BACKGROUND: The beta-lactam group of antibiotics kills bacteria by inhibiting the terminal stages of peptidoglycan metabolism. We have recently identified amoxicillin-resistant Helicobacter pylori, none of which expressed beta-lactamase. Penicillin-binding proteins (PBPs) represent a group of target enzymes for the beta-lactam antibiotic family, and alterations in PBPs have been described in other penicillin-resistant bacteria. The amoxicillin-resistant phenotype characteristically was lost after freezing but could be restored by consecutive transfers into gradient plates. MATERIALS AND METHODS: To determine whether amoxicillin resistance in H. pylori was related to alterations in any of the H. pylori PBPs, five H. pylori strains resistant to amoxicillin and three amoxicillin-sensitive strains were tested. PBPs were extracted from bacteria grown to logarithmic phase, labeled in vivo with 3H-benzylpenicillin, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography. Four main PBPs were separated from all amoxicillin-sensitive H. pylori strains. RESULTS: Only three of the four main PBPs were found in the amoxicillin-resistant H. pylori strains. The differentially detectable PBP (PBP D) had an apparent molecular weight of 30 to 32 kD. CONCLUSION: These results suggest that PBP D might play a role in the amoxicillin-resistant phenotype of H. pylori strains lacking beta-lactamase activity.

Different Penicillin-binding Protein Profiles in Amoxycillin-resistant Helicobacter Pylori / Dore, Maria Pina; Graham, Dy; Sepulveda, A. R.. - In: HELICOBACTER. - ISSN 1083-4389. - 4:3(1999), pp. 154-161.

Different Penicillin-binding Protein Profiles in Amoxycillin-resistant Helicobacter Pylori.

DORE, Maria Pina;
1999

Abstract

BACKGROUND: The beta-lactam group of antibiotics kills bacteria by inhibiting the terminal stages of peptidoglycan metabolism. We have recently identified amoxicillin-resistant Helicobacter pylori, none of which expressed beta-lactamase. Penicillin-binding proteins (PBPs) represent a group of target enzymes for the beta-lactam antibiotic family, and alterations in PBPs have been described in other penicillin-resistant bacteria. The amoxicillin-resistant phenotype characteristically was lost after freezing but could be restored by consecutive transfers into gradient plates. MATERIALS AND METHODS: To determine whether amoxicillin resistance in H. pylori was related to alterations in any of the H. pylori PBPs, five H. pylori strains resistant to amoxicillin and three amoxicillin-sensitive strains were tested. PBPs were extracted from bacteria grown to logarithmic phase, labeled in vivo with 3H-benzylpenicillin, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography. Four main PBPs were separated from all amoxicillin-sensitive H. pylori strains. RESULTS: Only three of the four main PBPs were found in the amoxicillin-resistant H. pylori strains. The differentially detectable PBP (PBP D) had an apparent molecular weight of 30 to 32 kD. CONCLUSION: These results suggest that PBP D might play a role in the amoxicillin-resistant phenotype of H. pylori strains lacking beta-lactamase activity.
Different Penicillin-binding Protein Profiles in Amoxycillin-resistant Helicobacter Pylori / Dore, Maria Pina; Graham, Dy; Sepulveda, A. R.. - In: HELICOBACTER. - ISSN 1083-4389. - 4:3(1999), pp. 154-161.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/48627
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