Analysis of genes encoding penicillin-binding proteins in clinical isolates of Acinetobacter baumannii.

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There is limited information on the role of penicillin-binding proteins (PBPs) in the resistance of Acinetobacter baumannii to β-lactams. This study presents an analysis of the allelic variations of PBP genes in A. baumannii isolates. Twenty-six A. baumannii clinical isolates (susceptible or resistant to carbapenems) from three teaching hospitals in Spain were included. The antimicrobial susceptibility profile, clonal pattern, and genomic species identification were also evaluated. Based on the six complete genomes of A. baumannii, the PBP genes were identified, and primers were designed for each gene. The nucleotide sequences of the genes identified that encode PBPs and the corresponding amino acid sequences were compared with those of ATCC 17978. Seven PBP genes and one monofunctional transglycosylase (MGT) gene were identified in the six genomes, encoding (i) four high-molecular-mass proteins (two of class A, PBP1a [ponA] and PBP1b [mrcB], and two of class B, PBP2 [pbpA or mrdA] and PBP3 [ftsI]), (ii) three low-molecular-mass proteins (two of type 5, PBP5/6 [dacC] and PBP6b [dacD], and one of type 7 (PBP7/8 [pbpG]), and (iii) a monofunctional enzyme (MtgA [mtgA]). Hot spot mutation regions were observed, although most of the allelic changes found translated into silent mutations. The amino acid consensus sequences corresponding to the PBP genes in the genomes and the clinical isolates were highly conserved. The changes found in amino acid sequences were associated with concrete clonal patterns but were not directly related to susceptibility or resistance to β-lactams. An insertion sequence disrupting the gene encoding PBP6b was identified in an endemic carbapenem-resistant clone in one of the participant hospitals.
Journal Article; Research Support, Non-U.S. Gov't;
MeSH Terms
Medical Subject Headings::Organisms::Bacteria::Gram-Negative Bacteria::Gram-Negative Aerobic Bacteria::Gram-Negative Aerobic Rods and Cocci::Moraxellaceae::Acinetobacter::Acinetobacter baumannii
Medical Subject Headings::Phenomena and Processes::Chemical Phenomena::Biochemical Phenomena::Molecular Structure::Amino Acid Sequence
Medical Subject Headings::Chemicals and Drugs::Chemical Actions and Uses::Pharmacologic Actions::Therapeutic Uses::Anti-Infective Agents::Anti-Bacterial Agents
Medical Subject Headings::Chemicals and Drugs::Organic Chemicals::Amides::Lactams::beta-Lactams::Carbapenems
Medical Subject Headings::Health Care::Health Care Facilities, Manpower, and Services::Health Facilities::Academic Medical Centers::Hospitals, Teaching
Medical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Primates::Haplorhini::Catarrhini::Hominidae::Humans
Medical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Diagnosis::Diagnostic Techniques and Procedures::Clinical Laboratory Techniques::Microbiological Techniques::Microbial Sensitivity Tests
Medical Subject Headings::Information Science::Information Science::Information Services::Documentation::Molecular Sequence Data
Medical Subject Headings::Chemicals and Drugs::Enzymes and Coenzymes::Enzymes::Penicillin-Binding Proteins
Medical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Variation::Mutation::Point Mutation
Medical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Genetic Techniques::Sequence Analysis::Sequence Analysis, DNA
Medical Subject Headings::Geographicals::Geographic Locations::Europe::Spain
Medical Subject Headings::Phenomena and Processes::Microbiological Phenomena::Bacterial Physiological Phenomena::Drug Resistance, Bacterial::beta-Lactam Resistance
Medical Subject Headings::Diseases::Bacterial Infections and Mycoses::Bacterial Infections::Gram-Negative Bacterial Infections::Moraxellaceae Infections::Acinetobacter Infections
DeCS Terms
CIE Terms
Secuencia de Aminoácidos, Hospitales Escuela, Pruebas de Sensibilidad Microbiana, Proteínas de Unión a las Penicilinas, Análisis de Secuencia de ADN, Resistencia beta-Lactámica
Cayô R, Rodríguez MC, Espinal P, Fernández-Cuenca F, Ocampo-Sosa AA, Pascual A, et al. Analysis of genes encoding penicillin-binding proteins in clinical isolates of Acinetobacter baumannii. Antimicrob. Agents Chemother. 2011; 55(12):5907-13