Genetic Approach To Study the Relationship between Penicillin-Binding Protein 3 Mutations and Haemophilus influenzae β-Lactam Resistance by Using Site-Directed Mutagenesis and Gene Recombinants

作者：Yumi Osaki, Yumiko Sanbongi, Midori Ishikawa, Hiroshi Kataoka, Takahisa Suzuki, Kumiko Maeda, Takashi Y. Ida · 发表于：Antimicrobial Agents and Chemotherapy · 年份：2005 · DOI：10.1128/aac.49.7.2834-2839.2005 · 被引用次数：70 · 研究领域：Antibiotic Resistance in Bacteria、Pneumonia and Respiratory Infections、Antibiotics Pharmacokinetics and Efficacy

To clarify the relationship between mutations commonly found for penicillin-binding protein 3 (PBP 3) of beta-lactamase-nonproducing ampicillin-resistant (BLNAR) Haemophilus influenzae isolates and beta-lactam resistance, single and multiple amino acid mutations at positions 377, 385, 389, 517, and 526 were introduced into PBP 3 of a beta-lactam-susceptible Rd strain by site-directed mutagenesis. Twelve isogenic recombinant strains were challenged with nine beta-lactam antibiotics. Replacement of the asparagine at position 526 with lysine (N526K) increased the resistance to imipenem eightfold and increased the resistance to various cephalosporins two- to eightfold. Substitution of threonine for serine at position 385 (S385T) and/or substitution of phenylalanine for leucine at position 389 (L389F), in addition to the N526K mutation, led to two- to fourfold additional increases in cephalosporin resistance. An isoleucine-to-methionine substitution at position 377 did not change the antibiotic sensitivity of any of the recombinant strains also carrying other PBP 3 mutations tested. Thirty-six clinical isolates carrying a PBP 3 gene (ftsI) with the S385T, L389F, R517H, and/or N526K mutation were chosen from among 279 clinical isolates collected in Japan, and the isolates were grouped into six classes on the basis of the patterns of the four mutations in PBP 3. Rd recombinants were made with each of the ftsI genes. The levels of resistance to beta-lactams varied between recombinant...