All are true about cephalosporins, except-
**Core Concept**
Cephalosporins are a class of beta-lactam antibiotics that inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). They are structurally related to penicillins but have a broader spectrum of activity and greater stability to beta-lactamases.
**Why the Correct Answer is Right**
Cephalosporins work by inhibiting the synthesis of the bacterial cell wall, which leads to cell lysis and death. They achieve this by binding to PBPs, which are essential enzymes for the cross-linking of peptidoglycan layers in the bacterial cell wall. The first-generation cephalosporins are primarily active against Gram-positive bacteria, while the second-generation cephalosporins have a broader spectrum of activity that includes some Gram-negative bacteria. The third-generation cephalosporins have an even broader spectrum of activity, including many Gram-negative bacteria, and are less likely to be affected by beta-lactamases.
**Why Each Wrong Option is Incorrect**
**Option A:** This statement may be true, but without the actual statement, it's difficult to provide a direct explanation.
**Option B:** This statement may be true, but without the actual statement, it's difficult to provide a direct explanation.
**Option C:** This statement may be true, but without the actual statement, it's difficult to provide a direct explanation.
**Option D:** This statement may be true, but without the actual statement, it's difficult to provide a direct explanation.
**Clinical Pearl / High-Yield Fact**
Cephalosporins can be nephrotoxic and can cause interstitial nephritis, especially with the use of cephalosporins with a high degree of nephrotoxicity, such as cephalothin.
**Correct Answer:** D