Partial sequence analysis of a tet(O) plasmid from a multiple-drug-resistant clinical isolate of Campylobacter jejuni revealed 10 genes or pseudogenes encoding different aminoglycoside inactivating enzymes, transposase-like genes, and multiple unknown genes from a variety of pathogenic and commensal bacteria. The plasmid could be mobilized by a P incompatibility group plasmid into Escherichia c...

Three clinical isolates of Staphylococcus aureus resistant to gentamicin and other aminoglycosides have been examined for antibiotic modifying enzymes. The strains contain a number of these enzymes, most of them similar to those commonly found in aminoglycoside-resistant gram-negative strains. All three strains (and a transductant derived from one of them) contain two enzymes mediating gentamic...

Clinical isolates of Providencia and Proteus with relative aminoglycoside resistance were tested for susceptibility to combinations of gentamicin or tobramycin with cephalothin or cefazolin. The minimal bactericidal concentration of aminoglycoside for one-third of the strains was reduced by fourfold or more in the presence of one-fourth of the minimal bactericidal concentration of either cephal...

Sir: As reported previously,1-5) aminoglycoside 6'-N-acetyltransferases [AAC(6')] in R factorcarrying Escherichia coli and Pseudomonas aeruginosa are involved in the mechanism of resistance to several aminoglycoside antibiotics such as kanamycin, kanamycin B, 3',4'dideoxykanamycin B (DKB) and ribostamycin. Gentamicin C1a and sisomicin are acetylated by these enzymes6,7). In this paper, we repor...

Aminoglycoside 2″-phosphotransferases are the major aminoglycoside-modifying enzymes in clinical isolates of enterococci and staphylococci. We describe a novel aminoglycoside 2″-phosphotransferase from the Gram-negative pathogen Campylobacter jejuni, which shares 78% amino acid sequence identity with the APH(2″)-Ia domain of the bifunctional aminoglycoside-modifying enzyme aminoglycoside (6') a...

Resistance to the polycationic antibiotic polymyxin B and expression of the outer-membrane protein OprH in the opportunistic pathogen Pseudomonas aeruginosa both involve the PhoP-PhoQ two-component regulatory system. The genes for this system form an operon with oprH, oprH-phoP-phoQ, that responds to Mg(2+) starvation and PhoP levels. In this study, the Mg(2+)-regulated promoter for this operon...

OBJECTIVES To investigate the prevalence of aminoglycoside resistance and genes encoding aminoglycoside-modifying enzymes (AME) in blood culture isolates of coagulase-negative staphylococci (CoNS) from neonates. MATERIALS AND METHODS A total of 180 isolates from 148 patients collected in a single neonatal unit over a 12 year period were examined for susceptibility to gentamicin, tobramycin, n...

Aminoglycosides are potent, broad spectrum, ribosome-targeting antibacterials whose clinical efficacy is seriously threatened by multiple resistance mechanisms. Here, we report the structural basis for 30S recognition by the novel plasmid-mediated aminoglycoside-resistance rRNA methyltransferase A (NpmA). These studies are supported by biochemical and functional assays that define the molecular...

BACKGROUND Staphylococcus aureus is one of the most important causative agents in community- and hospital-acquired infections. Aminoglycosides are powerful bactericidal drugs that are often used in combination with beta-lactams or glycopeptides to treat staphylococcal infections. OBJECTIVES The main objective of the present study was to determine the prevalence of aminoglycoside resistance am...