How do bacteria become resistant to beta lactams?

Question

Delilah Anderson · Accepted Answer

Some can produce an enzyme called beta lactamase that breaks down beta-lactam antibiotics.
Some efflux pump is also important

Beta-lactamase has a structure similar to D,D-transpeptidase, which allows it to bind to beta-lactam. However, unlike D,D-transpeptidase, it can also break down the beta lactam. This is how beta-lactam antibiotics work: they bind to the enzyme that forms the cell wall. The following amino acid residues are essential for beta-lactamase to function: 1) Lys73 OR Glu166 (unsure) - activate -CONH- group inside beta-lactam structure; 2) Ser70 - nucleophilic attack on carbonyl group inside beta-lactam structure; it is common to refer to this configuration as Ser-X-X-Lys; and 3) possibly - Ser130, Lys234 - protonation of nitrogen group inside beta-lactam structure. Antibiotic resistance can arise from a multitude of mechanisms, one of which is the use of a protein pump known as the efflux pump. Resistance to beta-lactam antibiotics such as ampicillin is linked to the CmeDEF-based efflux pump. Even though the most clinically significant substrates of efflux systems are antibiotics, it's likely that the majority of efflux pumps perform additional physiologically normal tasks. Examples of these include: See also Stuart Richardson's answer at https://tutor.hix.ai M. A. Webber and L. J. V. Piddock, "The importance of efflux pumps in bacterial antibiotic resistance," https://tutor.hix.ai The following link provides evidence of multiple antibiotic resistance in Campylobacter jejuni that is not mediated by CmeB or CmeF: Lilian Pumbwe, Luke P. Randall, Martin J. Woodward, and Laura J. V. Piddock. Campylobacter jejuni Masato Akiba, Jun Lin, Yi-Wen Barton, and Qijing Zhang. Interaction of CmeABC and CmeDEF in conferring antimicrobial resistance and preserving cell viability. https://tutor.hix.ai

Nolan Allen · Answer

undefined Bacteria become resistant to beta-lactam antibiotics through various mechanisms, including the production of beta-lactamase enzymes that hydrolyze the beta-lactam ring, altering the target site (penicillin-binding proteins), reducing permeability to the antibiotic, and actively pumping the antibiotic out of the cell through efflux pumps.