Class I beta-lactamases can produce resistance to all three generations of cephalosporin antibacterials. Class II includes uncommonly encountered constitutive chromosomal penicillinases . These constitutively produced enzymes are found in various entrerobacteriaceae and Pseudomonas aeruginosa . This plasmid is one of the reasons pseudomonas infections are so difficult to treat. Staphylococcal penicillinase is widespread and constititutes such a serious clinical problem that there is a whole category of penicillins to surmount it known as the antistaphylococcal penicillins .
Different plasmids produce lactamases with different specificities and turnover rates.
Different drugs have different susceptibilities to the enzymes. Moxalactam structure with some key functional groups noted. After Simon et al. 1985 Because one can identify specific problems that affect the clinical efficacy of drugs, one can also devise ways of overcoming those problems. One way is to systematically study structural modifications that confer certain characteristics, e.g., acid resistance or resistance to a particular beta-lactamase. You are invited to ponder the moxalactam structure in the following figure in which various sites are marked.