In enterococci, intrinsic low-level resistance to gentamicin does not abolish synergism with a cell wall-active antibiotic while high-level resistance due to acquired aminoglycoside-modifying enzymes does. To study the impact of intermediate levels of resistance to gentamicin (64 < MIC < 500 microg/ml), we selected in vitro three consecutive generations of mutants of Enterococcus faecalis JH2-2...

Both conventional and modified MicroScan Type 5 panels and Vitek Gram-Positive Susceptibility cards were compared with agar dilution screen plates for their abilities to detect high-level resistance to gentamicin and streptomycin in 235 enterococcal isolates, including 167 Enterococcus faecalis and 63 E. faecium isolates. The modified Type 5 panels contained dextrose-phosphate broth instead of ...

Methicillin- and gentamicin-resistant strains of Staphylococcus aureus isolated in Dublin hospitals have been classified into groups I, II, and III based on resistance to antimicrobial agents and plasmid profiles. Each group expresses a characteristic level of resistance to gentamicin, tobramycin, and sisomicin. Enzyme assays showed that resistant strains expressed 2"-aminoglycoside phosphotran...

pseudomonas aeruginosa is one of the most important pathogens that causes nosocomial infections and shows high level of antibiotic resistance. integrons are one of the transposable elements in bacteria and their role in antibiotic resistance has been well demonstrated. the aim of this study was a molecular characterization of the integron genes and the determination of the resistance or sensiti...

Pseudomonas aeruginosa is one of the most important pathogens that causes nosocomial infections and shows high level of antibiotic resistance. Integrons are one of the transposable elements in bacteria and their role in antibiotic resistance has been well demonstrated. The aim of this study was a molecular characterization of the integron genes and the determination of the resistance or sensiti...

We compared the dried MicroScan microdilution panel, Synergy Quad plate agar dilution, and high-potency disk diffusion screening methods for the detection of high-level aminoglycoside resistance in 815 enterococcal bloodstream isolates. Agreement between the three methods was 99% when testing for high-level gentamicin resistance and 96% when testing for high-level streptomycin resistance.

We report on the first occurrence of high-level gentamicin resistance (MICs > or = 512 microg/ml) in seven clinical isolates of Streptococcus pasteurianus from Hong Kong. These seven isolates were confirmed to be the species S. pasteurianus on the basis of nucleotide sequencing of the superoxide dismutase (sodA) gene. Epidemiological data as well as the results of pulse-field gel electrophoresi...