Modulation of Antimicrobial Effects of Beta-Lactams by Amino Acids in vitro

Prevention of noise- and drug-induced hearing loss with d-methionine

“…Because evidence thus far suggests that D-met does not interfere with the serum levels or antimicrobial action of aminoglycosides (Sha and Schacht, 2000;Herr et al, 2001) and may in fact enhance antimicrobial action (Gillissen et al, 1991;Caparros et al, 1992;Wecke et al, 1992), the potential for developing D-met as a safe and effective otoprotective agent for aminoglycoside use appears promising.…”

“…Because of the bacterial cell wall site of action, many studies concentrated more on the possible combinations of D-met with b-lactam antibiotics. D-Met increased the antimicrobial efficacy of imipenem and ampicillin against the ATCC 8739 strain of E. coli (Gillissen et al, 1991) and enhanced penicillin induced bacteriolysis against staphylococci (Wecke et al, 1992) in vitro. Because of the different mechanisms of actions of D-met and aminoglycosides, we anticipate that D-met will not interfere with, and may augment, the antimicrobial action of aminoglycosides.…”

Effect of Glycine on Helicobacter pylori In Vitro

“…As it is a metabolite of serine, it is not an essential amino acid for bacteria (11). The major mech- FIG.…”

“…Although glycine is toxic to humans when it is given in large amounts, it also has antibacterial potential (11,13,33). For example, Lactococcus lactis subspecies failed to grow in medium containing more than 2% glycine (15).…”

“…High concentrations of glycine induce bacteriolysis or morphological alterations in various bacteria (11,13,16,30,33). A possible mechanism of this effect may be inhibition of the reaction in which L-alanine is added to UDPacetylmuramic acid by UDP-N-acetylmuramate-alanine ligase (20).…”