Mycoplasma pneumoniae is innately resistant to penicillins and cephalosporins. This resistance is best explained by:
- A Production of extended-spectrum beta-lactamases
- B Absence of a peptidoglycan cell wall ✓
- C Altered DNA gyrase conferring target modification
- D Efflux pumps expelling the antibiotic before it enters the cell
Correct answer: B. Absence of a peptidoglycan cell wall
Explanation
Beta-lactam antibiotics act by inhibiting transpeptidation enzymes that cross-link peptidoglycan in the bacterial cell wall. Mycoplasma species are the smallest free-living bacteria and completely lack a cell wall, so they have no peptidoglycan target and are intrinsically resistant to all beta-lactams. They are instead treated with macrolides, tetracyclines or fluoroquinolones that act on intracellular targets.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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