded with mycolic acids (long-chain fatty acids), giving a very high lipid content. This waxy barrier slows or prevents entry of chemicals, drying, and immune attack, and it enables the bacteria to survive within macrophages and cause chronic infections. That combination—strong protection, environmental resilience, and intracellular persistence—boosts pathogenic potential compared with organisms that lack such a lipid-rich wall. The others listed rely more on their peptidoglycan structure or classical virulence factors rather than a lipid-heavy cell wall, so their pathogenicity isn’t driven by this waxy barrier in the same way.