Roles of AmpC ß-lactamase and LMM-PBPs in Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the most problematic versatile Gram-negative bacteria in causing opportunistic human infections which are particularly difficult to treat because of its intrinsic resistance to antibiotics; as a consequence of many intervening resistance mechanisms involving the ability to overproduce the chromosomally encoded cephalosporinases, Pae-AmpC. Low-molecular-mass penicillin-binding proteins (LMM-PBP) are a group of periplasmic enzymes that have DD-carboxypeptidase and/or DD-endopeptidase activities which participate in cell separation, peptidoglycan maturation and recycling. Binding of ¿-lactams with LMM-PBPs causes an increase in anhydromuropeptides and periplasmic AmpC overproduction to hydrolyze ¿-lactams. This study aimed to characterize the roles of Pae-AmpC and LMM-PBPs PBP4, PBP5 and PBP7 in PG composition and bacterial resistance in P. aeruginosa; also, to study the roles of these LMM-PBPs in Pae-ampC regulation. Moreover, it followed the roles of PBPs in the process of rod shape recovery of imipenem-induced P. aeruginosa spheroplasts. This study should be helpful to basic and clinical research concerning antibiotic resistance in P. aeruginosa.