title: Effect of glycine on Helicobacter pylori in vitro.
abstract: Glycine is the simplest amino acid and is used as a metabolic product in some bacteria. However, an excess of glycine inhibits the growth of many bacteria, and it is used as a nonspecific antiseptic agent due to its low level of toxicity in animals. The effect of glycine on Helicobacter pylori is not precisely known. The present study was conducted to investigate (i) the effect of glycine on clarithromycin (CLR)-resistant and -susceptible strains of H. pylori, (ii) the effect of glycine in combination with amoxicillin (AMX), and (iii) the postantibiotic effect (PAE). The MIC at which 90% of strains are inhibited for glycine was almost 2.5 mg/ml for 31 strains of H. pylori, including CLR-resistant strains. We constructed isogenic CLR-resistant mutant strains by natural transformation and investigated the difference between clinical wild-type strains and isogenic mutants. There were no differences in the MICs between CLR-resistant and -susceptible strains or between clinical wild-type and mutant strains. The combination of AMX and glycine showed synergistic activity, with the minimum bactericidal concentration of AMX with glycine decreasing to 1/10 that of AMX alone. Glycine showed no PAE against H. pylori. These results suggest that glycine may be a useful antimicrobial agent against H. pylori not only alone but also in combination with antibacterial drugs for the treatment of H. pylori-associated diseases. Glycine may represent a component of a new type of eradication therapy for CLR-resistant H. pylori.
authors.affiliation: Department of Therapeutic Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Minami
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ando
authors.forename: Shin-Nosuke
authors.initials: SN
authors.lastname: Hashikawa
authors.forename: Keizo
authors.initials: K
authors.lastname: Torii
authors.forename: Tadao
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Dawn A
authors.initials: DA
authors.lastname: Israel
authors.forename: Kenji
authors.initials: K
authors.lastname: Ina
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kusugami
authors.forename: Hidemi
authors.initials: H
authors.lastname: Goto
authors.forename: Michio
authors.initials: M
authors.lastname: Ohta
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D005998:Glycine / Q000494:pharmacology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics; D010406:Penicillins / Q000494:pharmacology
chemical_list: D004269:DNA, Bacterial; D010406:Penicillins; D000658:Amoxicillin; D005998:Glycine